1
|
De Schoenmacker I, Costa Marques D, Scheuren PS, Lütolf R, Gorrell LM, Mehli SC, Curt A, Rosner J, Hubli M. Novel neurophysiological evidence for preserved pain habituation across chronic pain conditions. Clin Neurophysiol 2024; 166:31-42. [PMID: 39094528 DOI: 10.1016/j.clinph.2024.07.007] [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: 09/01/2023] [Revised: 03/26/2024] [Accepted: 07/16/2024] [Indexed: 08/04/2024]
Abstract
OBJECTIVE The present study aimed to investigate whether subjective and objective measures of pain habituation can be used as potential markers for central sensitization across various chronic pain patients. METHODS Two blocks of contact-heat stimuli were applied to a non-painful area in 93 chronic pain patients (low back pain, neuropathic pain, and complex regional pain syndrome) and 60 healthy controls (HC). Habituation of pain ratings, contact-heat evoked potentials (CHEP), and sympathetic skin responses (SSR) was measured. RESULTS There was no significant difference in any measure of pain habituation between patients and HC. Even patients with apparent clinical signs of central sensitization showed no reduced pain habituation. However, prolonged baseline CHEP and SSR latencies (stimulation block 1) were found in patients compared to HC (CHEP: Δ-latency = 23 ms, p = 0.012; SSR: Δ-latency = 100 ms, p = 0.022). CONCLUSION Given the performed multimodal neurophysiological testing protocol, we provide evidence indicating that pain habituation may be preserved in patients with chronic pain and thereby be of limited use as a sensitive marker for central sensitization. These results are discussed within the framework of the complex interactions between pro- and antinociceptive mechanism as well as methodological issues. The prolonged latencies of CHEP and SSR after stimulation in non-painful areas may indicate subclinical changes in the integrity of thermo-nociceptive afferents, or a shift towards antinociceptive activity. This shift could potentially affect the relay of ascending signals. SIGNIFICANCE Our findings challenge the prevailing views in the literature and may encourage further investigations into the peripheral and central components of pain habituation, using advanced multimodal neurophysiological techniques.
Collapse
Affiliation(s)
- Iara De Schoenmacker
- Spinal Cord Injury Center, Balgrist University Hospital, University of Zurich, Zurich, Switzerland; Neuroscience Center Zurich, University of Zurich, Zurich, Switzerland.
| | - David Costa Marques
- 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 (ICORD), University of British Columbia, Vancouver, BC, Canada
| | - Robin Lütolf
- Spinal Cord Injury Center, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Lindsay M Gorrell
- Integrative Spinal Research Group, Department of Chiropractic Medicine, Balgrist University Hospital, University of Zurich, Switzerland
| | - Sarah C Mehli
- Spinal Cord Injury Center, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Armin Curt
- Spinal Cord Injury Center, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Jan Rosner
- Spinal Cord Injury Center, Balgrist University Hospital, University of Zurich, Zurich, Switzerland; Department of Neurology, University Hospital Bern, Inselspital, University of Bern, Bern, Switzerland; Danish Pain Research Center, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Michèle Hubli
- Spinal Cord Injury Center, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| |
Collapse
|
2
|
Dimitrova A, Harrington A, Memmott T, Sisley J, Oken B. Acupuncture-Induced Changes in Nociception, Measured by Pain-Related Evoked Potentials: A Pilot Mechanistic Study. JOURNAL OF INTEGRATIVE AND COMPLEMENTARY MEDICINE 2022; 28:862-869. [PMID: 35895503 PMCID: PMC9700342 DOI: 10.1089/jicm.2021.0369] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Objective: The nociceptive system has been implicated in acupuncture analgesia, although acupuncture's precise mechanism of action remains unknown. Electric pain-related evoked potentials (PREPs) have emerged as an effective and reliable electrophysiologic method for evaluation of the human nociceptive system by electric stimulation of nociceptive Aδ and C fibers. This pilot mechanistic study aims to assess the feasibility of using advanced PREP techniques together with electroacupuncture and to use PREPs to characterize acupuncture's effect on nociception. Methods: Seven healthy volunteers underwent a previously designed electroacupuncture protocol using acupoints in the legs bilaterally, which has been demonstrated to induce systemic analgesia. Advanced PREP techniques involving tripolar stimulating electrode, varying interstimulus interval, and incorporating a cognitive task during PREPs were used. PREPs were assessed before electroacupuncture, during electroacupuncture, and 30 min after electroacupuncture. Subjective pain perception in response to the PREP-related electric pain stimuli delivered to the nondominant hand was assessed on the visual analog scale (VAS) at baseline, during electroacupuncture, and 30 min postelectroacupuncture. Results: Reliable PREP N1, P1, and N2 waves were obtained from all subjects at the following average latencies: N1 = 131.5 msec, P1 = 189.4 msec, and N2 = 231.1 msec. Electroacupuncture caused a significant reduction in PREP N1P1 wave amplitudes from 25.6 to 15.4 μV (p = 0.006) and electric pain perception on the VAS-from 2.86 to 2.14 (p = 0.008), compared to baseline. These effects were sustained at 30 min postacupuncture with N1P1 wave amplitude 17.2 μV (p = 0.030) and VAS 2.28 (p = 0.030), compared to baseline. Conclusions: Electroacupuncture causes significant changes in objective nociception, measured by PREP N1P1 wave amplitudes, and in subjective nociception, measured by the VAS, and these effects are sustained for 30 min after electroacupuncture. Planned future studies will involve chronic pain populations and will aim to assess acupuncture's longer term analgesic effects.
Collapse
Affiliation(s)
- Alexandra Dimitrova
- Department of Neurology, Oregon Health & Science University, Portland, OR, USA
| | - Alisha Harrington
- Department of Neurology, Oregon Health & Science University, Portland, OR, USA
| | - Tab Memmott
- Department of Neurology, Oregon Health & Science University, Portland, OR, USA
| | - Jonathan Sisley
- Department of Neurology, Oregon Health & Science University, Portland, OR, USA
| | - Barry Oken
- Department of Neurology, Oregon Health & Science University, Portland, OR, USA
| |
Collapse
|
3
|
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: 0] [Impact Index Per Article: 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.
