1
|
Dhanapalaratnam R, Issar T, Wang LL, Tran D, Poynten AM, Milner KL, Kwai NC, Krishnan AV. Effect of Metformin on Peripheral Nerve Morphology in Type 2 Diabetes: A Cross-Sectional Observational Study. Diabetes 2024; 73:1875-1882. [PMID: 39167630 PMCID: PMC11493759 DOI: 10.2337/db24-0365] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2024] [Accepted: 08/09/2024] [Indexed: 08/23/2024]
Abstract
Diabetic peripheral neuropathy (DPN) affects ∼50% of the 500 million people with type 2 diabetes worldwide and is considered disabling and irreversible. The current study was undertaken to assess the effect of metformin on peripheral neuropathy outcomes in type 2 diabetes. Participants with type 2 diabetes (n = 69) receiving metformin were recruited and underwent clinical assessment, peripheral nerve ultrasonography, nerve conduction studies, and axonal excitability studies. Also concurrently screened were 318 participants who were not on metformin, and 69 were selected as disease control subjects and matched to the metformin participants for age, sex, diabetes duration, BMI, HbA1c, and use of other diabetes therapies. Medical record data over the previous 20 years were analyzed for previous metformin use. Mean tibial nerve cross-sectional area was lower in the metformin group (metformin 14.1 ± 0.7 mm2, nonmetformin 16.2 ± 0.9 mm2, P = 0.038), accompanied by reduction in neuropathy symptom severity (P = 0.021). Axonal excitability studies demonstrated superior axonal function in the metformin group, and mathematical modeling demonstrated that these improvements were mediated by changes in nodal Na+and K+conductances. Metformin treatment is associated with superior nerve structure and clinical and neurophysiological measures. Treatment with metformin may be neuroprotective in DPN. ARTICLE HIGHLIGHTS
Collapse
Affiliation(s)
- Roshan Dhanapalaratnam
- School of Clinical Medicine, University of New South Wales, Sydney, New South Wales, Australia
- Department of Neurology, Prince of Wales Hospital, Sydney, New South Wales, Australia
| | - Tushar Issar
- School of Clinical Medicine, University of New South Wales, Sydney, New South Wales, Australia
| | - Leiao Leon Wang
- School of Clinical Medicine, University of New South Wales, Sydney, New South Wales, Australia
| | - Darren Tran
- Department of Endocrinology, Prince of Wales Hospital, Sydney, New South Wales, Australia
| | - Ann M. Poynten
- School of Clinical Medicine, University of New South Wales, Sydney, New South Wales, Australia
- Department of Endocrinology, Prince of Wales Hospital, Sydney, New South Wales, Australia
| | - Kerry-Lee Milner
- School of Clinical Medicine, University of New South Wales, Sydney, New South Wales, Australia
- Department of Endocrinology, Prince of Wales Hospital, Sydney, New South Wales, Australia
| | - Natalie C.G. Kwai
- School of Medical, Indigenous and Health Sciences, University of Wollongong, Wollongong, New South Wales, Australia
| | - Arun V. Krishnan
- School of Clinical Medicine, University of New South Wales, Sydney, New South Wales, Australia
- Department of Neurology, Prince of Wales Hospital, Sydney, New South Wales, Australia
| |
Collapse
|
2
|
Bertini A, Lenti S, Libelli G, Ronco R, Oliveri S, Montemagno K, Priori A, Bocci T. When the diagnosis is in the patient's hand and in the neurologist's eye. Neurol Sci 2024; 45:4669-4677. [PMID: 38833097 PMCID: PMC11422281 DOI: 10.1007/s10072-024-07626-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2024] [Accepted: 05/25/2024] [Indexed: 06/06/2024]
Abstract
The objective of this study was to encompass current knowledge about pathophysiological mechanisms of those specific hand postures or deformities caused by central nervous system disorders. In the era of high-resolution neuroimaging and molecular biology, clinicians are progressively losing confidence with neurological examination. Careful hand observation is of key importance in order to differentiate neurological from non-neurological conditions, central from peripheral aetiologies, and organic from functional disorders. Localizing the potential anatomical site is essential to properly conduct subsequent exams. We provided a practical guide for clinicians to recognize hand patterns caused by central nervous system disorders, avoiding mimicking conditions, thus optimizing and prompting the diagnostic pathway.
Collapse
Affiliation(s)
- Alessandro Bertini
- "Aldo Ravelli" Center for Neurotechnology and Experimental Brain Therapeutics, Department of Health Sciences, University of Milan, Via Antonio di Rudinì 8, 20142, Milan, Italy
- Clinical Neurology Unit, Department of Health Sciences, Azienda Socio-Sanitaria Territoriale Santi Paolo E Carlo, University of Milan, Via Antonio di Rudinì 8, 20142, Milan, Italy
| | - Sveva Lenti
- "Aldo Ravelli" Center for Neurotechnology and Experimental Brain Therapeutics, Department of Health Sciences, University of Milan, Via Antonio di Rudinì 8, 20142, Milan, Italy
- Clinical Neurology Unit, Department of Health Sciences, Azienda Socio-Sanitaria Territoriale Santi Paolo E Carlo, University of Milan, Via Antonio di Rudinì 8, 20142, Milan, Italy
| | - Giorgia Libelli
- Neurology Unit, Department of Medicine and Surgery, University of Parma, Via Gramsci 14, 43126, Parma, Italy
| | - Riccardo Ronco
- "Aldo Ravelli" Center for Neurotechnology and Experimental Brain Therapeutics, Department of Health Sciences, University of Milan, Via Antonio di Rudinì 8, 20142, Milan, Italy
- Clinical Neurology Unit, Department of Health Sciences, Azienda Socio-Sanitaria Territoriale Santi Paolo E Carlo, University of Milan, Via Antonio di Rudinì 8, 20142, Milan, Italy
| | - Serena Oliveri
- "Aldo Ravelli" Center for Neurotechnology and Experimental Brain Therapeutics, Department of Health Sciences, University of Milan, Via Antonio di Rudinì 8, 20142, Milan, Italy
- Clinical Neurology Unit, Department of Health Sciences, Azienda Socio-Sanitaria Territoriale Santi Paolo E Carlo, University of Milan, Via Antonio di Rudinì 8, 20142, Milan, Italy
| | - Kora Montemagno
- "Aldo Ravelli" Center for Neurotechnology and Experimental Brain Therapeutics, Department of Health Sciences, University of Milan, Via Antonio di Rudinì 8, 20142, Milan, Italy
| | - Alberto Priori
- "Aldo Ravelli" Center for Neurotechnology and Experimental Brain Therapeutics, Department of Health Sciences, University of Milan, Via Antonio di Rudinì 8, 20142, Milan, Italy
- Clinical Neurology Unit, Department of Health Sciences, Azienda Socio-Sanitaria Territoriale Santi Paolo E Carlo, University of Milan, Via Antonio di Rudinì 8, 20142, Milan, Italy
| | - Tommaso Bocci
- "Aldo Ravelli" Center for Neurotechnology and Experimental Brain Therapeutics, Department of Health Sciences, University of Milan, Via Antonio di Rudinì 8, 20142, Milan, Italy.
- Clinical Neurology Unit, Department of Health Sciences, Azienda Socio-Sanitaria Territoriale Santi Paolo E Carlo, University of Milan, Via Antonio di Rudinì 8, 20142, Milan, Italy.
| |
Collapse
|
3
|
Tyberghein M, Manto F, Wang FC. The recovery cycle of excitability assessed by a conventional electrodiagnostic machine: A study in healthy volunteers and in Charcot-Marie-Tooth 1A patients. Clin Neurophysiol 2024; 167:167-176. [PMID: 39326122 DOI: 10.1016/j.clinph.2024.09.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2024] [Revised: 09/06/2024] [Accepted: 09/10/2024] [Indexed: 09/28/2024]
Abstract
OBJECTIVE To validate the 'paired pulses' technique with a conventional electrodiagnostic machine (CEM) for studying the axonal excitability recovery cycle (ERC). METHODS Paired pulses, with a variable inter-stimulus interval, were delivered at the wrist along the median nerve. The CEM repeatability was verified in a group of 15 healthy volunteers (test/retest analysis). ERC was then applied in 40 healthy volunteers and 10 patients with Charcot-Marie-Tooth type 1A (CMT1A), using both the threshold tracking (TT) reference method and CEM (basal condition, during and after ischemia). RESULTS CEM parameters evaluating absolute refractory and supernormal periods were reproducible (interclass correlation coefficient > 0.75). CEM results were consistent with TT method and literature data. In CMT1A, refractory and superexcitable periods were significantly reduced. According to receiving operator characteristic analysis, the CEM supernormal period area was the most relevant parameter for discriminating CMT1A from healthy volunteers (area under the curve = 0.98). CONCLUSIONS CEM was a valid procedure for studying ERC. CMT1A patients exhibited ERC alterations due to modifications in passive membrane properties and of nodal ion channel distribution resulting from demyelination. SIGNIFICANCE Studying ERC with CEM could be performed in routine practice in patients with peripheral neuropathies to provide information on motor axonal excitability.
Collapse
Affiliation(s)
- Maëlle Tyberghein
- Centre Hospitalier Universitaire de Liège, Department of Neurophysiology, Sart Tilman B35, 4000 Liège, Belgium.
| | - Florence Manto
- Centre Hospitalier Universitaire de Liège, Department of Neurophysiology, Sart Tilman B35, 4000 Liège, Belgium.
| | - François Charles Wang
- Centre Hospitalier Universitaire de Liège, Department of Neurophysiology, Sart Tilman B35, 4000 Liège, Belgium.
| |
Collapse
|
4
|
Tankisi H, Bostock H, Tan SV, Howells J, Ng K, Z'Graggen WJ. Muscle excitability testing. Clin Neurophysiol 2024; 164:1-18. [PMID: 38805900 DOI: 10.1016/j.clinph.2024.04.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2023] [Revised: 04/22/2024] [Accepted: 04/22/2024] [Indexed: 05/30/2024]
Abstract
Conventional electrophysiological methods, i.e. nerve conduction studies and electromyography are suitable methods for the diagnosis of neuromuscular disorders, however, they provide limited information about muscle fibre membrane properties and underlying disease mechanisms. Muscle excitability testing is a technique that provides in vivo information about muscle fibre membrane properties such as membrane potential and ion channel function. Since the 1960s, various methodologies have been suggested to examine muscle membrane properties but technical difficulties have limited its use. In 2009, an automated, fast and simple application, the so-called multi-fibre muscle velocity recovery cycles (MVRC) has accelerated the use of muscle excitability testing. Later, frequency ramp and repetitive stimulation protocols have been developed. Though this method has been used mainly in research for revealing disease mechanisms across a broad range of neuromuscular disorders, it may have additional diagnostic uses; value has been shown particularly in muscle channelopathies. This review will provide a description of the state-of-the art of methodological and clinical studies for muscle excitability testing.
Collapse
Affiliation(s)
- H Tankisi
- Department of Clinical Neurophysiology, Aarhus University Hospital, Aarhus, Denmark; Institute of Clinical Medicine, Aarhus University Hospital, Aarhus, Denmark.
| | - H Bostock
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, Queen Square, WC1N 3BG London, United Kingdom
| | - S V Tan
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, Queen Square, WC1N 3BG London, United Kingdom; Department of Neurology and Neurophysiology, Guys and St Thomas' NHS Foundation Trust, London, United Kingdom
| | - J Howells
- Central Clinical School, Faculty of Medicine and Health, University of Sydney, Sydney, Australia
| | - K Ng
- Department of Neurology and Neurophysiology, Royal North Shore Hospital, St Leonards, NSW, Australia; University of Sydney, Camperdown, NSW, Australia
| | - W J Z'Graggen
- Departments Neurology and Neurosurgery, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| |
Collapse
|
5
|
Stikvoort García DJL, Goedee HS, van Eijk RPA, van Schelven LJ, van den Berg LH, Sleutjes BTHM. Revisiting distinct nerve excitability patterns in patients with amyotrophic lateral sclerosis. Brain 2024; 147:2842-2853. [PMID: 38662766 PMCID: PMC11491535 DOI: 10.1093/brain/awae131] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Revised: 03/29/2024] [Accepted: 04/08/2024] [Indexed: 08/02/2024] Open
Abstract
Amyotrophic lateral sclerosis is a devastating neurodegenerative disease, characterized by loss of central and peripheral motor neurons. Although the disease is clinically and genetically heterogeneous, axonal hyperexcitability is a commonly observed feature that has been suggested to reflect an early pathophysiological step linked to the neurodegenerative cascade. Therefore, it is important to clarify the mechanisms causing axonal hyperexcitability and how these relate to the clinical characteristics of patients. Measures derived directly from a nerve excitability recording are frequently used as study end points, although their biophysical basis is difficult to deduce. Mathematical models can aid in the interpretation but are reliable only when applied to group-averaged recordings. Consequently, model estimates of membrane properties cannot be compared with clinical characteristics or treatment effects in individual patients, posing a considerable limitation in heterogeneous diseases, such as amyotrophic lateral sclerosis. To address these challenges, we revisited nerve excitability using a new pattern analysis-based approach (principal component analysis). We evaluated disease-specific patterns of excitability changes and established their biophysical origins. Based on the observed patterns, we developed new compound measures of excitability that facilitate the implementation of this approach in clinical settings. We found that excitability changes in amyotrophic lateral sclerosis patients (n = 161, median disease duration = 11 months) were characterized by four unique patterns compared with controls (n = 50, age and sex matched). These four patterns were best explained by changes in resting membrane potential (modulated by Na+/K+ currents), slow potassium and sodium currents (modulated by their gating kinetics) and refractory properties of the nerve. Consequently, we were able to show that altered gating of slow potassium channels was associated with, and predictive of, the rate of progression of the disease on the amyotrophic lateral sclerosis functional rating scale. Based on these findings, we designed four composite measures that capture these properties to facilitate implementation outside this study. Our findings demonstrate that changes in nerve excitability in patients with amyotrophic lateral sclerosis are dominated by four distinct patterns, each with a distinct biophysical origin. Based on this new approach, we provide evidence that altered slow potassium-channel function might play a role in the rate of disease progression. The magnitudes of these patterns, quantified using a similar approach or our new composite measures, have potential as efficient measures to study membrane properties directly in amyotrophic lateral sclerosis patients, and thus aid prognostic stratification and trial design.
Collapse
Affiliation(s)
| | - H Stephan Goedee
- Department of Neurology, Brain Centre Utrecht, University Medical Centre Utrecht, Utrecht, 3584CX, The Netherlands
| | - Ruben P A van Eijk
- Department of Neurology, Brain Centre Utrecht, University Medical Centre Utrecht, Utrecht, 3584CX, The Netherlands
- Biostatistics and Research Support, Julius Centre for Health Sciences and Primary Care, University Medical Centre Utrecht, Universiteitsweg 100, 3584CX, Utrecht, The Netherlands
| | - Leonard J van Schelven
- Department of Medical Technology and Clinical Physics, University Medical Centre Utrecht, 3584CX, Utrecht, The Netherlands
| | - Leonard H van den Berg
- Department of Neurology, Brain Centre Utrecht, University Medical Centre Utrecht, Utrecht, 3584CX, The Netherlands
| | - Boudewijn T H M Sleutjes
- Department of Neurology, Brain Centre Utrecht, University Medical Centre Utrecht, Utrecht, 3584CX, The Netherlands
| |
Collapse
|
6
|
Pavey NA, Menon P, Peterchev AV, Kiernan MC, Vucic S. Abnormalities of cortical stimulation strength-duration time constant in amyotrophic lateral sclerosis. Clin Neurophysiol 2024; 164:161-167. [PMID: 38901111 PMCID: PMC11345808 DOI: 10.1016/j.clinph.2024.05.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2024] [Revised: 04/23/2024] [Accepted: 05/26/2024] [Indexed: 06/22/2024]
Abstract
OBJECTIVES Strength-duration time constant (SDTC) may now be determined for cortical motor neurones, with activity mediated by transient Na+ conductances. The present study determined whether cortical SDTC is abnormal and linked to the pathogenesis of amyotrophic lateral sclerosis. METHODS Cortical SDTC and rheobase were estimated from 17 ALS patients using a controllable pulse parameter transcranial magnetic stimulation (cTMS) device. Resting motor thresholds (RMTs) were determined at pulse widths (PW) of 30, 45, 60, 90 and 120 µs and M-ratio of 0.1, using a figure-of-eight coil applied to the primary motor cortex. RESULTS SDTC was significantly reduced in ALS patients (150.58 ± 9.98 µs; controls 205.94 ± 13.7 µs, P < 0.01). The reduced SDTC correlated with a rate of disease progression (Rho = -0.440, P < 0.05), ALS functional rating score (ALSFRS-R) score (Rho = 0.446, P < 0.05), and disease duration (R = 0.428, P < 0.05). The degree of change in SDTC was greater in patients with cognitive abnormalities as manifested by an abnormal total Edinburgh Cognitive ALS Screen score (140.5 ± 28.7 µs, P < 0.001) and ALS-specific subscore (141.7 ± 33.2 µs, P = 0.003). CONCLUSIONS Cortical SDTC reduction was associated with a more aggressive ALS phenotype, or with more prominent cognitive impairment. SIGNIFICANCE An increase in transient Na+ conductances may account for the reduction in SDTC, linked to the pathogenesis of ALS.
