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:People with Multiple Sclerosis (pwMS) often exhibit generalized weakness that affects several activities of daily life, particularly those relying on balance and gait. While it is known that such a symptom has a strong impact on mobility, to what extent muscular strength is linked with functional mobility in men and women with MS remains mostly unexplored. The aim of this study is to assess the existence of possible sex-related differences in functional mobility in pwMS, also considering the muscular strength capacity. METHODS:Functional mobility and hand-grip strength (HGS) were assessed in 49 pwMS with mild-moderate disability using instrumental Timed-up-and-go (TUG) test carried out using an inertial sensor and digital dynamometry. We investigated the existence of sex-related differences in the duration of each TUG sub-phase and their correlation with the HGS. RESULTS:No sex-related differences in TUG performance (either in terms of overall or sub-phase time) were found. Similar large negative correlations were found in men and women with MS between HGS and overall TUG and walking phase duration. However, changes in strength have a more marked impact in women as indicated by the different slope of the HGS-TUG time relationship., In women, HGS also appears significantly correlated with all TUG sub-phases, while in men this occurs only for overall TUG and walking time. CONCLUSIONS:Rehabilitation and training programs for pwMS should take into account the peculiar features associated with the interaction between strength and mobility specific for each individual's sex to optimize their effectiveness.

Old age is associated with variability in gait motor output, particularly in females, and is linked to fall risk. However, little is known about how older age and sex affect variability in the outputs of individual joints, and how these variabilities contribute to the collective gait output. Healthy adults aged 18-99 years (N = 102, 57 females) completed six trials of straight walking at self-selected speed. Stride time variability (coefficient of variation) and variabilities of lower limb tridimensional joint angles (standard deviations: SD) were calculated. Age * Sex (A * S) mixed models were conducted on all measures and year-by-year rates of change were subsequently estimated. Correlations and stepwise linear regression analyses were computed between joint angular variabilities and stride time variability. Each year of age was associated with 0.022% higher stride time variability (A: p = .002), 0.07° lower variability in peak ankle dorsiflexion (A: p = .004), 0.002-0.098° higher variability in mean ankle inversion/eversion, mean pelvic obliquity, and pelvic rotation range of motion (A: p < .05), and 0.024° higher variability in knee flexion/extension range of motion in males (A * S: p = .003). Higher variability in mean ankle and hip flexion/extension and in mean ankle inversion/eversion correlated with (ρ = 0.211-0.336; ps < 0.05) and independently predicted higher stride time variability (ps < 0.05), together explaining 21.9% of variance. Results suggest that higher stride time variability with older age may be produced by a shift from sagittal plane variability to frontal plane variability at the ankle.

INTRODUCTION/BACKGROUND:To demonstrate the broad utility of the remotely supervised transcranial direct current stimulation (RS-tDCS) protocol developed to deliver at-home rehabilitation for individuals with multiple sclerosis (MS). METHODS:Stimulation delivered with the RS-tDCS protocol and paired with adaptive cognitive training was delivered to three different study groups of MS patients to determine the feasibility and tolerability of the protocol. The three studies each used consecutively increasing amounts of stimulation amperage (1.5, 2.0, and 2.5 mA, respectively) and session numbers (10, 20, and 40 sessions, respectively). RESULTS:High feasibility and tolerability of the stimulation were observed for n = 99 participants across three tDCS pilot studies. CONCLUSIONS:RS-tDCS is feasible and tolerable for MS participants. The RS-tDCS protocol can be used to reach those in locations without clinic access and be paired with training or rehabilitation in locations away from the clinic. This protocol could be used to deliver tDCS paired with training or rehabilitation activities remotely to service members and veterans.

In this study, we acquired and processed trunk accelerations during level walking in 85 children aged 8-13 years to calculate spatio-temporal parameters and Harmonic Ratio (HR), which is a metrics representative of gait smoothness and step-to-step symmetry. The results show that while spatio-temporal parameters remain unchanged once normalized considering individuals' anthropometry, significantly higher values of HR for both the antero-posterior and vertical directions were found in participants aged 12-13 with respect to those of 8-9. This indicates an improvement of gait symmetry, which suggests that the gait maturation process is still ongoing for the age ranges tested here.