Physiological measures of therapeutic response to interferon beta-1a treatment in remitting-relapsing MS

Motor Evoked Potential-A Pilot Study Looking at Reliability and Clinical Correlations in Multiple Sclerosis

PURPOSE

Multiple sclerosis (MS) is a clinically heterogeneous disease. Biomarkers that can assess pathological processes that are unseen with conventional imaging remain an unmet need in MS disease management. Motor evoked potentials (MEPs) could be such a biomarker. To determine and follow longitudinal MEP reliability and correlations with clinical measures in MS patients.

METHODS

This is a single-center study in alemtuzumab-treated MS patients to evaluate temporal reliability of MEPs, identify MEP minimum detectible differences, and explore correlations with existing clinical scales. Ten MS patients recently treated with alemtuzumab were evaluated every 6 months over 3 years. Clinical evaluations consisted of expanded disability status scale, timed 25-foot walk, 6-minute walk, and nine-hole peg test. MEPs were measured twice, 2 weeks apart, every 6 months.

RESULTS

Eight patients completed all 3 years of study. The intraclass correlation coefficient for MEP parameters ranged from 0.76 to 0.98. TA latency and amplitude with facilitation significantly and strongly correlated with all clinical measures, whereas the MEP duration modestly correlated. Biceps latency with facilitation significantly and moderately correlated with 9-hole peg test. Longitudinal correlations demonstrated good predictive values for either clinical deterioration or improvement.

CONCLUSIONS

MEPs have excellent intrapatient and intrarater reliability, and TA MEPs significantly and strongly correlated with expanded disability status scale, 6-minute walk, and timed 25-foot walk, whereas biceps MEPs significantly and moderately correlated with nine-hole peg test. Further studies using larger cohorts of MS patients are indicated.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov, Identifier: NCT02623946.

Clinical diagnostic utility of transcranial magnetic stimulation in neurological disorders. Updated report of an IFCN committee

The review provides a comprehensive update (previous report: Chen R, Cros D, Curra A, Di Lazzaro V, Lefaucheur JP, Magistris MR, et al. The clinical diagnostic utility of transcranial magnetic stimulation: report of an IFCN committee. Clin Neurophysiol 2008;119(3):504-32) on clinical diagnostic utility of transcranial magnetic stimulation (TMS) in neurological diseases. Most TMS measures rely on stimulation of motor cortex and recording of motor evoked potentials. Paired-pulse TMS techniques, incorporating conventional amplitude-based and threshold tracking, have established clinical utility in neurodegenerative, movement, episodic (epilepsy, migraines), chronic pain and functional diseases. Cortical hyperexcitability has emerged as a diagnostic aid in amyotrophic lateral sclerosis. Single-pulse TMS measures are of utility in stroke, and myelopathy even in the absence of radiological changes. Short-latency afferent inhibition, related to central cholinergic transmission, is reduced in Alzheimer's disease. The triple stimulation technique (TST) may enhance diagnostic utility of conventional TMS measures to detect upper motor neuron involvement. The recording of motor evoked potentials can be used to perform functional mapping of the motor cortex or in preoperative assessment of eloquent brain regions before surgical resection of brain tumors. TMS exhibits utility in assessing lumbosacral/cervical nerve root function, especially in demyelinating neuropathies, and may be of utility in localizing the site of facial nerve palsies. TMS measures also have high sensitivity in detecting subclinical corticospinal lesions in multiple sclerosis. Abnormalities in central motor conduction time or TST correlate with motor impairment and disability in MS. Cerebellar stimulation may detect lesions in the cerebellum or cerebello-dentato-thalamo-motor cortical pathways. Combining TMS with electroencephalography, provides a novel method to measure parameters altered in neurological disorders, including cortical excitability, effective connectivity, and response complexity.

Functional connectivity in multiple sclerosis after robotic rehabilitative treatment: A case report

RATIONALE

Multiple sclerosis (MS) is an inflammatory demyelinating disease of central nervous system and it is associated with an impaired motor function status. The efficacy of rehabilitation in promoting functional recovery and increasing quality of life in MS patients has been demonstrated.

PATIENT CONCERNS

A 47-year-old woman was diagnosed with relapsing-remitting multiple sclerosis (RRMS) in November 2014 because of left upper limb hypoesthesia and weakness with difficulty in hand manipulation skills (there was a 1-point Expanded Disability Status Scale (EDSS) progression, i.e., 2.5 vs 1.5). Magnetic resonance image (MRI) showed a new frontal right cortical high-signal-intensity lesion.

