Multimodal evoked potentials to assess the evolution of multiple sclerosis: a longitudinal study

The contribution of EEG to assess and treat motor disorders in multiple sclerosis

OBJECTIVE

Electroencephalography (EEG) can highlight significant changes in spontaneous electrical activity of the brain produced by altered brain network connectivity linked to inflammatory demyelinating lesions and neuronal loss occurring in multiple sclerosis (MS). In this review, we describe the main EEG findings reported in the literature to characterize motor network alteration in term of local activity or functional connectivity changes in patients with MS (pwMS).

METHODS

A comprehensive literature search was conducted to include articles with quantitative analyses of resting-state EEG recordings (spectrograms or advanced methods for assessing spatial and temporal dynamics, such as coherence, theory of graphs, recurrent quantification, microstates) or dynamic EEG recordings during a motor task, with or without connectivity analyses.

RESULTS

In this systematic review, we identified 26 original articles using EEG in the evaluation of MS-related motor disorders. Various resting or dynamic EEG parameters could serve as diagnostic biomarkers of motor control impairment to differentiate pwMS from healthy subjects or be related to a specific clinical condition (fatigue) or neuroradiological aspects (lesion load).

CONCLUSIONS

We highlight some key EEG patterns in pwMS at rest and during movement, both suggesting an alteration or disruption of brain connectivity, more specifically involving sensorimotor networks.

SIGNIFICANCE

Some of these EEG biomarkers of motor disturbance could be used to design future therapeutic strategies in MS based on neuromodulation approaches, or to predict the effects of motor training and rehabilitation in pwMS.

Transcranial magnetic stimulation enhances the specificity of multiple sclerosis diagnostic criteria: a critical narrative review

Background

Multiple sclerosis (MS) is an immune-mediated neurodegenerative disease that involves attacks of inflammatory demyelination and axonal damage, with variable but continuous disability accumulation. Transcranial magnetic stimulation (TMS) is a noninvasive method to characterize conduction loss and axonal damage in the corticospinal tract. TMS as a technique provides indices of corticospinal tract function that may serve as putative MS biomarkers. To date, no reviews have directly addressed the diagnostic performance of TMS in MS. The authors aimed to conduct a critical narrative review on the diagnostic performance of TMS in MS.

Methods

The authors searched the Embase, PubMed, Scopus, and Web of Science databases for studies that reported the sensitivity and/or specificity of any reported TMS technique compared to established clinical MS diagnostic criteria. Studies were summarized and critically appraised for their quality and validity.

Results

Seventeen of 1,073 records were included for data extraction and critical appraisal. Markers of demyelination and axonal damage-most notably, central motor conduction time (CMCT)-were specific, but not sensitive, for MS. Thirteen (76%), two (12%), and two (12%) studies exhibited high, unclear, and low risk of bias, respectively. No study demonstrated validity for TMS techniques as diagnostic biomarkers in MS.

Conclusions

CMCT has the potential to: (1) enhance the specificity of clinical MS diagnostic criteria by "ruling in" true-positives, or (2) revise a diagnosis from relapsing to progressive forms of MS. However, there is presently insufficient high-quality evidence to recommend any TMS technique in the diagnostic algorithm for MS.

Brainstem auditory-evoked responses among children afflicted by severely hypoxic CHD

MAIN AIM

To electrophysiologically determine the impact of moderate to severe chronic hypoxia (H) resulting from a wide array of CHD (HCHD) conditions on the integrity of brainstem function.

MATERIALS AND METHODS

Applying brainstem auditory-evoked response methodology, 30 chronically afflicted HCHD patients, who already had undergone heart surgery, were compared to 28 healthy control children (1-15 yo) matched by age, gender and socioeconomic condition. Blood oxygen saturation was clinically determined and again immediately before brainstem auditory-evoked response testing.

RESULTS

Among HCHD children, auditory wave latencies (I, III and V) were significantly longer (medians: I, 2.02 ms; III, 4.12 ms, and; V, 6.30 ms) compared to control (medians: I, 1.67ms; III, 3.72 ms, and; V, 5.65 ms), as well as interpeak intervals (HCHD medians: I-V, 4.25 ms, and; III-V, 2.25ms; control medians: I-V, 3.90 ms and, III-V, 1.80 ms) without significant differences in wave amplitudes between groups. A statistically significant and inverse correlation between average blood oxygen saturation of each group (control, 94%; HCHD, 78%) and their respective wave latencies and interpeak intervals was found.

CONCLUSIONS

As determined by brainstem auditory-evoked responses, young HCHD patients manifestly show severely altered neuronal conductivity in the auditory pathway strongly correlated with their hypoxic condition. These observations are strongly supported by different brainstem neurological and image studies showing that alterations, either in microstructure or function, result from the condition of chronic hypoxia in CHD. The non-altered wave amplitudes are indicative of relatively well-preserved neuronal relay nuclei.

Utility of the tibial nerve somatosensory evoked potentials in differentiating between neuromyelitis optica spectrum disorders and multiple sclerosis

BACKGROUND

Somatosensory evoked potentials (SEPs) are widely used for the diagnosis and evaluation of neuromyelitis optica spectrum disorder (NMOSD) and multiple sclerosis (MS). However, whether the parameters of tibial nerve SEPs can help to distinguish NMOSD from MS remains unclear. Thus, the aim of this study was to investigate the utility of tibial nerve SEP parameters in differentiating patients with NMOSD and MS.

METHODS

The clinical data of patients with NMOSD or MS treated in our institution between 2005 and 2021 were retrospectively extracted from our electronic database. Additional inclusion criteria were presentation with sensory symptoms in the lower extremities with corresponding lesions in the magnetic resonance images as well as available data on anti-aquaporin-4 antibodies and tibial nerve SEPs. The Z-scores of the N21-P38 interval (central sensory conduction time), P38 latency, and P38 amplitude were compared between the patients with NMOSD and MS. The relationship of disease severity with the parameters of the tibial nerve SEPs was also evaluated.

RESULTS

Twenty patients with NMOSD and 13 patients with MS were enrolled. The Z-scores of the N21-P38 interval and P38 latency were significantly higher in the MS group than in the NMOSD group (p < 0.05 and p < 0.01, respectively), whereas there was no difference in the Z-scores of the P38 amplitude between the two groups. In the MS group, only the N21-P38 interval and P38 latency were significantly correlated with disease severity (p < 0.05 and p < 0.01, respectively). In contrast, none of the tibial nerve SEP parameters were significantly correlated with disease severity in the NMOSD group.

CONCLUSION

Evaluation of the N21-P38 interval and P38 latency in tibial nerve SEPs potentially helps in differentiating between NMOSD and MS.

Somatosensory evoked potentials and magnetic resonance imaging of the central nervous system in early multiple sclerosis

BACKGROUND

Somatosensory evoked potentials (SSEP) are still broadly used, although not explicitly recommended, for the diagnostic work-up of suspected multiple sclerosis (MS).

OBJECTIVE

To relate disability, SSEP, and lesions on T2-weighted magnetic resonance imaging (MRI) in patients with early MS.

METHODS

In this monocentric retrospective study, we analyzed a cohort of patients with relapsing-remitting MS or clinically isolated syndrome, with a maximum disease duration of two years, as well as with available data on the score at the expanded disability status scale (EDSS), on SSEP, on whole spinal cord (SC) MRI, and on brain MRI.

RESULTS

Complete data of 161 patients were available. Tibial nerve SSEP (tSSEP) were less frequently abnormal than SC MRI (22% vs. 68%, p < 0.001). However, higher EDSS scores were significantly associated with abnormal tSSEP (median, 2.0 vs. 1.0; p = 0.001) but not with abnormal SC MRI (i.e., at least one lesion; median, 1.5 vs. 1.5; p = 0.7). Of the 35 patients with abnormal tSSEP, 32 had lesions on SC MRI, and 2 had corresponding lesions on brain MRI.

CONCLUSION

Compared to tSSEP, SC MRI is the more sensitive diagnostic biomarker regarding SC involvement. In early MS, lesions as detectable by T2-weighted MRI are the main driver of abnormal tSSEP. However, tSSEP were more closely associated with disability, which is compatible with a potential role of tSSEP as prognostic biomarker in complementation of MRI.

