Faculty Bibliography

OBJECTIVE:To evaluate whether multiple sessions of transcranial direct current stimulation (tDCS) applied to the primary motor (M1) cortex paired with aerobic exercise can improve walking functions in multiple sclerosis (MS). METHODS:MS participants were recruited for a double-blind, parallel-arm, randomized, sham-controlled trial and assigned to 10 sessions (5 d/wk for 2 weeks) of either active or sham tDCS paired with unloaded cycling for 20 minutes. Stimulation was administered over the left M1 cortex (2.5 mA; anode over C3/cathode over FP2). Gait spatiotemporal parameters were assessed using a wearable inertial sensor (10-meter and 2-minute walking tests). Measurements were collected at baseline, end of tDCS intervention, and 4-week postintervention to test for duration of any benefits. RESULTS:A total of 15 participants completed the study, nine in the active and six in the sham condition. The active and sham groups were matched according to gender (50% vs. 40% female), neurologic disability (median EDSS 5.5 vs. 5), and age (mean 52.1 ± 12.9 vs. 53.7 ± 9.8 years). The active group had a significantly greater increase in gait speed (0.87 vs. 1.20 m/s, p < 0.001) and distance covered during the 2-minute walking test (118.53 vs. 133.06 m, p < 0.001) at intervention end compared to baseline. At 4-week follow-up, these improvements were maintained (baseline vs. follow-up: gait speed 0.87 vs. 1.18 m/s, p < 0.001; distance traveled 118.53 vs. 143.82 m, p < 0.001). INTERPRETATION/CONCLUSIONS:Multiple sessions of tDCS paired with aerobic exercise lead to cumulative and persisting improvements in walking and endurance in patients with MS.

OBJECTIVE:To characterize disease severity and distribution of disability in pediatric-onset multiple sclerosis (POMS) and to develop an optimized modeling scale for measuring disability, we performed a multicenter retrospective analysis of disability scores in 873 persons with POMS over time and compared this to previously published data in adults with multiple sclerosis (MS). METHODS:This was a retrospective analysis of prospectively collected data collected from 12 centers of the US Network of Pediatric MS Centers. Patients were stratified by the number of years from first symptoms of MS to Expanded Disability Status Scale (EDSS) assessment and an MS severity score (Pediatric Multiple Sclerosis Severity Score [Ped-MSSS]) was calculated per criteria developed by Roxburgh et al. in 2005. RESULTS:In total, 873 patients were evaluated. In our cohort, 52%, 19.4%, and 1.5% of all patients at any time point reached an EDSS of 2.0, 3.0, and 6.0. Comparison of our Ped-MSSS scores and previously published adult Multiple Sclerosis Severity Scores (MSSS) showed slower progression of Ped-MSSS with increasing gaps between higher EDSS score and years after diagnosis. Decile scores in our POMS cohort for EDSS of 2.0, 3.0, and 6.0 were 8.00/9.46/9.94, 7.86/9.39/9.91, and 7.32/9.01/9.86 at 2, 5, and 10 years, respectively. Notable predictors of disease progression in both EDSS and Ped-MSSS models were ever having a motor relapse and EDSS at year 1. Symbol Digit Modalities Test (SDMT) scores were inversely correlated with duration of disease activity and cerebral functional score. CONCLUSIONS:Persons with POMS exhibit lower EDSS scores compared to persons with adult-onset MS. Use of a Ped-MSSS model may provide an alternative to EDSS scoring in clinical assessment of disease severity and disability accrual.

Incomplete relapse recovery contributes to disability accrual and earlier onset of secondary progressive multiple sclerosis. We sought to investigate the effect of age on relapse recovery. We identified patients with multiple sclerosis from two longitudinal prospective studies, with an Expanded Disability Status Scale (EDSS) score within 30 days after onset of an attack, and follow-up EDSS 6 months after attack. Adult patients with multiple sclerosis (n = 632) were identified from the Comprehensive Longitudinal Investigations in Multiple Sclerosis at Brigham study (CLIMB), and paediatric patients (n = 132) from the US Network of Paediatric Multiple Sclerosis Centers (NPMSC) registry. Change in EDSS was defined as the difference in EDSS between attack and follow-up. Change in EDSS at follow-up compared to baseline was significantly lower in children compared to adults (P = 0.001), as were several functional system scores. Stratification by decade at onset for change in EDSS versus age found for every 10 years of age, EDSS recovery is reduced by 0.15 points (P < 0.0001). A larger proportion of children versus adults demonstrated improvement in EDSS following an attack (P = 0.006). For every 10 years of age, odds of EDSS not improving increase by 1.33 times (P < 0.0001). Younger age is associated with improved recovery from relapses. Age-related mechanisms may provide novel therapeutic targets for disability accrual in multiple sclerosis.