Collapse
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, ,
| |
Collapse
|
4
|
De Schoenmacker I, Leu C, Curt A, Hubli M. Pain‐autonomic interaction is a reliable measure of pain habituation in healthy subjects. Eur J Pain 2022; 26:1679-1690. [PMID: 35671124 PMCID: PMC9544564 DOI: 10.1002/ejp.1990] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Revised: 05/16/2022] [Accepted: 06/04/2022] [Indexed: 11/24/2022]
Abstract
Background Habituation is a response decrement resulting from repeated stimuli. Reduced habituation to noxious stimuli is considered to be a proxy for central sensitization in subjects with chronic pain. Despite numerous investigations of pain habituation in relation to central sensitization, there is no consensus on the most sensitive and reliable readout, as well as analysis approach. Therefore, this study compared the usability and reliability of different readouts and habituation analysis approaches to measure pain habituation in response to repetitive heat simulation. Methods Three blocks of 20 contact heat stimuli were applied on the volar forearm of 20 healthy subjects on two separate visits. Habituation was assessed by three different readouts: pain ratings, contact heat evoked potentials (CHEPs) and heat‐induced sympathetic skin responses (SSRs). In addition, two different habituation analysis approaches were used: between the three stimulation blocks (between‐block) and within the first stimulation block (within‐block). Results Significant between‐block habituation for SSRs (p < 0.001), but not for pain ratings (p = 1.000) and CHEPs (p = 0.078) was found. There was significant within‐block habituation for pain ratings (p = 0.012) and SSRs (p < 0.001), but not for CHEPs (p = 0.246). Only the between‐block habituation of heat‐induced SSR was reliable between the two visits (first to second block: intraclass correlation coefficient [ICC] = 0.58, p = 0.030; first to third block: ICC = 0.64, p = 0.015). Conclusion Heat‐induced SSR as a measure of pain‐autonomic interaction revealed the strongest pain habituation and showed the highest test–retest reliability.
Collapse
Affiliation(s)
- Iara De Schoenmacker
- Spinal Cord Injury CenterBalgrist University Hospital, University of ZurichZurichSwitzerland
| | - Chiara Leu
- Spinal Cord Injury CenterBalgrist University Hospital, University of ZurichZurichSwitzerland
- Institute of NeuroscienceUniversité Catholique de LouvainBrusselsBelgium
| | - Armin Curt
- Spinal Cord Injury CenterBalgrist University Hospital, University of ZurichZurichSwitzerland
| | - Michèle Hubli
- Spinal Cord Injury CenterBalgrist University Hospital, University of ZurichZurichSwitzerland
| |
Collapse
|
5
|
Improved acquisition of contact heat evoked potentials with increased heating ramp. Sci Rep 2022; 12:925. [PMID: 35042939 PMCID: PMC8766469 DOI: 10.1038/s41598-022-04867-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Accepted: 12/29/2021] [Indexed: 12/05/2022] Open
Abstract
Contact heat evoked potentials (CHEPs) represent an objective and non-invasive measure to investigate the integrity of the nociceptive neuraxis. The clinical value of CHEPs is mostly reflected in improved diagnosis of peripheral neuropathies and spinal lesions. One of the limitations of conventional contact heat stimulation is the relatively slow heating ramp (70 °C/s). This is thought to create a problem of desynchronized evoked responses in the brain, particularly after stimulation in the feet. Recent technological advancements allow for an increased heating ramp of contact heat stimulation, however, to what extent these improve the acquisition of evoked potentials is still unknown. In the current study, 30 healthy subjects were stimulated with contact heat at the hand and foot with four different heating ramps (i.e., 150 °C/s, 200 °C/s, 250 °C/s, and 300 °C/s) to a peak temperature of 60 °C. We examined changes in amplitude, latency, and signal-to-noise ratio (SNR) of the vertex (N2-P2) waveforms. Faster heating ramps decreased CHEP latency for hand and foot stimulation (hand: F = 18.41, p < 0.001; foot: F = 4.19, p = 0.009). Following stimulation of the foot only, faster heating ramps increased SNR (F = 3.32, p = 0.024) and N2 amplitude (F = 4.38, p = 0.007). Our findings suggest that clinical applications of CHEPs should consider adopting faster heating ramps up to 250 °C/s. The improved acquisition of CHEPs might consequently reduce false negative results in clinical cohorts. From a physiological perspective, our results demonstrate the importance of peripherally synchronizing afferents recruitment to satisfactorily acquire CHEPs.
Collapse
|
6
|
Sun B, Wang H, Chen Z, Cui F, Yang F, Huang X. Contact Heat Evoked Potentials in China: Normal Values and Reproducibility. Front Hum Neurosci 2022; 15:747553. [PMID: 35087388 PMCID: PMC8789220 DOI: 10.3389/fnhum.2021.747553] [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: 07/26/2021] [Accepted: 12/16/2021] [Indexed: 11/13/2022] Open
Abstract
Background: Contact heat evoked potentials (CHEPs) is used to diagnose small fiber neuropathy (SFN). We established the normal values of CHEPs parameters in Chinese adults, optimized the test technique, and determined its reproducibility. Methods: We recruited 151 healthy adults (80 men; mean age, 37 ± 14 years). CHEPs was performed on the right forearm to determine the optimal number of stimuli, and then conducted at different sites to establish normal values, determine the effects of demographic characteristics and baseline temperature, and assess the short- (30 min) and long-term (1 year) reproducibility. N2 latency/height varied with age and sex, while P2 latency/height and N2–P2 amplitude varied with age. The optimal number of stimuli was three. Results: N2 latency/height (t = 5.45, P < 0.001) and P2 latency/height (χ2 = −4.06, P < 0.001) decreased and N2–P2 amplitude (t = −5.01, P < 0.001) and visual analog scale score (χ2 = −5.84, P < 0.001) increased with increased baseline temperature (35 vs. 32°C). CHEPs parameters did not differ with time (baseline vs. 30 min vs. 1 year). Conclusion: We established normal CHEPs values in Chinese adults. We found that CHEPs parameters changed with baseline temperature and that the short- and long-term test reproducibility were satisfactory.
Collapse
Affiliation(s)
- Bo Sun
- Neurological Department of the First Medical Center, Chinese PLA General Hospital, Beijing, China
- Geriatric Neurological Department of the Second Medical Center and National Clinical Research Center for Geriatric Diseases, Chinese PLA General Hospital, Beijing, China
| | - Hongfen Wang
- Neurological Department of the First Medical Center, Chinese PLA General Hospital, Beijing, China
| | - Zhaohui Chen
- Neurological Department of the First Medical Center, Chinese PLA General Hospital, Beijing, China
| | - Fang Cui
- Neurological Department of the First Medical Center, Chinese PLA General Hospital, Beijing, China
| | - Fei Yang
- Neurological Department of the First Medical Center, Chinese PLA General Hospital, Beijing, China
| | - Xusheng Huang
- Neurological Department of the First Medical Center, Chinese PLA General Hospital, Beijing, China
- *Correspondence: Xusheng Huang, ;
| |
Collapse
|
7
|
Lütolf R, Júlio SU, Schubert M, Hubli M. Intra-epidermal evoked potentials: A promising tool for spinal disorders? Neurophysiol Clin 2021; 52:44-57. [PMID: 34953638 DOI: 10.1016/j.neucli.2021.11.004] [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: 06/07/2021] [Revised: 11/23/2021] [Accepted: 11/23/2021] [Indexed: 10/19/2022] Open
Abstract
OBJECTIVES To test the robustness and signal-to-noise ratio of pain-related evoked potentials following intra-epidermal electrical stimulation (IES) compared to contact heat stimulation in healthy controls, and to explore the feasibility and potential added value of IES in the diagnosis of spinal disorders. METHODS Pain-related evoked potentials induced by IES (custom-made, non-invasive, concentric triple pin electrode with steel pins protruding 1 mm from the anode, triangularly separated by 7-10 mm respectively) and contact heat stimulation were compared in 30 healthy subjects. Stimuli were applied to four different body sites. Two IES intensities, i.e., high (individually adapted to contact heat painfulness) and low (1.5 times pain threshold), were used. Additionally, a 40-year-old patient with unilateral dissociated sensory loss due to a multi-segmental syringohydromyelia was assessed comparing IES and contact heat stimulation. RESULTS Both IES and contact heat stimulation led to robust pain-related evoked potentials recorded in all healthy subjects. Low intensity IES evoked potentials (14.1-38.0 µV) had similar amplitudes as contact heat evoked potentials (11.8-32.3 µV), while pain ratings on the numeric rating scale were lower for IES (0.8-2.5, compared to 1.5-3.9 for contact heat stimulation). High intensity IES led to evoked potentials with higher signal-to-noise ratio than low intensity IES and contact heat stimulation. The patient case showed impaired pain-related evoked potentials in segments with hypoalgesia for both IES modes. IES evoked potentials were preserved, with delayed latencies, while contact heat evoked potentials were abolished. CONCLUSION IES evoked robust pain-related cortical potentials, while being less painful in healthy controls. The improved signal-to-noise ratio supports the use of IES for objective segmental testing of nociceptive processing. This was highlighted in a spinal syndrome case, where IES as well as contact heat stimulation reliably detected impaired segmental nociception.
