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Júlio SU, Schneuwly M, Scheuren PS, Pfender N, Zipser CM, Hubli M, Schubert M. Intra-epidermal electrically evoked potentials are sensitive to detect degenerative cervical myelopathy suggesting their spinothalamic propagation. Clin Neurophysiol 2024; 167:229-238. [PMID: 39368346 DOI: 10.1016/j.clinph.2024.09.015] [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: 04/09/2024] [Revised: 09/03/2024] [Accepted: 09/07/2024] [Indexed: 10/07/2024]
Abstract
OBJECTIVE Degenerative cervical myelopathy (DCM) is a centromedullary spinal cord disorder mainly affecting crossing fibers. While contact heat evoked potentials (CHEPs) are sensitive in detecting DCM by testing spinothalamic integrity, somatosensory evoked potentials (dSSEPs) show unaffected dorsal column conduction. Intra-epidermal electrically evoked potentials (IEEPs) have unknown spinal propagation after noxious stimulation. We investigated (1) the spinothalamic tract propagation and (2) the discriminative power in detecting spinal pathology of IEEPs compared to CHEPs and dSSEPs in DCM. METHODS DCM was diagnosed by neurological examination regarding stenosis (MRI). Stimulation of C6, C8, and T4 dermatomes yielded dSSEPs, CHEPs, and IEEPs. (1) Spinal propagation was assessed through concordant or discordant responses, and (2) discriminative power was determined using receiver operating characteristic curves (ROC). RESULTS Twenty-seven patients (8F, 56 ± 12yrs) with DCM were analyzed and compared to age-matched healthy controls. IEEPs were abnormal in 43-54%, CHEPs in 37-69%, and dSSEPs in 4-12%. IEEPs showed high concordance with abnormalities of CHEPs (62-69%). ROC analyses showed good discriminative power of CHEPs and IEEPs contrary to dSSEPs. CONCLUSIONS The concordance of abnormal responses of CHEPs and IEEPs contrary to dSSEPs suggests spinothalamic propagation of IEEPs. SIGNIFICANCE Minimal differences between CHEPs and IEEPs suggest complementary potential by the combined testing of spinothalamic tract integrity.
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Affiliation(s)
- Sara U Júlio
- Spinal Cord Injury Center, Balgrist University Hospital, University of Zurich, Zurich, Switzerland.
| | - Miriam Schneuwly
- Spinal Cord Injury Center, Balgrist University Hospital, University of Zurich, Zurich, Switzerland.
| | - Paulina S Scheuren
- Spinal Cord Injury Center, Balgrist University Hospital, University of Zurich, Zurich, Switzerland; Department of Neurology, University Hospital Bern, Inselspital, University of Bern, Bern, Switzerland; International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, BC, Canada.
| | - Nikolai Pfender
- Spinal Cord Injury Center, Balgrist University Hospital, University of Zurich, Zurich, Switzerland.
| | - Carl M Zipser
- Spinal Cord Injury Center, Balgrist University Hospital, University of Zurich, Zurich, Switzerland.
| | - Michèle Hubli
- Spinal Cord Injury Center, Balgrist University Hospital, University of Zurich, Zurich, Switzerland.
| | - Martin Schubert
- Spinal Cord Injury Center, Balgrist University Hospital, University of Zurich, Zurich, Switzerland.