Collapse
Affiliation(s)
- Nathan A Pavey
- Brain and Nerve Research Centre, Concord Clinical School, University of Sydney, Concord Hospital, Sydney, Australia
| | - Parvathi Menon
- Brain and Nerve Research Centre, Concord Clinical School, University of Sydney, Concord Hospital, Sydney, Australia
| | - Angel V Peterchev
- Department of Biological Sciences, Dartmouth College, Hanover, NH, USA; Department of Biomedical Engineering, Duke University, Durham, NC, USA; Department of Psychiatry and Behavioural Sciences, Duke University, Durham, NC, USA; Department of Electrical and Computer Engineering, Duke University, Durham, NC, USA; Department of Neurosurgery, Duke University, Durham, NC, USA
| | | | - Steve Vucic
- Brain and Nerve Research Centre, Concord Clinical School, University of Sydney, Concord Hospital, Sydney, Australia.
| |
Collapse
|
7
|
Kirkwood PA. In Memoriam: Tom Sears. J Physiol 2024. [PMID: 38990102 DOI: 10.1113/jp286953] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2024] [Accepted: 06/24/2024] [Indexed: 07/12/2024] Open
|
8
|
Shin-Yi Lin C, Howells J, Rutkove S, Nandedkar S, Neuwirth C, Noto YI, Shahrizaila N, Whittaker RG, Bostock H, Burke D, Tankisi H. Neurophysiological and imaging biomarkers of lower motor neuron dysfunction in motor neuron diseases/amyotrophic lateral sclerosis: IFCN handbook chapter. Clin Neurophysiol 2024; 162:91-120. [PMID: 38603949 DOI: 10.1016/j.clinph.2024.03.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Revised: 02/07/2024] [Accepted: 03/12/2024] [Indexed: 04/13/2024]
Abstract
This chapter discusses comprehensive neurophysiological biomarkers utilised in motor neuron disease (MND) and, in particular, its commonest form, amyotrophic lateral sclerosis (ALS). These encompass the conventional techniques including nerve conduction studies (NCS), needle and high-density surface electromyography (EMG) and H-reflex studies as well as novel techniques. In the last two decades, new methods of assessing the loss of motor units in a muscle have been developed, that are more convenient than earlier methods of motor unit number estimation (MUNE),and may use either electrical stimulation (e.g. MScanFit MUNE) or voluntary activation (MUNIX). Electrical impedance myography (EIM) is another novel approach for the evaluation that relies upon the application and measurement of high-frequency, low-intensity electrical current. Nerve excitability techniques (NET) also provide insights into the function of an axon and reflect the changes in resting membrane potential, ion channel dysfunction and the structural integrity of the axon and myelin sheath. Furthermore, imaging ultrasound techniques as well as magnetic resonance imaging are capable of detecting the constituents of morphological changes in the nerve and muscle. The chapter provides a critical description of the ability of each technique to provide neurophysiological insight into the complex pathophysiology of MND/ALS. However, it is important to recognise the strengths and limitations of each approach in order to clarify utility. These neurophysiological biomarkers have demonstrated reliability, specificity and provide additional information to validate and assess lower motor neuron dysfunction. Their use has expanded the knowledge about MND/ALS and enhanced our understanding of the relationship between motor units, axons, reflexes and other neural circuits in relation to clinical features of patients with MND/ALS at different stages of the disease. Taken together, the ultimate goal is to aid early diagnosis, distinguish potential disease mimics, monitor and stage disease progression, quantify response to treatment and develop potential therapeutic interventions.
Collapse
Affiliation(s)
- Cindy Shin-Yi Lin
- Faculty of Medicine and Health, Central Clinical School, Brain and Mind Centre, University of Sydney, Sydney 2006, Australia.
| | - James Howells
- Central Clinical School, Faculty of Medicine and Health, University of Sydney, Sydney, Australia
| | - Seward Rutkove
- Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Sanjeev Nandedkar
- Natus Medical Inc, Middleton, Wisconsin, USA and Medical College of Wisconsin, Milwaukee, WI, USA
| | - Christoph Neuwirth
- Neuromuscular Diseases Unit/ALS Clinic, Kantonsspital, St. Gallen, Switzerland
| | - Yu-Ichi Noto
- Department of Neurology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Nortina Shahrizaila
- Division of Neurology, Department of Medicine, University of Malaya, Kuala Lumpur 50603, Malaysia
| | - Roger G Whittaker
- Newcastle University Translational and Clinical Research Institute (NUTCRI), Newcastle University., Newcastle Upon Tyne, United Kingdom
| | - Hugh Bostock
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, Queen Square, WC1N 3BG, London, United Kingdom
| | - David Burke
- Central Clinical School, Faculty of Medicine and Health, University of Sydney, Sydney, Australia
| | - Hatice Tankisi
- Department of Clinical Neurophysiology, Aarhus University Hospital and Department of Clinical Medicine, Aarhus University, Aarhus, Denmark.
| |
Collapse
|
9
|
Barkhaus PE, Nandedkar SD, de Carvalho M, Swash M, Stålberg EV. Revisiting the compound muscle action potential (CMAP). Clin Neurophysiol Pract 2024; 9:176-200. [PMID: 38807704 PMCID: PMC11131082 DOI: 10.1016/j.cnp.2024.04.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Revised: 04/15/2024] [Accepted: 04/21/2024] [Indexed: 05/30/2024] Open
Abstract
The compound muscle action potential (CMAP) is among the first recorded waveforms in clinical neurography and one of the most common in clinical use. It is derived from the summated muscle fiber action potentials recorded from a surface electrode overlying the studied muscle following stimulation of the relevant motor nerve fibres innervating the muscle. Surface recorded motor unit potentials (SMUPs) are the fundamental units comprising the CMAP. Because it is considered a basic, if not banal signal, what it represents is often underappreciated. In this review we discuss current concepts in the anatomy and physiology of the CMAP. These have evolved with advances in instrumentation and digitization of signals, affecting its quantitation and measurement. It is important to understand the basic technical and biological factors influencing the CMAP. If these influences are not recognized, then a suboptimal recording may result. The object is to obtain a high quality CMAP recording that is reproducible, whether the study is done for clinical or research purposes. The initial sections cover the relevant CMAP anatomy and physiology, followed by how these principles are applied to CMAP changes in neuromuscular disorders. The concluding section is a brief overview of CMAP research where advances in recording systems and computer-based analysis programs have opened new research applications. One such example is motor unit number estimation (MUNE) that is now being used as a surrogate marker in monitoring chronic neurogenic processes such as motor neuron diseases.
Collapse
Affiliation(s)
- Paul E. Barkhaus
- Department of Neurology, Medical College of Wisconsin, Milwaukee, WI USA
| | - Sanjeev D. Nandedkar
- Department of Neurology, Medical College of Wisconsin, Milwaukee, WI USA
- Natus Medical Inc., Hopewell Junction, NY, USA
| | - Mamede de Carvalho
- Instituto de Medicina Molecular and Institute of Physiology, Centro de Estudos Egas Moniz, Faculty of Medicine, University of Lisbon, Portugal
- Department of Neurosciences and Mental Health, CHULN-Hospital de Santa Maria, Lisbon, Portugal
| | - Michael Swash
- Barts and the London School of Medicine, Queen Mary University of London, London UK
| | - Erik V. Stålberg
- Department of Medical Sciences, Uppsala University, Uppsala, Sweden
| |
Collapse
|
10
|
Dhanapalaratnam R, Issar T, Poynten AM, Milner KL, Kwai NCG, Krishnan AV. Progression of axonal excitability abnormalities with increasing clinical severity of diabetic peripheral neuropathy. Clin Neurophysiol 2024; 160:12-18. [PMID: 38367309 DOI: 10.1016/j.clinph.2024.02.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Revised: 01/18/2024] [Accepted: 02/05/2024] [Indexed: 02/19/2024]
Abstract
OBJECTIVE Diabetic peripheral neuropathy (DPN) is a frequent complication for persons with type 2 diabetes. Previous studies have failed to demonstrate any significant impact of treatment for DPN. The present study assessed the role of axonal ion channel dysfunction in DPN and explored the hypothesis that there may be a progressive change in ion channel abnormalities that varied with disease stage. METHODS Neurophysiological studies were conducted using axonal excitability techniques, a clinical method of assessing ion channel dysfunction. Studies were conducted in 178 persons with type 2 diabetes, with participants allocated into four groups according to clinical severity of neuropathy, assessed using the Total Neuropathy Grade. RESULTS Analysis of excitability data demonstrated a progressive and stepwise reduction in two parameters that are related to the activity of Kv1.1 channels, namely superexcitability and depolarizing threshold electrotonus at 10-20 ms (p < 0.001), and mathematical modelling of axonal excitability findings supported progressive upregulation of Kv1.1 conductances with increasing greater disease severity. CONCLUSION The findings are consistent with a progressive upregulation of juxtaparanodal Kv1.1 conductances with increasing clinical severity of diabetic peripheral neuropathy. SIGNIFICANCE From a translational perspective, the study suggests that blockade of Kv1.1 channels using 4-aminopyridine derivatives such as fampridine may be a potential treatment for DPN.
Collapse
Affiliation(s)
- Roshan Dhanapalaratnam
- School of Clinical Medicine, UNSW Sydney, NSW 2031, Australia; Department of Neurology, Prince of Wales Hospital, Sydney, NSW 2031, Australia
| | - Tushar Issar
- School of Clinical Medicine, UNSW Sydney, NSW 2031, Australia
| | - Ann M Poynten
- School of Clinical Medicine, UNSW Sydney, NSW 2031, Australia; Department of Endocrinology, Prince of Wales Hospital, Sydney, NSW 2031, Australia
| | - Kerry-Lee Milner
- School of Clinical Medicine, UNSW Sydney, NSW 2031, Australia; Department of Endocrinology, Prince of Wales Hospital, Sydney, NSW 2031, Australia
| | - Natalie C G Kwai
- School of Medical, Indigenous and Health Sciences, University of Wollongong, Australia
| | - Arun V Krishnan
- School of Clinical Medicine, UNSW Sydney, NSW 2031, Australia; Department of Neurology, Prince of Wales Hospital, Sydney, NSW 2031, Australia.
| |
Collapse
|
11
|
Carroll AS, Park SB, Lin CSY, Taylor MS, Kwok F, Simon NG, Reilly MM, Kiernan MC, Vucic S. Axonal excitability as an early biomarker of nerve involvement in hereditary transthyretin amyloidosis. Clin Neurophysiol 2024; 159:81-95. [PMID: 38377648 DOI: 10.1016/j.clinph.2024.01.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Revised: 12/26/2023] [Accepted: 01/22/2024] [Indexed: 02/22/2024]
Abstract
OBJECTIVES The treatment of hereditary transthyretin amyloidosis polyneuropathy (ATTRv-PN) has been revolutionised by genetic therapies, with dramatic improvements in patient outcomes. Whilst the optimal timing of treatment initiation remains unknown, early treatment is desirable. Consequently, the aim of the study was to develop biomarkers of early nerve dysfunction in ATTRv-PN. METHODS Ulnar motor and sensory axonal excitability studies were prospectively undertaken on 22 patients with pathogenic hereditary transthyretin amyloid (ATTRv) gene variants, 12 with large fibre neuropathy (LF+) and 10 without (LF-), with results compared to age- and sex-matched healthy controls. RESULTS In motor axons we identified a continuum of change from healthy controls, to LF- and LF+ ATTRv with progressive reduction in hyperpolarising threshold electrotonus (TEh40(10-20 ms): p = 0.04, TEh40(20-40 ms): p = 0.01 and TEh40(90-10 ms): p = 0.01), suggestive of membrane depolarisation. In sensory axons lower levels of subexcitability were observed on single (SubEx) and double pulse (SubEx2) recovery cycle testing in LF+ (SubEx: p = 0.015, SubEx2: p = 0.015, RC(2-1): p = 0.04) suggesting reduced nodal slow potassium conductance, which promotes sensory hyperexcitability, paraesthesia and pain. There were no differences in sensory or motor excitability parameters when comparing different ATTRv variants. CONCLUSIONS These progressive changes seen across the disease spectrum in ATTRv-PN suggest that axonal excitability has utility to identify early and progressive nerve dysfunction in ATTRv, regardless of genotype. SIGNIFICANCE Axonal excitability is a promising early biomarker of nerve dysfunction in ATTRv-PN.
Collapse
Affiliation(s)
- Antonia S Carroll
- Brain and Mind Centre, Faculty of Medicine and Health, Translational Research Collective University of Sydney, and Department of Neurology, Royal Prince Alfred Hospital, Sydney, Australia; Westmead Amyloidosis Centre, Westmead Hospital, University of Sydney, Sydney, Australia; Centre for Neuromuscular Disease, Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, UK.
| | - Susanna B Park
- Brain and Mind Centre, Faculty of Medicine and Health, School of Medical Sciences, University of Sydney, Sydney, Australia
| | - Cindy S Y Lin
- Brain and Mind Centre, Faculty of Medicine and Health, Translational Research Collective University of Sydney, and Department of Neurology, Royal Prince Alfred Hospital, Sydney, Australia
| | - Mark S Taylor
- Westmead Amyloidosis Centre, Westmead Hospital, University of Sydney, Sydney, Australia
| | - Fiona Kwok
- Westmead Amyloidosis Centre, Westmead Hospital, University of Sydney, Sydney, Australia
| | - Neil G Simon
- Faculty of Medicine and Health Sciences, Macquarie University, Sydney, Australia
| | - Mary M Reilly
- Centre for Neuromuscular Disease, Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, UK
| | - Matthew C Kiernan
- Brain and Mind Centre, Faculty of Medicine and Health, Translational Research Collective University of Sydney, and Department of Neurology, Royal Prince Alfred Hospital, Sydney, Australia
| | - Steve Vucic
- Brain and Nerve Centre, Concord Hospital, University of Sydney, Sydney, Australia
| |
Collapse
|
12
|
Cruz R, Tramontin AF, Oliveira AS, Caputo F, Denadai BS, Greco CC. Ischemic preconditioning increases spinal excitability and voluntary activation during maximal plantar flexion contractions in men. Scand J Med Sci Sports 2024; 34:e14591. [PMID: 38429941 DOI: 10.1111/sms.14591] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Revised: 01/29/2024] [Accepted: 02/21/2024] [Indexed: 03/03/2024]
Abstract
The enigmatic benefits of acute limb ischemic preconditioning (IP) in enhancing muscle force and exercise performance have intrigued researchers. This study sought to unravel the underlying mechanisms, focusing on increased neural drive and the role of spinal excitability while excluding peripheral factors. Soleus Hoffmann (H)-reflex /M-wave recruitment curves and unpotentiated supramaximal responses were recorded before and after IP or a low-pressure control intervention. Subsequently, the twitch interpolation technique was applied during maximal voluntary contractions to assess conventional parameters of neural output. Following IP, there was an increase in both maximum normalized force and voluntary activation (VA) for the plantar flexor group, with negligible peripheral alterations. Greater benefits were observed in participants with lower VA levels. Despite greater H-reflex gains, soleus volitional (V)-wave and sEMG amplitudes remained unchanged. In conclusion, IP improves muscle force via enhanced neural drive to the muscles. This effect appears associated, at least in part, to reduced presynaptic inhibition and/or increased motoneuron excitability. Furthermore, the magnitude of the benefit is inversely proportional to the skeletal muscle's functional reserve, making it particularly noticeable in under-recruited muscles. These findings have implications for the strategic application of the IP procedure across diverse populations.