Collapse
Affiliation(s)
- Robin Lütolf
- Spinal Cord Injury Center, Balgrist University Hospital, University of Zurich, Zurich, Switzerland.
| | - Sara U Júlio
- 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
| | - Michèle Hubli
- Spinal Cord Injury Center, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| |
Collapse
|
8
|
Rosner J, Scheuren PS, Stalder SA, Curt A, Hubli M. Pinprick Evoked Potentials-Reliable Acquisition in Healthy Human Volunteers. PAIN MEDICINE 2021; 21:736-746. [PMID: 31216028 DOI: 10.1093/pm/pnz126] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
OBJECTIVE Pinprick evoked potentials (PEPs) represent a novel tool to assess the functional integrity of mechano-nociceptive pathways with a potential toward objectifying sensory deficits and gain seen in neurological disorders. The aim of the present study was to evaluate the feasibility and reliability of PEPs with respect to age, stimulation site, and skin type. METHODS Electroencephalographic responses evoked by two pinprick stimulation intensities (128 mN and 256 mN) applied at three sites (hand dorsum, palmar digit II, and foot dorsum) were recorded in 30 healthy individuals. Test-retest reliability was performed for the vertex negative-positive complex amplitudes, N-latencies, and pain ratings evoked by the 256mN stimulation intensity. RESULTS Feasibility of PEP acquisition was demonstrated across age groups, with higher proportions of evoked potentials (>85%) for the 256mN stimulation intensity. Reliability analyses, that is, Bland-Altman and intraclass correlation coefficients, revealed poor to excellent reliability upon retest depending on the stimulation sites. CONCLUSIONS This study highlights the reliability of PEP acquisition from cervical and lumbar segments across clinically representative age groups. Future methodological improvements might further strengthen PEP reliability in order to complement clinical neurophysiology of sensory nerve fibers by a more specific assessment of mechano-nociceptive pathways. Beyond looking at sensory deficits, PEPs may also become applicable to revealing signs of central sensitization, complementing the clinical assessment of mechanical hyperalgesia.
Collapse
Affiliation(s)
- Jan Rosner
- Spinal Cord Injury Center, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Paulina Simonne Scheuren
- Spinal Cord Injury Center, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Stephanie Anja Stalder
- Spinal Cord Injury Center, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Armin Curt
- 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
| |
Collapse
|
9
|
An intensity matched comparison of laser- and contact heat evoked potentials. Sci Rep 2021; 11:6861. [PMID: 33767259 PMCID: PMC7994633 DOI: 10.1038/s41598-021-85819-w] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 01/28/2021] [Indexed: 11/08/2022] Open
Abstract
Previous studies comparing laser (LEPs) and contact heat evoked potentials (CHEPs) consistently reported higher amplitudes following laser compared to contact heat stimulation. However, none of the studies matched the perceived pain intensity, questioning if the observed difference in amplitude is due to biophysical differences between the two methods or a mismatch in stimulation intensity. The aims of the current study were twofold: (1) to directly compare the brain potentials induced by intensity matched laser and contact heat stimulation and (2) investigate how capsaicin-induced secondary hyperalgesia modulates LEPs and CHEPs. Twenty-one healthy subjects were recruited and measured at four experimental sessions: (1) CHEPs + sham, (2) LEPs + sham, (3) CHEPs + capsaicin, and (4) LEPs + capsaicin. Baseline (sham) LEPs latency was significantly shorter and amplitude significantly larger compared to CHEPs, even when matched for perceived pain. Neither CHEPs nor LEPs was sensitive enough to detect secondary hyperalgesia. These differences provide evidence that a faster heating rate results in an earlier and more synchronized LEPs than CHEPs. To our knowledge, this was the first study to match perceived intensity of contact heat and laser stimulations, revealing distinct advantages associated with the acquisition of LEPs.
Collapse
|
10
|
Jutzeler CR, Linde LD, Rosner J, Hubli M, Curt A, Kramer JLK. Single-trial averaging improves the physiological interpretation of contact heat evoked potentials. Neuroimage 2020; 225:117473. [PMID: 33099013 DOI: 10.1016/j.neuroimage.2020.117473] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Revised: 09/12/2020] [Accepted: 10/14/2020] [Indexed: 10/23/2022] Open
Abstract
Laser and contact heat evoked potentials (LEPs and CHEPs, respectively) provide an objective measure of pathways and processes involved in nociception. The majority of studies analyzing LEP or CHEP outcomes have done so based on conventional, across-trial averaging. With this approach, evoked potential components are potentially confounded by latency jitter and ignore relevant information contained within single trials. The current study addressed the advantage of analyzing nociceptive evoked potentials based on responses to noxious stimulations within each individual trial. Single-trial and conventional averaging were applied to data previously collected in 90 healthy subjects from 3 stimulation locations on the upper limb. The primary analysis focused on relationships between single and across-trial averaged CHEP outcomes (i.e., N2P2 amplitude and N2 and P2 latencies) and subject characteristics (i.e., age, sex, height, and rating of perceived intensity), which were examined by way of linear mixed model analysis. Single-trial averaging lead to larger N2P2 amplitudes and longer N2 and P2 latencies. Age and ratings of perceived intensity were the only subject level characteristics associated with CHEPs outcomes that significantly interacted with the method of analysis (conventional vs single-trial averaging). The strength of relationships for age and ratings of perceived intensity, measured by linear fit, were increased for single-trial compared to conventional across-trial averaged CHEP outcomes. By accounting for latency jitter, single-trial averaging improved the associations between CHEPs and physiological outcomes and should be incorporated as a standard analytical technique in future studies.