Neural stem cell transplantation in patients with progressive multiple sclerosis: an open-label, phase 1 study

Innovative pro-regenerative treatment strategies for progressive multiple sclerosis (PMS), combining neuroprotection and immunomodulation, represent an unmet need. Neural precursor cells (NPCs) transplanted in animal models of multiple sclerosis have shown preclinical efficacy by promoting neuroprotection and remyelination by releasing molecules sustaining trophic support and neural plasticity. Here we present the results of STEMS, a prospective, therapeutic exploratory, non-randomized, open-label, single-dose-finding phase 1 clinical trial ( NCT03269071 , EudraCT 2016-002020-86), performed at San Raffaele Hospital in Milan, Italy, evaluating the feasibility, safety and tolerability of intrathecally transplanted human fetal NPCs (hfNPCs) in 12 patients with PMS (with evidence of disease progression, Expanded Disability Status Scale ≥6.5, age 18-55 years, disease duration 2-20 years, without any alternative approved therapy). The safety primary outcome was reached, with no severe adverse reactions related to hfNPCs at 2-year follow-up, clearly demonstrating that hfNPC therapy in PMS is feasible, safe and tolerable. Exploratory secondary analyses showed a lower rate of brain atrophy in patients receiving the highest dosage of hfNPCs and increased cerebrospinal fluid levels of anti-inflammatory and neuroprotective molecules. Although preliminary, these results support the rationale and value of future clinical studies with the highest dose of hfNPCs in a larger cohort of patients.

Treatment of Patients with Multiple Sclerosis Transitioning Between Relapsing and Progressive Disease

Multiple sclerosis (MS) is a chronic autoimmune demyelinating and neurodegenerative disease of the central nervous system with a wide variety of clinical phenotypes. In spite of the phenotypic classification of MS patients, current data provide evidence that diffuse neuroinflammation and neurodegeneration coexist in all MS forms, the latter gaining increasing clinical relevance in progressive phases. Given that the transition phase of relapsing-remitting MS (RRMS) to secondary progressive MS (SPMS) is not well defined, and widely accepted criteria for SPMS are lacking, randomised controlled trials (RCTs) specifically designed for the transition phase have not been conducted. This review summarizes primary and secondary analyses and reports derived from phase III prospective clinical RCTs listed in PubMed of compounds authorised through the European Medicines Agency (EMA) and the US Food and Drug Administration (FDA) for the treatment of MS. The best data are available for interferon beta-1a (IFNb-1a) subcutaneous (s.c.), IFNb-1b s.c., mitoxantrone and siponimod, the latter being the most modern compound with likely the best risk-to-effect ratio. Moreover, there is a labels discrepancy for many disease-modifying treatments (DMTs) between the FDA and EMA, which have to be taken into consideration when opting for a specific DMT.

Individual differences in visual evoked potential latency are associated with variance in brain tissue volume in people with multiple sclerosis: An analysis of brain function-structure correlates

Visual evoked potentials (VEP) index visual pathway functioning, and are often used for clinical assessment and as outcome measures in people with multiple sclerosis (PwMS). VEPs may also reflect broader neural disturbances that extend beyond the visual system, but this possibility requires further investigation. In the present study, we examined the hypothesis that delayed latency of the P100 component of the VEP would be associated with broader structural changes in the brain in PwMS. We obtained VEP latency for a standard pattern-reversal checkerboard stimulus paradigm, in addition to Magnetic Resonance Imaging (MRI) measures of whole brain volume (WBV), gray matter volume (GMV), white matter volume (WMV), and T2-weighted fluid attenuated inversion recovery (FLAIR) white matter lesion volume (FLV). Correlation analyses indicated that prolonged VEP latency was significantly associated with lower WBV, GMV, and WMV, and greater FLV. VEP latency remained significantly associated with WBV, GMV, and WMV even after controlling for the variance associated with inter-ocular latency, age, time between VEP and MRI assessments, and other MRI variables. VEP latency delays were most pronounced in PwMS that exhibited low volume in both white and gray matter simultaneously. Furthermore, PwMS that had delayed VEP latency based on a clinically relevant cutoff (VEP latency ≥ 113 ms) in both eyes had lower WBV, GMV, and WMV and greater FLV in comparison to PwMS that had normal VEP latency in one or both eyes. The findings suggest that PwMS that have delayed latency in both eyes may be particularly at risk for exhibiting greater brain atrophy and lesion volume. These analyses also indicate that VEP latency may index combined gray matter and white matter disturbances, and therefore broader network connectivity and efficiency. VEP latency may therefore provide a surrogate marker of broader structural disturbances in the brain in MS.

Using personalized prognosis in the treatment of relapsing multiple sclerosis: A practical guide

The clinical course of multiple sclerosis (MS) is highly variable among patients, thus creating important challenges for the neurologist to appropriately treat and monitor patient progress. Despite some patients having apparently similar symptom severity at MS disease onset, their prognoses may differ greatly. To this end, we believe that a proactive disposition on the part of the neurologist to identify prognostic “red flags” early in the disease course can lead to much better long-term outcomes for the patient in terms of reduced disability and improved quality of life. Here, we present a prognosis tool in the form of a checklist of clinical, imaging and biomarker parameters which, based on consensus in the literature and on our own clinical experiences, we have established to be associated with poorer or improved clinical outcomes. The neurologist is encouraged to use this tool to identify the presence or absence of specific variables in individual patients at disease onset and thereby implement sufficiently effective treatment strategies that appropriately address the likely prognosis for each patient.

Repeat infusion of autologous bone marrow cells in progressive multiple sclerosis - A phase I extension study (SIAMMS II)

BACKGROUND

During the safety and feasibility 'Study of Intravenous Autologous Marrow in Multiple Sclerosis (SIAMMS)', intravenous infusion of autologous marrow was well tolerated. The efficacy of the approach is being explored in a placebo-controlled randomised controlled trial (ACTiMuS, NCT01815632) but it is not known whether repeated infusions will be required to optimise benefit. The objective of the current study was to explore the safety and feasibility of repeat treatment with intravenous autologous bone marrow for patients with progressive multiple sclerosis (MS).

METHODS

'SIAMMS II' was a prospective, single centre phase I extension study in which participants in the SIAMMS study were offered repeat bone marrow harvest and infusion of autologous, unfractionated bone marrow as a day-case procedure. The primary outcome measure was number of adverse events and secondary outcome measures included change in clinical rating scales of disability, global evoked potential and cranial magnetic resonance imaging (MRI).

RESULTS

In total, 4 of the 6 participants in the SIAMMS study had repeat bone marrow harvest and infusion of filtered autologous marrow as a day case procedure which was well tolerated. There were no serious adverse effects. Additional outcome measures including clinical scales, global evoked potentials and cranial MRI were stable.

CONCLUSION

SIAMMS II demonstrates the safety and feasibility of repeated, non-myeloablative autologous bone marrow-derived cell therapy in progressive MS.

Cervical vestibular evoked myogenic potentials and video head impulse test studies: alternative methods for detecting brainstem involvement in multiple sclerosis

BACKGROUND

Brainstem involvement (BSI) has been reported as a major predictive factor for future disability in Multiple Sclerosis (MS).

AIMS/OBJECTIVES

To evaluate whether Cervical Vestibular Evoked Myogenic Potentials (cVEMPs) and Video Head Impulse Test (vHIT) can be used to detect demyelinating lesions in vestibular pathways in MS.

MATERIAL AND METHODS

Fifty three people with MS and 40 controls were evaluated with Dizziness Handicap Inventory (DHI), vHIT and cVEMP.

RESULTS

The median value of DHI in MS group was significantly higher than controls (p<.001). According to vHIT results, while the results of horizontal canal vestibulo-ocular reflex gain in group with brain stem involvement (gBSI (+)) were significantly different from both controls and group without brain stem involvement (gBSI (-)) (p= .036 and .024, respectively), results of gBSI (-) were similar with controls (p= .858). When cVEMP results were examined, mean P1 wave latency in gBSI (+) was significantly longer than controls (p= .002), but difference between gBSI (-) and controls and gBSI (+) was not statistically significant (p= .104 and .279, respectively).

CONCLUSIONS AND SIGNIFICANCE

vHIT and cVEMP can be used in diagnosis and follow-up of people with MS without demyelinating brainstem lesions on MRI.