Collapse
Affiliation(s)
- Rogério Cruz
- Human Performance Laboratory, São Paulo State University (UNESP), Biosciences Institute, Campus Rio Claro, Brazil
- Human Performance Research Group, Santa Catarina State University, Florianópolis, Brazil
| | | | | | - Fabrizio Caputo
- Human Performance Research Group, Santa Catarina State University, Florianópolis, Brazil
| | - Benedito Sérgio Denadai
- Human Performance Laboratory, São Paulo State University (UNESP), Biosciences Institute, Campus Rio Claro, Brazil
| | - Camila Coelho Greco
- Human Performance Laboratory, São Paulo State University (UNESP), Biosciences Institute, Campus Rio Claro, Brazil
| |
Collapse
|
13
|
Sagalajev B, Zhang T, Abdollahi N, Yousefpour N, Medlock L, Al-Basha D, Ribeiro-da-Silva A, Esteller R, Ratté S, Prescott SA. Absence of paresthesia during high-rate spinal cord stimulation reveals importance of synchrony for sensations evoked by electrical stimulation. Neuron 2024; 112:404-420.e6. [PMID: 37972595 DOI: 10.1016/j.neuron.2023.10.021] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Revised: 08/24/2023] [Accepted: 10/18/2023] [Indexed: 11/19/2023]
Abstract
Electrically activating mechanoreceptive afferents inhibits pain. However, paresthesia evoked by spinal cord stimulation (SCS) at 40-60 Hz becomes uncomfortable at high pulse amplitudes, limiting SCS "dosage." Kilohertz-frequency SCS produces analgesia without paresthesia and is thought, therefore, not to activate afferent axons. We show that paresthesia is absent not because axons do not spike but because they spike asynchronously. In a pain patient, selectively increasing SCS frequency abolished paresthesia and epidurally recorded evoked compound action potentials (ECAPs). Dependence of ECAP amplitude on SCS frequency was reproduced in pigs, rats, and computer simulations and is explained by overdrive desynchronization: spikes desychronize when axons are stimulated faster than their refractory period. Unlike synchronous spikes, asynchronous spikes fail to produce paresthesia because their transmission to somatosensory cortex is blocked by feedforward inhibition. Our results demonstrate how stimulation frequency impacts synchrony based on axon properties and how synchrony impacts sensation based on circuit properties.
Collapse
Affiliation(s)
- Boriss Sagalajev
- Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada
| | - Tianhe Zhang
- Boston Scientific Neuromodulation, Valencia, CA 25155, USA
| | - Nooshin Abdollahi
- Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada; Institute of Biomedical Engineering, University of Toronto, Toronto, ON M5S 3G9, Canada
| | - Noosha Yousefpour
- Department of Pharmacology and Therapeutics, McGill University, Montreal, QC H3G 1Y6, Canada
| | - Laura Medlock
- Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada; Institute of Biomedical Engineering, University of Toronto, Toronto, ON M5S 3G9, Canada
| | - Dhekra Al-Basha
- Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada; Department of Physiology, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Alfredo Ribeiro-da-Silva
- Department of Pharmacology and Therapeutics, McGill University, Montreal, QC H3G 1Y6, Canada; Department of Anatomy and Cell Biology, McGill University, Montreal, QC H3A 0C7, Canada
| | | | - Stéphanie Ratté
- Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada
| | - Steven A Prescott
- Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada; Institute of Biomedical Engineering, University of Toronto, Toronto, ON M5S 3G9, Canada; Department of Physiology, University of Toronto, Toronto, ON M5S 1A8, Canada.
| |
Collapse
|
14
|
Witkowski G, Szulczyk B, Nurowska E, Jurek M, Pasierski M, Lipiec A, Charzewska A, Dawidziuk M, Milewski M, Owsiak S, Rola R, Sienkiewicz Jarosz H, Hoffman-Zacharska D. Functional Characteristics of the Nav1.1 p.Arg1596Cys Mutation Associated with Varying Severity of Epilepsy Phenotypes. Int J Mol Sci 2024; 25:1745. [PMID: 38339022 PMCID: PMC10855957 DOI: 10.3390/ijms25031745] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2023] [Revised: 01/20/2024] [Accepted: 01/25/2024] [Indexed: 02/12/2024] Open
Abstract
Mutations of the SCN1A gene, which encodes the voltage-dependent Na+ channel's α subunit, are associated with diverse epileptic syndromes ranging in severity, even intra-family, from febrile seizures to epileptic encephalopathy. The underlying cause of this variability is unknown, suggesting the involvement of additional factors. The aim of our study was to describe the properties of mutated channels and investigate genetic causes for clinical syndromes' variability in the family of five SCN1A gene p.Arg1596Cys mutation carriers. The analysis of additional genetic factors influencing SCN1A-associated phenotypes was conducted through exome sequencing (WES). To assess the impact of mutations, we used patch clamp analysis of mutated channels expressed in HEK cells and in vivo neural excitability studies (NESs). In cells expressing the mutant channel, sodium currents were reduced. NESs indicated increased excitability of peripheral motor neurons in mutation carriers. WES showed the absence of non-SCA1 pathogenic variants that could be causative of disease in the family. Variants of uncertain significance in three genes, as potential modifiers of the most severe phenotype, were identified. The p.Arg1596Cys substitution inhibits channel function, affecting steady-state inactivation kinetics. Its clinical manifestations involve not only epileptic symptoms but also increased excitability of peripheral motor fibers. The role of Nav1.1 in excitatory neurons cannot be ruled out as a significant factor of the clinical phenotype.
Collapse
Affiliation(s)
- Grzegorz Witkowski
- First Department of Neurology, Institute of Psychiatry and Neurology, Sobieskiego 9, 02-957 Warsaw, Poland; (S.O.); (H.S.J.)
- Military Institute of Aviation Medicine, Krasinskiego 54/56, 01-755 Warsaw, Poland;
| | - Bartlomiej Szulczyk
- Chair and Department of Pharmacotherapy and Pharmaceutical Care, Faculty of Pharmacy, The Medical University of Warsaw, Banacha 1b, 02-097 Warsaw, Poland; (B.S.); (E.N.); (M.P.)
| | - Ewa Nurowska
- Chair and Department of Pharmacotherapy and Pharmaceutical Care, Faculty of Pharmacy, The Medical University of Warsaw, Banacha 1b, 02-097 Warsaw, Poland; (B.S.); (E.N.); (M.P.)
| | - Marta Jurek
- Department of Medical Genetics, Institute of Mother and Child, Kasprzaka 17a, 01-211 Warsaw, Poland; (M.J.); (A.C.); (M.M.); (D.H.-Z.)
| | - Michal Pasierski
- Chair and Department of Pharmacotherapy and Pharmaceutical Care, Faculty of Pharmacy, The Medical University of Warsaw, Banacha 1b, 02-097 Warsaw, Poland; (B.S.); (E.N.); (M.P.)
| | - Agata Lipiec
- Clinic of Pediatric Neurology, Institute of Mother and Child, Kasprzaka 17a, 01-211 Warsaw, Poland;
| | - Agnieszka Charzewska
- Department of Medical Genetics, Institute of Mother and Child, Kasprzaka 17a, 01-211 Warsaw, Poland; (M.J.); (A.C.); (M.M.); (D.H.-Z.)
| | - Mateusz Dawidziuk
- Department of Medical Genetics, Institute of Mother and Child, Kasprzaka 17a, 01-211 Warsaw, Poland; (M.J.); (A.C.); (M.M.); (D.H.-Z.)
| | - Michal Milewski
- Department of Medical Genetics, Institute of Mother and Child, Kasprzaka 17a, 01-211 Warsaw, Poland; (M.J.); (A.C.); (M.M.); (D.H.-Z.)
| | - Szymon Owsiak
- First Department of Neurology, Institute of Psychiatry and Neurology, Sobieskiego 9, 02-957 Warsaw, Poland; (S.O.); (H.S.J.)
| | - Rafal Rola
- Military Institute of Aviation Medicine, Krasinskiego 54/56, 01-755 Warsaw, Poland;
| | - Halina Sienkiewicz Jarosz
- First Department of Neurology, Institute of Psychiatry and Neurology, Sobieskiego 9, 02-957 Warsaw, Poland; (S.O.); (H.S.J.)
| | - Dorota Hoffman-Zacharska
- Department of Medical Genetics, Institute of Mother and Child, Kasprzaka 17a, 01-211 Warsaw, Poland; (M.J.); (A.C.); (M.M.); (D.H.-Z.)
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Miecznikowa 1, 02-096 Warsaw, Poland
| |
Collapse
|
15
|
Carmland ME, Kreutzfeldt MD, Holbech JV, Brask-Thomsen PK, Krøigård T, Hansen PN, Tankisi H, Jensen TS, Bach FW, Sindrup SH, Finnerup NB. The effect of lacosamide in peripheral neuropathic pain: A randomized, double-blind, placebo-controlled, phenotype-stratified trial. Eur J Pain 2024; 28:105-119. [PMID: 37565715 DOI: 10.1002/ejp.2165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Revised: 07/14/2023] [Accepted: 07/19/2023] [Indexed: 08/12/2023]
Abstract
BACKGROUND Neuropathic pain is common and difficult to treat. The sodium channel blocker lacosamide is efficacious in animal models of pain, but its effect on neuropathic pain in humans is inconclusive. METHODS In a multicentre, randomized, double-blinded placebo-controlled phenotype stratified trial, we examined if lacosamide produced better pain relief in patients with the irritable nociceptor phenotype compared to those without. The primary outcome was the change in daily average pain from baseline to last week of 12 weeks of treatment. Secondary and tertiary outcomes included pain relief, patient global impression of change and presence of 30% and 50% pain reduction. RESULTS The study was prematurely closed with 93 patients included and 63 randomized to lacosamide or placebo in a 2:1 ratio, of which 49 fulfilled the per protocol criteria and was used for the primary objective. We did not find a better effect of lacosamide in patients with the irritable nociceptor phenotype, the 95% CI for the primary objective was 0.41 (-1.2 to 2.0). For all patients randomized, lacosamide had no effect on the primary outcome, but significantly more patients were responders to lacosamide than during placebo, with an NNT of 4.0 (95% CI 2.3-16.1) and 5.0 (95% CI 2.8-24.5) for 30% and 50% pain reduction respectively. We did not identify any predictors for response. Lacosamide was generally well tolerated. CONCLUSION We could not confirm that lacosamide was more efficacious in patients with the irritable nociceptor type, but the study was prematurely closed, so we cannot exclude a small difference. SIGNIFICANCE Treatment of neuropathic pain is often a trial and error process. Little is known about which patient benefit from which kind of medication. The sodium channel blocker lacosamide shows variable effect on neuropathic pain. Pain sensory phenotype, as defined by quantitative sensory testing, did not predict response to treatment with lacosamide.
Collapse
Affiliation(s)
- Malin Erika Carmland
- Danish Pain Research Center, Department of Clinical Medicine, Aarhus University, Aarhus N, Denmark
- Department of Neurology, Aarhus University Hospital, Aarhus, Denmark
| | | | | | | | - Thomas Krøigård
- Department of Neurology, Odense University Hospital, Odense, Denmark
| | | | - Hatice Tankisi
- Department of Clinical Neurophysiology, Aarhus University Hospital, Aarhus, Denmark
- Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Troels Staehelin Jensen
- Danish Pain Research Center, Department of Clinical Medicine, Aarhus University, Aarhus N, Denmark
| | - Flemming Winther Bach
- Department of Neurology, Aarhus University Hospital, Aarhus, Denmark
- Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | | | - Nanna Brix Finnerup
- Danish Pain Research Center, Department of Clinical Medicine, Aarhus University, Aarhus N, Denmark
- Department of Neurology, Aarhus University Hospital, Aarhus, Denmark
| |
Collapse
|
16
|
Lugg A, Schindle M, Sivak A, Tankisi H, Jones KE. Nerve excitability measured with the TROND protocol in amyotrophic lateral sclerosis: a systematic review and meta-analysis. J Neurophysiol 2023; 130:1480-1491. [PMID: 37910562 DOI: 10.1152/jn.00174.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Revised: 10/30/2023] [Accepted: 10/31/2023] [Indexed: 11/03/2023] Open
Abstract
This meta-analysis assessed the 30+ nerve excitability indices generated by the TROND protocol to identify potential biomarkers for amyotrophic lateral sclerosis (ALS). A comprehensive search was conducted in multiple databases to identify human studies that tested median motor axons. Forest plot analyses were performed using a random-effects model to determine the pooled effect (Z-score), heterogeneity (I2), and Cohen's d for potential biomarker identification. Out of 2,866 studies, 23 studies met the inclusion criteria, incorporating data from 719 controls and 942 patients with ALS. Seven indices emerged as potential biomarkers: depolarizing threshold electrotonus (TEd) 90-100 ms, strength-duration time constant (SDTC), superexcitability, TEd 40-60 ms, resting I/V slope, 50% depolarizing I/V, and subexcitability (ranked by the magnitude of the difference between patients and controls from largest to smallest). In a sensitivity analysis focusing on patients with larger compound muscle action potentials (CMAPs), only four indices were potential biomarkers: TEd 10-20 ms, TEd 90-100 ms, superexcitability, and SDTC. Among the extensive range of 30+ excitability indices generated by the TROND protocol, we have identified seven indices that effectively differentiate patients with ALS from healthy controls. Furthermore, a smaller subset of four indices shows promise as potential biomarkers when the CMAP remains relatively large. However, most studies were considered to be at moderate risk of bias due to case-control designs and absence of sensitivity and specificity calculations, underscoring the need for more prospective diagnostic test-accuracy studies with appropriate disease controls.NEW & NOTEWORTHY This meta-analysis uncovers seven potential axonal excitability biomarkers for lower motor neuron pathology in ALS, shedding light on ion channel dysfunction. The identified dysfunction aligns with the primary pathology-protein homeostasis disruption. These biomarkers could fill a gap to detect presymptomatic spread of the disease in the spinal cord and monitor treatments targeting protein homeostasis and limiting spread, toward enhancing patient care.
Collapse
Affiliation(s)
- Anna Lugg
- Faculty of Kinesiology, Sport, and Recreation, University of Alberta, Edmonton, Alberta, Canada
| | - Mason Schindle
- Faculty of Kinesiology, Sport, and Recreation, University of Alberta, Edmonton, Alberta, Canada
| | - Allison Sivak
- University of Alberta Library, Edmonton, Alberta, Canada
| | - Hatice Tankisi
- Department of Clinical Neurophysiology, Aarhus University Hospital, Aarhus, Denmark
| | - Kelvin E Jones
- Faculty of Kinesiology, Sport, and Recreation, University of Alberta, Edmonton, Alberta, Canada
- Neuroscience and Mental Health Institute, Edmonton, Alberta, Canada
| |
Collapse
|
17
|
Li T, Kandula T, Cohn RJ, Kiernan MC, Park SB, Farrar MA. Prospective assessment of vincristine-induced peripheral neuropathy in paediatric acute lymphoblastic leukemia. Clin Neurophysiol 2023; 154:157-168. [PMID: 37633123 DOI: 10.1016/j.clinph.2023.08.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Revised: 07/30/2023] [Accepted: 08/02/2023] [Indexed: 08/28/2023]
Abstract
OBJECTIVE Vincristine is a mainstay treatment for paediatric cancers, particularly acute lymphoblastic leukemia (ALL), with common toxicity including vincristine-induced peripheral neuropathy (VIPN). The present study comprehensively assessed VIPN outcomes in patients receiving vincristine treatment for ALL. METHODS Children diagnosed with ALL commencing vincristine treatment were prospectively evaluated (baseline, post-induction, pre-reinduction, post-reinduction, follow-up). VIPN was examined clinically using the Balis sensory/motor scale, neurophysiologically using axonal excitability techniques and quality-of-life using Pediatric Quality of Life Inventory. RESULTS Thirty-one patients were recruited to this study (age = 6.8 ± 4.4; 61.3% female). Incidence of motor VIPN (motor Balis grade > 0) symptoms were higher than sensory VIPN (sensory Balis grade > 0) at post-induction (92.0% vs 36.0%) and post-reinduction (81.8% vs 22.7%) vincristine treatment. Neurophysiological assessment also demonstrated greater change in motor axonal excitability parameters compared to sensory parameters including changes in depolarising threshold electrotonus (P < 0.0125), superexcitability and subexcitability parameters (all P < 0.0125). Follow-up assessment demonstrated persisting VIPN symptoms with reduced quality-of-life scores compared to baseline. CONCLUSIONS Clinical and neurophysiological evaluation of VIPN suggests vincristine produces a motor-prominent sensorimotor neuropathy in children which persisted at follow-up. SIGNIFICANCE VIPN signs and symptoms develop early in the treatment course, in line with axonal excitability profiles. Early detection of significant nerve changes may support timely implementation of neuroprotection strategies.