Collapse
Affiliation(s)
- Catherine R Jutzeler
- Swiss Federal Institute of Technology (ETH Zurich), Department of Biosystems Science and Engineering, Mattenstrasse 26, 4058 Basel, Switzerland; SIB Swiss Institute of Bioinformatics, Switzerland; Spinal Cord Injury Center, University Hospital Balgrist, University of Zurich, Zurich, Switzerland.
| | - Lukas D Linde
- ICORD, University of British Columbia, 818W 10th Ave, Vancouver, British Columbia, Canada; Department of Anesthesiology, Pharmacology & Therapeutics, Faculty of Medicine, University of British Columbia, 818W 10th Ave, Vancouver, British Columbia, Canada; Djavad Mowafaghian Centre for Brain Health, University of British Columbia, 818W 10th Ave, Vancouver, British Columbia, Canada
| | - Jan Rosner
- Spinal Cord Injury Center, University Hospital Balgrist, University of Zurich, Zurich, Switzerland; Department of Neurology, University Hospital Bern, Inselspital, University of Bern, Bern, Switzerland
| | - Michèle Hubli
- Spinal Cord Injury Center, University Hospital Balgrist, University of Zurich, Zurich, Switzerland
| | - Armin Curt
- Spinal Cord Injury Center, University Hospital Balgrist, University of Zurich, Zurich, Switzerland
| | - John L K Kramer
- ICORD, University of British Columbia, 818W 10th Ave, Vancouver, British Columbia, Canada; Department of Anesthesiology, Pharmacology & Therapeutics, Faculty of Medicine, University of British Columbia, 818W 10th Ave, Vancouver, British Columbia, Canada; Djavad Mowafaghian Centre for Brain Health, University of British Columbia, 818W 10th Ave, Vancouver, British Columbia, Canada.
| |
Collapse
|
11
|
Degenerative cervical myelopathy - update and future directions. Nat Rev Neurol 2020; 16:108-124. [PMID: 31974455 DOI: 10.1038/s41582-019-0303-0] [Citation(s) in RCA: 222] [Impact Index Per Article: 55.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/11/2019] [Indexed: 11/09/2022]
Abstract
Degenerative cervical myelopathy (DCM) is the leading cause of spinal cord dysfunction in adults worldwide. DCM encompasses various acquired (age-related) and congenital pathologies related to degeneration of the cervical spinal column, including hypertrophy and/or calcification of the ligaments, intervertebral discs and osseous tissues. These pathologies narrow the spinal canal, leading to chronic spinal cord compression and disability. Owing to the ageing population, rates of DCM are increasing. Expeditious diagnosis and treatment of DCM are needed to avoid permanent disability. Over the past 10 years, advances in basic science and in translational and clinical research have improved our understanding of the pathophysiology of DCM and helped delineate evidence-based practices for diagnosis and treatment. Surgical decompression is recommended for moderate and severe DCM; the best strategy for mild myelopathy remains unclear. Next-generation quantitative microstructural MRI and neurophysiological recordings promise to enable quantification of spinal cord tissue damage and help predict clinical outcomes. Here, we provide a comprehensive, evidence-based review of DCM, including its definition, epidemiology, pathophysiology, clinical presentation, diagnosis and differential diagnosis, and non-operative and operative management. With this Review, we aim to equip physicians across broad disciplines with the knowledge necessary to make a timely diagnosis of DCM, recognize the clinical features that influence management and identify when urgent surgical intervention is warranted.
Collapse
|
12
|
Linde LD, Haefeli J, Jutzeler CR, Rosner J, McDougall J, Curt A, Kramer JLK. Contact Heat Evoked Potentials Are Responsive to Peripheral Sensitization: Requisite Stimulation Parameters. Front Hum Neurosci 2020; 13:459. [PMID: 31998104 PMCID: PMC6966714 DOI: 10.3389/fnhum.2019.00459] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Accepted: 12/16/2019] [Indexed: 12/20/2022] Open
Abstract
The sensitizing effect of capsaicin has been previously characterized using laser and contact heat evoked potentials (LEPs and CHEPs) by stimulating in the primary area of hyperalgesia. Interestingly, only CHEPs reveal changes consistent with notion of peripheral sensitization (i.e., reduced latencies). The aim of this study was to investigate contact heat stimulation parameters necessary to detect peripheral sensitization related to the topical application of capsaicin, and therefore significantly improve the current method of measuring peripheral sensitization via CHEPs. Rapid contact heat stimulation (70°C/s) was applied from three different baseline temperatures (35, 38.5, and 42°C) to a 52°C peak temperature, before and after the topical application of capsaicin on the hand dorsum. Increased pain ratings in the primary area of hyperalgesia were accompanied by reduced N2 latency. Changes in N2 latency were, however, only significant following stimulation from 35 and 38.5°C baseline temperatures. These findings suggest that earlier recruitment of capsaicin-sensitized afferents occurs between 35 and 42°C, as stimulations from 42°C baseline were unchanged by capsaicin. This is in line with reduced thresholds of type II A-delta mechanoheat (AMH) nociceptors following sensitization. Conventional CHEP stimulation, with a baseline temperature below 42°C, is well suited to objectively detect evidence of peripheral sensitization.
Collapse
Affiliation(s)
- Lukas D Linde
- ICORD, The University of British Columbia, Vancouver, BC, Canada.,School of Kinesiology, The University of British Columbia, Vancouver, BC, Canada
| | - Jenny Haefeli
- Brain and Spinal Injury Center, Department of Neurosurgery, University of California, San Francisco, San Francisco, CA, United States
| | - Catherine R Jutzeler
- ICORD, The University of British Columbia, Vancouver, BC, Canada.,School of Kinesiology, The University of British Columbia, Vancouver, BC, Canada.,Spinal Cord Injury Center, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Jan Rosner
- Spinal Cord Injury Center, Balgrist University Hospital, University of Zurich, Zurich, Switzerland.,Department of Neurology, University Hospital Bern, Inselspital, University of Bern, Bern, Switzerland
| | - Jessica McDougall
- ICORD, The University of British Columbia, Vancouver, BC, Canada.,School of Rehabilitation Sciences, Faculty of Medicine, The University of British Columbia, Vancouver, BC, Canada
| | - Armin Curt
- Spinal Cord Injury Center, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - John L K Kramer
- ICORD, The University of British Columbia, Vancouver, BC, Canada.,School of Kinesiology, The University of British Columbia, Vancouver, BC, Canada
| |
Collapse
|
13
|
Albu S, Meagher MW. Divergent effects of conditioned pain modulation on subjective pain and nociceptive-related brain activity. Exp Brain Res 2019; 237:1735-1744. [PMID: 31030281 DOI: 10.1007/s00221-019-05545-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Accepted: 04/24/2019] [Indexed: 12/22/2022]
Abstract
BACKGROUND AND OBJECTIVES Pain is a complex experience involving both nociceptive and affective-cognitive mechanisms. The present study evaluated whether modulation of pain perception, employing a conditioned pain modulation (CPM) paradigm, is paralleled by changes in contact heat-evoked potentials (CHEPs), a brain response to nociceptive stimuli. METHODS Participants were 25 healthy, pain-free, college students (12 males, 13 females, mean age 19.24 ± 0.97 years). Twenty computer-controlled heat stimuli were delivered to the non-dominant forearm and CHEPs were recorded at Cz using a 32-channel EEG system. After each stimulus, participants rated the intensity of the heat pain using the 0-100 numerical rating scale. The latency and amplitude of N2, P2 components as well as single-sweep spectral analysis of individual CHEPs were measured offline. For CPM, participants had to submerge their dominant foot into a neutral (32 °C) or noxious (0 °C) water bath. CHEPs and heat pain ratings were recorded in 3 different conditions: without CPM, after neutral CPM (32 °C) and after noxious CPM (0 °C). RESULTS The noxious CPM induced a facilitatory pain response (p = 0.001) with an increase in heat pain following noxious CPM compared to neutral CPM (p = 0.001) and no CPM (p = 0.001). Changes in CHEPs did not differ between conditions when measured as N2-P2 peak-to-peak amplitude (p = 0.33) but the CPM significantly suppressed the CHEPs-related delta power (p = 0.03). Changes in heat pain in the noxious CPM were predicted by trait catastrophizing variables (p = 0.04). CONCLUSION The current study revealed that pain facilitatory CPM is related to suppression of CHEPs delta power which could be related to dissociation between brain responses to noxious heat and pain perception.