The usefulness of visual evoked potentials in the assessment of the pediatric multiple sclerosis

BACKGROUND

To evaluate the significance of visual evoked potentials (VEP) in the early diagnosis of optic neuritis (ON) and detecting clinically silent lesions in pediatric multiple sclerosis (PedMS). This study represents one of the largest series of PedMS which evaluated characteristics of VEP in PedMS patients.

METHODS

This was a retrospective study on 52 PedMS patients, aged 7-17 years. VEP analysis were done for all patients, after the first attack of disease and were compared to control subjects according to the pattern-reversal VEP findings.

RESULTS

The mean age of patients was 15.65 ± 1.89 years with male to female ratio of 16 (30.8%): 36 (69.2%). All of the patients had a relapsing-remitting course of the disease. ON was discovered on the initial attack in 18 (34.6%) patients, while 30 (57.7%) patients had ON in the second attack. Pathological VEP findings were present in 40 (76.9%) patients, of which 22 (42.3%) PedMS patients had clinically silent lesions. Prolonged latency of P100 waves in the PedMS group was statistically significant when compared to control subjects. The amplitude N1P1 showed a correlation with residual visual deficit.

CONCLUSION

Our results show that ON is a common initial manifestation of PedMS in the Serbian PedMS population. The prolonged P100 latency is the main indicator of ON. VEP is an objective, fast and accessible diagnostic method for detecting clinical and subclinical lesions. Thus, VEP deserves evaluation to be considered as an additional criterion for PedMS diagnosis.

Clinical, Neurophysiological, and MRI Markers of Fampridine Responsiveness in Multiple Sclerosis-An Explorative Study

Objective: Persons with multiple sclerosis (PwMS), already established as responders or non-responders to Fampridine treatment, were compared in terms of disability measures, physical and cognitive performance tests, neurophysiology, and magnetic resonance imaging (MRI) outcomes in a 1-year explorative longitudinal study.

Materials and Methods: Data from a 1-year longitudinal study were analyzed. Examinations consisted of the timed 25-foot walk test (T25FW), six spot step test (SSST), nine-hole peg test (9-HPT), five times sit-to-stand test (5-STS), symbol digit modalities test (SDMT), transcranial magnetic stimulation (TMS) elicited motor evoked potentials (MEP) examining central motor conduction times (CMCT), peripheral motor conduction times (PMCT) and their amplitudes, electroneuronography (ENG) of the lower extremities, and brain structural MRI measures.

Results: Forty-one responders and eight non-responders to Fampridine treatment were examined. There were no intergroup differences except for the PMCT, where non-responders had prolonged conduction times compared to responders to Fampridine. Six spot step test was associated with CMCT throughout the study. After 1 year, CMCT was further prolonged and cortical MEP amplitudes decreased in both groups, while PMCT and ENG did not change. Throughout the study, CMCT was associated with the expanded disability status scale (EDSS) and 12-item multiple sclerosis walking scale (MSWS-12), while SDMT was associated with number of T2-weighted lesions, lesion load, and lesion load normalized to brain volume.

Conclusions: Peripheral motor conduction time is prolonged in non-responders to Fampridine when compared to responders. Transcranial magnetic stimulation-elicited MEPs and SDMT can be used as markers of disability progression and lesion activity visualized by MRI, respectively.

Clinical Trial Registration:www.ClinicalTrials.gov, identifier: NCT03401307.

Optical Coherence Tomography and Visual Evoked Potentials as Prognostic and Monitoring Tools in Progressive Multiple Sclerosis

Understanding the mechanisms underlying progression and developing new treatments for progressive multiple sclerosis (PMS) are among the major challenges in the field of central nervous system (CNS) demyelinating diseases. Over the last 10 years, also because of some technological advances, the visual pathways have emerged as a useful platform to study the processes of demyelination/remyelination and their relationship with axonal degeneration/protection. The wider availability and technological advances in optical coherence tomography (OCT) have allowed to add information on structural neuroretinal changes, in addition to functional information provided by visual evoked potentials (VEPs). The present review will address the role of the visual pathway as a platform to assess functional and structural damage in MS, focusing in particular on the role of VEPs and OCT, alone or in combination, in the prognosis and monitoring of PMS.

Subclinical anterior optic pathway involvement in early multiple sclerosis and clinically isolated syndromes

Optical coherence tomography (OCT) is gaining increasing relevance in the assessment of patients with multiple sclerosis. Converging evidence point to the view that neuro-retinal changes, in eyes without acute optic neuritis, reflect inflammatory and neurodegenerative processes taking place throughout the CNS. The present study aims at exploring the usefulness of OCT as a marker of inflammation and disease burden in the earliest phases of the disease. Thus, a cohort of 150 consecutive patients underwent clinical, neurophysiological and brain MRI assessment as well as lumbar puncture as part of their diagnostic workup for a neurological episode suggestive of inflammatory CNS disorder; among those 32 patients had another previous misdiagnosed episode. For the present study, patients also received a visual pathway assessment (OCT, visual evoked potentials, visual acuity), measurement of CSF inflammatory markers (17 cytokines-chemokines, extracellular vesicles of myeloid origin), and dosage of plasma neurofilaments. Subclinical optic nerve involvement is frequently found in clinically isolated syndromes by visual evoked potentials (19.2%). OCT reveals ganglion cell layer asymmetries in 6.8% of patients; retinal fibre layer asymmetries, despite being more frequent (17.8%), display poor specificity. The presence of subclinical involvement is associated with a greater disease burden. Second, ganglion cell layer thinning reflects the severity of disease involvement even beyond the anterior optic pathway. In fact, the ganglion cell layer in eyes without evidence of subclinical optic involvement is correlated with Expanded Disability Status Scale, low contrast visual acuity, disease duration, brain lesion load, presence of gadolinium enhancing lesions, abnormalities along motor and somatosensory evoked potentials, and frequency of CSF-specific oligoclonal bands. Third, the inner nuclear layer thickens in a post-acute (1.1-3.7 months) phase after a relapse, and this phenomenon is counteracted by steroid treatment. Likewise, a longitudinal analysis on 65 patients shows that this swelling is transient and returns to normal values after 1 year follow-up. Notwithstanding, the clinical, MRI, serological and CSF markers of disease activity considered in the study are strictly associated with one another, but none of them are associated with the inner nuclear layer. Our findings challenge the current hypothesis that the inner nuclear layer is an acute phase marker of inflammatory activity. The present study suggests that instrumental evidence of subclinical optic nerve involvement is associated with a greater disease burden in clinically isolated syndrome. Neuro-retinal changes are present since the earliest phases of the disease and yield important information regarding the neurodegenerative and inflammatory processes occurring in the CNS.

Multimodal Evoked Potentials as Candidate Prognostic and Response Biomarkers in Clinical Trials of Multiple Sclerosis

SUMMARY

Evoked potentials (EPs) measure quantitatively and objectively the alterations of central signal propagation in multiple sclerosis and have long been used for diagnosis. More recently, their utility for prognosis has been demonstrated in several studies, summarizing multiple EP modalities in a single score. In particular, visual, somatosensory, and motor EPs are useful because of their sensitivity to pathology in the frequently affected optic nerve, somatosensory tract, and pyramidal system. Quantitative EP scores show higher sensitivity to change than clinical assessment and may be used to monitor disease progression. Visual EP and the visual system have served as a model to study remyelinating therapies in the setting of acute and chronic optic neuritis. This review presents rationale and evidence for using multimodal EP as prognostic and response biomarkers in clinical trials, targeting remyelination or halting disease progression in multiple sclerosis.

