A study of clinical, MRI and multimodality evoked potentials in neurologic Wilson disease

The aims of this study were evaluate motor, somatosensory, visual and auditory brainstem evoked potential (MEP, SEP, VEP, ABER) changes in Wilson disease (WD) and correlate these with magnetic resonance imaging (MRI) and clinical findings.
Neurologic WD diagnosed on the basis of clinical, ceruloplasmin and Kayser–Fleischer ring were evaluated including pedigree charting, hepatic, renal, hematologic and osteoarticular manifestations. Blood counts, serum chemistry, MRI, MEP to tibialis anterior, tibial SEP, VEP and ABER were performed. Evoked potential (EP) changes were correlated with clinical and MRI findings.
Eighteen WD patients were recruited from 17 families whose mean age was 16 years. Movement disorders were present in 14, cognitive decline in 12 and pyramidal signs in 12 patients. MRI revealed involvement of basal ganglia in 80%, thalamus in 40%, brain stem in 46.7% and subcortical white matter in 53.3%. MEP was abnormal in 35.7%, SEP in 30.8%, VEP in 57% and ABER in 61.5% patients; the latter three EP changes were subclinical. Frequency and number of EP abnormalities were higher with increasing severity of illness.
SEP, VEP and ABER reveals subclinical abnormality and MEP helps in documenting both clinical and subclinical abnormalities. Number of EP abnormalities increases with increasing clinical severity of WD.     

Survival, and time to an advanced disease state or progression, of untreated patients with moderately severe multiple sclerosis in a multicenter observational database: relevance for design of a clinical trial for high dose immunosuppressive therapy with autologous hematopoietic stem cell transplantation

Despite prolonged survival, patients with multiple sclerosis (MS) experience considerable morbidity, which adversely impacts quality of life. To assess the risk-benefit of a clinical trial of high dose immunosuppressive therapy with autologous hematopoietic stem cell transplantation for MS, we sought to determine the natural history of the disease in a comparison group of untreated patients. We identified 285 individuals with 2132 combined observation years (median: 5.6 years; 5th to 95th percentile: 1-21 years), with Expanded Disability Status Scale (EDSS) scores of 3.0-5.5 at baseline observation. Disease-related mortality was zero at five years, 5.4% at 10 years, and 22% at 15 years (40 patients contributing to the data point; 95% confidence interval: 4-32%). Risk for progression to advanced disability, defined as an EDSS score of 8, was very low for the subgroup with a baseline EDSS score of 3-3.5; however, for those with a baseline EDSS score of 4-5.5, 3% had advanced disability after two years, 5% after three years, 6% after four years, 12% after five years, and 40% after 10 years. The estimated probability of disease progression, defined as an increase in EDSS score by > or = 1.0 sustained for at least 180 days, was 5% after one year, 14% after two years, 22% after three years, 38% after five years, 57% after 10 years, and >80% after 20 years of observation. The relevance of these features to the design of the clinical trial is discussed.     

APOE genotype is a major predictor of long-term progression of disability in MS

BACKGROUND AND OBJECTIVE: The authors recently reported that the APOE epsilon4 allele is associated with significantly greater progression of disability in a 2-year follow-up of patients with MS. In this study, these findings are substantiated and extended in a much larger group of patients followed for up to 40 years. METHODS: Two hundred five patients with clinically definite MS who were genotyped for the APOE epsilon4 carrier state were included. Groups of patients with (n = 41) and without (n = 164) APOE epsilon4 alleles were compared for latency to expanded disability status scale (EDSS) scores of 4.0 and 6.0 by Kaplan-Meier analysis with the log rank test. The results were adjusted for age at onset and sex by Cox regression analysis. RESULTS: The APOE epsilon4 allele frequency in patients with MS (0.10) was similar to that in the general Israeli population. There was a significant effect of APOE genotype on the latency to reach EDSS 4.0 and 6.0 (p = 0.0002 and p = 0.0006 by two-tailed log rank test). Median latencies were shorter by 12 and 11 years in the APOE epsilon4 group for these outcomes. These results were significant after adjustment for age at onset and sex. CONCLUSIONS: The APOE epsilon4 allele is associated with significantly faster progression of disability in MS. This is the first genetic factor to be identified with a major impact on the progression of disability in this disease.     