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Jiang Z, Davies B, Zipser C, Margetis K, Martin A, Matsoukas S, Zipser-Mohammadzada F, Kheram N, Boraschi A, Zakin E, Obadaseraye OR, Fehlings MG, Wilson J, Yurac R, Cook CE, Milligan J, Tabrah J, Widdop S, Wood L, Roberts EA, Rujeedawa T, Tetreault L. The value of Clinical signs in the diagnosis of Degenerative Cervical Myelopathy - A Systematic review and Meta-analysis. Global Spine J 2024; 14:1369-1394. [PMID: 37903098 PMCID: PMC11289551 DOI: 10.1177/21925682231209869] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/01/2023] Open
Abstract
STUDY DESIGN Delayed diagnosis of degenerative cervical myelopathy (DCM) is likely due to a combination of its subtle symptoms, incomplete neurological assessments by clinicians and a lack of public and professional awareness. Diagnostic criteria for DCM will likely facilitate earlier referral for definitive management. OBJECTIVES This systematic review aims to determine (i) the diagnostic accuracy of various clinical signs and (ii) the association between clinical signs and disease severity in DCM? METHODS A search was performed to identify studies on adult patients that evaluated the diagnostic accuracy of a clinical sign used for diagnosing DCM. Studies were also included if they assessed the association between the presence of a clinical sign and disease severity. The QUADAS-2 tool was used to evaluate the risk of bias of individual studies. RESULTS This review identified eleven studies that used a control group to evaluate the diagnostic accuracy of various signs. An additional 61 articles reported on the frequency of clinical signs in a cohort of DCM patients. The most sensitive clinical tests for diagnosing DCM were the Tromner and hyperreflexia, whereas the most specific tests were the Babinski, Tromner, clonus and inverted supinator sign. Five studies evaluated the association between the presence of various clinical signs and disease severity. There was no definite association between Hoffmann sign, Babinski sign or hyperreflexia and disease severity. CONCLUSION The presence of clinical signs suggesting spinal cord compression should encourage health care professionals to pursue further investigation, such as neuroimaging to either confirm or refute a diagnosis of DCM.
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Affiliation(s)
- Zhilin Jiang
- King’s College Hospital, NHS Foundation Trust, London, UK
| | | | - Carl Zipser
- Spinal Cord Injury Center, Balgrist University Hospital, Zurich, Switzerland
| | | | - Allan Martin
- Department of Neurosurgery, University of California Davis, Sacramento, CA, USA
| | - Stavros Matsoukas
- Department of Neurosurgery, Icahn School of Medicine at Mount Sinai, New York, NY
| | | | - Najmeh Kheram
- Spinal Cord Injury Center, Balgrist University Hospital, Zurich, Switzerland
- The Interface Group, Institute of Physiology, University of Zurich, Zurich, Switzerland
| | - Andrea Boraschi
- The Interface Group, Institute of Physiology, University of Zurich, Zurich, Switzerland
| | - Elina Zakin
- New York University Langone, Department of Neurology, New York, NY, USA
| | | | - Michael G. Fehlings
- University of Toronto Division of Neurosurgery and Spinal Program, Toronto, ON, Canada
| | - Jamie Wilson
- University of Nebraska Medical Center, Omaha, NE, USA
| | - Ratko Yurac
- University del Desarrollo, Clinica Alemana de Santiago, Chile
| | | | - Jamie Milligan
- Department of Family Medicine, McMaster University, Hamilton, ON, USA
| | - Julia Tabrah
- Hounslow and Richmond Community Healthcare, Teddington, UK
| | | | - Lianne Wood
- Nottingham University Hospital, Nottingham, UK
| | | | | | - Lindsay Tetreault
- New York University Langone, Department of Neurology, New York, NY, USA
| | - AO Spine RECODE-DCM Diagnostic Criteria Incubator
- King’s College Hospital, NHS Foundation Trust, London, UK
- University of Cambridge, Cambridge, UK
- Spinal Cord Injury Center, Balgrist University Hospital, Zurich, Switzerland
- Department of Neurosurgery, Icahn School of Medicine at Mount Sinai, New York, NY
- Department of Neurosurgery, University of California Davis, Sacramento, CA, USA
- The Interface Group, Institute of Physiology, University of Zurich, Zurich, Switzerland