Collapse
Affiliation(s)
- Tiffany Li
- Brain and Mind Centre, Sydney Medical School, University of Sydney, Sydney, New South Wales, Australia
| | - Tejaswi Kandula
- Department of Neurology, Sydney Children's Hospital, Sydney, New South Wales, Australia; Discipline of Paediatrics and Child Health, School of Clinical Medicine, UNSW Medicine and Health, UNSW Sydney, New South Wales, Australia
| | - Richard J Cohn
- Kids Cancer Centre, Sydney Children's Hospital, New South Wales, Australia; Discipline of Paediatrics and Child Health, School of Clinical Medicine, UNSW Medicine and Health, UNSW Sydney, New South Wales, Australia
| | - Matthew C Kiernan
- Brain and Mind Centre, Sydney Medical School, University of Sydney, Sydney, New South Wales, Australia
| | - Susanna B Park
- Faculty of Medicine and Health, School of Medical Sciences, University of Sydney, Sydney, New South Wales, Australia.
| | - Michelle A Farrar
- Department of Neurology, Sydney Children's Hospital, Sydney, New South Wales, Australia; Discipline of Paediatrics and Child Health, School of Clinical Medicine, UNSW Medicine and Health, UNSW Sydney, New South Wales, Australia
| |
Collapse
|
18
|
Stikvoort García DJL, Sleutjes BTHM, van Schelven LJ, Goedee HS, van den Berg LH. Diagnostic accuracy of nerve excitability and compound muscle action potential scan derived biomarkers in amyotrophic lateral sclerosis. Eur J Neurol 2023; 30:3068-3078. [PMID: 37354059 DOI: 10.1111/ene.15954] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Revised: 06/19/2023] [Accepted: 06/20/2023] [Indexed: 06/26/2023]
Abstract
BACKGROUND AND PURPOSE The lack of reliable early biomarkers still causes substantial diagnostic delays in amyotrophic lateral sclerosis (ALS). The aim was to assess the diagnostic accuracy of a novel electrophysiological protocol in patients with suspected motor neuron disease (MND). METHODS Consecutive patients with suspected MND were prospectively recruited at our tertiary referral centre for MND in Utrecht, The Netherlands. Procedures were performed in accordance with the Standards for Reporting of Diagnostic Accuracy. In addition to the standard diagnostic workup, an electrophysiological protocol of compound muscle action potential (CMAP) scans and nerve excitability tests was performed on patients' thenar muscles. The combined diagnostic yield of nerve excitability and CMAP scan based motor unit number estimation was compared to the Awaji and Gold Coast criteria and their added value was determined. RESULTS In all, 153 ALS or progressive muscular atrophy patients, 63 disease controls and 43 healthy controls were included. Our electrophysiological protocol had high diagnostic accuracy (area under the curve [AUC] 0.85, 95% confidence interval [95% CI] 0.80-0.90), even in muscles with undetectable axon loss (AUC 0.78, 95% CI 0.70-0.85) and in bulbar-onset patients (AUC 0.85, 95% CI 0.73-0.95). Twenty-four of 33 (73%) ALS patients who could not be diagnosed during the same visit were correctly identified, as well as 8/13 (62%) ALS patients not meeting the Gold Coast criteria and 49/59 (83%) ALS patients not meeting the Awaji criteria during this first visit. CONCLUSIONS Our practical and non-invasive electrophysiological protocol may improve early diagnosis in clinically challenging patients with suspected ALS. Routine incorporation may boost early diagnosis, enhance patient selection and generate baseline measures for clinical trials.
Collapse
Affiliation(s)
- D J L Stikvoort García
- Department of Neurology, Brain Center Utrecht, University Medical Center Utrecht, Utrecht, The Netherlands
| | - B T H M Sleutjes
- Department of Neurology, Brain Center Utrecht, University Medical Center Utrecht, Utrecht, The Netherlands
| | - L J van Schelven
- Department of Medical Technology and Clinical Physics, University Medical Center Utrecht, Utrecht, The Netherlands
| | - H S Goedee
- Department of Neurology, Brain Center Utrecht, University Medical Center Utrecht, Utrecht, The Netherlands
| | - L H van den Berg
- Department of Neurology, Brain Center Utrecht, University Medical Center Utrecht, Utrecht, The Netherlands
| |
Collapse
|
19
|
Chien CY, Wang JD, Lin CC. Nerve excitability test and lead toxicity: a case-control study. J Occup Med Toxicol 2023; 18:19. [PMID: 37653420 PMCID: PMC10472560 DOI: 10.1186/s12995-023-00385-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Accepted: 08/11/2023] [Indexed: 09/02/2023] Open
Abstract
BACKGROUND Although conventional electrophysiological parameters have been proposed as clinical indicators for monitoring lead neuropathies, their correlations with blood lead level are weak. In this study, we investigated the applicability of nerve excitability tests (NETs) to evaluate lead intoxication. METHODS Fourteen workers who were exposed to lead with an elevated blood level ranging from 17.8 to 64.9 µg/dL and 20 healthy controls with similar ages and body heights were enrolled. Both workers and controls underwent nerve conduction studies (NCSs), motor evoked potentials (MEPs) with transcranial magnetic stimulation (TMS), and NETs. RESULTS NCSs showed prolonged distal latencies and decreased motor nerve conduction velocity of median nerves in the workers but without significant correlation to blood lead level (BLL). Significantly prolonged MEP latency was observed in the workers (+ 6 ms). NETs demonstrated hyperpolarized resting membrane potentials in stimulus-response curves and changes in the property of potassium channels under a hyperpolarized current in threshold electrotonus, implying that lead hyperpolarized nerves by interfering with potassium channels. NETs also showed a better correlation with BLL than conventional electrophysiological parameters. CONCLUSIONS Axonal hyperpolarization and central conduction delay are more apparently reflecting elevated BLL than NCS. NET may have the potential for early detection of lead neuropathy.
Collapse
Affiliation(s)
- Chung-Yao Chien
- Department of Neurology, College of Medicine, National Cheng Kung University Hospital, National Cheng Kung University, 138 Sheng Li Road, Tainan, 704, Taiwan
| | - Jung-Der Wang
- Department of Public Health, College of Medicine, National Cheng Kung University, Tainan, Taiwan
- Department of Occupational and Environmental Medicine, National Cheng Kung University Hospital, Tainan, Taiwan
| | - Chou-Ching Lin
- Department of Neurology, College of Medicine, National Cheng Kung University Hospital, National Cheng Kung University, 138 Sheng Li Road, Tainan, 704, Taiwan.
- Department of Biomedical Engineering, National Cheng Kung University, Tainan, Taiwan.
| |
Collapse
|
20
|
Ros LA, Sleutjes BT, Stikvoort García DJ, Goedee HS, Asselman FL, van den Berg LH, van der Pol WL, Wadman RI. Feasibility and tolerability of multimodal peripheral electrophysiological techniques in a cohort of patients with spinal muscular atrophy. Clin Neurophysiol Pract 2023; 8:123-131. [PMID: 37554725 PMCID: PMC10404501 DOI: 10.1016/j.cnp.2023.06.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2023] [Revised: 05/27/2023] [Accepted: 06/17/2023] [Indexed: 08/10/2023] Open
Abstract
OBJECTIVE Electrophysiological techniques are emerging as an aid in identifying prognostic or therapeutic biomarkers in patients with spinal muscular atrophy (SMA), but electrophysiological assessments may be burdensome for patients. We, therefore, assessed feasibility and tolerability of multimodal peripheral non-invasive electrophysiological techniques in a cohort of patients with SMA. METHODS We conducted a single center, longitudinal cohort study investigating the feasibility and tolerability of applying multimodal electrophysiological techniques to the median nerve unilaterally. Techniques consisted of the compound muscle action potential scan, motor nerve excitability tests, repetitive nerve stimulation and sensory nerve action potential. We assessed tolerability using the numeric rating scale (NRS), ranging from 0 (no pain) to 10 (worst possible pain), and defined the protocol to be tolerable if the NRS score ≤ 3. The protocol was considered feasible if it could be performed according to test and quality standards. RESULTS We included 71 patients with SMA types 1-4 (median 39 years; range 13-67) and 63 patients at follow-up. The protocol was feasible in 98% of patients and was well-tolerated in up to 90% of patients. Median NRS score was 2 (range 0-6 at baseline and range 0-4 at follow-up (p < 0.01)). None of the patients declined follow-up assessment. CONCLUSIONS Multimodal, peripheral, non-invasive, electrophysiological techniques applied to the median nerve are feasible and well-tolerated in adolescents and adults with SMA types 1-4. SIGNIFICANCE Our study supports the use of non-invasive multimodal electrophysiological assessments in adolescents and adults with SMA types 1-4.
Collapse
Affiliation(s)
- Leandra A.A. Ros
- Department of Neurology, University Medical Center Utrecht, UMC Utrecht Brain Center, Utrecht University, Utrecht, The Netherlands
| | - Boudewijn T.H.M. Sleutjes
- Department of Neurology, University Medical Center Utrecht, UMC Utrecht Brain Center, Utrecht University, Utrecht, The Netherlands
| | - Diederik J.L. Stikvoort García
- Department of Neurology, University Medical Center Utrecht, UMC Utrecht Brain Center, Utrecht University, Utrecht, The Netherlands
| | - H. Stephan Goedee
- Department of Neurology, University Medical Center Utrecht, UMC Utrecht Brain Center, Utrecht University, Utrecht, The Netherlands
| | - Fay-Lynn Asselman
- Department of Neurology, University Medical Center Utrecht, UMC Utrecht Brain Center, Utrecht University, Utrecht, The Netherlands
| | - Leonard H. van den Berg
- Department of Neurology, University Medical Center Utrecht, UMC Utrecht Brain Center, Utrecht University, Utrecht, The Netherlands
| | | | - Renske I. Wadman
- Corresponding author at: Department of Neurology, University Medical Center Utrecht, UMC Utrecht Brain Center, Heidelberglaan 100, 3508 GA, Utrecht, The Netherlands.
| |
Collapse
|
21
|
Menon P, Pavey N, Aberra AS, van den Bos MAJ, Wang R, Kiernan MC, Peterchev AV, Vucic S. Dependence of cortical neuronal strength-duration properties on TMS pulse shape. Clin Neurophysiol 2023; 150:106-118. [PMID: 37060842 PMCID: PMC10280814 DOI: 10.1016/j.clinph.2023.03.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2022] [Revised: 02/13/2023] [Accepted: 03/08/2023] [Indexed: 04/17/2023]
Abstract
OBJECTIVE The aim of present study was to explore the effects of different combinations of transcranial magnetic stimulation (TMS) pulse width and pulse shape on cortical strength-duration time constant (SDTC) and rheobase measurements. METHODS Resting motor thresholds (RMT) at pulse widths (PW) of 30, 45, 60, 90 and 120 µs and M-ratios of 0.2, 0.1 and 0.025 were determined using figure-of-eight coil with initial posterior-to-anterior induced current. The M-ratio indicates the relative phases of the induced current with lower values signifying a more unidirectional stimulus. Strength-duration time constant (SDTC) and rheobase were estimated for each M-ratio and various PW combinations. Simulations of biophysically realistic cortical neuron models assessed underlying neuronal populations and physiological mechanisms mediating pulse shape effects on strength-duration properties. RESULTS The M-ratio exerted significant effect on SDTC (F(2,44) = 4.386, P = 0.021), which was longer for M-ratio of 0.2 (243.4 ± 61.2 µs) compared to 0.025 (186.7 ± 52.5 µs, P = 0.034). Rheobase was significantly smaller when assessed with M-ratio 0.2 compared to 0.025 (P = 0.026). SDTC and rheobase values were most consistent with pulse width sets of 30/45/60/90/120 µs, 30/60/90/120 µs, and 30/60/120 µs. Simulation studies indicated that isolated pyramidal neurons in layers 2/3, 5, and large basket-cells in layer 4 exhibited SDTCs comparable to experimental results. Further, simulation studies indicated that reducing transient Na+ channel conductance increased SDTC with larger increases for higher M-ratios. CONCLUSIONS Cortical strength-duration curve properties vary with pulse shape, and the modulating effect of the hyperpolarising pulse phase on cortical axonal transient Na+ conductances could account for these changes, although a shift in the recruited neuronal populations may contribute as well. SIGNIFICANCE The dependence of the cortical strength-duration curve properties on the TMS pulse shape and pulse width selection underscores the need for consistent measurement methods across studies and the potential to extract information about pathophysiological processes.
Collapse
Affiliation(s)
- Parvathi Menon
- Brain and Nerve Research Centre, Concord Clinical School, University of Sydney, Concord Hospital, Sydney, Australia
| | - Nathan Pavey
- Brain and Nerve Research Centre, Concord Clinical School, University of Sydney, Concord Hospital, Sydney, Australia
| | - Aman S Aberra
- Department of Biological Sciences, Dartmouth College, Hanover, NH, USA
| | - Mehdi A J van den Bos
- Brain and Nerve Research Centre, Concord Clinical School, University of Sydney, Concord Hospital, Sydney, Australia
| | - Ruochen Wang
- Department of Biomedical Engineering, Duke University, Durham, NC, USA
| | | | - Angel V Peterchev
- Department of Biomedical Engineering, Duke University, Durham, NC, USA; Department of Psychiatry and Behavioural Sciences, Duke University, Durham, NC, USA; Department of Electrical and Computer Engineering, Duke University, Durham, NC, USA; Department of Neurosurgery, Duke University, Durham, NC, USA.
| | - Steve Vucic
- Brain and Nerve Research Centre, Concord Clinical School, University of Sydney, Concord Hospital, Sydney, Australia.
| |
Collapse
|
22
|
Pia H, Nochi Z, Kristensen AG, Pelz B, Goetz M, Hoeink JN, Blockeel AJ, Mouraux A, Truini A, Finnerup NB, Phillips KG, Treede RD, Tankisi H. The test–retest reliability of large and small fiber nerve excitability testing with threshold tracking. Clin Neurophysiol Pract 2023; 8:71-78. [PMID: 37181417 PMCID: PMC10172996 DOI: 10.1016/j.cnp.2023.03.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Revised: 03/08/2023] [Accepted: 03/26/2023] [Indexed: 04/09/2023] Open
Abstract
Objective Standard nerve excitability testing (NET) predominantly assesses Aα- and Aβ-fiber function, but a method examining small afferents would be of great interest in pain studies. Here, we examined the properties of a novel perception threshold tracking (PTT) method that preferentially activates Aδ-fibers using weak currents delivered by a novel multipin electrode and compared its reliability with NET. Methods Eighteen healthy subjects (mean age:34.06 ± 2.0) were examined three times with motor and sensory NET and PTT in morning and afternoon sessions on the same day (intra-day reliability) and after a week (inter-day reliability). NET was performed on the median nerve, while PTT stimuli were delivered through a multipin electrode located on the forearm. During PTT, subjects indicated stimulus perception via a button press and the intensity of the current was automatically increased or decreased accordingly by Qtrac software. This allowed changes in the perception threshold to be tracked during strength-duration time constant (SDTC) and threshold electrotonus protocols. Results The coefficient of variation (CoV) and interclass coefficient of variation (ICC) showed good-excellent reliability for most NET parameters. PTT showed poor reliability for both SDTC and threshold electrotonus parameters. There was a significant correlation between large (sensory NET) and small (PTT) fiber SDTC when all sessions were pooled (r = 0.29, p = 0.03). Conclusions Threshold tracking technique can be applied directly to small fibers via a psychophysical readout, but with the current technique, the reliability is poor. Significance Further studies are needed to examine whether Aβ-fiber SDTC may be a surrogate biomarker for peripheral nociceptive signalling.