Quantitative MRI in patients with clinically isolated syndromes suggestive of demyelination

OBJECTIVE: To assess the long-term predictive value of quantitative lesion load measurement on brain MRIs in patients after a 10-year follow-up who presented initially with a clinically isolated syndrome of the optic nerve, brainstem, or spinal cord. BACKGROUND: Quantitative MRI measurement is being used in treatment trials as a surrogate marker in MS, but there is a lack of long-term MRI follow-up data in assessing the natural course of the disease from the earliest stages. METHODS: Using a semiautomated threshold technique, the total lesion volume (TLV), the course of the disease, and disability were assessed in 58 patients at onset and after 5 and 10 years. RESULTS: The TLV at presentation correlated significantly (r = 0.81, p = 0.0001) with the TLV and also with the Expanded Disability Status Scale (EDSS) score (r = 0.45, p = 0.001) at 10-year follow-up. In contrast there was no correlation of the TLV at 5 years with subsequent change in EDSS score over the next 5 years (r = 0.18, p = 0.12). The change in TLV over the first 5 years in patients who developed clinically definite MS (CDMS) differed significantly according to the type of disease course (relapsing-remitting with disability, secondary progressive, or benign) manifesting at 10-year follow-up. CONCLUSION: Quantification of changes detected by T2-weighted brain MRI at the earliest clinical stages is strongly predictive of the subsequent development of CDMS as well as the clinical course and level of disability 10 years later.     

Electrophysiological and clinical correlates of corpus callosum atrophy in patients with multiple sclerosis

Abstract

Multiple sclerosis (MS) is an idiopathic inflammatory demyelinating disorder of the central nervous system (CNS) characterized by demyelination and axonal degeneration. Corpus callosum (CC) is commonly involved during the disease process leading to atrophy (93%). Currently, there are no established markers of disease progression and the interplay of processes leading to brain atrophy in MS remains unknown. The primary aim of this study was to assess the frequency of CC atrophy in MS patients. Furthermore, the relationship between expanded disability status scale (EDSS) and transcranial magnetic stimulation (TMS) evoked motor potentials (MEP) were assessed to capture disease effects by independent parameters. Seventy-nine MS patients and 50 controls were included and their CC volumes were assessed. Out of 79 patients, 31 patients (39·2%) had CC atrophy. The distribution of EDSS scores among the group with CC atrophy [13 (32%) patients with EDSS 0–2; 11 (58%) patients with EDSS 2–4; 19 (24%) patients with EDSS ≥4] was not statistically significant (p>0·05). MEP latency was abnormal in 34 (43%) patients, 67 (85%) patients had abnormal MEP amplitude and CMCT was abnormal in 32 (41%) patients. The relation between EDSS and MEP was statistically significant among the patient population including the subgroup of patients with CC atrophy (p<0.05). Our results lacked to provide an association between disability and CC atrophy, but there was a correlation between CC atrophy and TMS evoked motor potentials. Early evolution of axonal degeneration and brain atrophy should be considered in terms of follow-up measures to provide long-term efficiency impacting disability, progression and brain atrophy.     

Prognostic value of multimodal evoked potentials in multiple sclerosis: the EP score