- New York University Langone, Department of Neurology, New York, NY, USA
- Department of Surgery, Asaba Specialist Hospital, Asaba, Nigeria
- University of Toronto Division of Neurosurgery and Spinal Program, Toronto, ON, Canada
- University of Nebraska Medical Center, Omaha, NE, USA
- University del Desarrollo, Clinica Alemana de Santiago, Chile
- Duke University Medical Center, Durham, NC
- Department of Family Medicine, McMaster University, Hamilton, ON, USA
- Hounslow and Richmond Community Healthcare, Teddington, UK
- Myelopathy.org, Cambridge, UK
- Nottingham University Hospital, Nottingham, UK
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3
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Cunha NSC, Grippe T, Boechat-Barros R, Fernandez RNM, Brandão PRP, Chen R, Cardoso F. Evaluation of the Cutaneous Silent Period in a Healthy Brazilian Population. J Clin Neurophysiol 2023; 40:541-546. [PMID: 35349508 DOI: 10.1097/wnp.0000000000000921] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
PURPOSE To establish cutaneous silent period (CSP) normative values and investigate the variables that may influence them. METHODS We tested 41 healthy subjects. All subjects underwent nerve conduction studies, and we evaluated the CSP in both arms. RESULTS Four subjects did not have CSP and were excluded. The analyses were performed in the healthy group composed of 23 women and 14 men, with a mean age of 35 (range, 19-64) years. The CSP median duration was 23.2 milliseconds (ms), with 2 to 98th percentile at 11.3 and 48.7 ms. The median onset latency was 87.9 (range, 72.9-109) ms, and the median end latency was 112 (range, 93.8-138) ms. The CSP onset latency positively correlated with height, whereas CSP end latency and duration were weakly but significantly associated with age. Some measurements of ulnar nerve conduction study also correlated with CSP measures. The interrater coefficients for the primary measures of onset and end latency demonstrates the reproducibility of the method. CONCLUSIONS The CSP with the fifth digit stimulation and recording from the abductor digiti minimi muscle is a valid diagnostic tool that can be used in clinical practice.
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Affiliation(s)
- Natalia S C Cunha
- Department of Medical Sciences, Universidade de Brasília Brasília, Brazil
- Department of Child Neurology, Hospital da Criança de Brasília José de Alencar Brasília, Brazil
| | - Talyta Grippe
- Department of Neurophysiology, Instituto Hospital de Base do Distrito Federal Brasília, Brazil
- Krembil Research Institute, Toronto, Canada
- Movement Disorders Unit, Internal Medicine Department, Universidade Federal de Minas Gerais Belo Horizonte, Brazil
| | | | - Rubens N M Fernandez
- Department of Child Neurology, Hospital da Criança de Brasília José de Alencar Brasília, Brazil
- Department of Neurophysiology, Instituto Hospital de Base do Distrito Federal Brasília, Brazil
| | - Pedro Renato P Brandão
- Neuroscience and Behavior Lab, Universidade de Brasília Brasilia, Brazil; and
- Neurology Unit, Hospital Sírio-Libanês Brasilia, Brazil
| | | | - Francisco Cardoso
- Movement Disorders Unit, Internal Medicine Department, Universidade Federal de Minas Gerais Belo Horizonte, Brazil
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Jawad ZY, Hamdan FB, Nema IS. Neurophysiologic evaluation of patients with cervical spondylotic myelopathy. THE EGYPTIAN JOURNAL OF NEUROLOGY, PSYCHIATRY AND NEUROSURGERY 2022. [DOI: 10.1186/s41983-022-00595-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Abstract
Background
Cervical spondylotic myelopathy (CSM) is a neurodegenerative disease caused by repetitive spinal cord damage that has resulted in significant clinical morbidity. The clinical evaluation of signs and symptoms, as well as neuroimaging and several neurophysiological tests, are used to make the diagnosis.
Objectives
To investigate changes in the cutaneous silent period (CuSP), cortical silent period (CoSP), and H-reflex in CSM patients, and to correlate these tests with the Japanese Orthopedic Association (JOA) score and Nurick’s grading, as well as to determine the diagnostic value of each of them.