Effectiveness of Brainstem Auditory Evoked Potentials Scoring in Evaluating Brainstem Dysfunction and Disability Among Individuals With Multiple Sclerosis

Purpose The brainstem dysfunction in multiple sclerosis (MS) often causes significant functional impairment leading to disability. This study aims to explore modified brainstem auditory evoked potential (BAEP) scores based on the pattern of BAEP abnormalities and relate with brainstem symptoms, brainstem functional system scores (BFSS), brainstem lesions, and disability. Method Forty-five participants with relapsing-remitting MS and 45 age- and gender-matched healthy controls underwent case history assessment, otoscopic examination, pure-tone audiometry, and BAEP testing. Also, neurological examination (Expanded Disability Status Scale, FSS scales) and magnetic resonance imaging were carried out on MS participants. Patterns of BAEP abnormalities were categorized and converted to BAEP scores. Results Out of 45 participants' brainstem symptoms, BFSS > 1, brainstem lesions (magnetic resonance imaging), and BAEP abnormalities were observed in 75.6%, 42.2%, 62.2%, and 55.56% of participants, respectively. Waves V and III abnormalities were more common among MS participants and showed a significant difference from the control group in the Mann-Whitney U test. Chi-square test did not show a significant association of BAEP abnormalities with brainstem symptoms and lesions but showed significant association with BFSS. The mean and standard deviation of BAEP scores in MS participants were 1.73 + 2.37. All healthy controls showed BAEP scores of 0. BAEP scores in MS participants showed significant correlation with BFSS scores and predict Expanded Disability Status Scale scores. Conclusion BAEP scores based on the pattern of BAEP abnormality can be a valid and useful measure in evaluating brainstem functions and predicting disability in MS.

The Use of Motor-Evoked Potentials in Clinical Trials in Multiple Sclerosis

SUMMARY

Motor-evoked potentials (MEPs) can be used to assess the integrity of the descending corticospinal tract in the laboratory. Evoked potentials (EPs) have been widely used in the past for the diagnosis of multiple sclerosis (MS), but they are now becoming more useful in assessing the prognosis of the disease. Motor-evoked potentials have been included in EP scales that have demonstrated good correlations with clinical disability. Soon after the onset of MS, it is possible to detect an ongoing process of neurodegeneration and axonal loss. Axonal loss is probably responsible for the disability and disease progression that occurs in MS. Given the good correlations of EPs in detecting disease progression in MS, they have been used to monitor the effects of drugs used to treat the disease. Several clinical trials used MEPs as part of their EP evaluation, but MEPs have never been used as a measure of efficacy in clinical trials testing neuroprotective agents, although MEPs could be a very promising tool to measure neuroprotection and remyelination resulting from these drugs. To be used in multicenter clinical trials, MEP readings should be comparable between centers. Standardized multicenter EP assessment with central reading has been demonstrated to be feasible and reliable. Although MEP measurements have been correlated with clinical scores and other measures of neurodegeneration, further validation of MEP amplitude measurements is needed regarding their validity, reliability, and sensitivity before they can be routinely used in clinical drug trials in MS.

Visual evoked potential latency predicts cognitive function in people with multiple sclerosis

Prior studies have reported an association between visual evoked potentials (VEPs) and cognitive performance in people with multiple sclerosis (PwMS), but the specific mechanisms that account for this relationship remain unclear. We examined the relationship between VEP latency and cognitive performance in a large sample of PwMS, hypothesizing that VEP latency indexes not only visual system functioning but also general neural efficiency. Standardized performance index scores were obtained for the domains of memory, executive function, visual-spatial processing, verbal function, attention, information processing speed, and motor skills, as well as global cognitive performance (NeuroTrax battery). VEP P100 component latency was obtained using a standard checkerboard pattern-reversal paradigm. Prolonged VEP latency was significantly associated with poorer performance in multiple cognitive domains, and with the number of cognitive domains in which performance was ≥ 1 SD below the normative mean. Relationships between VEP latency and cognitive performance were significant for information processing speed, executive function, attention, motor skills, and global cognitive performance after controlling for disease duration, visual acuity, and inter-ocular latency differences. This study provides evidence that VEP latency delays index general neural inefficiency that is associated with cognitive disturbances in PwMS.

Promoting remyelination in multiple sclerosis

The greatest unmet need in multiple sclerosis (MS) are treatments that delay, prevent or reverse progression. One of the most tractable strategies to achieve this is to therapeutically enhance endogenous remyelination; doing so restores nerve conduction and prevents neurodegeneration. The biology of remyelination-centred on the activation, migration, proliferation and differentiation of oligodendrocyte progenitors-has been increasingly clearly defined and druggable targets have now been identified in preclinical work leading to early phase clinical trials. With some phase 2 studies reporting efficacy, the prospect of licensed remyelinating treatments in MS looks increasingly likely. However, there remain many unanswered questions and recent research has revealed a further dimension of complexity to this process that has refined our view of the barriers to remyelination in humans. In this review, we describe the process of remyelination, why this fails in MS, and the latest research that has given new insights into this process. We also discuss the translation of this research into clinical trials, highlighting the treatments that have been tested to date, and the different methods of detecting remyelination in people.

A cross-sectional comparison of performance, neurophysiological and MRI outcomes of responders and non-responders to fampridine treatment in multiple sclerosis - An explorative study

OBJECTIVE

To compare baseline physical and cognitive performance, neurophysiological, and magnetic resonance imaging (MRI) outcomes and examinetheir interrelationship inparticipants with Multiple Sclerosis (MS), already established aseither responder or non-responder to Fampridine treatment, andto examine associationswiththe expanded disability status scale (EDSS) and 12-item MS walking scale (MSWS-12).

METHODS

Baseline data from an explorative longitudinal observational study were analyzed. Participants underwent the Timed 25-Foot Walk Test (T25FW), Six Spot Step Test (SSST), Nine-Hole Peg Test, Five Times Sit-to-Stand Test, Symbol Digit Modalities Test (SDMT), neurophysiological testing, including central motor conduction time (CMCT), peripheral motor conduction time (PMCT), motor evoked potential (MEP) amplitudesand electroneuronographyof the lower extremities, and brain MRI (brain volume, number and volume of T2-weighted lesions and lesion load normalized to brain volume).

RESULTS

41 responders and 8 non-responders were examined. There were no intergroup differences inphysical performance, cognitive, neurophysiological, andMRI outcomes (p > 0.05).CMCT was associated withT25FW, SSST, EDSS, and MSWS-12,(p < 0.05). SDMT was associated with the number and volume of T2-weighted lesions, and lesion load normalized to brain volume (p < 0.05).

CONCLUSION

No differences were identified between responders and non-responders to Fampridine treatment regarding physical and cognitive performance, neurophysiological or MRI outcomes. The results call for cautious interpretation and further large-scale studies are needed to expand ourunderstanding of underlying mechanisms discriminating Fampridine responders and non-responders.CMCT may be used as a marker of disability and walking impairment, while SDMT was associated with white matter lesions estimated by MRI. ClinicalTrials.gov identifier: NCT03401307.

Cognitive Event-Related Potentials-The P300 Wave Is a Prognostic Factor of Long-Term Disability Progression in Patients With Multiple Sclerosis

PURPOSE

Multiple sclerosis (MS) is a chronic disorder with a variable course. The aim of our study was to find out whether cognitive event-related potentials are prognostic for patient disability at the 15-year follow-up.

METHODS

In the observed cohort of patients with MS, we examined the event-related potentials at baseline (2003). Functional status (Expanded Disability Status Scale score) was then assessed 15 years later, and the prognostic model was developed using binary logistic regression analysis. The independent variables included demographic (age, sex, and education), clinical (disability in 2003), radiologic (MRI lesion load), and event-related potentials parameters. The prognostic accuracy of the proposed model was evaluated by calculating the area under the receiver-operating characteristics curve.

RESULTS

The study sample consisted of 85 patients with MS. The mean age was 35.5 (SD, 11.2) years, and the median disability score was 3.0 (1-7) in 2003 and 5.0 (1.5-9.5) in 2018. The significant prognostic factors of poor Expanded Disability Status Scale are higher baseline Expanded Disability Status Scale, longer MS duration, and prolonged P300 latency. The sensitivity and specificity of the cutoff at 5.0 for the disability score were 94% and 89%, respectively, with the area under the receiver-operating characteristics curve 0.94 (95% confidence interval, 0.889-0.984; P < 0.001).

CONCLUSIONS

The results show that out of event-related potentials, the P300 wave latency is a prognostic of long-term disability progression in patients with MS.

Evolution of tongue somatosensory evoked potentials in people with multiple sclerosis

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A significant deterioration of the trigeminal sensory pathway function occurs in pwMS.

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Cervical spinal cord lesions were negative predictor of tSSEP improvement.

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There is a moderate to high correlation between ordinal and quantitative tSSEP scores calculations.

Introduction

The aim of the present study was to investigate the long-term evolution of tongue somatosensory evoked potentials (tSSEP) in people with multiple sclerosis (pwMS).