Evoked potentials (EPs) have long been used as diagnostic tools in multiple sclerosis (MS), although their importance decreased as magnetic resonance imaging (MRI) became available. However, the prognostic value of EPs in MS has not been completely established. The aim of the study was to analyze the prognostic significance of EPs in a cohort of MS cases. From the Verona University Hospital MS Clinic database we retrospectively identified 80 MS patients who underwent a complete neurophysiological evaluation, including visual, brain stem, somatosensory and motor EPs and who were followed for at least 5 years after the study. EPs abnormalities were quantified through an index of global EPs alteration (EP score). The relationship between EP score and disability in terms of Expanded Disability Status Scale (EDSS) was analyzed by the Kaplan–Meier survival method and Spearman ρ correlation coefficient. ROC curves were used to determine the best EP score cut off to predict different EDSS endpoints. For each endpoint, sensitivity, specificity, positive and negative predictive value of EP score were calculated. We found a significant correlation (p < 0.001) between EP score and EDSS score at the time of neurophysiological study and at 1, 3 and 5 years of follow-up, particularly for motor and somatosensory EPs. Kaplan–Meier curves confirmed an increased risk of disability in those patients with EP score higher than the median value. EP score of 8 or 9 showed the highest sensitivity and specificity in predicting EDSS 4.0 and 6.0. EPs are reliable procedures to predict disability in MS patients. The correlation between EPs abnormalities and EDSS is higher than between conventional MRI and EDSS.     

Plasma S100beta and NSE levels and progression in multiple sclerosis

Plasma levels of the glial cell marker S100beta and the neuronal marker neuron-specific enolase (NSE) are elevated in various conditions of central nervous system damage. In this study we investigated whether plasma levels of S100beta and NSE are related to disease progression in multiple sclerosis (MS). Plasma levels of S100beta and NSE were measured in 25 patients with relapsing remitting MS (RRMS), 23 with secondary progressive MS (SPMS) and 16 with primary progressive MS (PPMS). All MS patients were in a clinically stable phase. Progression and disability were evaluated during a follow-up period of five years. We found that plasma NSE levels were lower in patients with clinically relevant worsening on the Expanded Disability Status Scale (EDSS), defined as 1 point increase from EDSS <6.0 or 0.5 point increase from EDSS> or =6 after five years (p=0.042), and in patients with a progressive disease course (p=0.01). There was a significant negative correlation between plasma NSE levels and both EDSS and Multiple Sclerosis Severity Status (MSSS) scores at baseline and after five years of follow-up (r=-0.33 and -0.38, p=0.027 and 0.003). There were no significant differences between patient groups in plasma S100beta levels. Plasma NSE levels appear inversely related to disease progression in MS.     

Utilization of the multiple sclerosis functional composite in follow-up: relationship to disease phenotype, disability and treatment strategies

As multiple sclerosis (MS) has a dynamic process, monitoring of the disability is important in the remission period. The main aim of the present study was to investigate the usefulness of MSFC instead of EDSS in the follow-up period of MS. In addition, evaluation of the effect of immunomodulatory therapy, and the difference among the type of MS in follow-up was purposed. One hundred and eighty-three patients with definite MS were enrolled in the present study. Patients were diagnosed as having relapsing-remitting (RR) MS (n=149) or secondary progressive (SP) MS (n=34). Fifty-eight out of 149 RRMS patients who had at least two relapses in the last 2 years have received any of the immunomodulator agents. The Multiple Sclerosis Functional Composite (MSFC) and Expanded Disability Status Scale (EDSS) were performed at baseline and after 2 years to assess disability. Patients who were under disease modifying therapy were assessed before the treatment and 2 years after starting the treatment. Cross-sectional correlations between MSFC and EDSS score at baseline and follow-up were studied. Patients were divided into three subgroups: (1) RRMS patients who did not receive disease modifying therapy (DMT)--non-DMT group, (2) RRMS patients who received DMT--DMT group, (3) SPMS patients who did not receive DMT--SPMS group. EDSS and MSFC scores got worsened significantly at the end of the second year. Decreases in either EDSS or MSFC scores were more prominent in SPMS group. The most significant worsening was found in T25WT. The most prominent and significant decrease was in PASAT of SPMS group. Moderately strong cross-sectional correlations were found between MSFC and EDSS scores at baseline and follow-up. The most prominent correlation was between EDSS and T25WT scores with an excellent correlation. We concluded that the MSFC assesses aspects of neurological function not measured by the EDSS, suggesting that it is more sensitive to detect change over time and better able to demonstrate a therapeutic effect. The pattern of correlations among the MSFC, its components, and the EDSS supported the validity of MSFC.     