Collapse
|
23
|
Ruijs TQ, Koopmans IW, de Kam ML, van Esdonk MJ, Koltzenburg M, Groeneveld GJ, Heuberger JA. Effects of Mexiletine and Lacosamide on Nerve Excitability in Healthy Subjects: A Randomized, Double-Blind, Placebo-Controlled, Crossover Study. Clin Pharmacol Ther 2022; 112:1008-1019. [PMID: 35762293 PMCID: PMC9795956 DOI: 10.1002/cpt.2694] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Accepted: 06/12/2022] [Indexed: 01/01/2023]
Abstract
Selective voltage-gated sodium channel blockers are of growing interest as treatment for pain. For drug development of such compounds, it would be critical to have a biomarker that can be used for proof-of-mechanism. We aimed to evaluate whether drug-induced changes in sodium conductance can be detected in the peripheral nerve excitability profile in 18 healthy subjects. In a randomized, double-blind, 3-way crossover study, effects of single oral doses of 333 mg mexiletine and 300 mg lacosamide were compared with placebo. On each study visit, motor and sensory nerve excitability measurements of the median nerve were performed (predose; and 3 and 6 hours postdose) using Qtrac. Treatment effects were calculated using an analysis of covariance (ANCOVA) with baseline as covariate. Mexiletine and lacosamide had significant effects on multiple motor and sensory nerve excitability variables. Depolarizing threshold electrotonus (TEd40 (40-60 ms)) decreased by mexiletine (estimated difference (ED) -1.37% (95% confidence interval (CI): -2.20, -0.547; P = 0.002) and lacosamide (ED -1.27%, 95% CI: -2.10, -0.443; P = 0.004) in motor nerves. Moreover, mexiletine and lacosamide decreased superexcitability (less negative) in motor nerves (ED 1.74%, 95% CI: 0.615, 2.87; P = 0.004, and ED 1.47%, 95% CI: 0.341, 2.60; P = 0.013, respectively). Strength-duration time constant decreased after lacosamide in motor- (ED -0.0342 ms, 95% CI: -0.0571, -0.0112; P = 0.005) and sensory nerves (ED -0.0778 ms, 95% CI: -0.116, -0.0399; P < 0.001). Mexiletine and lacosamide significantly decrease excitability of motor and sensory nerves, in line with their suggested mechanism of action. Results of this study indicate that nerve excitability threshold tracking can be an effective pharmacodynamic biomarker. The method could be a valuable tool in clinical drug development.
Collapse
Affiliation(s)
- Titia Q. Ruijs
- Centre for Human Drug ResearchLeidenThe Netherlands,Leiden University Medical CentreLeidenThe Netherlands
| | - Ingrid W. Koopmans
- Centre for Human Drug ResearchLeidenThe Netherlands,Leiden University Medical CentreLeidenThe Netherlands
| | | | | | | | - Geert Jan Groeneveld
- Centre for Human Drug ResearchLeidenThe Netherlands,Leiden University Medical CentreLeidenThe Netherlands
| | | |
Collapse
|
24
|
Ng K. Bringing nerve excitability out of the research laboratory into the clinic. Clin Neurophysiol Pract 2022; 7:317-318. [PMID: 36345534 PMCID: PMC9636407 DOI: 10.1016/j.cnp.2022.10.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Accepted: 10/06/2022] [Indexed: 11/06/2022] Open
Affiliation(s)
- Karl Ng
- Department of Neurology and Clinical Neurophysiology, Royal North Shore Hospital and The University of Sydney, Reserve Rd, St Leonards, Sydney, NSW, Australia
| |
Collapse
|
25
|
Neuroplasticity of peripheral axonal properties after ischemic stroke. PLoS One 2022; 17:e0275450. [PMID: 36194586 PMCID: PMC9531785 DOI: 10.1371/journal.pone.0275450] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Accepted: 09/15/2022] [Indexed: 11/19/2022] Open
Abstract
OBJECTIVE This study investigated how peripheral axonal excitability changes in ischemic stroke patients with hemiparesis or hemiplegia, reflecting the plasticity of motor axons due to corticospinal tract alterations along the poststroke stage. METHODS Each subject received a clinical evaluation, nerve conduction study, and nerve excitability test. Nerve excitability tests were performed on motor median nerves in paretic and non-paretic limbs in the acute stage of stroke. Control nerve excitability test data were obtained from age-matched control subjects. Some patients underwent excitability examinations several times in subacute or chronic stages. RESULTS A total of thirty patients with acute ischemic stroke were enrolled. Eight patients were excluded due to severe entrapment neuropathy in the median nerve. The threshold current for 50% compound muscle action potential (CMAP) was higher in paretic limbs than in control subjects. Furthermore, in the cohort with severe patients (muscle power ≤ 3/5 in affected hands), increased threshold current for 50% CMAP and reduced subexcitability were noted in affected limbs than in unaffected limbs. In addition, in the subsequent study of those severe patients, threshold electrotonus increased in the hyperpolarization direction: TEh (100-109 ms), and the minimum I/V slope decreased. The above findings suggest the less excitable and less accommodation in lower motor axons in the paretic limb caused by ischemic stroke. CONCLUSION Upper motor neuron injury after stroke can alter nerve excitability in lower motor neurons, and the changes are more obvious in severely paretic limbs. The accommodative changes of axons progress from the subacute to the chronic stage after stroke. Further investigation is necessary to explore the downstream effects of an upper motor neuron insult in the peripheral nerve system.
Collapse
|
26
|
Hargreaves R, Akinsanya K, Ajit SK, Dhruv NT, Driscoll J, Farina P, Gavva N, Gill M, Houghton A, Iyengar S, Jones C, Kavelaars A, Kaykas A, Koroshetz WJ, Laeng P, Laird JM, Lo DC, Luthman J, Munro G, Oshinsky ML, Sittampalam GS, Woller SA, Tamiz AP. Preclinical target validation for non-addictive therapeutics development for pain. Expert Opin Ther Targets 2022; 26:811-822. [DOI: 10.1080/14728222.2022.2147063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Affiliation(s)
| | | | - Seena K. Ajit
- Department of Pharmacology, Drexel University College of Medicine, Philadelphia, Pennsylvania, United States
| | - Neel T. Dhruv
- National Institute of Neurological Disorders and Stroke, Bethesda, Maryland, United States
| | - Jamie Driscoll
- National Institute of Mental Health, Bethesda, Maryland, United States
| | - Peter Farina
- Canaan Partners, Westport, Connecticut, United States
| | - Narender Gavva
- Drug Discovery Sciences, Takeda Pharmaceuticals, San Diego, California, United States
| | - Marie Gill
- National Institute of Neurological Disorders and Stroke, Bethesda, Maryland, United States
| | | | - Smriti Iyengar
- National Institute of Neurological Disorders and Stroke, Bethesda, Maryland, United States
| | - Carrie Jones
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee, United States
| | - Annemieke Kavelaars
- The University of Texas MD Anderson Cancer Center, Houston, Texas, United States
| | | | - Walter J. Koroshetz
- National Institute of Neurological Disorders and Stroke, Bethesda, Maryland, United States
| | - Pascal Laeng
- National Institute of Neurological Disorders and Stroke, Bethesda, Maryland, United States
| | - Jennifer M. Laird
- Eli Lilly and Company, Windlesham, United Kingdom of Great Britain and Northern Ireland
| | - Donald C. Lo
- National Center for Advancing Translational Sciences, Bethesda, Maryland, United States
| | | | | | - Michael L. Oshinsky
- National Institute of Neurological Disorders and Stroke, Bethesda, Maryland, United States
| | - G. Sitta Sittampalam
- National Center for Advancing Translational Sciences, Bethesda, Maryland, United States
| | - Sarah A. Woller
- National Institute of Neurological Disorders and Stroke, Bethesda, Maryland, United States
| | - Amir P. Tamiz
- National Institute of Neurological Disorders and Stroke, Bethesda, Maryland, United States
| |
Collapse
|
27
|
Pre-Synaptic GABAA in NaV1.8+ Primary Afferents Is Required for the Development of Punctate but Not Dynamic Mechanical Allodynia following CFA Inflammation. Cells 2022; 11:cells11152390. [PMID: 35954234 PMCID: PMC9368720 DOI: 10.3390/cells11152390] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 07/26/2022] [Accepted: 07/27/2022] [Indexed: 01/27/2023] Open
Abstract
Hypersensitivity to mechanical stimuli is a cardinal symptom of neuropathic and inflammatory pain. A reduction in spinal inhibition is generally considered a causal factor in the development of mechanical hypersensitivity after injury. However, the extent to which presynaptic inhibition contributes to altered spinal inhibition is less well established. Here, we used conditional deletion of GABAA in NaV1.8-positive sensory neurons (Scn10aCre;Gabrb3fl/fl) to manipulate selectively presynaptic GABAergic inhibition. Behavioral testing showed that the development of inflammatory punctate allodynia was mitigated in mice lacking pre-synaptic GABAA. Dorsal horn cellular circuits were visualized in single slices using stimulus-tractable dual-labelling of c-fos mRNA for punctate and the cognate c-Fos protein for dynamic mechanical stimulation. This revealed a substantial reduction in the number of cells activated by punctate stimulation in mice lacking presynaptic GABAA and an approximate 50% overlap of the punctate with the dynamic circuit, the relative percentage of which did not change following inflammation. The reduction in dorsal horn cells activated by punctate stimuli was equally prevalent in parvalbumin- and calretinin-positive cells and across all laminae I–V, indicating a generalized reduction in spinal input. In peripheral DRG neurons, inflammation following complete Freund’s adjuvant (CFA) led to an increase in axonal excitability responses to GABA, suggesting that presynaptic GABA effects in NaV1.8+ afferents switch from inhibition to excitation after CFA. In the days after inflammation, presynaptic GABAA in NaV1.8+ nociceptors constitutes an “open gate” pathway allowing mechanoreceptors responding to punctate mechanical stimulation access to nociceptive dorsal horn circuits.
Collapse
|
28
|
Rich MM, Housley SN, Nardelli P, Powers RK, Cope TC. Imbalanced Subthreshold Currents Following Sepsis and Chemotherapy: A Shared Mechanism Offering a New Therapeutic Target? Neuroscientist 2022; 28:103-120. [PMID: 33345706 PMCID: PMC8215085 DOI: 10.1177/1073858420981866] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Both sepsis and treatment of cancer with chemotherapy are known to cause neurologic dysfunction. The primary defects seen in both groups of patients are neuropathy and encephalopathy; the underlying mechanisms are poorly understood. Analysis of preclinical models of these disparate conditions reveal similar defects in ion channel function contributing to peripheral neuropathy. The defects in ion channel function extend to the central nervous system where lower motoneurons are affected. In motoneurons the defect involves ion channels responsible for subthreshold currents that convert steady depolarization into repetitive firing. The inability to correctly translate depolarization into steady, repetitive firing has profound effects on motor function, and could be an important contributor to weakness and fatigue experienced by both groups of patients. The possibility that disruption of function, either instead of, or in addition to neurodegeneration, may underlie weakness and fatigue leads to a novel approach to therapy. Activation of serotonin (5HT) receptors in a rat model of sepsis restores the normal balance of subthreshold currents and normal motoneuron firing. If an imbalance of subthreshold currents also occurs in other central nervous system neurons, it could contribute to encephalopathy. We hypothesize that pharmacologically restoring the proper balance of subthreshold currents might provide effective therapy for both neuropathy and encephalopathy in patients recovering from sepsis or treatment with chemotherapy.
Collapse
Affiliation(s)
- Mark M. Rich
- Department of Neuroscience, Cell Biology and Physiology, Wright State University, Dayton, OH, USA
| | - Stephen N. Housley
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA,Integrated Cancer Research Center, Parker H. Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA, USA
| | - Paul Nardelli
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA
| | - Randall K. Powers
- Department of Physiology and Biophysics, University of Washington, Seattle, WA, USA
| | - Timothy C. Cope
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA,Integrated Cancer Research Center, Parker H. Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA, USA,Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA, USA
| |
Collapse
|
29
|
Themistocleous AC, Kristensen AG, Sola R, Gylfadottir SS, Bennedsgaard K, Itani M, Krøigård T, Ventzel L, Sindrup SH, Jensen TS, Bostock H, Serra J, Finnerup NB, Tankisi H, Bennett DLH. Axonal excitability does not differ between painful and painless diabetic or chemotherapy-induced distal symmetrical polyneuropathy in a multi-centre observational study. Ann Neurol 2022; 91:506-520. [PMID: 35150149 PMCID: PMC9313833 DOI: 10.1002/ana.26319] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 01/18/2022] [Accepted: 02/07/2022] [Indexed: 11/16/2022]
Abstract
Objective Axonal excitability reflects ion channel function, and it is proposed that this may be a biomarker in painful (vs painless) polyneuropathy. Our objective was to investigate the relationship between axonal excitability parameters and chronic neuropathic pain in deeply phenotyped cohorts with diabetic or chemotherapy‐induced distal symmetrical polyneuropathy. Methods Two hundred thirty‐nine participants with diabetic polyneuropathy were recruited from sites in the UK and Denmark, and 39 participants who developed chemotherapy‐induced polyneuropathy were recruited from Denmark. Participants were separated into those with probable or definite neuropathic pain and those without neuropathic pain. Axonal excitability of large myelinated fibers was measured with the threshold tracking technique. The stimulus site was the median nerve, and the recording sites were the index finger (sensory studies) and abductor pollicis brevis muscle (motor studies). Results Participants with painless and painful polyneuropathy were well matched across clinical variables. Sensory and motor axonal excitability measures, including recovery cycle, threshold electrotonus, strength–duration time constant, and current–threshold relationship, did not show differences between participants with painful and painless diabetic polyneuropathy, and there were only minor changes for chemotherapy‐induced polyneuropathy. Interpretation Axonal excitability did not significantly differ between painful and painless diabetic or chemotherapy‐induced polyneuropathy in a multicenter observational study. Threshold tracking assesses the excitability of myelinated axons; the majority of nociceptors are unmyelinated, and although there is some overlap of the "channelome" between these axonal populations, our results suggest that alternative measures such as microneurography are required to understand the relationship between sensory neuron excitability and neuropathic pain. ANN NEUROL 2022;91:506–520
Collapse
Affiliation(s)
| | - Alexander Gramm Kristensen
- Department of Clinical Medicine, Aarhus University, Aarhus, Denmark.,Department of Clinical Neurophysiology, Aarhus University Hospital, Aarhus, Denmark
| | - Roma Sola
- Neuroscience Technologies, Barcelona, Spain.,MC Mutual, Barcelona, Spain
| | - Sandra Sif Gylfadottir
- Danish Pain Research Center, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark.,Department of Neurology, Aarhus University Hospital, Aarhus, Denmark
| | - Kristine Bennedsgaard
- Danish Pain Research Center, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark.,Department of Neurology, Aarhus University Hospital, Aarhus, Denmark
| | - Mustapha Itani
- Department of Neurology, Odense University Hospital, Odense, Denmark
| | - Thomas Krøigård
- Department of Neurology, Odense University Hospital, Odense, Denmark
| | - Lise Ventzel
- Danish Pain Research Center, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | | | - Troels Staehelin Jensen
- Danish Pain Research Center, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark.,Department of Neurology, Aarhus University Hospital, Aarhus, Denmark
| | - Hugh Bostock
- UCL Queen Square Institute of Neurology, London, United Kingdom
| | - Jordi Serra
- Neuroscience Technologies, Barcelona, Spain.,MC Mutual, Barcelona, Spain
| | - Nanna B Finnerup
- Danish Pain Research Center, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark.,Department of Neurology, Aarhus University Hospital, Aarhus, Denmark
| | - Hatice Tankisi
- Department of Clinical Medicine, Aarhus University, Aarhus, Denmark.,Department of Clinical Neurophysiology, Aarhus University Hospital, Aarhus, Denmark
| | - David L H Bennett
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| |
Collapse
|
30
|
Tankisi H, Bostock H, Grafe P. A test to determine the site of abnormal neuromuscular refractoriness. Clin Neurophysiol Pract 2022; 7:1-6. [PMID: 34984248 PMCID: PMC8693356 DOI: 10.1016/j.cnp.2021.11.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Revised: 09/18/2021] [Accepted: 11/07/2021] [Indexed: 10/26/2022] Open
Abstract
Objective The relative refractory period (RRP) of motor axons is an important parameter in nerve excitability tests of the recovery cycle (RC). Abnormalities may have a site in the axonal membrane, the neuromuscular junction, or in a dysfunction of the muscle. We aimed in this study to determine the site of abnormality, using a modified protocol of the conventional RC test, whereby an additional supramaximal stimulus is added at the same interstimulus interval as in RC recordings (RCSM). Methods Twenty-four healthy subjects aged 37.8 ± 2.4 years (mean ± SE) were examined with median nerve excitability testing using RC and RCSM protocols at normal temperature (34.1 ± 0.2 °C). The recordings were repeated in 12 subjects after selective cooling of the thenar muscle (25.2 ± 0.7 °C) and in 12 subjects after cooling the nerve trunk at the wrist (24.9 ± 0.3 °C). Results After cooling the nerve, RRP measured with RC and RCSM were prolonged similarly (medians by 1.8 ms, and 2.1 ms respectively). In contrast, cooling the muscle prolonged RRP measured with RC (by 1.3 ms), but did not significantly prolong RRP measured with RCSM. RRPs measured by RC and RCSM were significantly different when cooling was at the muscle (P = 5.10-4), but not when cooling was at the nerve (P = 0.57). Conclusions A difference between RC and RCSM indicates abnormal excitability distal to the axonal membrane under the stimulating electrode. Significance Combining RCSM with the conventional RC protocol should help to localize the site of abnormal neuromuscular refractoriness.