Methods

Out of initial 121 participants, after two-year follow-up, the data were available for 74 and after four-year follow-up for 58 pwMS. In all pwMS complete neurological examination, brain MRI, cervical spinal cord MRI (if available) and tSSEP were performed at baseline visit (M0). Complete neurological examination and tSSEP were performed 2 and 4 years later (M24 and M48). tSSEP results were interpreted in the form of ordinal tSSEP score and quantitative tSSEP zscore calculated from the sum of z-transformed tSSEP latencies.

Results

Differences in tSSEP scores and tSSEP zscores in three different timepoints showed significant worsening of both scores over time. For the tSSEP score the difference was significant for M0-M24 and M0-M48 visits, but not for M24-M48 visits. For the tSSEP zscore the difference was significant for M0-M48 and M24-M48 visits, but not for M0-M24 visits. The only significant negative predictor found for the tSSEP score improvement was presence of cervical spinal cord lesions on the MRI. A moderate to high correlation was observed between both forms of tSSEP score at all three timepoints.

Conclusion

This study demonstrates a significant deterioration of trigeminal sensory pathway in MS over time, giving further insight into trigeminal system damage in pwMS.

Deciphering the Morphology of Motor Evoked Potentials

Motor Evoked Potentials (MEPs) are used to monitor disability progression in multiple sclerosis (MS). Their morphology plays an important role in this process. Currently, however, there is no clear definition of what constitutes a normal or abnormal morphology. To address this, five experts independently labeled the morphology (normal or abnormal) of the same set of 1,000 MEPs. The intra- and inter-rater agreement between the experts indicates they agree on the concept of morphology, but differ in their choice of threshold between normal and abnormal morphology. We subsequently performed an automated extraction of 5,943 time series features from the MEPs to identify a valid proxy for morphology, based on the provided labels. To do this, we compared the cross-validation performances of one-dimensional logistic regression models fitted to each of the features individually. We find that the approximate entropy (ApEn) feature can accurately reproduce the majority-vote labels. The performance of this feature is evaluated on an independent test set by comparing to the majority vote of the neurologists, obtaining an AUC score of 0.92. The model slightly outperforms the average neurologist at reproducing the neurologists consensus-vote labels. We can conclude that MEP morphology can be consistently defined by pooling the interpretations from multiple neurologists and that ApEn is a valid continuous score for this. Having an objective and reproducible MEP morphological abnormality score will allow researchers to include this feature in their models, without manual annotation becoming a bottleneck. This is crucial for large-scale, multi-center datasets. An exploratory analysis on a large single-center dataset shows that ApEn is potentially clinically useful. Introducing an automated, objective, and reproducible definition of morphology could help overcome some of the barriers that are currently obstructing broad adoption of evoked potentials in daily care and patient follow-up, such as standardization of measurements between different centers, and formulating guidelines for clinical use.

REM Sleep without atonia correlates with abnormal vestibular-evoked myogenic potentials in isolated REM sleep behavior disorder

STUDY OBJECTIVES

The neurophysiological hallmark of REM sleep behavior disorder (RBD) is loss of atonia during REM sleep. Indeed, signs and symptoms of neurodegeneration can occur after years, even decades, from its beginning. This study aimed to measure neurophysiological alterations of the brainstem that potentially correlate with the severity of atonia loss, and determining whether a prodromal neurodegenerative disorder underlines this condition when it occurs as an isolated condition (iRBD).

METHODS

Subjects with iRBD and matched healthy controls were recruited. The study included the recording of one-night polysomnography, vestibular-evoked myogenic potentials (VEMPs), and a [123I]-FP-CIT dopamine transporter (DAT) scan. The quantification of REM sleep without atonia (RSWA) was made according to two previously published manual methods and one automated method.

RESULTS

The rate of alteration of VEMPs and VEMP score were significantly higher in iRBD patients than controls. Moreover, VEMP score was negatively correlated with the automated REM atonia index; a marginal statistical significance was also reached for the positive correlation with the visual tonic electromyographic parameter, while the other correlations, including that with DAT-scan score were not statistically significant.

CONCLUSIONS

Brainstem neurophysiology in iRBD can be assessed by VEMPs and their alterations may possibly indicate an early expression of the neurodegenerative process underlying this disorder at the brainstem level, which awaits future longitudinal confirmation. The correlation between RSWA and VEMP alteration might also represent a prodromal aspect anticipating the possible evolution from iRBD to neurodegeneration, whereas DAT-scan abnormalities might represent a later step in this evolution.

Early diagnosis of secondary progressive multiple sclerosis: focus on fluid and neurophysiological biomarkers

BACKGROUND AND AIMS

Most patients with multiple sclerosis presenting with a relapsing-remitting disease course at diagnosis transition to secondary progressive multiple sclerosis (SPMS) 1-2 decades after onset. SPMS is characterized by predominant neurodegeneration and atrophy. These pathogenic hallmarks result in unsatisfactory treatment response in SPMS patients. Therefore, early diagnosis of SPMS is necessary for prompt treatment decisions. The aim of this review was to assess neurophysiological and fluid biomarkers that have the potential to monitor disease progression and support early SPMS diagnosis.

METHODS

We performed a systematic review of studies that analyzed the role of neurophysiological techniques and fluid biomarkers in supporting SPMS diagnosis using the preferred reporting items for systematic reviews and meta-analyses statement.

RESULTS

From our initial search, we selected 24 relevant articles on neurophysiological biomarkers and 55 articles on fluid biomarkers.

CONCLUSION

To date, no neurophysiological or fluid biomarker is sufficiently validated to support the early diagnosis of SPMS. Neurophysiological measurements, including short interval intracortical inhibition and somatosensory temporal discrimination threshold, and the neurofilament light chain fluid biomarker seem to be the most promising. Cross-sectional studies on an adequate number of patients followed by longitudinal studies are needed to confirm the diagnostic and prognostic value of these biomarkers. A combination of neurophysiological and fluid biomarkers may be more sensitive in detecting SPMS conversion.

Visual Evoked Potentials as a Biomarker in Multiple Sclerosis and Associated Optic Neuritis

: ABSTRACT:: Multiple sclerosis (MS) is an inflammatory, degenerative disease of the central nervous system (CNS) characterized by progressive neurological decline over time. The need for better "biomarkers" to more precisely capture and track the effects of demyelination, remyelination, and associated neuroaxonal injury is a well-recognized challenge in the field of MS. To this end, visual evoked potentials (VEPs) have a role in assessing the extent of demyelination along the optic nerve, as a functionally eloquent CNS region. Moreover, VEPs testing can be used to predict the extent of recovery after optic neuritis (ON) and capture disabling effects of clinical and subclinical demyelination events in the afferent visual pathway. In this review, the evolving role of VEPs in the diagnosis of patients with ON and MS and the utility of VEPs testing in determining therapeutic benefits of emerging MS treatments is discussed.

Machine learning analysis of motor evoked potential time series to predict disability progression in multiple sclerosis

Background

Evoked potentials (EPs) are a measure of the conductivity of the central nervous system. They are used to monitor disease progression of multiple sclerosis patients. Previous studies only extracted a few variables from the EPs, which are often further condensed into a single variable: the EP score. We perform a machine learning analysis of motor EP that uses the whole time series, instead of a few variables, to predict disability progression after two years. Obtaining realistic performance estimates of this task has been difficult because of small data set sizes. We recently extracted a dataset of EPs from the Rehabiliation & MS Center in Overpelt, Belgium. Our data set is large enough to obtain, for the first time, a performance estimate on an independent test set containing different patients.

Methods

We extracted a large number of time series features from the motor EPs with the highly comparative time series analysis software package. Mutual information with the target and the Boruta method are used to find features which contain information not included in the features studied in the literature. We use random forests (RF) and logistic regression (LR) classifiers to predict disability progression after two years. Statistical significance of the performance increase when adding extra features is checked.

Results

Including extra time series features in motor EPs leads to a statistically significant improvement compared to using only the known features, although the effect is limited in magnitude (ΔAUC = 0.02 for RF and ΔAUC = 0.05 for LR). RF with extra time series features obtains the best performance (AUC = 0.75±0.07 (mean and standard deviation)), which is good considering the limited number of biomarkers in the model. RF (a nonlinear classifier) outperforms LR (a linear classifier).