Determination of CSF guanase activity in multiple sclerosis: a comparative study on various parameters to monitor the disease activity

Forty two patients with multiple sclerosis (MS) were subjected to determination of CSF guanase activity, CSF IgG concentration, Tibbling's IgG index and Kurtzke's expanded disability status scale (EDSS) together with multimodal evoked potentials (MEPs), which consisted of somatosensory evoked potentials to arm and leg stimulation, visual evoked potential and auditory brainstem response. All patients were divided into active (n = 28) and inactive (n = 14) group, where an "active" was defined as a case revealing a relapse within one month prior to the study. The results were as follows: 1. CSF guanase activity was significantly high in active MS as compared with inactive MS (p less than 0.001), and the same trend was found in CSF IgG concentration (p less than 0.01), but not in IgG index. 2. Abnormal MEP was closely associated with elevated CSF guanase activity in active MS (p less than 0.05), but not in inactive MS. 3. In regard to the disease activity, EDSS was significantly high in active MS as compared with inactive MS (p less than 0.01), and EDSS was also significantly high in abnormal MEP group (p less than 0.001). 4. EDSS was closely correlated with CSF guanase activity in active MS (p less than 0.005), but not in inactive MS. 5. Judging from serial determinations of the parameters in 6 patients, CSF guanase activity, less susceptive to steroid hormone therapy than CSF immunoglobulin level, was found parallel to EDSS, however, both CSF IgG concentration and IgG index failed to correlated with EDSS. In summary, CSF guanase activity was thought to be a sensitive parameter in multiple sclerosis, reflecting not only the disease activity but also spatial involvement in the CNS.     

An approach to estimating the intangible costs of multiple sclerosis according to disability in Catalonia, Spain

Multiple sclerosis (MS) is a chronic demyelinating disease, which represents a great economic burden to society. Cost-of-illness studies of MS tend to underestimate the intangible costs related to pain, anxiety and helplessness. The purpose of this study was to estimate the intangible costs of MS, and determine whether these costs increase as disability progresses. We studied 211 consecutive patients with MS who attended our MS unit. Patients mean age was 41.6 (SD: 10.7) years, 69% were female, and their mean Expanded Disability Status Scale (EDSS) score was 2.47 (SD: 2.05). Quality-of-life was measured with the EuroQoL visual analogue scale. Quality-adjusted life year (QALY) was calculated for each patient. Patients were grouped into five disability stages according to their EDSS, and QALY was compared between patients and a group of healthy controls matched by age and sex. A benchmark value was ascribed to each QALY lost, and the intangible costs per patient-year were calculated as Euros 0 (EDSS =0), Euros 1100 (EDSS =1-3), Euros 8250 (EDSS =3.5-5.5), Euros 9900 (EDSS =6-7) and Euros 11,000 (EDSS >7.5). Sensitivity analysis showed a similar progression of costs. We conclude that intangible costs are relevant in MS, especially when disability increases. Although the method to calculate the costs remains controversial, we consider that they should be included in cost analysis of MS.     

Magnetic stimulation motor evoked potential in multiple sclerosis. Comparison with visual evoked potentials, brain stem auditory evoked potentials and somatosensory evoked potentials]

This study consists of 45 patients with clinically definite MS, laboratory supported definite MS and clinically probable MS. We compared MEP results with other multimodal evoked potentials (VEP, BAEP and SEP). The abnormal rate of MEP was 87.6%, which was the highest. Abnormal MEP showed prolonged central motor conduction time (CMCT), consistent with pathological change of the demyelination. There was a evident correlation between the abnormal MEP and VEP, which is consistent with the most common MS (Devic Syndrome) in our country.     