Collapse
Affiliation(s)
- Hatice Tankisi
- Department of Clinical Neurophysiology, Aarhus University Hospital, Aarhus, Denmark
| | - Hugh Bostock
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, UK
| | - Peter Grafe
- Institute of Physiology, Ludwig-Maximilians University Munich, Germany
| |
Collapse
|
31
|
Caetano A, Pereira P, de Carvalho M. Influence of age and gender in the sensory nerve fibers excitability. Brain Behav 2022; 12:e2467. [PMID: 34964304 PMCID: PMC8785620 DOI: 10.1002/brb3.2467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/09/2021] [Revised: 11/01/2021] [Accepted: 11/29/2021] [Indexed: 12/01/2022] Open
Abstract
OBJECTIVES To assess the influence of age and gender on sensory nerve axonal excitability parameters. METHODS Thirty-three healthy subjects (21 women) were included, with a mean age of 34.6 (range 21-76). Median sensory nerve excitability measurements (index finger) were performed using the TRONDNF nerve excitability protocol of the QTRAC program. RESULTS Peak sensory nerve action potential (SNAP) amplitude was significantly higher among women (27.1 vs. 9.2 μV; p = .022), and strength-duration time constant (SDTC) was significantly higher in men (0.7 vs. 0.5; p = .011), not dependent on age. Greater age was negatively correlated with resting I/V slope, not dependent on gender (r = -0.4; p = .024). No other changes in excitability properties with increasing age were found. CONCLUSIONS Physiological features like as age and gender do not have a relevant impact on sensory nerve excitability measurements, which can have implications regarding pharmacological treatments.
Collapse
Affiliation(s)
- André Caetano
- Faculdade de Medicina, Instituto de Fisiologia, Instituto de Medicina Molecular, Universidade de Lisboa, Lisbon, Portugal.,Department of Neurology, Centro Hospitalar de Lisboa Ocidental, Hospital de Egas Moniz, Lisbon, Portugal
| | - Pedro Pereira
- Department of Neurology, Hospital Garcia de Orta, Almada, Portugal
| | - Mamede de Carvalho
- Faculdade de Medicina, Instituto de Fisiologia, Instituto de Medicina Molecular, Universidade de Lisboa, Lisbon, Portugal.,Department of Neurosciences, Centro Hospitalar de Lisboa Norte, Hospital de Santa Maria, Lisbon, Portugal
| |
Collapse
|
32
|
Alaamel A, Şahin R, Hashan M, Taşkınoğlu T, Özel T, Erdem N, Uysal H. Axonal excitability findings in acute inflammatory demyelinating polyneuropathy related to SARS-CoV-2. NEUROL SCI NEUROPHYS 2022. [DOI: 10.4103/nsn.nsn_111_21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
|
33
|
McIlduff C, Wainger B, Freeman R, Samaan S, Yator I, Gutierrez H, Verga S, Rutkove S. The threshold tracking nerve conduction study technique: Experience of clinical users unfamiliar with a research-grade neuronal excitability system. Clin Neurophysiol Pract 2022; 7:319-324. [PMID: 36353647 PMCID: PMC9637722 DOI: 10.1016/j.cnp.2022.08.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Revised: 08/04/2022] [Accepted: 08/22/2022] [Indexed: 11/06/2022] Open
Abstract
Threshold tracking nerve conduction studies (TTNCSs) measure axon excitability. TTNCSs can objectively characterize neuronal dysfunction and treatment response. An available research-grade TTNCS system has not been widely implemented . Clinical electrophysiologists with varying levels of experience can perform TTNCSs. A user-friendly system and education about TTNCSs could broaden use of the technique.
Objective To 1) explore if clinical electrophysiologists with different degrees of experience performing standard nerve conduction studies could run a threshold tracking nerve conduction study (TTNCS) protocol and 2) learn how clinical users view a research-grade TTNCSs neuronal excitability system. Methods Five clinical electrophysiologists conducted a TTNCS session using QTracS and then completed a questionnaire describing their impressions. Results All of the electrophysiologists completed the QTracS protocol on an initial attempt. Perceived strengths comprised the ease of preparatory steps and quick protocol speed. Identified drawbacks included an unwieldly user-interface. The electrophysiologists indicated that knowledge of TTNCS principles and applications would be critical for incorporation of the method into clinical use. Conclusions This pilot study suggests that clinical electrophysiologists can carry out TTNCSs with a research-grade system. The development of a more user-friendly program, along with dedicated education and training, could lead to wider application of the TTNCS technique. Significance Considered together with clinical presentation and other biomarkers, increased use of TTNCSs could provide improved assessment of neuromuscular disease and treatment response.
Collapse
|
34
|
The additional diagnostic value of motor nerve excitability testing in chronic axonal neuropathy. Clin Neurophysiol Pract 2022; 7:27-33. [PMID: 35128215 PMCID: PMC8803553 DOI: 10.1016/j.cnp.2021.12.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Revised: 12/23/2021] [Accepted: 12/27/2021] [Indexed: 11/29/2022] Open
Abstract
Nerve excitability testing was correlated with conventional nerve conduction studies. Nerve excitability testing was similar in patients with and without neuropathy and normal nerve conduction. There is no support for the potential additional diagnostic value of nerve excitability testing in mixed etiology neuropathy.
Objective To explore potential differences in motor nerve excitability testing (NET) variables at group levels between patients with a clinical diagnosis of polyneuropathy (PNP), which did not fulfil diagnostic criteria of conventional nerve conduction studies (NCS) and patients without polyneuropathy. Such differences could support a role for NET in increasing the diagnostic sensitivity of NCS in chronic axonal PNP. Methods Motor NET was performed using the median nerve in patients with a clinical suspicion of PNP in addition to conventional NCS, skin biopsies, corneal confocal microscopy and structured clinical evaluation including scoring of neuropathy symptoms and signs. Results Of the 57 patients included, 32 had PNP, half of which had NCS, which fulfilled criteria for PNP (NCS+ PNP). There were no significant differences for any of the NET variables between PNP patients with non-diagnostic conventional NCS (NCS− PNP) and patients without PNP. Rheobase was increased, and Ted (undershoot) and subexcitability were decreased in NCS+ PNP. Sural amplitude, peroneal nerve F-wave latency and tibial nerve F-wave-latency were correlated with subexcitability, and tibial nerve motor amplitude was correlated with rheobase. Conclusions NET was correlated with conventional NCS and no differences were found between NCS− PNP patients and patients without PNP. Significance NET does not seem to offer any additional diagnostic value in chronic mixed etiology neuropathy.
Collapse
|
35
|
Carroll AS, Howells J, Lin CS, Park SB, Simon N, Reilly MM, Vucic S, Kiernan MC. Differences in nerve excitability properties across upper limb sensory and motor axons. Clin Neurophysiol 2021; 136:138-149. [DOI: 10.1016/j.clinph.2021.12.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 11/16/2021] [Accepted: 12/07/2021] [Indexed: 11/24/2022]
|
36
|
iMAX: A new tool for assessment of motor axon excitability. A multicenter prospective study. Clin Neurophysiol 2021; 133:20-28. [PMID: 34800836 DOI: 10.1016/j.clinph.2021.10.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Revised: 10/19/2021] [Accepted: 10/20/2021] [Indexed: 11/23/2022]
Abstract
OBJECTIVE This study was undertaken to establish by a multicentric approach the reliability of a new technique evaluating motor axon excitability. METHODS The minimal threshold, the lowest stimulus intensity allowing a maximal response by 1 mA increments (iUP) and then by 0.1 mA adjustments (iMAX) were prospectively derived from three nerves (median, ulnar, fibular) in four university centers (Liège, Marseille, Fraiture, Nice). iMAX procedure was applied in 28 healthy volunteers (twice) and 32 patients with Charcot-Marie-Tooth (CMT1a), chronic inflammatory demyelinating polyneuropathy (CIDP), Guillain-Barré syndrome (SGB) or axonal neuropathy. RESULTS Healthy volunteers results were not significantly different between centers. Correlation coefficients between test and retest were moderate (> 0.5). Upper limits of normal were established using the 95th percentile. Comparison of volunteers and patient groups indicated significant increases in iMAX parameters especially for the CMT1a and CIDP groups. In CMT1a, iMAX abnormalities were homogeneous at the three stimulation sites, which was not the case for CIDP. CONCLUSIONS The iMAX procedure is reliable and allows the monitoring of motor axon excitability disorders. SIGNIFICANCE The iMAX technique should prove useful to monitor motor axonal excitability in routine clinical practice as it is a fast, non-invasive procedure, easily applicable without specific software or devices.
Collapse
|
37
|
Corcia P, Bede P, Pradat PF, Couratier P, Vucic S, de Carvalho M. Split-hand and split-limb phenomena in amyotrophic lateral sclerosis: pathophysiology, electrophysiology and clinical manifestations. J Neurol Neurosurg Psychiatry 2021; 92:1126-1130. [PMID: 34285065 DOI: 10.1136/jnnp-2021-326266] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/01/2021] [Accepted: 07/05/2021] [Indexed: 11/03/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disorder affecting the upper and lower motor neurons. A key clinical feature of ALS is the absence of accurate, early-stage diagnostic indicators. 'Split-hand syndrome' was first described in ALS at the end of the last century and a considerable body of literature suggests that the split-hand phenomenon may be an important clinical feature of ALS. Considering the published investigations, it is conceivable that the 'split-hand syndrome' results from the associated upper and lower motor neuron degeneration, whose interaction remains to be fully clarified. Additionally, other split syndromes have been described in ALS involving upper or lower limbs, with a nuanced description of clinical and neurophysiological manifestations that may further aid ALS diagnosis. In this review, we endeavour to systematically present the spectrum of the 'split syndromes' in ALS from a clinical and neurophysiology perspective and discuss their diagnostic and pathogenic utility.
Collapse
Affiliation(s)
- Philippe Corcia
- Centre Constitutif de Référence SLA, CHU Bretonneau, Tours, France
| | - Peter Bede
- Computational Neuroimaging Group, Trinity College Dublin, Ireland.,Pitié-Salpêtrière University Hospital, Sorbonne University, Paris, France
| | - Pierre-François Pradat
- Neurology, Hopital Pitie-Salpetriere, Paris, France.,LIB, Université Pierre et Marie Curie Faculté de Médecine, Paris, Île-de-France, France
| | | | - Steve Vucic
- Westmead Clinical School, Westmead Hospital, University of Sydney, Sydney, New South Wales, Australia.,Sydney Medical School, The University of Sydney, Sydney, New South Wales, Australia
| | - Mamede de Carvalho
- Instituto de Fisiologia, Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisbon, Lisbon, Portugal.,Department of Neurosciences and Mental Health, Hospital de Santa Maria, Lisboa, Portugal
| |
Collapse
|
38
|
Effect of exenatide on peripheral nerve excitability in type 2 diabetes. Clin Neurophysiol 2021; 132:2532-2539. [PMID: 34455311 DOI: 10.1016/j.clinph.2021.05.033] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Revised: 04/26/2021] [Accepted: 05/25/2021] [Indexed: 12/31/2022]
Abstract
OBJECTIVE To assess the effect of exenatide (a GLP-1 receptor agonist), dipeptidyl peptidase-IV (DPP-IV) inhibitors, and sodium-glucose co-transporter 2 (SGLT-2) inhibitors on measures of peripheral nerve excitability in patients with type 2 diabetes. METHODS Patients receiving either exenatide (n = 32), a DPP-IV inhibitor (n = 31), or a SGLT-2 inhibitor (n = 27) underwent motor nerve excitability assessments. Groups were similar in age, sex, HbA1c, diabetes duration, lipids, and neuropathy severity. An additional 10 subjects were assessed prospectively over 3 months while oral anti-hyperglycaemic therapy was kept constant. A cohort of healthy controls (n = 32) were recruited for comparison. RESULTS Patients receiving a DPP-IV or SGLT-2 inhibitor demonstrated abnormalities in peak threshold reduction, S2 accommodation, superexcitability, and subexcitability. In contrast, patients treated with exenatide were observed to have normal nerve excitability. In the prospective arm, exenatide therapy was associated with an improvement in nerve function as patients demonstrated corrections in S2 accommodation, superexcitability, and subexcitability at follow-up. These changes were independent of the reductions in HbA1c following exenatide treatment. CONCLUSIONS Exenatide was associated with an improvement in measures of nerve excitability in patients with type 2 diabetes. SIGNIFICANCE Exenatide may improve peripheral nerve function in type 2 diabetes.
Collapse
|
39
|
Britten-Jones AC, Kamel JT, Roberts LJ, Braat S, Craig JP, MacIsaac RJ, Downie LE. Investigating the Neuroprotective Effect of Oral Omega-3 Fatty Acid Supplementation in Type 1 Diabetes (nPROOFS1): A Randomized Placebo-Controlled Trial. Diabetes 2021; 70:1794-1806. [PMID: 33952620 DOI: 10.2337/db21-0136] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Accepted: 04/29/2021] [Indexed: 11/13/2022]
Abstract
This randomized, double-masked, placebo-controlled trial evaluated the effects of oral omega-3 (n-3) fatty acid supplementation on peripheral nerves in type 1 diabetes. Participants with type 1 diabetes were assigned (1:1) to n-3 (1,800 mg/day fish oil) or placebo (600 mg/day olive oil) supplements for 180 days. The primary outcome was change from baseline in central corneal nerve fiber length (CNFL) at day 180. Secondary outcomes included change in other corneal nerve parameters, corneal sensitivity, peripheral small and large nerve fiber function, and ocular surface measures. Efficacy was analyzed according to the intention-to-treat principle. Safety assessments included diabetic retinopathy grade and adverse events. Between July 2017 and September 2019, 43 participants received n-3 (n = 21) or placebo (n = 22) supplements. All participants, except for two assigned to placebo, completed the trial. At day 180, the estimated increase in CNFL in the n-3 group, compared with placebo, was 2.70 mm/mm2 (95% CI 1.64, 3.75). The Omega-3 Index increased relative to placebo (3.3% [95% CI 2.4, 4.2]). There were no differences in most small or large nerve fiber functional parameters. Adverse events were similar between groups. In conclusion, we found in this randomized controlled trial that long-chain n-3 supplements impart corneal neuroregenerative effects in type 1 diabetes, indicating a role in modulating peripheral nerve health.
Collapse
Affiliation(s)
| | - Jordan T Kamel
- Department of Medicine, University of Melbourne, Fitzroy, Australia
- Centre for Clinical Neurosciences and Neurological Research, St. Vincent's Hospital Melbourne, Fitzroy, Australia
| | - Leslie J Roberts
- Department of Medicine, University of Melbourne, Fitzroy, Australia
- Centre for Clinical Neurosciences and Neurological Research, St. Vincent's Hospital Melbourne, Fitzroy, Australia
| | - Sabine Braat
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, University of Melbourne, Parkville, Australia
- Methods and Implementation Support for Clinical Health research platform, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville, Australia
| | - Jennifer P Craig
- Department of Ophthalmology, New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand
| | - Richard J MacIsaac
- Department of Medicine, University of Melbourne, Fitzroy, Australia
- Department of Endocrinology and Diabetes, St. Vincent's Hospital Melbourne, Fitzroy, Australia
| | - Laura E Downie
- Department of Optometry and Vision Sciences, University of Melbourne, Parkville, Australia
| |
Collapse
|
40
|
Predictive Biomarkers of Oxaliplatin-Induced Peripheral Neurotoxicity. J Pers Med 2021; 11:jpm11070669. [PMID: 34357136 PMCID: PMC8306803 DOI: 10.3390/jpm11070669] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 07/09/2021] [Accepted: 07/13/2021] [Indexed: 12/15/2022] Open
Abstract
Oxaliplatin (OXA) is a platinum compound primarily used in the treatment of gastrointestinal cancer. OXA-induced peripheral neurotoxicity (OXAIPN) is the major non-hematological dose-limiting toxicity of OXA-based chemotherapy and includes acute transient neurotoxic effects that appear soon after OXA infusion, and chronic non-length dependent sensory neuronopathy symmetrically affecting both upper and lower limbs in a stocking-and-glove distribution. No effective strategy has been established to reverse or treat OXAIPN. Thus, it is necessary to early predict the occurrence of OXAIPN during treatment and possibly modify the OXA-based regimen in patients at high risk as an early diagnosis and intervention may slow down neuropathy progression. However, identifying which patients are more likely to develop OXAIPN is clinically challenging. Several objective and measurable early biomarkers for OXAIPN prediction have been described in recent years, becoming useful for informing clinical decisions about treatment. The purpose of this review is to critically review data on currently available or promising predictors of OXAIPN. Neurological monitoring, according to predictive factors for increased risk of OXAIPN, would allow clinicians to personalize treatment, by monitoring at-risk patients more closely and guide clinicians towards better counseling of patients about neurotoxicity effects of OXA.