Collapse
Affiliation(s)
- Sergiu Albu
- Institute Guttmann, Neurorehabilitation Hospital, Camí Can Ruti s/n, Badalona, 08916, Barcelona, Spain.
| | - Mary W Meagher
- Department of Psychological and Brain Sciences, Texas A&M University, College Station, TX, 77843, USA
| |
Collapse
|
14
|
Rosner J, Rinert J, Ernst M, Curt A, Hubli M. Cold evoked potentials: Acquisition from cervical dermatomes. Neurophysiol Clin 2019; 49:49-57. [DOI: 10.1016/j.neucli.2018.11.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Revised: 11/26/2018] [Accepted: 11/26/2018] [Indexed: 01/06/2023] Open
|
15
|
Abstract
Clinical neurophysiologic investigation of pain pathways in humans is based on specific techniques and approaches, since conventional methods of nerve conduction studies and somatosensory evoked potentials do not explore these pathways. The proposed techniques use various types of painful stimuli (thermal, laser, mechanical, or electrical) and various types of assessments (measurement of sensory thresholds, study of nerve fiber excitability, or recording of electromyographic reflexes or cortical potentials). The two main tests used in clinical practice are quantitative sensory testing and pain-related evoked potentials (PREPs). In particular, PREPs offer the possibility of an objective assessment of nociceptive pathways. Three types of PREPs can be distinguished depending on the type of stimulation used to evoke pain: laser-evoked potentials, contact heat evoked potentials, and intraepidermal electrical stimulation evoked potentials (IEEPs). These three techniques investigate both small-diameter peripheral nociceptive afferents (mainly Aδ nerve fibers) and spinothalamic tracts without theoretically being able to differentiate the level of lesion in the case of abnormal results. In routine clinical practice, PREP recording is a reliable method of investigation for objectifying the existence of a peripheral or central lesion or loss of function concerning the nociceptive pathways, but not the existence of pain. Other methods, such as nerve fiber excitability studies using microneurography, more directly reflect the activities of nociceptive axons in response to provoked pain, but without detecting or quantifying the presence of spontaneous pain. These methods are more often used in research or experimental study design. Thus, it should be kept in mind that most of the results of neurophysiologic investigation performed in clinical practice assess small fiber or spinothalamic tract lesions rather than the neuronal mechanisms directly at the origin of pain and they do not provide objective quantification of pain.
Collapse
Affiliation(s)
- Jean-Pascal Lefaucheur
- Excitabilité Nerveuse et Thérapeutique, Faculté de Médecine de Créteil, Université Paris-Est-Créteil, Hôpital Henri Mondor, Créteil, France; Service de Physiologie-Explorations Fonctionnelles, Hôpital Henri Mondor, Créteil, France.
| |
Collapse
|
16
|
Normative data of contact heat evoked potentials from the lower extremities. Sci Rep 2018; 8:11003. [PMID: 30030450 PMCID: PMC6054620 DOI: 10.1038/s41598-018-29145-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Accepted: 07/05/2018] [Indexed: 12/27/2022] Open
Abstract
Contact heat evoked potentials (CHEPs) have become an acknowledged research tool in the assessment of the integrity of the nociceptive system and gained importance in the diagnostic work-up of patients with suspected small fiber neuropathy. For the latter, normative values for CHEP amplitude and latency are indispensable for a clinically meaningful interpretation of the results gathered in patients. To this end, CHEPs were recorded in 100 healthy subjects over a wide age range (20–80 years) and from three different dermatomes of the lower extremities (L2, L5, and S2). A normal baseline (35–52 °C) and increased baseline stimulation (42–52 °C) were applied. Statistical analysis revealed significant effects of stimulation site, stimulation intensity, and sex on CHEP parameters (N2 latency, N2P2 amplitude, and NRS). Significant positive correlations of body height with N2 latency, and pain ratings with N2P2 amplitudes were observed. This is the first time that normative values have been obtained from multiple dermatomes of the lower extremities. The present dataset will facilitate the clinical application of CHEPs in the neurophysiological diagnosis of small fiber neuropathy and by discerning pathological findings help establish a proximal-distal gradient of nerve degeneration in polyneuropathies.
Collapse
|
17
|
Rosner J, Hubli M, Hostettler P, Scheuren PS, Rinert J, Kramer JLK, Hupp M, Curt A, Jutzeler CR. Contact heat evoked potentials: Reliable acquisition from lower extremities. Clin Neurophysiol 2018; 129:584-591. [PMID: 29414402 DOI: 10.1016/j.clinph.2017.12.034] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Revised: 11/28/2017] [Accepted: 12/17/2017] [Indexed: 12/27/2022]
Abstract
OBJECTIVE To investigate test-retest reliability of contact heat evoked potentials (CHEPs) from lower extremities using two different stimulation protocols, i.e., normal and increased baseline temperature. METHODS A total of 32 able-bodied subjects were included and a subset (N = 22) was retested. CHEPs were recorded from three different dermatomes of the lower extremity (i.e., L2, L5, and S2). Test-retest reliability of CHEPs acquisition after simulation in various lower limb dermatomes using different stimulation protocols was analyzed. RESULTS The study revealed an improved acquisition of CHEPS employing the increased baseline protocol, particularly when stimulating more distal sites, i.e., dermatome L5 and S2. Based on repeatability coefficients, CHEP latency (N2 potential) emerged as the most robust CHEP parameter. Although CHEP amplitudes (N2P2 complex) and pain ratings were decreased in the retest, amplitudes still showed fair to excellent intraclass correlation coefficients using normal baseline or increased baseline temperature, respectively. CONCLUSIONS This is the first study to demonstrate that CHEPs acquisition from the lower extremities is improved by increasing the baseline temperature of the thermode. SIGNIFICANCE This study highlights the usability of CHEPs as a viable diagnostic method to study small fiber integrity.