Conclusions

Using machine learning methods on EPs shows promising predictive performance. Using additional EP time series features beyond those already in use leads to a modest increase in performance. Larger datasets, preferably multi-center, are needed for further research. Given a large enough dataset, these models may be used to support clinicians in their decision making process regarding future treatment.

Phase-synchrony evaluation of EEG signals for Multiple Sclerosis diagnosis based on bivariate empirical mode decomposition during a visual task

BACKGROUND AND OBJECTIVE

Despite the widespread prevalence of Multiple Sclerosis (MS), the study of brain interactions is still poorly understood. Moreover, there has always been a great need to automate the MS diagnosis procedure to eliminate the evaluation errors thereby improving its consistency and reliability. To address these issues, in this work, we proposed a robust pattern recognition algorithm as a computer-aided diagnosis system. This method is based on calculating the pairwise phase-synchrony of EEG recordings during a visual task. Initially, the bivariate empirical mode decomposition (BEMD) was applied to extract the intrinsic mode functions (IMFs). The phases of these IMFs were then obtained using the Hilbert transform to be utilized in the mean phase coherence (MPC), a measure for phase-synchrony calculation. After the construction of the feature space using MPC values, the ReliefF algorithm was applied for dimension reduction. Finally, the best distinguishing features were input to a k-nearest neighbor (KNN) classifier. The results revealed a higher level of network synchronization in the posterior regions of the brain and desynchronization in the anterior regions among the MS group as compared with the normal subjects. In the validation phase, the leave-one-subject-out cross-validation (LOOCV) method was used to assess the validity of the proposed algorithm. We achieved an accuracy, sensitivity, and specificity of 93.09%, 91.07%, and 95.24% for red-green, 90.44%, 88.39%, and 92.62% for luminance, and 87.44%, 87.05%, and 87.86% for blue-yellow tasks, respectively. The experimental results demonstrated the reliability of the presented method to be generalized in the field of automated MS diagnosis systems.

Assessments of vessel density and foveal avascular zone metrics in multiple sclerosis: an optical coherence tomography angiography study

BACKGROUND/OBJECTIVES

To investigate optical coherence tomography angiography (OCT-A) findings of foveal avascular zone (FAZ) metrics and macular & peripapillary vessel densities (VD) in subjects with multiple sclerosis (MS).

METHODS

The study design was prospective and cross-sectional. FAZ metrics and VDs of the superficial capillary plexus (SCP), deep capillary plexus (DCP), retinal peripapillary capillary plexus (RPCP) along with the structural OCT measurements were scanned by using the Nidek's RS-3000 Advance in MS patients and healthy controls. All subject also underwent an assessment of visual evoked potentials (VEPs). The relationships between the OCT-A parameters with other clinical findings were analysed.

RESULTS

Forty-seven MS patients (94 eyes) and 61 healthy volunteers (122 eyes) were included in this study. Thirty-five eyes of the MS patients had an ON history. The structural OCT measurements were significantly differed between the groups (P < 0.001). All FAZ metrics were inversely correlated with central foveal thickness (CFT) (P < 0.001). The FAZ area and perimeter were inversely correlated with the VD of both SCP and DCP (P < 0.05). The VDs of SCP and DCP were significantly differed between the study groups (P < 0.001). The VEP latency was inversely correlated with the retinal nerve fibre layer, macular and ganglion cell layer thicknesses, the VD of SCP, and the VD of the DCP (P < 0.001).

CONCLUSIONS

Based on OCT angiography, VDs of macular and peripapillary area may be useful in detecting damage from ON in patients with MS.

Percutaneous Venous Angioplasty in Patients with Multiple Sclerosis and Chronic Cerebrospinal Venous Insufficiency: A Randomized Wait List Control Study

BACKGROUND

Venous percutaneous transluminal angioplasty (vPTA) in patients with multiple sclerosis (MS) and chronic cerebrospinal venous insufficiency (CCSVI) have shown contradictory results. The aim of the study is to evaluate the efficacy of the procedure in a randomized wait list control study.

METHODS

66 adults with neurologist-confirmed diagnosis of MS and sonographic diagnosis of CCSVI were allocated into vPTA-yes group (n = 31) or vPTA-not group (n = 35, control group). vPTA was performed immediately 15 days after randomization in the PTA-yes group and 6 months later in the control group. Evoked potentials (EPs), clinical-functional measures (CFMs), and upper limb kinematic measures (ULKMs) were measured at baseline (T0) and six months after in both groups, just before the venous angioplasty in the vPTA-not group (T1).

RESULTS

Comparing the vPTA-yes and vPTA-not group, the CFM-derived composite functional outcome showed 11 (37%) versus 7 (20%) improved, 1 (3%) versus 3 (8%) stable, 0 versus 7 (20%) worsened, and 19 (61%) versus 18 (51%) mixed patients (χ² = 8.71, df = 3, P = 0.03). Unadjusted and adjusted (for baseline confounding variables) odds ratio at 95% confidence interval were, respectively, 1.93 (1.3-2.8), P value 0.0007, and 1.85 (1.2-1.7), P value 0.002. EP- and ULKM-derived composite functional outcome showed no significant difference between the two groups.

CONCLUSIONS

Venous angioplasty can positively impact a few CFMs especially for the quality of life but achieving disability improvement is unlikely.

Developing therapeutic strategies to promote myelin repair in multiple sclerosis

Introduction: Approved disease-modifying therapies for multiple sclerosis (MS) lessen inflammatory disease activity that causes relapses and MRI lesions. However, chronic inflammation and demyelination lead to axonal degeneration and neuronal loss, for which there currently is no effective treatment. There has been increasing interest in developing repair-promoting strategies, but there are important unanswered questions regarding the mechanisms and appropriate methods to evaluate these treatments. Areas covered: The rationale for remyelinating agents in MS is discussed, with an overview of both myelin physiology and endogenous repair mechanisms. This is followed by a discussion of the identification and development of potential remyelinating drugs. Potential biomarkers of remyelination are reviewed, including considerations regarding measuring remyelination in clinical trials. Information and data were obtained from a search of recent literature through PubMed. Peer-reviewed original articles and review articles were included. Expert opinion: There are several obstacles to the translation of potential remyelinating agents to clinical trials, particularly uncertainty regarding the most appropriate study population and method to monitor remyelination. Refinements in clinical trial design and outcome measurement, potentially via advanced imaging techniques, are needed to optimize detection of repair in patients with MS.

Pathophysiological and cognitive mechanisms of fatigue in multiple sclerosis

Fatigue is one of the most common symptoms in multiple sclerosis (MS), with a major impact on patients' quality of life. Currently, treatment proceeds by trial and error with limited success, probably due to the presence of multiple different underlying mechanisms. Recent neuroscientific advances offer the potential to develop tools for differentiating these mechanisms in individual patients and ultimately provide a principled basis for treatment selection. However, development of these tools for differential diagnosis will require guidance by pathophysiological and cognitive theories that propose mechanisms which can be assessed in individual patients. This article provides an overview of contemporary pathophysiological theories of fatigue in MS and discusses how the mechanisms they propose may become measurable with emerging technologies and thus lay a foundation for future personalised treatments.

Multicentre assessment of motor and sensory evoked potentials in multiple sclerosis: reliability and implications for clinical trials

Background

Motor and sensory evoked potentials (EP) are potential candidate biomarkers for clinical trials in multiple sclerosis.

Objective

To determine test -retest reliability of motor EP (MEP) and sensory EP (SEP) and associated EP-scores in patients with multiple sclerosis.

Methods

In three centres, 16 relapsing and five progressive multiple sclerosis patients had MEPs and SEPs 1-29 days apart. Five neurophysiologists independently marked latencies by central reading. By variance component analysis, we estimated the critical difference (absolute reliability) for cross-sectional group comparison, comparison of longitudinal group changes, within-subject minimal detectable change and defined within-subject improvement.

Results

Cortical SEP responses and cortico-muscular MEP latencies were more reliable than central conduction times. For comparison of 20 subjects per arm, cross-sectional group difference ranged from 0.7 to 3.9 ms and 1.1 to 1.7, group difference in longitudinal changes from 0.4 to 1.8 ms and 0.36 to 0.62, within-subject minimal detectable change from 1.2 to 5.8 ms and 1.2 to 2.0, within-subject improvement from 0.8 to 3.8ms and 0.8 to 1.3, for single EP modalities and EP scores, respectively.