Clinical relevance of long-latency SEPs and VEPs during coma and emergence from coma

Follow-up measurements of long-latency visual (VEP) and somatosensory (SEP) evoked potentials were performed on 30 comatose patients. Twenty-seven of the patients had severe head injury, 2 had encephalitis and 1 was in a posthypoxic state. For the SEP study a mechanical vibration stimulus was used, applied 60 times at intervals of 10 sec. The same rate was used for visual stimulation. The late EP components were classified by a signal-to-noise ratio (SNR), whereby an SNR of less than 2.6 is characteristic of a questionable or unmeasurable EP and an SNR greater than 2.6 is evidence of a clearly existing EP; the clinical state was scored using the Glasgow Coma Scale (GCS); the patient outcome was assessed 6 months after the injury using the Glasgow Outcome Scale. The highest correlation (r = 0.72) was found between the clinical state, represented by the GCS, and the SEP. A similar correlation (r = 0.66) was obtained between the GCS and the vertex VEP. The occipital VEP showed no correlation. Emergence from coma and recovery was accompanied by an increase of the SEP and an increasing spread of the VEP over the whole scalp. Most patients with a clear long-latency SEP in coma had a favourable outcome; a missing or a questionable SEP indicated a poor outcome.     

Cerebrospinal fluid immunoglobulins and multiple sclerosis. Correspondence with magnetic resonance imaging and visually evoked potential changes

The clinical (disability) and paraclinical (visually evoked potential [VEP]/magnetic resonance imaging [MRI]) data of patients with definite or probable multiple sclerosis (MS) were compared with their cerebrospinal fluid (CSF) immunoglobulins taken within the same period of time. For patients with definite diagnosis by the Schumacher criteria (n = 61) we found significant correlations between CSF immunoglobulin content (absolute gamma-globulin value [aggv]) and quantified MRI factors (r = .47), between aggv and the sum of VEP latencies of both eyes (r = .53), and also between MRI and VEP changes (r = .62). This was not true for the patients with a probable MS diagnosis and for patients with first attacks. No correlations were evident between aggv and disability status or duration of the illness. The results give support to recent neuropathologic and experimental findings in animals indicating close pathogenic connections between CSF immunoglobulins and demyelination in MS.     

Evidence of axonal damage in the early stages of multiple sclerosis and its relevance to disability

OBJECTIVE: To assess axonal damage and its contribution to disability at different stages of multiple sclerosis (MS). BACKGROUND: Recent in vivo imaging and in situ pathologic studies have demonstrated that substantial axonal damage accompanies the inflammatory lesions of MS. However, the relation of axonal damage to the duration of MS and its contribution to disability at different stages of the disease remain poorly defined. DESIGN: We performed proton magnetic resonance spectroscopic imaging in 88 patients with a wide range of clinical disability and disease duration to measure N-acetylaspartate (NAA, an index of axonal integrity) relative to creatine (Cr) in a large central brain volume that included mostly normal-appearing white matter on magnetic resonance imaging. RESULTS: We observed that the NAA/Cr values were abnormally low in the early stages of MS, even before significant disability (measured using the Expanded Disability Status Scale [EDSS]) was evident clinically, and declined more rapidly with respect to EDSS at lower than at higher EDSS scores (P<.001). The correlation of NAA/Cr values with EDSS score was significantly (P<.03) stronger in patients with mild disability (EDSS score <5, Spearman rank order correlation = -0.54, P<.001) than in patients with more severe disability (EDSS score >/=5, Spearman rank order correlation = -0.1, P<.9). When similar analyses were performed in patients with MS grouped for duration of disease, the subgroup with early disease duration (<5 years) also showed central brain NAA/Cr resonance intensity ratios significantly lower than healthy controls (P<.001). CONCLUSION: Cerebral axonal damage begins and contributes to disability from the earliest stages of the disease.     

Evoked potentials and CSF-immunoglobulins in MS: relationship to disease duration, disability, and functional status

In 100 MS patients, BAEP and tibial SEP abnormality rates increased significantly with disease duration and clinical disability. VEP correlated non-linearly with disease duration, and median nerve SEP correlated with disability. In multifactorial analysis, however, BAEP correlated significantly only with clinical brainstem and cerebellar signs. These results suggest that evoked potentials correlate more strongly with neurological status of the functional subsystems than either overall disability or disease duration. These findings indirectly suggest that evoked potentials may be useful monitors during large therapeutical trials in MS patients.     