Collapse
Affiliation(s)
- J Rosner
- Spinal Cord Injury Center, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - M Hubli
- Spinal Cord Injury Center, Balgrist University Hospital, University of Zurich, Zurich, Switzerland.
| | - P Hostettler
- Spinal Cord Injury Center, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - P S Scheuren
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, British Columbia, Canada
| | - J Rinert
- Spinal Cord Injury Center, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - J L K Kramer
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, British Columbia, Canada; School of Kinesiology, University of British Columbia, Vancouver, British Columbia, Canada
| | - M Hupp
- Spinal Cord Injury Center, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - A Curt
- Spinal Cord Injury Center, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - C R Jutzeler
- Spinal Cord Injury Center, Balgrist University Hospital, University of Zurich, Zurich, Switzerland; International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, British Columbia, Canada
| |
Collapse
|
18
|
Özgül ÖS, Maier C, Enax-Krumova EK, Vollert J, Fischer M, Tegenthoff M, Höffken O. High test-retest-reliability of pain-related evoked potentials (PREP) in healthy subjects. Neurosci Lett 2017; 647:110-116. [PMID: 28342940 DOI: 10.1016/j.neulet.2017.03.037] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2017] [Revised: 03/18/2017] [Accepted: 03/20/2017] [Indexed: 01/01/2023]
Abstract
Pain-related evoked potentials (PREP) is an established electrophysiological method to evaluate the signal transmission of electrically stimulated A-delta fibres. Although prerequisite for its clinical use, test-retest-reliability and side-to-side differences of bilateral stimulation in healthy subjects have not been examined yet. We performed PREP twice within 3-14days in 33 healthy subjects bilaterally by stimulating the dorsal hand. Detection (DT) and pain thresholds (PT) after electrical stimulation, the corresponding pain ratings, latencies of P0, N1, P1 and N2 components and the corresponding amplitudes were assessed. Impact of electrically induced pain intensity, age, sex, and arm length on PREP was analysed. MANOVA, t-Test, interclass correlation coefficient (ICC), standard error of measurement (SEM), smallest real difference (SRD), Bland-Altmann-Analysis as well as ANCOVA were used for statistical analysis. Measurement from both sides on both days resulted in mean N1-latencies from 142.39±18.12ms to 144.03±16.62ms and in mean N1P1-amplitudes from 39.04±12.26μV to 40.53±12.9μV. Analysis of a side-to-side effect showed for the N1-latency a F-value of 0.038 and for the N1P1-amplitude of 0.004 (p>0.8). We found intraclass correlation coefficients (ICC) from 0.88 to 0.93 and a standard error of measurement (SEM)<10% of mean values for all measurements concerning the N1-Latency and N1P1-amplitude. Intraclass correlation coefficients, standard error of measurement and Bland-Altman-Analyses revealed excellent test-retest-reliability for N1-latency and N1P1-amplitude without systematic error and there was no side-to-side effect on PREP. N1-latency (r=0.35, p<0.05) and N1P1-amplitude (r=-0.45, p<0.05) correlated with age and additionally N1-latency correlated with arm length (r=0.45, p<0.001). In contrast, pain intensity during the stimulation had no effect on both N1-latency and N1P1-amplitude. In summary, PREP showed high test-retest-reliability and negligible side-to-side differences concerning the commonly used parameters N1-latency and N1P1-amplitude.
Collapse
Affiliation(s)
- Özüm Simal Özgül
- Department of Neurology, Berufsgenossenschaftliches Universitätsklinikum Bergmannsheil GmbH, Ruhr-University Bochum, Bochum, Germany
| | - Christoph Maier
- Department of Pain Medicine, Berufsgenossenschaftliches Universitätsklinikum Bergmannsheil GmbH, Ruhr-University Bochum, Bochum, Germany
| | - Elena K Enax-Krumova
- Department of Neurology, Berufsgenossenschaftliches Universitätsklinikum Bergmannsheil GmbH, Ruhr-University Bochum, Bochum, Germany
| | - Jan Vollert
- Department of Pain Medicine, Berufsgenossenschaftliches Universitätsklinikum Bergmannsheil GmbH, Ruhr-University Bochum, Bochum, Germany
| | - Marc Fischer
- Department of Pain Medicine, Berufsgenossenschaftliches Universitätsklinikum Bergmannsheil GmbH, Ruhr-University Bochum, Bochum, Germany
| | - Martin Tegenthoff
- Department of Neurology, Berufsgenossenschaftliches Universitätsklinikum Bergmannsheil GmbH, Ruhr-University Bochum, Bochum, Germany
| | - Oliver Höffken
- Department of Neurology, Berufsgenossenschaftliches Universitätsklinikum Bergmannsheil GmbH, Ruhr-University Bochum, Bochum, Germany.
| |
Collapse
|
19
|
Jutzeler CR, Rosner J, Rinert J, Kramer JLK, Curt A. Normative data for the segmental acquisition of contact heat evoked potentials in cervical dermatomes. Sci Rep 2016; 6:34660. [PMID: 27708413 PMCID: PMC5052572 DOI: 10.1038/srep34660] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Accepted: 09/13/2016] [Indexed: 01/04/2023] Open
Abstract
Contact heat evoked potentials (CHEPs) represent a neurophysiological approach to assess conduction in the spinothalamic tract. The aim of this study was to establish normative values of CHEPs acquired from cervical dermatomes (C4, C6, C8) and examine the potential confounds of age, sex, and height. 101 (49 male) healthy subjects of three different age groups (18–40, 41–60, and 61–80 years) were recruited. Normal (NB, 35–52 °C) followed by increased (IB, 42–52 °C) baseline stimulation protocols were employed to record CHEPs. Multi-variate linear models were used to investigate the effect of age, sex, and height on the CHEPs parameters (i.e., N2 latency, N2P2 amplitude, rating of perceived intensity). Compared to NB, IB stimulation reduced latency jitter within subjects, yielding larger N2P2 amplitudes, and decreased inter-subject N2 latency variability. Age was associated with reduced N2P2 amplitude and prolonged N2 latency. After controlling for height, male subjects had significantly longer N2 latencies than females during IB stimulation. The study provides normative CHEPs data in a large cohort of healthy subjects from segmentally examined cervical dermatomes. Age and sex were identified as important factors contributing to N2 latency and N2P2 amplitude. The normative data will improve the diagnosis of spinal cord pathologies.