Methods
Twenty patients (14 males and 6 females) with CSM were clinically diagnosed and documented by magnetic resonance imaging (MRI), and they were paired with another 20 healthy volunteers (13 males and 7 females) as a control group. CuSP, CoSP, and H-reflex tests were performed on both groups.
Results
In CSM patients, CuSP latency and duration are substantially longer and shorter in CSM patients, respectively. The degree of changes in CuSP latency is well correlated with the severity of the disease. Further, CoSP duration is significantly shortened. The H-reflex parameters did not differ significantly between the patient and control groups.
Conclusion
The shortened CoSP’s duration and the prolonged CuSP's latency suggest malfunction of the inhibitory and excitatory circuits in the spinal cord. The CuSP is more sensitive and specific than the CoSP in the diagnosis of a patient with CSM.
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Yu Z, Pan W, Chen J, Peng X, Ling Z, Zou X. Application of electrophysiological measures in degenerative cervical myelopathy. Front Cell Dev Biol 2022; 10:834668. [PMID: 36016659 PMCID: PMC9395596 DOI: 10.3389/fcell.2022.834668] [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: 12/13/2021] [Accepted: 07/06/2022] [Indexed: 11/13/2022] Open
Abstract
Degenerative cervical myelopathy (DCM) is one of the leading causes of progressive spinal cord dysfunction in the elderly. Early diagnosis and treatment of DCM are essential to avoid permanent disability. The pathophysiology of DCM includes chronic ischemia, destruction of the blood–spinal cord barrier, demyelination, and neuronal apoptosis. Electrophysiological studies including electromyography (EMG), nerve conduction study (NCS), motor evoked potentials (MEPs) and somatosensory evoked potentials (SEPs) are useful in detecting the presymptomatic pathological changes of the spinal cord, and thus supplementing the early clinical and radiographic examinations in the management of DCM. Preoperatively, they are helpful in detecting DCM and ruling out other diseases, assessing the spinal cord compression level and severity, predicting short- and long-term prognosis, and thus deciding the treatment methods. Intra- and postoperatively, they are also useful in monitoring neurological function change during surgeries and disease progression during follow-up rehabilitation. Here, we reviewed articles from 1979 to 2021, and tried to provide a comprehensive, evidence-based review of electrophysiological examinations in DCM. With this review, we aim to equip spinal surgeons with the basic knowledge to diagnosis and treat DCM using ancillary electrophysiological tests.
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Affiliation(s)
- Zhengran Yu
- Guangdong Provincial Key Laboratory of Orthopaedics and Traumatology, Department of Spine Surgery, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
- Department of Spine Surgery, Orthopedics Center of Guangdong Provincial People’s Hospital and Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Wenxu Pan
- Department of Gastroenterology, Guangzhou Women and Children’s Medical Center, Jinan University, Guangzhou, China
| | - Jiacheng Chen
- Guangdong Provincial Key Laboratory of Orthopaedics and Traumatology, Department of Spine Surgery, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - Xinsheng Peng
- Guangdong Provincial Key Laboratory of Orthopaedics and Traumatology, Department of Spine Surgery, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - Zemin Ling
- Guangdong Provincial Key Laboratory of Orthopaedics and Traumatology, Department of Spine Surgery, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
- *Correspondence: Zemin Ling, ; Xuenong Zou, ,
| | - Xuenong Zou
- Guangdong Provincial Key Laboratory of Orthopaedics and Traumatology, Department of Spine Surgery, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