Conclusions

Multicentre EP assessment with central EP reading is feasible and reliable. The critical difference is reasonably low to detect significant group changes and to define responders. The results support the concept of using EP and EP-scores as candidate response biomarkers for quantification of disease progression and for studying remyelination in multiple sclerosis.

Is the triple stimulation technique a better quantification tool of motor dysfunction than motor evoked potentials in multiple sclerosis?

The triple stimulation technique (TST) was rarely used in multiple sclerosis (MS). This study aimed to compare TST and motor evoked potentials (MEP) for the quantification of motor dysfunction. Central motor conduction based on MEP (four limbs) and TST (upper limbs) was assessed in 28 MS patients with a median Expanded Disability Status Scale (EDSS) of 4. EDSS, timed 25-foot walk (T25FW), grasping strength and motor components of the MS functional composite were evaluated. Regression analysis was used to assess the relationship between MEP, TST and clinical findings. TST was negatively correlated with EDSS (r = - 0.74, p < 0.0001) and to a lesser extent with T25FW (r = - 0.47, p < 0.05), and grasping strength (r = - 0.43, p < 0.05). A multiple regression analysis underlined the better correlation between clinical data and TST (R² = 0.56, p < 0.0005) than with MEP (0.03 < R² < 0.22, p > 0.05). This study evidenced the value of TST as a quantification tool of motor dysfunction. TST appeared to reflect a global disability since it was correlated not only to hand function but also to walking capacity.

Prospective study of clinical, neurophysiological and urodynamic findings in multiple sclerosis patients undergoing percutaneous transluminal venous angioplasty

OBJECTIVE

Verify whether Percutaneous Transluminal Angioplasty (PTA) may affect neural conduction properties in Multiple Sclerosis (MS) patients, thereby modifying patients' disability, with prospective neurophysiological, urodynamic, clinical and subjective well-being evaluations.

METHODS

In 55 out of 72 consecutively screened MS patients, the following procedures were carried out before (T0), at 2-6 months (T1) and at 6-15 months (T2) after a diagnostic phlebography, eventually followed by the PTA intervention if chronic cerebrospinal venous insufficiency (CCSVI) was diagnosed: clinical/objective evaluation (Expanded Disability Status Scale, EDSS), ratings of subjective well-being, evaluation of urodynamic functions and multimodal EPs (visual, acoustic, upper and lower limbs somatosensory and motor evoked potentials).

RESULTS

The number of dropouts was relatively high, and a complete set of neurophysiological and clinical data remained available for 37 patients (19 for urological investigations). The subjective well-being score significantly increased at T1 and returned close to basal values at T2, but their degree of objective disability did not change. Nevertheless, global EP-scores (indexing the impairment in conductivity of central pathways in multiple functional domains) significantly increased from T0 (7.9 ± 6.0) to T1 (9.2 ± 6.3) and from T0 to T2 (9.8 ± 6.3), but not from T1 and T2 (p > 0.05). Neurogenic urological lower tract dysfunctions slightly increased throughout the study.

CONCLUSIONS

The PTA intervention did not induce significant changes in disability in the present cohort of MS patients, in line with recent evidence of clinical inefficacy of this procedure.

SIGNIFICANCE

Absence of multimodal neurophysiological and functional testing changes in the first 15 months following PTA suggests that conduction properties of neural pathways are unaffected by PTA. Current findings suggest that the short-lived (2-6 months), post-PTA, beneficial effect on subjective well-being measures experienced by MS patients is likely related to a placebo effect.

Vestibular Evoked Myogenic Potentials Are Abnormal in Idiopathic REM Sleep Behavior Disorder

Objectives: To investigate brainstem function in idiopathic REM sleep Behavior Disorder (iRBD), a condition occurring as a result of a derangement of connections within brainstem structures, with a battery of Vestibular Evoked Myogenic Potentials (VEMPs), neurophysiological tools suited for the functional investigation of the brainstem. Neurophysiological data were correlated with clinical characteristics of patients.

Methods: Twenty patients with iRBD and 22 healthy controls underwent cervical (cVEMP), masseter (mVEMP) and ocular (oVEMP) VEMP recording. Patients were assessed clinically according to presence of motor as well as non-motor symptoms such as constipation, depression, and hyposmia. Also, they were screened for postural instability through the Berg Balance Scale (BBS). VEMPs were categorized as for increasing degrees of abnormalities, namely latency delay, amplitude reduction and absence; a VEMP score was built accordingly.

Results: Compared with controls, iRBD had higher rates of abnormalities both in the VEMP battery (iRBD 75%, Controls 23%; p < 0.01) as well as in each single VEMP (cVEMP: 45 vs. 5%; mVEMP: 65 vs. 13.6%; oVEMP: 50 vs. 5%; p < 0.01), which exhibited significantly lower amplitudes (cVEMP and oVEMP: p < 0.0001; mVEMP: p = 0.001) in iRBD. Within altered reflexes, absence was predominant in oVEMP (81%), amplitude reduction in mVEMP (50%) and cVEMP (70%). Severity of VEMP alterations was significantly higher in iRBD compared with controls (p < 0.05 for all VEMPs), as indicated by the larger VEMP scores in the former. The oVEMP score correlated inversely with poor performances on the BBS.

Conclusion: VEMPs unveil consistent and extensive brainstem abnormalities in iRBD patients. Further studies are warranted for testing the potential of VEMPs in the monitoring of the evolution of iRBD over time.

Cortical Excitability and Interhemispheric Connectivity in Early Relapsing-Remitting Multiple Sclerosis Studied With TMS-EEG

Evoked potentials (EPs) are well established in clinical practice for diagnosis and prognosis in multiple sclerosis (MS). However, their value is limited to the assessment of their respective functional systems. Here, we used transcranial magnetic stimulation (TMS) coupled with electroencephalography (TMS-EEG) to investigate cortical excitability and spatiotemporal dynamics of TMS-evoked neural activity in MS patients. Thirteen patients with early relapsing–remitting MS (RRMS) with a median Expanded Disability Status Scale (EDSS) of 1.0 (range 0–2.5) and 16 age- and gender-matched healthy controls received single-pulse TMS of left and right primary motor cortex (L-M1 and R-M1), respectively. Resting motor threshold for L-M1 and R-M1 was increased in MS patients. Latencies and amplitudes of N45, P70, N100, P180, and N280 TMS-evoked EEG potentials (TEPs) were not different between groups, except a significantly increased amplitude of the N280 TEP in the MS group, both for L-M1 and R-M1 stimulation. Interhemispheric signal propagation (ISP), estimated from the area under the curve of TEPs in the non-stimulated vs. stimulated M1, also did not differ between groups. In summary, findings show that ISP and TEPs were preserved in early-stage RRMS, except for an exaggerated N280 amplitude. Our findings indicate that TMS-EEG is feasible in testing excitability and connectivity in cortical neural networks in MS patients, complementary to conventional EPs. However, relevance and pathophysiological correlates of the enhanced N280 will need further study.

No evidence of disease activity is associated with reduced rate of axonal retinal atrophy in MS

Objective:

To explore, in a longitudinal study, the usefulness of optical coherence tomography (OCT) in monitoring people with multiple sclerosis (MS) by testing the association between retinal nerve fiber layer (RNFL) thinning and clinical and brain MRI criteria of no evidence of disease activity (NEDA).

Methods:

OCT, visual evoked potentials (VEPs), and disability, using the Expanded Disability Status Scale (EDSS), were tested at baseline and after 2 years in 72 patients, 63 with routine yearly brain MRI.

Results:

Longitudinal mean binocular RNFL thinning, in absence of optic neuritis during follow-up, was correlated with EDSS worsening, also controlling for baseline EDSS, RNFL, disease duration, and MS subtype (Spearman ρ −0.462, p < 0.001; partial correlation coefficient −0.437, p < 0.001). At follow-up, patients classified as NEDA (20; 31.7%) had RNFL loss of −0.93 μm ± 1.35 SD, while patients with active disease had −2.83 μm ± 2 SD thinning (t test; p < 0.001). At logistic regression, mean RNFL reduction correctly classified 76.2% of patients as NEDA at 2 years (R2 0.355; p = 0.003). A cutoff of −1.25 μm RNFL loss classified NEDA status with specificity 81.4% and sensitivity 80% (receiver operating characteristic curve: area under the curve 0.8; p < 0.001). No significant longitudinal correlations were found between changes in RNFL and in VEP latencies or scores.