Clinical and Radiological Characteristics in Multiple Sclerosis Patients with Large Cavitary Lesions

Background: Large cavitary lesions are not typical for multiple sclerosis (MS). Cavitary white matter changes may be seen in megalencephalic leukoencephalopathy with subcortical cysts, Alexander disease, mitochondrial leukoencephalopathies, vanishing white matter disease, leukoencephalopathy with calcifications and cysts, cytomegalovirus infection, and cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy. Objective: To analyze clinical and radiological characteristics in MS patients with large cavitary lesions. Methods: We studied MS patients with large cavitary brain lesions. Patient characteristics, disease onset/duration/subtype, expanded disability status scale (EDSS), Mini Mental State (MMS), corpus callosum lesions, history of segmental myelitis, CSF oligoclonal bands (OCB), visual evoked potentials (VEP), vanishing white matter disease genetic analysis, and characteristics of the cavitary lesions were analyzed. Results: Nine patients were analyzed, 1 man and 8 women. Mean age of disease onset was 38.5 years. Mean disease duration was 9 years. Three patients had initial relapsing-remitting MS and 6 patients had primary-progressive MS. Mean EDSS was 4.5. Mean MMS was 20/30. Segmental myelitis was present in 6 cases. OCB were found in 6 patients. VEP was performed in 6 patients, and pathological in all but one. Vanishing white matter disease genetic analysis was performed and negative in 5 patients. Inferior corpus callosum lesions were seen in all patients with available sagittal FLAIR sequences. Cavitary lesions were strictly supratentorial, and located inside the diffuse leukoencephalopathy, with often a posterior predominance. Conclusion: MS patients with large cavitary lesions seem to represent an MS subgroup, predominantly women, with relatively late disease onset, predominantly primary-progressive type, relatively high EDSS scores, and severe cognitive dysfunction.     

The influence of immunomodulation on psycho-neuroimmunological functions in benign multiple sclerosis

OBJECTIVES: In multiple sclerosis (MS), several neuroimmunomodulatory effectors are known, including melatonin. They are able to influence disease-related neurophysiogical changes (disability or impaired vision) as well as neuropsychological performance (e.g. cognition and depression). In this study we assessed the relationship between immunomodulation on psycho-neuroimmunological functions in benign multiple sclerosis. METHODS: We evaluated 26 young female patients with benign MS treated with/without immunomodulating therapies with regard to their physical disabilities (Expanded Disability Status Scale, EDSS), their visually evoked potentials (VEP), their plasma melatonin concentrations as well as their performance regarding emotional and cognitive tests and compared them with healthy matched controls. RESULTS: Patients with MS showed deficits in cognitive and emotional functions compared to healthy controls, which were in accordance with their increase in EDSS over time. However, in contrast to untreated patients, patients receiving immunotherapy showed significantly increased dysfunction with respect to actual mood (p = 0.02) and a tendency to increased depression scores (p = 0.072). However, neither treatment subgroup had cognitive deficits. In untreated patients, melatonin levels correlated with reduced scores in the cognitive tests (p = 0.045) but not with depression or VEP latencies. Patients with long-standing MS (>10 years) showed a significant correlation (p = 0.01) to their increased depression scores and their melatonin levels, but no correlation with VEP or cognitive dysfunction, compared to patients with shorter disease duration (< or =10 years). CONCLUSION: These results indicate that in MS all aspects of the psycho-neuroimmunological network can be affected. Despite the potential influence of immunomodulation on depression, no connection with melatonin representing the retinohypothalamic tract/pineal gland circuits could be detected. However, visual perception as well as visuoconstructive abilities were affected in MS patients. Neuropsychological tests in MS should concentrate on cognitive variables, which reflect the clinical status more accurately and may be used to monitor disease-modifying therapies.     