DIAGNOSIS

Neurological and MRI examination were suggestive of MS diagnosis.

INTERVENTIONS

Patient was treated with robotic rehabilitation and evaluated by a Glove Analyzer for fMRI system (GAF). Functional MRI (fMRI) was acquired before and at the end of rehabilitative treatment performed with robotic device (Armeo-power).

OUTCOMES

At the end of the rehabilitation program, most of the behavioral parameters, GAF and fMRI evaluation, showed a significative improvement. Moreover, fMRI showed a significantly increased functional activation within the sensory-motor network in the active, motor task.

LESSONS

Our findings suggest a possible restorative effect of robotics on brain networks. Moreover, we may argue that GAF may be a valuable tool in assessing functional recovery after upper limb rehabilitation, especially of associated to fMRI examination.

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.

Disease-specific quality of life in multiple sclerosis: the effect of disease modifying treatment

Disease specific quality of life was measured in the Leeds Multiple Sclerosis (MS) Treatment Programme (n-/210) using the self-report Leeds MS Quality of Life (LMSQoL) scale. The results showed a significant and sustained increase in quality of life associated with ‘disease modifying’ treatment. This contrasts with the Expanded Disability Status Scores (EDSS), which showed no measurable improvement. An increase in the LMSQoL score did not correlate with baseline age, disease duration, disability or number of prior relapses. There was no significant difference in treatment effect between relapsing-remitting and secondary progressive MS patients, or between patients receiving different products. However, patients with a poor quality of life at baseline showed the most benefit from treatment. Those who had their treatment stopped due to progression, side-effects or lack of effect had significantly lower LMSQoL scores on treatment. In this study, the LMSQoL scale was responsive to change and was easy to administer in a clinical setting.

The use of transcranial magnetic stimulation in diagnosis, prognostication and treatment evaluation in multiple sclerosis

Despite advances in brain imaging which have revolutionised the diagnosis and monitoring of patients with Multiple Sclerosis (MS), current imaging techniques have limitations, including poor correlation with clinical disability and prognosis. There is growing evidence that electrophysiological techniques may provide complementary functional information which can aid in diagnosis, prognostication and perhaps even monitoring of treatment response in patients with MS. Transcranial magnetic stimulation (TMS) is an underutilised technique with potential to assist diagnosis, predict prognosis and provide an objective surrogate marker of clinical progress and treatment response. This review explores the existing body of evidence relating to the use of TMS in patients with MS, outlines the practical aspects and scope of TMS testing and reviews the current evidence relating to the use of TMS in diagnosis, disease classification, prognostication and response to symptomatic and disease-modifying therapies.

Clinical neurophysiology of multiple sclerosis

The availability of new treatments able to modify the natural course of multiple sclerosis (MS) has generated interest in paraclinical measures to monitor disease evolution. Among these, neurophysiologic measures, mainly evoked potentials (EPs), are used in the functional assessment of central sensorimotor and cognitive networks affected by MS. EP abnormalities may reveal subclinical lesions, objectivate the involvement of sensory and motor pathways in the presence of vague disturbances, and provide indications of the demyelinating nature of the disease process. However, their diagnostic value is much lower than that of magnetic resonance imaging, and is more sensitive to brain and cervical spinal cord lesions. The application of EPs in assessing disease severity and monitoring the evolution of nervous damage is more promising, thanks to their good correlation with disability in cross-sectional and longitudinal studies, and potential use as paraclinical endpoints in clinical trials. Recent evidence indicates that EPs performed early in the disease may help to predict a worse future progression in the long term. If confirmed, these data suggest the possible usefulness of EPs in the early identification of patients who are more likely to develop future disability, thus requiring more frequent monitoring or being potential candidates for more aggressive disease-modifying treatments.

A qualitative review of the neurophysiological underpinnings of fatigue in multiple sclerosis

Fatigue is debilitating in multiple sclerosis (MS) and may have multiple causes. Recent investigations into objectively measurable correlates of fatigue have used transcranial magnetic stimulation (TMS) to examine a range of neurophysiological measures of neural excitability that may be altered in patients with MS. This qualitative review was conducted to test the hypothesis that changes in neural excitability are a contributing factor in MS-related fatigue. A search of the English language literature led to the compilation and synthesis of original research papers in which various aspects of neural excitability and neural transmission were measured using TMS in patients with MS. The resulting papers were classified into three categories of study relevant to fatigue: abnormalities in excitability and their correlation with self-reported fatigue; effects of exercise-induced fatigue on neural excitability; and effects of fatigue medications on neural excitability. Evidence of an association between fatigue and intracortical inhibition is both limited and conflicting, and no evidence suggests associations of fatigue with corticomotor excitability or neuronal conduction. Pharmacologically-induced changes in fatigue were found to correlate with changes in intracortical excitability. No conclusions could be drawn regarding neural excitability and exercise-induced fatigue, due to variability in study populations, outcome measures, and exercise protocols across different studies. Suggestions for future studies in this area are proposed with a view to identifying potentially modifiable factors contributing to fatigue in MS.