Conclusions:

NEDA is associated with a relatively preserved RNFL over 2 years. A greater neuroretinal loss was detected even in patients with clinical evidence of disease activity independently from changes in brain MRI lesions, prompting further validation of OCT as an additional tool in MS monitoring.

Is the Choosing Wisely® campaign model applicable to the management of multiple sclerosis in France? A GRESEP pilot study

BACKGROUND

Launched in the US in 2012, Choosing Wisely^® is a campaign promoted by the American Board of Internal Medicine (ABIM) Foundation with the goal of improving healthcare effectiveness by avoiding wasteful or unnecessary medical tests, treatments and procedures. It uses concise recommendations produced by national medical societies to start discussions between physicians and patients on the relevance of these services as part of a shared decision-making process. The Multiple Sclerosis Focus Group (Groupe de Reflexion Autour de la Sclérose en Plaques; GRESEP) undertook a pilot study to assess the relevance and feasibility of this approach in the management of multiple sclerosis (MS) in France.

METHODS

Recommendations were developed using the formal consensus method from the guidelines of the French National Health Authority (HAS). A steering committee selected the themes and drafted concise evidence reviews. An independent rating group then assessed these recommendations for clarity, relevance and feasibility.

RESULTS

Seven recommendations were accepted: (1) avoid systematic ordering of multimodal evoked potential studies for diagnosing MS; (2) do not treat MS relapses with low-dose oral corticosteroids; (3) when treating MS relapse with high-dose corticosteroids, the systematic use of the intravenous route is unnecessary if the oral route can be used; (4) systematic hospitalization is not necessary for treating MS relapse with high-dose corticosteroid therapy, particularly if the oral route is used, except for the first treated relapse and the presence of exclusion or non-eligibility criteria; (5) in the absence of clinical signs or symptoms of urinary infection, avoid systematic screening with urine microscopy and culture before the administration of corticosteroid therapy for MS relapse in patients using intermittent self-catheterization; (6) avoid antibiotic treatment of clinically asymptomatic MS patients using intermittent self-catheterization, even if urine microscopy and culture reveal the presence of microorganisms; and (7) avoid introducing symptomatic drug treatment for MS-related fatigue.

CONCLUSION

This pilot study, the first of its kind in France, has demonstrated the relevance and feasibility of adapting the Choosing Wisely^® model to MS by practitioners specializing in the disorder. However, the acceptability of these recommendations by other practitioners in other specialist fields as well as their impact on everyday clinical practices now need to be studied.

Multiple biomarkers improve the prediction of multiple sclerosis in clinically isolated syndromes

OBJECTIVES

Since its introduction, MRI had a major impact on the early and more precise diagnosis of multiple sclerosis (MS), and the 2010 diagnostic criteria even allow a diagnosis to be made just after a single attack if stringent MRI criteria are met. Several other clinical and paraclinical markers have been reported to be associated with an increased risk of MS independently of MRI in patients with clinically isolated syndromes (CIS), but the incremental usefulness of adding them to the current criteria has not been evaluated. In this study, we determined whether multiple biomarkers improved the prediction of MS in patients with CIS in a real-world clinical practice.

MATERIALS AND METHODS

This was a retrospective study involving patients with CIS admitted to our department between 2000 and 2013. We evaluated baseline clinical, MRI, neurophysiological, and cerebrospinal fluid (CSF) data.

RESULTS

During follow-up (median, 7.2 years), 127 of 243 participants (mean age, 31.6 years) developed MS. Cox proportional-hazards models adjusted for established MRI criteria, age at onset, number of T1 lesions, and presence of CSF oligoclonal bands significantly predicted the risk of developing MS at 2 and 5 years. The use of multiple biomarkers led to 29% net reclassification improvement at 2 years (P<.001) and 30% at 5 years (P<.001).

CONCLUSIONS

The simultaneous addition of several biomarkers significantly improved the risk stratification for MS in patients with CIS beyond that of a model based only on established MRI criteria.

Fluid biomarker and electrophysiological outcome measures for progressive MS trials

Progressive multiple sclerosis (MS) is characterized by insidious clinical worsening that is difficult to accurately quantify and predict. Biofluid markers and electrophysiological measures are potential candidate outcome measures in clinical trials, allowing the quantification of nervous damage occurring in the disease. Neurofilaments are highly specific neuronal proteins. They may have come closest to such applications by their higher concentrations repeatedly demonstrated in cerebrospinal fluid (CSF) in all stages of MS, during relapses, their responsiveness to disease-modifying treatments in relapsing and progressive MS and their associations with measures of inflammatory and degenerative magnetic resonance imaging (MRI) outcomes. Digital single-molecule array (Simoa) technology improves accuracy of bioassays in the quantification of neurofilament light chain (NfL) in serum and plasma. NfL seems to mark a common final path of neuroaxonal injury independent of specific causal pathways. CSF and blood levels of NfL are highly correlated across various diseases including MS, suggesting that blood measurements may be useful in assessing response to treatment and predicting future disease activity. Other biomarkers like matrix metalloproteinases, chemokines, or neurotrophic factors have not been studied to a similar extent. Such measures, especially in blood, need further validation to enter the trial arena or clinical practice. The broadening armamentarium of highly sensitive assay technologies in the future may shed even more light on patient heterogeneity and mechanisms leading to disability in MS. Evoked potentials (EPs) are used in clinical practice to measure central conduction of central sensorimotor pathways. They correlate with and predict the severity of clinical involvement of their corresponding function. Their validation for use in multicenter studies is still lacking, with the exception of visual EPs. If further validated, EPs and fluid biomarkers would represent useful outcome measures for clinical trials, being related to specific mechanisms of the ongoing pathologic changes.

Cytotoxic CD4+ T Cells Drive Multiple Sclerosis Progression

Multiple sclerosis (MS) is the leading cause of chronic neurological disability in young adults. The clinical disease course of MS varies greatly between individuals, with some patients progressing much more rapidly than others, making prognosis almost impossible. We previously discovered that cytotoxic CD4+ T cells (CD4+ CTL), identified by the loss of CD28, are able to migrate to sites of inflammation and that they contribute to tissue damage. Furthermore, in an animal model for MS, we showed that these cells are correlated with inflammation, demyelination, and disability. Therefore, we hypothesize that CD4+ CTL drive progression of MS and have prognostic value. To support this hypothesis, we investigated whether CD4+ CTL are correlated with worse clinical outcome and evaluated the prognostic value of these cells in MS. To this end, the percentage of CD4+CD28null T cells was measured in the blood of 176 patients with relapsing-remitting MS (=baseline). Multimodal evoked potentials (EP) combining information on motoric, visual, and somatosensoric EP, as well as Kurtzke expanded disability status scale (EDSS) were used as outcome measurements at baseline and after 3 and 5 years. The baseline CD4+CD28null T cell percentage is associated with EP (P = 0.003, R2 = 0.28), indicating a link between these cells and disease severity. In addition, the baseline CD4+CD28null T cell percentage has a prognostic value since it is associated with EP after 3 years (P = 0.005, R2 = 0.29) and with EP and EDSS after 5 years (P = 0.008, R2 = 0.42 and P = 0.003, R2 = 0.27). To the best of our knowledge, this study provides the first direct link between the presence of CD4+ CTL and MS disease severity, as well as its prognostic value. Therefore, we further elaborate on two important research perspectives: 1° investigating strategies to block or reverse pathways in the formation of these cells resulting in new treatments that slow down MS disease progression, 2° including immunophenotyping in prediction modeling studies to aim for personalized medicine.

A new role for evoked potentials in MS? Repurposing evoked potentials as biomarkers for clinical trials in MS

Evoked potentials (EP) characterize signal conduction in selected tracts of the central nervous system in a quantifiable way. Since alteration of signal conduction is the main mechanism of symptoms and signs in multiple sclerosis (MS), multimodal EP may serve as a representative measure of the functional impairment in MS. Moreover, EP have been shown to be predictive for disease course, and thus might help to select patient groups at high risk of progression for clinical trials. EP can detect deterioration, as well as improvement of impulse propagation, independently from the mechanism causing the change. Therefore, they are candidates for biomarkers with application in clinical phase-II trials. Applicability of EP in multicenter trials has been limited by different standards of registration and assessment.