Intracortical excitability in patients with relapsing–remitting and secondary progressive multiple sclerosis

We designed this study to investigate possible correlations between variables measuring primary motor cortex excitability detected by single and paired-pulse transcranial magnetic stimulation (TMS) and the severity of clinical manifestations in patients with multiple sclerosis (MS). Thirty patients with MS in remission, 16 with relapsing–remitting (RR), 14 with secondary progressive disease (SP) and 17 healthy subjects participated in the study. In each subject, the central motor conduction time (CMCT) was calculated, and single-pulse and paired-pulse TMS at 3 and 10 ms interstimulus intervals was delivered over the primary motor cortex of the dominant hemisphere to measure the amplitude of motor-evoked potentials (MEPs), motor threshold (MTh), intracortical inhibition (ICI) and facilitation (ICF). Correlations were determined between the patients’ TMS findings and magnetic resonance imaging (MRI) (lesion load) and clinical features (expanded disability status scale, EDSS score). EDSS scores were significantly higher in SPMS than in RRMS patients. The MTh was significantly higher, and the MEP was significantly smaller in SPMS patients than in RRMS patients and control subjects. All patients had longer CMCTs than healthy subjects. In all patients, paired-pulse TMS elicited an inhibited test MEP at the 3-ms ISI and a facilitated test MEP at the 10 ms ISI. Post hoc analysis showed that ICI was significantly lower in SPMS patients than in those with RRMS and healthy subjects. EDSS scores correlated significantly with TMS measures (MEP, ICI, CMCT and MTh), but not with MRI lesion load. It was found that intracortical excitability as measured with TMS differs according to the clinical course of MS; it remains normal in patients with low EDSS scores and is altered in patients with high EDSS scores.     

No Effect of Long-Term Vigabatrin Treatment on Central Nervous System Conduction in Patients with Refractory Epilepsy: Results of a Multicenter Study of Somatosensory and Visual Evoked Potentials

Summary: Purpose: In dogs, vigabatrin (VGB) has been associated with intramyelinic edema producing delayed central conduction in somatosensory and visual evoked potentials (SEP, VEP). No such effects have been reported in humans. We assessed whether abnormalities of central conduction could be detected prospectively in patients with epilepsy treated with VGB as long-term add-on medication. Methods: Two hundred one patients with refractory partial epilepsy were enrolled and monitored for as long as 2 years. VGB was added to the treatment at an average dose of 2–3g/ day. Conduction in somatosensory and visual pathways was assessed by median nerve SEP and pattern VEP recordings performed at inclusion and once every 6 months. The upper limit and test-retest variability of EP latencies were evaluated at time of enrollment in the patient group. Prolonged N13-N20 or P14-N20 SEP intervals and P100 VEP latency >2.5 SD above the baseline mean, observed on repeated runs in the same session and exceeding the test-retest variability at enrollment were considered to indicate central conduction slowing. Results: One hundred nine patients completed the 2-year study period, and 92 discontinued VGB, of whom 37 were monitored with regard to EP until the end of the study. No consistent change in SEP or VEP was observed in the entire group during VGB treatment. The number of occasional EP values outside the baseline range in patients treated with VGB similar to that in patients whose VGB treatment had been discontinued. Conclusions: We detected no evidence of changes in SEP and VEP attributable to altered neuronal conduction in the CNS during long-term VGB treatment.     

Memory decline evolves independently of disease activity in MS

BACKGROUND: The natural history of cognitive impairment in multiple sclerosis (MS) and its relationship with disease activity is not well known. In this study, we evaluate a prospective cohort of 44 MS patients who were followed every 3 months for 2 years. Cognitive evaluation was done at baseline and by the end of the study using the Brief Repeatable Battery-Neuropsychology. Clinical evaluation included assessment of new relapses and changes in disability (Extended Disability Status Scale (EDSS)) confirmed at 6 months. RESULTS: We found that verbal memory performance deteriorates after 2 years in patients with MS. These changes were observed in stable and active patients both in terms of relapses and disability progression, even at the beginning of the disease, and in patients with or without cognitive impairment at study entry. Attention and executive functions measured with the symbol digit modality test (SDMT) declined after 2 years in patients with confirmed disability progression. Furthermore, SDMT performance correlated with the EDSS change. CONCLUSIONS: Our findings indicate that verbal memory steadily declines in patients with MS from the beginning of the disease and independently of other parameters of disease activity.