- *Correspondence: Zemin Ling, ; Xuenong Zou, ,
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Discrepancy between functional recovery and cutaneous silent period change in surgically treated degenerative cervical myelopathy: a prospective pilot study. Spinal Cord 2019; 57:1076-1083. [DOI: 10.1038/s41393-019-0314-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2019] [Revised: 06/03/2019] [Accepted: 06/04/2019] [Indexed: 02/05/2023]
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Kofler M, Leis A, Valls-Solé J. Cutaneous silent periods – Part 1: Update on physiological mechanisms. Clin Neurophysiol 2019; 130:588-603. [DOI: 10.1016/j.clinph.2019.01.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Revised: 12/28/2018] [Accepted: 01/08/2019] [Indexed: 12/14/2022]
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Cutaneous silent periods – Part 2: Update on pathophysiology and clinical utility. Clin Neurophysiol 2019; 130:604-615. [DOI: 10.1016/j.clinph.2019.01.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Revised: 12/28/2018] [Accepted: 01/08/2019] [Indexed: 02/08/2023]
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Vasko P, Bocek V, Mencl L, Haninec P, Stetkarova I. Preserved cutaneous silent period in cervical root avulsion. J Spinal Cord Med 2017; 40:175-180. [PMID: 26312387 PMCID: PMC5430474 DOI: 10.1179/2045772315y.0000000053] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
OBJECTIVE Brachial plexus injuries are usually severe and involve the entire brachial plexus, sometimes occurring with root avulsions. Imaging and electrodiagnostic studies are an essential part of the lesion evaluation; however, the results sometimes show a discrepancy. The cutaneous silent period (SP) is a spinal inhibitory reflex mediated by small-diameter A-delta nociceptive fibers. The aim of the study was to determine if cutaneous SP testing may serve as a useful aid in evaluation of brachial plexus injury and/or in the diagnosis of root avulsion. METHODS In 19 patients with traumatic brachial plexus injury (15 males, age 18-62 years) we performed a clinical examination, CT myelography and neurophysiological testing. A needle EMG was obtained from muscles supplied by C5-T1 myotomes. Cutaneous SP was recorded after painful stimuli were delivered to the thumb (C6 dermatome), middle (C7) and little (C8) fingers while subjects maintained voluntary contraction of intrinsic hand muscles. RESULTS Electrodiagnostic and imaging studies confirmed root avulsion (partial or total) maximally involving C5, C6 roots in 12 patients, whereas only in 4 of them the cutaneous SP was partially absent. In the remaining subjects, the cutaneous SP was preserved. CONCLUSION In brachial plexopathy even with plurisegmental root avulsion, the cutaneous SP was mostly preserved. This method cannot be recommended as a reliable test for diagnosis of single root avulsion; however, it can provide a quick physiological confirmation of functional afferent A-delta fibers through damaged roots and/or trunks. The clinicians may add this test to the diagnosis of spinal cord dysfunction.
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Affiliation(s)
- Peter Vasko
- Department of Neurology, Third Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Vaclav Bocek
- Department of Neurology, Third Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Libor Mencl
- Department of Neurosurgery, Third Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Pavel Haninec
- Department of Neurosurgery, Third Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Ivana Stetkarova
- Department of Neurology, Third Faculty of Medicine, Charles University, Prague, Czech Republic,Correspondence to: Ivana Stetkarova, Head of Department of Neurology, Third Faculty of Medicine, Charles University of Prague, Ruska 87, Prague 10, Czech Republic, 100 00.