Collapse
|
41
|
English AW, Berglund K, Carrasco D, Goebel K, Gross RE, Isaacson R, Mistretta OC, Wynans C. Bioluminescent Optogenetics: A Novel Experimental Therapy to Promote Axon Regeneration after Peripheral Nerve Injury. Int J Mol Sci 2021; 22:ijms22137217. [PMID: 34281270 PMCID: PMC8269199 DOI: 10.3390/ijms22137217] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Revised: 06/24/2021] [Accepted: 06/25/2021] [Indexed: 11/18/2022] Open
Abstract
Functional recovery after peripheral nerve injury (PNI) is poor, mainly due to the slow and incomplete regeneration of injured axons. Experimental therapies that increase the excitability of the injured axons have proven remarkably successful in promoting regeneration, but their clinical applicability has been limited. Bioluminescent optogenetics (BL-OG) uses luminopsins, fusion proteins of light-generating luciferase and light-sensing ion channels that could be used to increase neuronal excitability if exposed to a suitable substrate. Excitatory luminopsins were expressed in motoneurons of transgenic mice and in wildtype mice transduced with adeno-associated viral vectors. Intraperitoneal administration of coelenterazine (CTZ), a known luciferase substrate, generated intense bioluminescence in peripheral axons. This bioluminescence increased motoneuron excitability. A single administration of CTZ immediately after sciatic nerve transection and repair markedly enhanced motor axon regeneration. Compound muscle action potentials were 3–4 times larger than controls by 4 weeks after injury. The results observed with transgenic mice were comparable to those of mice in which the luminopsin was expressed using viral vectors. Significantly more motoneurons had successfully reinnervated muscle targets four weeks after nerve injury in BL-OG treated mice than in controls. Bioluminescent optogenetics is a promising therapeutic approach to enhancing axon regeneration after PNI.
Collapse
Affiliation(s)
- Arthur W. English
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA; (D.C.); (K.G.); (R.I.); (O.C.M.); (C.W.)
- Department of Rehabilitation Medicine, Emory University School of Medicine, Atlanta, GA 30322, USA
- Correspondence:
| | - Ken Berglund
- Department of Neurosurgery, Emory University School of Medicine, Atlanta, GA 30322, USA; (K.B.); (R.E.G.)
| | - Dario Carrasco
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA; (D.C.); (K.G.); (R.I.); (O.C.M.); (C.W.)
| | - Katharina Goebel
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA; (D.C.); (K.G.); (R.I.); (O.C.M.); (C.W.)
| | - Robert E. Gross
- Department of Neurosurgery, Emory University School of Medicine, Atlanta, GA 30322, USA; (K.B.); (R.E.G.)
| | - Robin Isaacson
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA; (D.C.); (K.G.); (R.I.); (O.C.M.); (C.W.)
| | - Olivia C. Mistretta
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA; (D.C.); (K.G.); (R.I.); (O.C.M.); (C.W.)
| | - Carly Wynans
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA; (D.C.); (K.G.); (R.I.); (O.C.M.); (C.W.)
| |
Collapse
|
42
|
Palomés-Borrajo G, Badia J, Navarro X, Penas C. Nerve Excitability and Neuropathic Pain is Reduced by BET Protein Inhibition After Spared Nerve Injury. THE JOURNAL OF PAIN 2021; 22:1617-1630. [PMID: 34157407 DOI: 10.1016/j.jpain.2021.05.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Revised: 05/19/2021] [Accepted: 05/23/2021] [Indexed: 11/27/2022]
Abstract
Neuropathic pain is a common disability produced by enhanced neuronal excitability after nervous system injury. The pathophysiological changes that underlie the generation and maintenance of neuropathic pain require modifications of transcriptional programs. In particular, there is an induction of pro-inflammatory neuromodulators levels, and changes in the expression of ion channels and other factors intervening in the determination of the membrane potential in neuronal cells. We have previously found that inhibition of the BET proteins epigenetic readers reduced neuroinflammation after spinal cord injury. Within the present study we aimed to determine if BET protein inhibition may also affect neuroinflammation after a peripheral nerve injury, and if this would beneficially alter neuronal excitability and neuropathic pain. For this purpose, C57BL/6 female mice underwent spared nerve injury (SNI), and were treated with the BET inhibitor JQ1, or vehicle. Electrophysiological and algesimetry tests were performed on these mice. We also determined the effects of JQ1 treatment after injury on neuroinflammation, and the expression of neuronal components important for the maintenance of axon membrane potential. We found that treatment with JQ1 affected neuronal excitability and mechanical hyperalgesia after SNI in mice. BET protein inhibition regulated cytokine expression and reduced microglial reactivity after injury. In addition, JQ1 treatment altered the expression of SCN3A, SCN9A, KCNA1, KCNQ2, KCNQ3, HCN1 and HCN2 ion channels, as well as the expression of the Na+/K+ ATPase pump subunits. In conclusion, both, alteration of inflammation, and neuronal transcription, could be the responsible epigenetic mechanisms for the reduction of excitability and hyperalgesia observed after BET inhibition. Inhibition of BET proteins is a promising therapy for reducing neuropathic pain after neural injury.
Collapse
Affiliation(s)
- Georgina Palomés-Borrajo
- Institute of Neurosciences, Dept. Cell Biology, Physiology and Immunology, Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Universitat Autònoma de Barcelona, Bellaterra, Spain
| | - Jordi Badia
- Institute of Neurosciences, Dept. Cell Biology, Physiology and Immunology, Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Universitat Autònoma de Barcelona, Bellaterra, Spain
| | - Xavier Navarro
- Institute of Neurosciences, Dept. Cell Biology, Physiology and Immunology, Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Universitat Autònoma de Barcelona, Bellaterra, Spain
| | - Clara Penas
- Institute of Neurosciences, Dept. Cell Biology, Physiology and Immunology, Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Universitat Autònoma de Barcelona, Bellaterra, Spain.
| |
Collapse
|
43
|
Consensus for experimental design in electromyography (CEDE) project: Terminology matrix. J Electromyogr Kinesiol 2021; 59:102565. [PMID: 34102383 DOI: 10.1016/j.jelekin.2021.102565] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Revised: 05/08/2021] [Accepted: 05/20/2021] [Indexed: 11/22/2022] Open
Abstract
Consensus on the definition of common terms in electromyography (EMG) research promotes consistency in the EMG literature and facilitates the integration of research across the field. This paper presents a matrix developed within the Consensus for Experimental Design in Electromyography (CEDE) project, providing definitions for terms used in the EMG literature. The definitions for physiological and technical terms that are common in EMG research are included in two tables, with key information on each definition provided in a comment section. A brief outline of some basic principles for recording and analyzing EMG is included in an appendix, to provide researchers new to EMG with background and context for understanding the definitions of physiological and technical terms. This terminology matrix can be used as a reference to aid researchers new to EMG in reviewing the EMG literature.
Collapse
|
44
|
Marshall A, Alam U, Themistocleous A, Calcutt N, Marshall A. Novel and Emerging Electrophysiological Biomarkers of Diabetic Neuropathy and Painful Diabetic Neuropathy. Clin Ther 2021; 43:1441-1456. [PMID: 33906790 DOI: 10.1016/j.clinthera.2021.03.020] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2020] [Revised: 03/26/2021] [Accepted: 03/27/2021] [Indexed: 12/14/2022]
Abstract
PURPOSE Diabetic peripheral neuropathy (DPN) is the most common complication of diabetes. Small and large peripheral nerve fibers can be involved in DPN. Large nerve fiber damage causes paresthesia, sensory loss, and muscle weakness, and small nerve fiber damage is associated with pain, anesthesia, foot ulcer, and autonomic symptoms. Treatments for DPN and painful DPN (pDPN) pose considerable challenges due to the lack of effective therapies. To meet these challenges, there is a major need to develop biomarkers that can reliably diagnose and monitor progression of nerve damage and, for pDPN, facilitate personalized treatment based on underlying pain mechanisms. METHODS This study involved a comprehensive literature review, incorporating article searches in electronic databases (Google Scholar, PubMed, and OVID) and reference lists of relevant articles with the authors' substantial expertise in DPN. This review considered seminal and novel research and summarizes emerging biomarkers of DPN and pDPN that are based on neurophysiological methods. FINDINGS From the evidence gathered from 145 papers, this submission describes emerging clinical neurophysiological methods with potential to act as biomarkers for the diagnosis and monitoring of DPN as well as putative future roles as predictors of response to antineuropathic pain medication in pDPN. Nerve conduction studies only detect large fiber damage and do not capture pathology or dysfunction of small fibers. Because small nerve fiber damage is prominent in DPN, additional biomarkers of small nerve fiber function are needed. Activation of peripheral nociceptor fibers using laser, heat, or targeted electrical stimuli can generate pain-related evoked potentials, which are an objective neurophysiological measure of damage along the small fiber pathways. Assessment of nerve excitability, which provides a surrogate of axonal properties, may detect alterations in function before abnormalities are detected by nerve conduction studies. Microneurography and rate-dependent depression of the Hoffmann-reflex can be used to dissect underlying pain-generating mechanisms arising from the periphery and spinal cord, respectively. Their role in informing mechanistic-based treatment of pDPN as well as facilitating clinical trials design is discussed. IMPLICATIONS The neurophysiological methods discussed, although currently not practical for use in busy outpatient settings, detect small fiber and early large fiber damage in DPN as well as disclosing dominant pain mechanisms in pDPN. They are suited as diagnostic and predictive biomarkers as well as end points in mechanistic clinical trials of DPN and pDPN.
Collapse
Affiliation(s)
- Anne Marshall
- Musculoskeletal Biology, Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool, United Kingdom; Division of Diabetes, Endocrinology and Gastroenterology, School of Medical Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Uazman Alam
- Division of Diabetes, Endocrinology and Gastroenterology, School of Medical Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom; Cardiovascular and Metabolic Medicine, Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool, United Kingdom
| | - Andreas Themistocleous
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom; Brain Function Research Group, School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Nigel Calcutt
- Department of Pathology, University of California, San Diego, La Jolla, California
| | - Andrew Marshall
- Musculoskeletal Biology, Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool, United Kingdom; Department of Clinical Neurophysiology, The Walton Centre, Liverpool, United Kingdom; Division of Neuroscience and Experimental Psychology, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom.
| |
Collapse
|
45
|
Kristensen AG, Gylfadottir S, Itani M, Kuwabara S, Krøigård T, Khan KS, Finnerup NB, Andersen H, Jensen TS, Sindrup S, Tankisi H. Sensory and motor axonal excitability testing in early diabetic neuropathy. Clin Neurophysiol 2021; 132:1407-1415. [PMID: 34030050 DOI: 10.1016/j.clinph.2021.02.397] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Revised: 01/30/2021] [Accepted: 02/01/2021] [Indexed: 11/16/2022]
Abstract
OBJECTIVE The aim of the present study was to gain insight into the pathophysiology of diabetic polyneuropathy (DPN) and examine the diagnostic value of sensory and motor axonal excitability testing. METHODS One hundred and eleven type 2 diabetics with and without DPN (disease duration: 6.36 ± 0.25 years) and 60 controls were included. All participants received a thorough clinical examination including Michigan Neuropathy Screening Instrument (MNSI) score, nerve conduction studies (NCS), and sensory and motor excitability tests. Patients were compared by the likelihood of neuropathy presence, ranging from no DPN (17), possible/probable DPN (46) to NCS-confirmed DPN (48). RESULTS Motor excitability tests showed differences in rheobase and depolarizing threshold electrotonus measures between NCS-confirmed DPN group and controls but no changes in hyperpolarising threshold electrotonus or recovery cycle parameters. Sensory excitability showed even less changes despite pronounced sensory NCS abnormalities. There were only weak correlations between the above motor excitability parameters and clinical scores. CONCLUSIONS Changes in excitability in the examined patient group were subtle, perhaps because of the relatively short disease duration. SIGNIFICANCE Less pronounced excitability changes than NCS suggest that axonal excitability testing is not of diagnostic value for early DPN and does not provide information on the mechanisms.
Collapse
Affiliation(s)
- A G Kristensen
- Department of Clinical Neurophysiology, Aarhus University Hospital, Denmark; Danish Pain Research Center, Department of Clinical Medicine, Aarhus University, Denmark
| | - S Gylfadottir
- Danish Pain Research Center, Department of Clinical Medicine, Aarhus University, Denmark; Department of Neurology, Aarhus University Hospital, Denmark
| | - M Itani
- Department of Neurology, Odense University Hospital, Denmark
| | - S Kuwabara
- Department of Neurology, Graduate School of Medicine, Chiba University, Japan
| | - T Krøigård
- Department of Neurology, Odense University Hospital, Denmark
| | - K S Khan
- Department of Neurology, Aarhus University Hospital, Denmark
| | - N B Finnerup
- Danish Pain Research Center, Department of Clinical Medicine, Aarhus University, Denmark; Department of Neurology, Aarhus University Hospital, Denmark
| | - H Andersen
- Department of Neurology, Aarhus University Hospital, Denmark
| | - T S Jensen
- Danish Pain Research Center, Department of Clinical Medicine, Aarhus University, Denmark; Department of Neurology, Aarhus University Hospital, Denmark
| | - S Sindrup
- Department of Neurology, Odense University Hospital, Denmark
| | - H Tankisi
- Department of Clinical Neurophysiology, Aarhus University Hospital, Denmark.
| |
Collapse
|
46
|
Issar T, Tummanapalli SS, Borire AA, Kwai NCG, Poynten AM, Arnold R, Markoulli M, Krishnan AV. Impact of the metabolic syndrome on peripheral nerve structure and function in type 2 diabetes. Eur J Neurol 2021; 28:2074-2082. [PMID: 33682297 DOI: 10.1111/ene.14805] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2020] [Accepted: 02/25/2021] [Indexed: 12/15/2022]
Abstract
BACKGROUND AND PURPOSE There is a strong association between the metabolic syndrome in diabetes and the development of peripheral neuropathy; however, the pathophysiological mechanisms remain unknown. METHODS Participants with type 2 diabetes and metabolic syndrome (T2DM/MetS, n = 89) and type 2 diabetes alone (T2DM; n = 59) underwent median nerve ultrasound and excitability studies to assess peripheral nerve structure and function. A subset of T2DM/MetS (n = 24) and T2DM (n = 22) participants underwent confocal microscopy to assess central and inferior whorl corneal nerve structure. Neuropathy severity was assessed using the modified Toronto Clinical Neuropathy Score (mTCNS). Diabetes groups were similar for age, sex distribution, diabetes duration, hemoglobin A1c , insulin treatment, and renal function. Sixty healthy controls similar for age and sex distribution were recruited for comparison. RESULTS Participants with T2DM/MetS manifested with a greater mTCNS compared to T2DM (p < 0.05). Median nerve cross-sectional area was larger in the T2DM/MetS group compared to the T2DM cohort (p < 0.05). Participants with T2DM/MetS had reductions in central (all p < 0.01) and inferior whorl (all p < 0.05) nerve measures. Compared to T2DM, the T2DM/MetS group demonstrated more severe changes in nerve excitability measures, which was due to reduced sodium channel permeability and sodium-potassium pump function. In comparison, only sodium channel permeability was reduced in the T2DM group. CONCLUSIONS Compared to participants with type 2 diabetes alone, those with diabetes and metabolic syndrome manifested greater alterations in peripheral nerve structure and function, which may be due to reduced function of the sodium-potassium pump.