Collapse
Affiliation(s)
- Catherine R Jutzeler
- Spinal Cord Injury Center, University Hospital Balgrist, University of Zurich, Zurich, Switzerland.,ICORD, University of British Columbia, Vancouver, British Columbia, Canada
| | - Jan Rosner
- Spinal Cord Injury Center, University Hospital Balgrist, University of Zurich, Zurich, Switzerland
| | - Janosch Rinert
- Spinal Cord Injury Center, University Hospital Balgrist, University of Zurich, Zurich, Switzerland
| | - John L K Kramer
- ICORD, University of British Columbia, Vancouver, British Columbia, Canada.,School of Kinesiology, University of British Columbia, Vancouver, BC, Canada
| | - Armin Curt
- Spinal Cord Injury Center, University Hospital Balgrist, University of Zurich, Zurich, Switzerland
| |
Collapse
|
20
|
Vinik AI, Casellini C, Névoret ML. Alternative Quantitative Tools in the Assessment of Diabetic Peripheral and Autonomic Neuropathy. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2016; 127:235-85. [PMID: 27133153 DOI: 10.1016/bs.irn.2016.03.010] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Here we review some seldom-discussed presentations of diabetic neuropathy, including large fiber dysfunction and peripheral autonomic dysfunction, emphasizing the impact of sympathetic/parasympathetic imbalance. Diabetic neuropathy is the most common complication of diabetes and contributes additional risks in the aging adult. Loss of sensory perception, loss of muscle strength, and ataxia or incoordination lead to a risk of falling that is 17-fold greater in the older diabetic compared to their young nondiabetic counterparts. A fall is accompanied by lacerations, tears, fractures, and worst of all, traumatic brain injury, from which more than 60% do not recover. Autonomic neuropathy has been hailed as the "Prophet of Doom" for good reason. It is conducive to increased risk of myocardial infarction and sudden death. An imbalance in the autonomic nervous system occurs early in the evolution of diabetes, at a stage when active intervention can abrogate the otherwise relentless progression. In addition to hypotension, many newly recognized syndromes can be attributed to cardiac autonomic neuropathy such as orthostatic tachycardia and bradycardia. Ultimately, this constellation of features of neuropathy conspire to impede activities of daily living, especially in the patient with pain, anxiety, depression, and sleep disorders. The resulting reduction in quality of life may worsen prognosis and should be routinely evaluated and addressed. Early neuropathy detection can only be achieved by assessment of both large and small- nerve fibers. New noninvasive sudomotor function technologies may play an increasing role in identifying early peripheral and autonomic neuropathy, allowing rapid intervention and potentially reversal of small-fiber loss.
Collapse
Affiliation(s)
- A I Vinik
- Eastern Virginia Medical School, Strelitz Diabetes and Neuroendocrine Center, Norfolk, VA, United States.
| | - C Casellini
- Eastern Virginia Medical School, Strelitz Diabetes and Neuroendocrine Center, Norfolk, VA, United States
| | - M-L Névoret
- Impeto Medical Inc., San Diego, CA, United States
| |
Collapse
|
21
|
Abstract
Functional neurologic disorders are largely genuine and represent conversion disorders, where the dysfunction is unconscious, but there are some that are factitious, where the abnormality is feigned and conscious. Malingering, which can have the same manifestations, is similarly feigned, but not considered a genuine disease. There are no good methods for differentiating these three entities at the present time. Physiologic studies of functional weakness and sensory loss reveal normal functioning of primary motor and sensory cortex, but abnormalities of premotor cortex and association cortices. This suggests a top-down influence creating the dysfunction. Studies of functional tremor and myoclonus show that these disorders utilize normal voluntary motor structures to produce the involuntary movements, again suggesting a higher-level abnormality. Agency is abnormal and studies shows that dysfunction of the temporoparietal junction may be a correlate. The limbic system is overactive and might initiate involuntary movements, but the mechanism for this is not known. The limbic system would then be the source of top-down dysfunction. It can be speculated that the involuntary movements are involuntary due to lack of proper feedforward signaling.
Collapse
Affiliation(s)
- M Hallett
- Human Motor Control Section, National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA
| |
Collapse
|
22
|
Kramer J, Jutzeler C, Haefeli J, Curt A, Freund P. Discrepancy between perceived pain and cortical processing: A voxel-based morphometry and contact heat evoked potential study. Clin Neurophysiol 2016; 127:762-768. [DOI: 10.1016/j.clinph.2015.02.054] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Revised: 01/28/2015] [Accepted: 02/25/2015] [Indexed: 01/11/2023]
|
23
|
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]
|
24
|
Jutzeler CR, Curt A, Kramer JLK. Effectiveness of High-Frequency Electrical Stimulation Following Sensitization With Capsaicin. THE JOURNAL OF PAIN 2015; 16:595-605. [PMID: 25866256 DOI: 10.1016/j.jpain.2015.03.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Revised: 02/16/2015] [Accepted: 03/13/2015] [Indexed: 11/26/2022]
Abstract
UNLABELLED Although nonnoxious, high-frequency electrical stimulation applied segmentally (ie, conventional transcutaneous electrical nerve stimulation [TENS]) has been proposed to modulate pain, the mechanisms underlying analgesia remain poorly understood. To further elucidate how TENS modulates pain, we examined evoked responses to noxious thermal stimuli after the induction of sensitization using capsaicin in healthy volunteers. We hypothesized that sensitization caused by capsaicin application would unmask TENS analgesia, which could not be detected in the absence of sensitization. Forty-nine healthy subjects took part in a series of experiments. The experiments comprised the application of topical capsaicin (.075%) on the left hand in the C6 dermatome, varying the location of TENS (segmental, left C6 dermatome, vs extrasegmental, right shoulder), and assessing rating of perception (numeric rating scale: 0-10) and evoked potentials to noxious contact heat stimuli. The extrasegmental site was included as a control condition because previous studies indicate no analgesic effect to remote conventional TENS. Conventional TENS had no significant effect on rating or sensory evoked potentials in subjects untreated with capsaicin. However, segmental TENS applied in conjunction with capsaicin significantly reduced sensation to noxious thermal stimuli following a 60-minute period of sensitization. PERSPECTIVE The study indicates that sensitization with capsaicin unmasks the analgesic effect of conventional TENS on perception of noxious contact heat stimuli. Our findings indicate that TENS may be interacting segmentally to modulate distinct aspects of sensitization, which in turn results in analgesia to thermal stimulation.
Collapse
Affiliation(s)
- Catherine R Jutzeler
- Spinal Cord Injury Center, University Hospital Balgrist, University of Zurich, Zurich, Switzerland.