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The contribution of neurophysiology in the diagnosis and management of cervical spondylotic myelopathy: a review. Spinal Cord 2016; 54:756-766. [PMID: 27241448 DOI: 10.1038/sc.2016.82] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Revised: 03/24/2016] [Accepted: 04/06/2016] [Indexed: 12/11/2022]
Abstract
STUDY DESIGN Topical review of the literature. OBJECTIVE The objective of this review article was to assess indications and usefulness of various neurophysiological techniques in diagnosis and management of cervical spondylogenic myelopathy (CSM). METHODS The MEDLINE, accessed by Pubmed and EMBASE electronic databases, was searched using the medical subject headings: 'compressive myelopathy', 'cervical spondylotic myelopathy (CSM)', 'cervical spondylogenic myelopathy', 'motor evoked potentials (MEPs)', 'transcranial magnetic stimulation', 'somatosensory evoked potentials (SEPs)', 'electromyography (EMG)', 'nerve conduction studies (NCS)' and 'cutaneous silent period (CSP)'. RESULTS SEPs and MEPs recording can usefully supplement clinical examination and neuroimaging findings in assessing the spinal cord injury level and severity. Segmental cervical cord dysfunction can be revealed by an abnormal spinal N13 response, whereas the P14 potential is a reliable marker of dorsal column impairment. MEPs may also help in the differential diagnosis between spinal cord compression and neurodegenerative disorders. SEPs and MEPs are also useful in follow-up evaluation of sensory and motor function during surgical treatment and rehabilitation. EMG and NCS improve the sensitivity of cervical radiculopathy detection and may help rule out peripheral nerve problems that can cause symptoms that are similar to those of CSM. CSP also shows a high sensitivity for detecting CSM. CONCLUSION Neuroimaging, especially magnetic resonance imaging, represents the procedure of choice for the diagnosis of CSM, but a correct interpretation of morphological findings can be achieved only if they are correlated with functional data. The studies reported in this review highlight the crucial role of the electrophysiological studies in diagnosis and management of CSM.
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Ulrich A, Min K, Curt A. High sensitivity of contact-heat evoked potentials in “snake-eye” appearance myelopathy. Clin Neurophysiol 2015; 126:1994-2003. [DOI: 10.1016/j.clinph.2014.12.020] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2013] [Revised: 11/30/2014] [Accepted: 12/10/2014] [Indexed: 12/12/2022]
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Leis AA, Kofler M, Stetkarova I, Stokic DS. The cutaneous silent period is preserved in cervical radiculopathy: significance for the diagnosis of cervical myelopathy. EUROPEAN SPINE JOURNAL : OFFICIAL PUBLICATION OF THE EUROPEAN SPINE SOCIETY, THE EUROPEAN SPINAL DEFORMITY SOCIETY, AND THE EUROPEAN SECTION OF THE CERVICAL SPINE RESEARCH SOCIETY 2010; 20:236-9. [PMID: 21132557 DOI: 10.1007/s00586-010-1627-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2010] [Revised: 09/01/2010] [Accepted: 11/07/2010] [Indexed: 10/18/2022]
Abstract
Electromyographic (EMG) activity from voluntarily contracting hand muscles undergoes transient suppression following nociceptive fingertip stimulation. This suppression is mediated by a spinal inhibitory reflex designated the cutaneous silent period (CSP). The CSP is abolished or altered in a variety of myelopathic conditions. However, before the CSP can gain acceptance as an aid in the diagnosis of myelopathy, the contribution of non-myelopathic conditions that can interrupt the afferent pathways responsible for the CSP needs to be considered. Accordingly, we examined the effect of radiculopathy on the CSP. Nociceptive stimulation was applied to thumb (C6 dermatome), middle (C7) and little (C8) fingers of 23 patients with cervical radiculopathy. Four or more CSP responses were recorded in abductor pollicis brevis muscle following digital stimulation. The patients had C6 (n = 10), C7 (n = 7), or C8 (n = 6) radiculopathy documented by EMG. A complete CSP was elicited in 21 of 23 patients with comparable latencies and durations irrespective of digit stimulated. We conclude that the CSP is preserved in radiculopathy, probably because afferent impulses are carried by smaller, slower conducting 'injury-resistant' A-delta fibers. These results provide important missing evidence that ensures specificity of CSP alterations in the diagnosis of cervical myelopathy. The finding that the CSP is spared in radiculopathy should open the door for investigators and clinicians to adopt this simple spinal inhibitory reflex as a physiologic aid in the diagnosis of spinal cord dysfunction.
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Affiliation(s)
- A Arturo Leis
- Center for Neuroscience and Neurological Recovery, Methodist Rehabilitation Center, Jackson, MS 39216, USA.