Systematic review of disease-modifying therapies to assess unmet needs in multiple sclerosis: tolerability and adherence

Reviews of therapeutic drugs usually focus on the highly selected and closely monitored patient populations from randomized controlled trials. The objective of this study was to review systematically the tolerability and adherence of multiple sclerosis disease-modifying therapies, using data from both randomized controlled trials and observational settings. Relevant literature was identified using predefined search terms, and adverse event and study discontinuation data were extracted and categorized according to study type (randomized controlled trial or observational) and study duration. A total of 151 papers were selected for analysis; 33% were classified as randomized controlled trials and 62% as observational studies. Most of the papers concerned interferon preparations and glatiramer acetate; the limited available information on mitoxantrone and natalizumab precluded extensive examination of these. The most common adverse events were flu-like symptoms (interferon therapies only) and injection-site reactions. Mean discontinuation rates ranged from 16% to 27%. There were no marked differences in tolerability or adherence data from randomized controlled trials and observational studies, but the incidence of adverse events remained high in lengthy studies and discontinuations accumulated with time. The present systematic review of randomized clinical trial and observational data highlights the tolerability and adherence issues associated with commonly used first-line multiple sclerosis treatments.

Natalizumab restores evoked potential abnormalities in patients with relapsing-remitting multiple sclerosis

BACKGROUND AND OBJECTIVE

The objective of this study was to examine the effects of natalizumab on functional parameters assessed by evoked potentials (visual [VEP], somatosensory [SEP] and motor evoked potentials [MEP]) in a cohort study in relapsing-remitting multiple sclerosis patients.

METHODS

EP data of 44 patients examined 12 months prior to natalizumab treatment, at the timepoint of treatment initiation and 1 year later were compared. Sum scores (VEP, MEP, SEP) were evaluated and correlated with the Expanded Disability Status Scale.

RESULTS

Improvement of the VEP sum score was found in 33% of natalizumab-treated patients but only in 9% of the same patients prior to treatment (p = 0.041). A comparable situation was found for SEP (improvement: 32% versus 5%; worsening: 11% versus 37%; p = 0.027). For MEP no significant differences were seen (improvement: 10% versus 18%; worsening: 5% versus 29%; p = 0.60). EP recordings (VEP = SEP > MEP) have the capacity to demonstrate treatment effects of natalizumab on a functional level.

CONCLUSIONS

Natalizumab therapy increases the percentage of patients showing stable or even ameliorated electrophysiological parameters in the investigated functional systems.

Brain activation in multiple sclerosis: a BOLD fMRI study of the effects of fatiguing hand exercise

Background

Multiple sclerosis (MS) patients experience fatigue as a chronic symptom that decreases quality of life. Commonly, fatigue in MS patients is manifested as decreased motor function during or after physical activity and is associated with changes in brain metabolism.

Objective

To determine brain activation patterns in MS patients and healthy controls during a simple motor task before and after fatiguing hand-grip exercise.

Methods

Functional magnetic resonance imaging (fMRI) scans were conducted on 10 MS patients and 13 healthy controls during 4-finger flexion and extension in rested and fatigued states.

Results

Before the fatigue protocol, MS patients had greater activation in the contralateral primary motor cortex, insula, and cingulate gyrus than controls. Following fatiguing exercise, controls showed increased activation of precentral gyrus and insula while patients did not show any activation increases and actually decreased activity to the insula.

Conclusion

Results indicate that before fatiguing exercise, MS patients marshaled more brain activation compared to controls, which may represent functionally adaptive changes in response to demyelination. This increased activation may suggest that patients require more effort to perform even simple motor tasks, possibly because peripheral or central signals for fatigue are chronically enhanced. When fatigued further by muscle contraction, brain activation cannot be further increased.

Assessing walking speed in clinical research: a systematic review

OBJECTIVE

To provide a systematic review and describe how assessments of walking speed are reported in the health care literature.