Collapse
Affiliation(s)
- Tushar Issar
- Prince of Wales Clinical School, UNSW Sydney, Sydney, NSW, Australia
| | | | - Adeniyi A Borire
- Prince of Wales Clinical School, UNSW Sydney, Sydney, NSW, Australia
| | - Natalie C G Kwai
- Prince of Wales Clinical School, UNSW Sydney, Sydney, NSW, Australia.,Department of Exercise Physiology, UNSW Sydney, Sydney, NSW, Australia
| | - Ann M Poynten
- Department of Endocrinology, Prince of Wales Hospital, Sydney, NSW, Australia
| | - Ria Arnold
- Department of Exercise Physiology, UNSW Sydney, Sydney, NSW, Australia
| | - Maria Markoulli
- School of Optometry & Vision Science, UNSW Sydney, Sydney, NSW, Australia
| | - Arun V Krishnan
- Prince of Wales Clinical School, UNSW Sydney, Sydney, NSW, Australia
| |
Collapse
|
47
|
Altered sensory nerve excitability in fibromyalgia. J Formos Med Assoc 2021; 120:1611-1619. [PMID: 33642123 DOI: 10.1016/j.jfma.2021.02.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 12/23/2020] [Accepted: 02/02/2021] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND/PURPOSE To investigate nerve excitability changes in patients with fibromyalgia and the correlation with clinical severity. METHODS We enrolled 20 subjects with fibromyalgia and 22 sex and age-matched healthy subjects to receive nerve excitability test and nerve conduction study to evaluate the peripheral axonal function. RESULTS In the fibromyalgia cohort, the sensory axonal excitability test revealed increased superexcitability (%) (P = 0.029) compared to healthy control. Correlational study showed a negative correlation between increased subexcitability (%) (r = -0.534, P = 0.022) with fibromyalgia impact questionnaire (FIQ) score. Computer modeling confirmed that the sensory axon excitability pattern we observed in fibromyalgia cohort was best explained by increased Barrett-Barrett conductance, which was thought to be attributed to paranodal fast K+ channel dysfunction. CONCLUSION The present study revealed that paranodal sensory K+ conductance was altered in patients with fibromyalgia. The altered conductance indicated dysfunction of paranodal fast K+ channels, which is known to be associated with the generation of pain.
Collapse
|
48
|
Mouraux A, Bannister K, Becker S, Finn DP, Pickering G, Pogatzki-Zahn E, Graven-Nielsen T. Challenges and opportunities in translational pain research - An opinion paper of the working group on translational pain research of the European pain federation (EFIC). Eur J Pain 2021; 25:731-756. [PMID: 33625769 PMCID: PMC9290702 DOI: 10.1002/ejp.1730] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
For decades, basic research on the underlying mechanisms of nociception has held promise to translate into efficacious treatments for patients with pain. Despite great improvement in the understanding of pain physiology and pathophysiology, translation to novel, effective treatments for acute and chronic pain has however been limited, and they remain an unmet medical need. In this opinion paper bringing together pain researchers from very different disciplines, the opportunities and challenges of translational pain research are discussed. The many factors that may prevent the successful translation of bench observations into useful and effective clinical applications are reviewed, including interspecies differences, limited validity of currently available preclinical disease models of pain, and limitations of currently used methods to assess nociception and pain in non-human and human models of pain. Many paths are explored to address these issues, including the backward translation of observations made in patients and human volunteers into new disease models that are more clinically relevant, improved generalization by taking into account age and sex differences, and the integration of psychobiology into translational pain research. Finally, it is argued that preclinical and clinical stages of developing new treatments for pain can be improved by better preclinical models of pathological pain conditions alongside revised methods to assess treatment-induced effects on nociception in human and non-human animals. Significance: For decades, basic research of the underlying mechanisms of nociception has held promise to translate into efficacious treatments for patients with pain. Despite great improvement in the understanding of pain physiology and pathophysiology, translation to novel, effective treatments for acute and chronic pain has however been limited, and they remain an unmet medical need.
Collapse
Affiliation(s)
- André Mouraux
- Institute of Neuroscience (IONS), UCLouvain, Brussels, Belgium
| | - Kirsty Bannister
- Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
| | - Susanne Becker
- Department of Cognitive and Clinical Neuroscience, Central Institute of Mental Health, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany.,Integrative Spinal Research, Department of Chiropractic Medicine, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - David P Finn
- Pharmacology and Therapeutics, Centre for Pain Research, School of Medicine, National University of Ireland Galway, Galway, Ireland
| | - Gisèle Pickering
- Department of Clinical Pharmacology, Inserm CIC 1405, University Hospital, CHU Clermont-Ferrand, France.,Fundamental and Clinical Pharmacology of Pain, University Clermont Auvergne, Clermont-Ferrand, France
| | - Esther Pogatzki-Zahn
- Department of Anesthesiology, Critical Care Medicine and Pain Therapy, University Hospital Muenster, Muenster, Germany
| | - Thomas Graven-Nielsen
- Center for Neuroplasticity and Pain (CNAP), Department of Health Science and Technology, Faculty of Medicine, Aalborg University, Aalborg, Denmark
| |
Collapse
|
49
|
Wainger BJ, Macklin EA, Vucic S, McIlduff CE, Paganoni S, Maragakis NJ, Bedlack R, Goyal NA, Rutkove SB, Lange DJ, Rivner MH, Goutman SA, Ladha SS, Mauricio EA, Baloh RH, Simmons Z, Pothier L, Kassis SB, La T, Hall M, Evora A, Klements D, Hurtado A, Pereira JD, Koh J, Celnik PA, Chaudhry V, Gable K, Juel VC, Phielipp N, Marei A, Rosenquist P, Meehan S, Oskarsson B, Lewis RA, Kaur D, Kiskinis E, Woolf CJ, Eggan K, Weiss MD, Berry JD, David WS, Davila-Perez P, Camprodon JA, Pascual-Leone A, Kiernan MC, Shefner JM, Atassi N, Cudkowicz ME. Effect of Ezogabine on Cortical and Spinal Motor Neuron Excitability in Amyotrophic Lateral Sclerosis: A Randomized Clinical Trial. JAMA Neurol 2021; 78:186-196. [PMID: 33226425 DOI: 10.1001/jamaneurol.2020.4300] [Citation(s) in RCA: 83] [Impact Index Per Article: 27.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Importance Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease of the motor nervous system. Clinical studies have demonstrated cortical and spinal motor neuron hyperexcitability using transcranial magnetic stimulation and threshold tracking nerve conduction studies, respectively, although metrics of excitability have not been used as pharmacodynamic biomarkers in multi-site clinical trials. Objective To ascertain whether ezogabine decreases cortical and spinal motor neuron excitability in ALS. Design, Setting, and Participants This double-blind, placebo-controlled phase 2 randomized clinical trial sought consent from eligible participants from November 3, 2015, to November 9, 2017, and was conducted at 12 US sites within the Northeast ALS Consortium. Participants were randomized in equal numbers to a higher or lower dose of ezogabine or to an identical matched placebo, and they completed in-person visits at screening, baseline, week 6, and week 8 for clinical assessment and neurophysiological measurements. Interventions Participants were randomized to receive 600 mg/d or 900 mg/d of ezogabine or a matched placebo for 10 weeks. Main Outcomes and Measures The primary outcome was change in short-interval intracortical inhibition (SICI; SICI-1 was used in analysis to reflect stronger inhibition from an increase in amplitude) from pretreatment mean at screening and baseline to the full-dose treatment mean at weeks 6 and 8. The secondary outcomes included levels of cortical motor neuron excitability (including resting motor threshold) measured by transcranial magnetic stimulation and spinal motor neuron excitability (including strength-duration time constant) measured by threshold tracking nerve conduction studies. Results A total of 65 participants were randomized to placebo (23), 600 mg/d of ezogabine (23), and 900 mg/d of ezogabine (19 participants); 45 were men (69.2%) and the mean (SD) age was 58.3 (8.8) years. The SICI-1 increased by 53% (mean ratio, 1.53; 95% CI, 1.12-2.09; P = .009) in the 900-mg/d ezogabine group vs placebo group. The SICI-1 did not change in the 600-mg/d ezogabine group vs placebo group (mean ratio, 1.15; 95% CI, 0.87-1.52; P = .31). The resting motor threshold increased in the 600-mg/d ezogabine group vs placebo group (mean ratio, 4.61; 95% CI, 0.21-9.01; P = .04) but not in the 900-mg/d ezogabine group vs placebo group (mean ratio, 1.95; 95% CI, -2.64 to 6.54; P = .40). Ezogabine caused a dose-dependent decrease in excitability by several other metrics, including strength-duration time constant in the 900-mg/d ezogabine group vs placebo group (mean ratio, 0.73; 95% CI, 0.60 to 0.87; P < .001). Conclusions and Relevance Ezogabine decreased cortical and spinal motor neuron excitability in participants with ALS, suggesting that such neurophysiological metrics may be used as pharmacodynamic biomarkers in multisite clinical trials. Trial Registration ClinicalTrials.gov Identifier: NCT02450552.
Collapse
Affiliation(s)
- Brian J Wainger
- The Sean M. Healey and AMG Center for ALS and the Neurological Clinical Research Institute, Department of Neurology, Massachusetts General Hospital, Boston.,Department of Anesthesia, Critical Care & Pain Medicine, Massachusetts General Hospital, Boston.,Harvard Medical School, Boston MA.,Harvard Stem Cell Institute, Cambridge.,Broad Institute of MIT and Harvard, Cambridge
| | - Eric A Macklin
- Harvard Medical School, Boston MA.,Biostatistics Center, Massachusetts General Hospital, Boston, Massachusetts
| | - Steve Vucic
- Department of Neurology, Westmead Hospital, Westmead, New South Wales, Australia
| | - Courtney E McIlduff
- Harvard Medical School, Boston MA.,Department of Neurology, Beth Israel Deaconess Medical Center, Boston, Massachusetts
| | - Sabrina Paganoni
- The Sean M. Healey and AMG Center for ALS and the Neurological Clinical Research Institute, Department of Neurology, Massachusetts General Hospital, Boston.,Harvard Medical School, Boston MA.,Department of Physical Medicine and Rehabilitation, Spaulding Rehabilitation Hospital, Boston, Massachusetts
| | | | - Richard Bedlack
- Department of Neurology, Duke University Medical Center, Durham, North Carolina
| | - Namita A Goyal
- Department of Neurology, University of California Irvine, Irvine
| | - Seward B Rutkove
- Harvard Medical School, Boston MA.,Department of Neurology, Beth Israel Deaconess Medical Center, Boston, Massachusetts
| | - Dale J Lange
- Department of Neurology, Hospital for Special Surgery, New York, New York
| | - Michael H Rivner
- Department of Neurology, Augusta University Medical Center, Augusta, Georgia
| | | | - Shafeeq S Ladha
- Department of Neurology, Barrow Neurological Institute, Phoenix, Arizona
| | | | - Robert H Baloh
- Department of Neurology, Cedars Sinai Medical Center, Los Angeles, California
| | - Zachary Simmons
- Department of Neurology, Penn State Hershey Medical Center, Hershey, Pennsylvania
| | - Lindsay Pothier
- The Sean M. Healey and AMG Center for ALS and the Neurological Clinical Research Institute, Department of Neurology, Massachusetts General Hospital, Boston
| | - Sylvia Baedorf Kassis
- The Sean M. Healey and AMG Center for ALS and the Neurological Clinical Research Institute, Department of Neurology, Massachusetts General Hospital, Boston
| | - Thuong La
- The Sean M. Healey and AMG Center for ALS and the Neurological Clinical Research Institute, Department of Neurology, Massachusetts General Hospital, Boston
| | - Meghan Hall
- Department of Neurology, Barrow Neurological Institute, Phoenix, Arizona
| | - Armineuza Evora
- The Sean M. Healey and AMG Center for ALS and the Neurological Clinical Research Institute, Department of Neurology, Massachusetts General Hospital, Boston
| | - David Klements
- The Sean M. Healey and AMG Center for ALS and the Neurological Clinical Research Institute, Department of Neurology, Massachusetts General Hospital, Boston
| | - Aura Hurtado
- Harvard Medical School, Boston MA.,Department of Psychiatry, Massachusetts General Hospital, Boston
| | - Joao D Pereira
- The Sean M. Healey and AMG Center for ALS and the Neurological Clinical Research Institute, Department of Neurology, Massachusetts General Hospital, Boston.,Harvard Medical School, Boston MA
| | - Joan Koh
- The Sean M. Healey and AMG Center for ALS and the Neurological Clinical Research Institute, Department of Neurology, Massachusetts General Hospital, Boston
| | - Pablo A Celnik
- Department of Neurology, Johns Hopkins University, Baltimore, Maryland
| | - Vinay Chaudhry
- Department of Neurology, Johns Hopkins University, Baltimore, Maryland
| | - Karissa Gable
- Department of Neurology, Duke University Medical Center, Durham, North Carolina
| | - Vern C Juel
- Department of Neurology, Duke University Medical Center, Durham, North Carolina
| | - Nicolas Phielipp
- Department of Neurology, University of California Irvine, Irvine
| | - Adel Marei
- Department of Neurology, Hospital for Special Surgery, New York, New York
| | - Peter Rosenquist
- Department of Psychiatry, Augusta University Medical Center, Augusta, Georgia
| | - Sean Meehan
- School of Kinesiology, University of Michigan, Ann Arbor
| | | | - Richard A Lewis
- Department of Neurology, Cedars Sinai Medical Center, Los Angeles, California
| | - Divpreet Kaur
- Department of Neurology, Penn State Hershey Medical Center, Hershey, Pennsylvania
| | | | - Clifford J Woolf
- Harvard Medical School, Boston MA.,Department of Neurology, Boston Children's Hospital, Boston, Massachusetts
| | - Kevin Eggan
- The Sean M. Healey and AMG Center for ALS and the Neurological Clinical Research Institute, Department of Neurology, Massachusetts General Hospital, Boston.,Harvard Medical School, Boston MA.,Harvard Stem Cell Institute, Cambridge.,Broad Institute of MIT and Harvard, Cambridge.,Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, Massachusetts
| | | | - James D Berry
- The Sean M. Healey and AMG Center for ALS and the Neurological Clinical Research Institute, Department of Neurology, Massachusetts General Hospital, Boston.,Harvard Medical School, Boston MA
| | - William S David
- The Sean M. Healey and AMG Center for ALS and the Neurological Clinical Research Institute, Department of Neurology, Massachusetts General Hospital, Boston.,Harvard Medical School, Boston MA
| | - Paula Davila-Perez
- Harvard Medical School, Boston MA.,Department of Neurology, Beth Israel Deaconess Medical Center, Boston, Massachusetts
| | - Joan A Camprodon
- The Sean M. Healey and AMG Center for ALS and the Neurological Clinical Research Institute, Department of Neurology, Massachusetts General Hospital, Boston.,Harvard Medical School, Boston MA.,Department of Psychiatry, Massachusetts General Hospital, Boston
| | - Alvaro Pascual-Leone
- Harvard Medical School, Boston MA.,Marcus Institute and Center for Memory Health, Hebrew SeniorLife, Boston, Massachusetts.,Institut Guttmann, Universitat Autonoma, Barcelona, Spain
| | - Matthew C Kiernan
- Brain and Mind Centre, University of Sydney, Sydney, New South Wales, Australia.,Department of Neurology, Royal Prince Alfred Hospital, Sydney, New South Wales, Australia
| | - Jeremy M Shefner
- Department of Neurology, Barrow Neurological Institute, Phoenix, Arizona
| | - Nazem Atassi
- The Sean M. Healey and AMG Center for ALS and the Neurological Clinical Research Institute, Department of Neurology, Massachusetts General Hospital, Boston.,Harvard Medical School, Boston MA
| | - Merit E Cudkowicz
- The Sean M. Healey and AMG Center for ALS and the Neurological Clinical Research Institute, Department of Neurology, Massachusetts General Hospital, Boston.,Harvard Medical School, Boston MA
| |
Collapse
|
50
|
Turan Z, Zinnuroğlu M. Peripheral axonal excitability in hemiplegia related to subacute stroke. Turk J Med Sci 2020; 50:1983-1992. [PMID: 32682362 PMCID: PMC7775702 DOI: 10.3906/sag-2004-306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2020] [Accepted: 07/18/2020] [Indexed: 11/07/2022] Open
Abstract
Background/aim This study aims to investigate peripheral nerve excitability in patients with subacute stroke. Materials and methods The study was performed in 29 stroke patients within the subacute period and 29 healthy controls using QTRAC software and TRONDNF protocol. The threshold electrotonus, recovery cycle, stimulus-response, strength-duration, and current-threshold relationships were recorded. Results The membrane was more hyperpolarized, and excitability was decreased in the hemiplegic side. The impairment of inward rectifying channel function, degree of hyperpolarization, and decrease of excitability were directly related to the Brunnstrom stages, which were more pronounced in lower stages. Conclusion The lower motor neurons were affected at the level of axonal channels as a result of upper motor neuron lesions. It can be due to dying back neuropathy, homeostasis, and neurovascular regulation changes in the axonal environment, activity-dependent plastic changes, loss of drive coming from the central nervous system, or a combination of these factors.
Collapse
Affiliation(s)
- Zeynep Turan
- Department of Physical Medicine and Rehabilitation, Koç University Hospital, İstanbul, Turkey
| | - Murat Zinnuroğlu
- Department of Physical Medicine and Rehabilitation, Faculty of Medicine, Gazi University, Ankara, Turkey
| |
Collapse
|