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Abstract
STUDY DESIGN Clinical, neuroradiologic, and neurophysiologic description of 21 patients with compressive cervical spondylotic myelopathy (CCSM). OBJECTIVE To describe the utility of cutaneous silent periods (CSPs) for functional evaluation of mild CCSM. SUMMARY OF BACKGROUND DATA Electroneurography, electromyography, and somatosensory and motor evoked potentials (SEPs, MEPs) are routinely used for comprehensive functional neurophysiological evaluation of CCSM. CSPs have been reported in various intramedullary spinal cord lesions, however, they have not been systematically studied in mild CCSM. METHODS We investigated 21 patients with multilevel CCSM as documented by magnetic resonance imaging. We recorded CSPs in thenar muscles after noxious digit II stimulation and compared them with median and tibial nerve SEPs and MEPs obtained from abductor digiti minimi and tibialis anterior muscles. Electroneurography and electromyography were obtained in affected myotomes. RESULTS CSP onset and end latencies were delayed, and CSP duration was shortened, in CCSM patients. CSP abnormalities were present in 17 patients of whom all, but 1 presented with intramedullary magnetic resonance imaging hyperintensity. All 11 limbs affected by hypalgesia and thermhypesthesia had abnormal CSPs, whereas no spinothalamic deficit was noted in any limb with normal CSPs. CSP onset latency was inversely correlated with JOA score and N13 amplitude, and was positively correlated with central motor conduction time to abductor digiti minimi. CSP duration was inversely correlated with central motor conduction time to tibialis anterior. Electromyographic abnormalities were found in 7 patients. CONCLUSION We confirm the value of neurophysiological evaluation of CCSM. MEPs were more frequently abnormal than SEPs. CSP abnormalities were almost equally sensitive as upper limb MEPs, and were highly associated with spinothalamic dysfunction. The high correlation of CSP abnormalities with corticospinal tract dysfunction suggests supraspinal influence on CSPs. Our findings corroborate the utility of CSP testing in the comprehensive assessment of intramedullary spinal cord dysfunction in CCSM.
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14
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Sensory modulation of voluntary and TMS-induced activation in hand muscles. Exp Brain Res 2008; 188:399-409. [DOI: 10.1007/s00221-008-1372-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2007] [Accepted: 04/02/2008] [Indexed: 11/26/2022]
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15
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Lo YL, Tan YE, Fook-Chong S, Boolsambatra P, Yue WM, Chan LL, Tan SB. Role of Spinal Inhibitory Mechanisms in Whiplash Injuries. J Neurotrauma 2007; 24:1055-67. [PMID: 17600520 DOI: 10.1089/neu.2006.0222] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Whiplash injury, commonly encountered in road traffic accidents, is a major cause of morbidity. Its pathophysiology is not well understood, and diagnosis remains clinical. Imaging and electrophysiological methods have not provided objective diagnostic evidence. Availability of a sensitive and specific diagnostic method would be of high clinical interest. We studied 20 consecutive patients with chronic whiplash injury. Despite persistent symptoms, most had minimal neurological findings. Cutaneous silent period (CSP), a nociceptive spinal inhibitory electromyographic reflex, showed 90% sensitivity and 90% specificity for its diagnosis. In contrast, only two patients (10%) had abnormal transcranial magnetic stimulation findings, and another two (10%) showed abnormal electromyography. Magnetic resonance imaging (MRI) showed cervical cord abnormalities in only two of 20 (10%) patients. None of the patients had abnormal somatosensory evoked potential studies. Our findings suggest that neurological dysfunction of whiplash may occur at several possible spinal cord localities in the CSP functional pathway. The use of this simple, quick, and sensitive method is advocated in the diagnostic work up of whiplash injury.
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Affiliation(s)
- Yew-Long Lo
- Department of Neurology, National Neuroscience Institute, Singapore General Hospital, Singapore.
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