METHODS

MEDLINE electronic database and bibliographies of select articles were searched for terms describing walking speed and distances walked. The search was limited to English language journals from 1996 to 2006. The initial title search yielded 793 articles. A review of the abstracts reduced the number to 154 articles. Of these, 108 provided sufficient information for inclusion in the current review.

RESULTS

Of the 108 studies included in the review 61 were descriptive, 39 intervention and 8 randomized controlled trials. Neurological (n=55) and geriatric (n=27) were the two most frequent participant groups in the studies reviewed. Instruction to walk at a usual or normal speed was reported in 55 of the studies, while 31 studies did not describe speed instructions. A static (standing) start was slightly more common than a dynamic (rolling) start (30 vs 26 studies); however, half of the studies did not describe the starting protocol. Walking 10, 6 and 4 m was the most common distances used, and reported in 37, 20 and 11 studies respectively. Only four studies included information on whether verbal encouragement was given during the walking task.

CONCLUSIONS

Tests of walking speed have been used in a wide range of populations. However, methodologies and descriptions of walking tests vary widely from study to study, which makes comparison difficult. There is a need to find consensus for a standardized walking test methodology.

Relationship between test methodology and mean velocity in timed walk tests: a review

OBJECTIVE

To assess the degree to which test methodology affects outcomes in clinical evaluations of walking speed.

DATA SOURCES

Medline database and reference lists from relevant articles.

STUDY SELECTION

We conducted electronic searches by using various combinations of terms related to clinical evaluations of walking speed. Resultant abstracts were then reviewed, and the methods and results section of promising full-text articles were searched for detailed descriptions of walk-test methodologies and results. Ultimately, articles were limited to the most common participant groups, older adults (aged) and individuals with neurologic conditions (neuro). The final sample included 46 studies.

DATA EXTRACTION

Three aspects of test methodology (pace, starting protocol, distance timed) were extracted for use as independent variables. Group mean age was extracted for use as a covariate. Group mean velocity was extracted for use as the dependent variable. Data were extracted by a single investigator.

DATA SYNTHESIS

Usual and/or comfortable pace was reported nearly twice as often as fast pace in both groups. Static-start protocols were more frequently used in aged studies, whereas dynamic (ie, rolling) starts were more common in neuro studies. Distances of 6 and 10m were most common in aged and neuro studies, respectively. Multivariate analyses (analysis of covariance) showed that only pace was significantly related to the mean velocity in both groups (aged: pace, P<.01; starting protocol, P=.21; distance, P=.05; neuro: pace, P=.01; starting protocol, P=.63; distance, P=.49). However, methodology-related differences in the distribution (95% confidence intervals) of performance scores across certain clinical standards were noted within all 3 methodology variables.

CONCLUSIONS

Clinical assessments of walking velocity are not conducted uniformly. Common methodologic factors may influence the clinical interpretation of walk performances. Universal walk-test methodology is warranted to improve intergroup comparisons and the development of useful clinical criteria and consensus norms.

Prospective clinical and electrophysiological follow-up on a multiple sclerosis population treated with interferon beta-1 a

Objective To analyse transcranial magnetic stimulation (TMS) variables in a prospective six-month follow-up pilot study on patients suffering from relapsing-remitting multiple sclerosis (RRMS), satisfying inclusion criteria for interferon (IFN) beta-1a treatment.

Background So far, no predictive factors are available as to the course of RRMS treated with IFN beta-1 a.

Design/methods Fifteen RRMS patients were studied before (month 0 (M0)) and after IFN beta-1a onset (M3, M6). The parameters analysed were motor functional score (mFS), Expanded Disability Status Scale (EDSS), and TMS variables - central motor conduction time (CMCT) and amplitude ratio (AR).

Results Four of the six patients with no motor signs at inclusion, subsequently showed signs of pyramidal dysfunction. All had abnormal M0_TMS variables. The number of M0_TMS abnormalities per patient was greatest in the group that showed mFS worsening, and was significantly correlated with M6_EDSS. The M0_CMCT was significantly correlated with M6_EDSS. During follow-up, the number of patients with abnormal TMS variables decreased from 12/15 to 4/15, and the total number of abnormalities decreased from 33.3 to 16.7%.

Conclusions TMS variables might be predictive of disease progression. The improvement observed here in the TMS variables may reflect an improvement in MS patients undergoing IFN beta treatment. Multiple Sclerosis 2007; 13: 348-356. http://msj.sagepub.com