| | - Armin Curt
- Spinal Cord Injury Center, University Hospital Balgrist, University of Zurich, Zurich, Switzerland
| | - John L K Kramer
- Spinal Cord Injury Center, University Hospital Balgrist, University of Zurich, Zurich, Switzerland; School of Kinesiology, International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, British Columbia, Canada
| |
Collapse
|
25
|
Lagerburg V, Bakkers M, Bouwhuis A, Hoeijmakers JG, Smit AM, Van Den Berg SJ, Hordijk-De Boer I, Brouwer-Van Der Lee MD, Kranendonk D, Reulen JP, Faber CG, Merkies IS. Contact heat evoked potentials: Normal values and use in small-fiber neuropathy. Muscle Nerve 2015; 51:743-9. [DOI: 10.1002/mus.24465] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2014] [Revised: 09/06/2014] [Accepted: 09/22/2014] [Indexed: 12/16/2022]
Affiliation(s)
- Vera Lagerburg
- Department of Clinical Physics; Catharina Hospital; Eindhoven The Netherlands
| | - Mayienne Bakkers
- Department of Neurology Maastricht University Medical Centre; P.O. Box 5800 6202 AZ Maastricht The Netherlands
| | - Anne Bouwhuis
- Department of Neurology Maastricht University Medical Centre; P.O. Box 5800 6202 AZ Maastricht The Netherlands
| | - Janneke G.J. Hoeijmakers
- Department of Neurology Maastricht University Medical Centre; P.O. Box 5800 6202 AZ Maastricht The Netherlands
| | - Arjen M. Smit
- Department of Clinical Neurophysiology; Spaarne Hospital; Hoofddorp The Netherlands
| | | | | | | | - Douwe Kranendonk
- Department of Neurology Spaarne Hospital Hoofddorp; The Netherlands
| | - Jos P.H. Reulen
- Department of Clinical Neurophysiology Maastricht University Medical Centre; Maastricht The Netherlands
| | - Catharina G. Faber
- Department of Neurology Maastricht University Medical Centre; P.O. Box 5800 6202 AZ Maastricht The Netherlands
| | | |
Collapse
|
26
|
Awai L, Curt A. Preserved Sensory-Motor Function Despite Large-Scale Morphological Alterations in a Series of Patients with Holocord Syringomyelia. J Neurotrauma 2015; 32:403-10. [DOI: 10.1089/neu.2014.3536] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Lea Awai
- Spinal Cord Injury Center, Balgrist University Hospital, University of Zurich, Switzerland
| | - Armin Curt
- Spinal Cord Injury Center, Balgrist University Hospital, University of Zurich, Switzerland
| |
Collapse
|
27
|
Kalsi-Ryan S, Wilson J, Yang JM, Fehlings MG. Neurological Grading in Traumatic Spinal Cord Injury. World Neurosurg 2014; 82:509-18. [DOI: 10.1016/j.wneu.2013.01.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2012] [Revised: 10/10/2012] [Accepted: 01/03/2013] [Indexed: 01/25/2023]
|
28
|
Haefeli J, Kramer JLK, Blum J, Curt A. Heterotopic and homotopic nociceptive conditioning stimulation: distinct effects of pain modulation. Eur J Pain 2014; 18:1112-9. [PMID: 24443293 DOI: 10.1002/j.1532-2149.2014.00454.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/10/2013] [Indexed: 12/24/2022]
Abstract
BACKGROUND Within an area, habituation and sensitization represent well-established modulatory effects to repetitive noxious input. Less is known regarding the nociceptive conditioning effects between body sites - i.e., how stimulating one site may affect another. Therefore, we investigated the effects of nociceptive stimulation of anatomically distinct locations (shoulder and hand) on pain rating and evoked potentials (i.e., contact heat-evoked potentials). METHODS The effect of stimulation order was assessed in eight healthy subjects. The shoulder was examined before the hand or the hand before the shoulder. All subjects underwent both conditions (shoulder before hand and hand before shoulder) on separate days. In an additional 30 subjects (total n = 38), between retesting the shoulder or the hand, conditioning stimulation in the respective other location (i.e., hand or shoulder) was applied. Both analyses focused upon changes in the magnitude of evoked pain responses in relation to the respective area being conditioned by heterotopic stimulation. RESULTS When the shoulder was stimulated before the hand, N2P2 amplitude was significantly reduced. In contrast, stimulating the hand before the shoulder resulted in significant response increments (shorter N2 latency). Additionally, conditioning stimulation of the hand resulted in increased pain rating to shoulder stimulation. CONCLUSIONS Overall, these findings indicate that response modulation to noxious contact heat stimulation depends upon conditioning stimulus location. These effects represent changes beyond conventional habituation due to repeated stimulation in the same area.
Collapse
Affiliation(s)
- J Haefeli
- Spinal Cord Injury Center, University Hospital Balgrist, University of Zurich, Switzerland
| | | | | | | |
Collapse
|
29
|
Reproducibility of contact heat evoked potentials (CHEPs) over a 6months interval. Clin Neurophysiol 2013; 124:2242-7. [DOI: 10.1016/j.clinph.2013.05.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2012] [Revised: 02/01/2013] [Accepted: 05/08/2013] [Indexed: 01/02/2023]
|
30
|
Velstra IM, Bolliger M, Baumberger M, Rietman JS, Curt A. Epicritic Sensation in Cervical Spinal Cord Injury: Diagnostic Gains Beyond Testing Light Touch. J Neurotrauma 2013; 30:1342-8. [DOI: 10.1089/neu.2012.2828] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Affiliation(s)
| | - Marc Bolliger
- Spinal Cord Injury Centre, Balgrist University Hospital, Zurich, Switzerland
- European Multicenter Study about Human Spinal Cord Injury (EM SCI), Zurich, Switzerland
| | - Michael Baumberger
- Department of Acute and Rehabilitation Medicine, Swiss Paraplegic Centre, Nottwil, Switzerland
| | - Johan Swanik Rietman
- Roessingh Research and Development, Laboratory of Biomechanical Engineering, University of Twente, Enschede, The Netherlands
| | - Armin Curt
- Spinal Cord Injury Centre, Balgrist University Hospital, Zurich, Switzerland
- European Multicenter Study about Human Spinal Cord Injury (EM SCI), Zurich, Switzerland
| |
Collapse
|
31
|
Ulrich A, Haefeli J, Blum J, Min K, Curt A. Improved diagnosis of spinal cord disorders with contact heat evoked potentials. Neurology 2013; 80:1393-9. [DOI: 10.1212/wnl.0b013e31828c2ed1] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Objective:To evaluate the sensitivity of contact heat evoked potentials (CHEPs) compared with dermatomal somatosensory evoked potentials (dSSEPs) and clinical sensory testing in myelopathic spinal cord disorders (SCDs).Methods:In a prospective cohort study, light-touch (LT) and pinprick (PP) testing was complemented by dermatomal CHEPs and dSSEPs in patients with a confirmed SCD as defined by MRI. Patients with different etiologies (i.e., traumatic and nontraumatic) and varying degrees of spinal cord damage (i.e., completeness) were included. SCD was distinguished into 3 categories according to MRI pattern and neurologic examination: a) complete, b) incomplete-diffuse, and c) central or anterior cord damage.Results:Seventy-five patients were included (complete n = 7, incomplete-diffuse n = 33, central/anterior n = 35). In total, 319 dermatomes were tested with combined CHEPs and dSSEPs. CHEPs, dSSEPs, and clinical sensory testing were comparably sensitive to detect the myelopathy in complete (CHEPs 100%, dSSEPs 91%, PP and LT 82%) and incomplete-diffuse (CHEPs 92%, dSSEPs and PP 86%, LT 81%, p > 0.05 for all comparisons) cord damage. In central/anterior cord damage, CHEPs showed a significantly higher sensitivity than dSSEPs (89% compared with 24%, p < 0.001) and clinical sensory testing (PP 62%, LT 57%, p < 0.05). A subclinical sensory impairment was detected more frequently by CHEPs than dSSEPs (60% compared with 29%, p = 0.001).Conclusions:Assessment of spinothalamic pathways with CHEPs is reliable and revealed the highest sensitivity in all SCDs. Specifically in incomplete lesions that spare dorsal pathways, CHEPs are sensitive to complement the clinical diagnosis.
Collapse
|
32
|
Improving the acquisition of nociceptive evoked potentials without causing more pain. Pain 2013; 154:235-241. [DOI: 10.1016/j.pain.2012.10.027] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2012] [Revised: 09/07/2012] [Accepted: 10/18/2012] [Indexed: 11/19/2022]
|