Effects of Nonconsecutive Sessions of Transcranial Direct Current Stimulation and Stationary Cycling on Walking Capacity in Individuals With Multiple Sclerosis

Effects of non-pharmacological interventions on gait and balance of persons with Multiple Sclerosis: A narrative review

BACKGROUND

Multiple Sclerosis (MS) is among the most common reasons for disability in young adults. Mobility impairment, primarily related to gait and balance, is ranked as the preeminent concern among persons with MS (PwMS). Gait and balance dysfunction can directly affect the quality of life and activities of daily life in PwMS, hence the importance of effective treatment strategies. Previous studies have demonstrated the positive effect of various non-pharmacological rehabilitation methods, including physiotherapy and electrical stimulation, on gait and mobility in PwMS. Non-pharmacological methods can be tailored to the individual needs and abilities of each patient, allowing healthcare providers to create personalized training programs. Furthermore, these methods typically result in minimal or no side effects.

PURPOSE

This review provides a comprehensive overview of an array of non-pharmacological treatment approaches aimed at enhancing ambulatory performance in PwMS.

METHODS

We performed a narrative review of the original papers available in PubMed, investigating the effects of different nonmedical approaches on the gait and balance performance of the PwMS. Reviewed treatment approaches include "exercise, physical rehabilitation, dual-task (DT) rehabilitation, robot-assisted rehabilitation, virtual reality-assisted rehabilitation, game training, electrical stimulation devices, auditory stimulation, visual feedback, and shoe insoles".

RESULTS AND CONCLUSIONS

Eighty articles were meticulously reviewed. Our study highlights the positive effects of non-pharmacological interventions on patients' quality of life, reducing disability, fatigue, and muscle spasticity. While some methods, including exercise and physiotherapy, showed substantial promise, further research is needed to evaluate whether visual biofeedback and auditory stimulation are preferable over conventional approaches. Additionally, approaches such as functional electrical stimulation, non-invasive brain stimulation, and shoe insoles demonstrate substantial short-term benefits, prompting further investigation into their long-term effects. Non-pharmacological interventions can serve as a valuable complement to medication-based approaches.

Effectiveness of transcranial direct current stimulation on balance and gait in patients with multiple sclerosis: systematic review and meta-analysis of randomized clinical trials

BACKGROUND

Motor impairments are very common in neurological diseases such as multiple sclerosis. Noninvasive brain stimulation could influence the motor function of patients.

OBJECTIVE

The aim of this meta-analysis was to evaluate the effectiveness of transcranial direct current stimulation (tDCS) on balance and gait ability in patients with multiple sclerosis. Additionally, a secondary aim was to compare the influence of the stimulation location of tDCS on current effectiveness.

METHODS

A search was conducted for randomized controlled trials published up to May 2023 comparing the application of tDCS versus a sham or control group. The primary outcome variables were balance and gait ability.

RESULTS

Eleven studies were included in the qualitative analysis, and ten were included in the quantitative analysis, which included 230 patients with multiple sclerosis. The average effect of tDCS on gait functionality was superior to that of the control group (SMD = -0.71; 95% CI, -1.05 to -0.37). However, the overall results of the tDCS vs. sham effect on static balance did not show significant differences between groups (MD = 1.26, 95% CI, -1.31 to 3.82). No significant differences were found when different locations of tDCS were compared.

CONCLUSIONS

These results reveal that tDCS is an effective treatment for improving gait ability with a low quality of evidence. However, the application of tDCS has no effect on static balance in patients with multiple sclerosis with very low quality of evidence. Similarly, there seems to be no difference regarding the stimulation area with tDCS.

Chronic Functional Adaptations Induced by the Application of Transcranial Direct Current Stimulation Combined with Exercise Programs: A Systematic Review of Randomized Controlled Trials

The present systematic review aimed to determine the chronic effects of the combination of transcranial direct current stimulation (tDCS) and exercise on motor function and performance outcomes. We performed a systematic literature review in the databases MEDLINE and Web of Science. Only randomized control trials that measured the chronic effect of combining exercise (comprising gross motor tasks) with tDCS during at least five sessions and measured any type of motor function or performance outcome were included. A total of 22 interventions met the inclusion criteria. Only outcomes related to motor function or performance were collected. Studies were divided into three groups: (a) healthy population (n = 4), (b) neurological disorder population (n = 14), and (c) musculoskeletal disorder population (n = 4). The studies exhibited considerable variability in terms of tDCS protocols, exercise programs, and outcome measures. Chronic use of tDCS in combination with strength training does not enhance motor function in healthy adults. In neurological disorders, the results suggest no additive effect if the exercise program includes the movements pretending to be improved (i.e., tested). However, although evidence is scarce, tDCS may enhance exercise-induced adaptations in musculoskeletal conditions characterized by pain as a limiting factor of motor function.

Non-invasive brain stimulation on clinical symptoms in multiple sclerosis patients: A systematic review and meta-analysis

BACKGROUND

Non-invasive brain stimulation (NIBS) has demonstrated mixed effects on the clinical symptoms of multiple sclerosis. This systematic review and meta-analysis aimed to evaluate the effects of NIBS techniques on the most common symptoms of MS.

METHODS

A literature search was performed until October 2022 which included randomized controlled trials and quasi-experimental studies that used sham-controlled NIBS in patients with MS. We calculated the Hedge's effect sizes of each domain of interest and their 95% confidence intervals (95% CIs) and performed random effects meta-analyses.

RESULTS

A total of 49 studies were included in the systematic review (944 participants). Forty-four eligible studies were included for quantitative analysis, of which 33 applied transcranial direct current stimulation (tDCS), 9 transcranial magnetic stimulation (TMS), and 2 transcranial random noise stimulation (tRNS). We found a significant decrease in fatigue (ES:  - 0.86, 95% CI:  - 1.22 to - 0.51, p < 0.0001), pain (ES: - 1.91, 95% CI, - 3.64 to - 0.19, p=  0.03) and psychiatric symptoms (ES: - 1.44, 95% CI - 2.56 to - 0.32, p = 0.01) in favor of tDCS compared with the sham. On the other hand, there was no strong evidence showing tDCS effectiveness on motor performance and cognition (ES: - 0.03, 95% CI - 0.35 to 0.28, p = 0.83 and ES: 0.71, 95% CI, - 0.09 to 1.52, p = 0.08, respectively). Regarding TMS, we found a significant decrease in fatigue (ES: - 0.45, 95% CI: - 0.84 to -0.07, p = 0.02) and spasticity levels (ES: - 1.11, 95% CI: - 1.48 to - 0.75, p < 0.00001) compared to the sham. However, there was no strong evidence of the effectiveness of TMS on motor performance (ES: - 0.39, 95% CI - 0.95 to 0.16, p = 0.16). Finally, there was no significant evidence showing the effectiveness of tRNS on fatigue levels (ES: - 0.28, 95% CI: - 1.02 to 0.47, p = 0.46) and cognitive improvement (ES: - 0.04, 95% CI: - 0.6, 0.52, p = 0.88) compared with the sham.

CONCLUSIONS

Overall, most studies have investigated the effects of tDCS on MS symptoms, particularly fatigue. The symptom that most benefited from NIBS was fatigue, while the least to benefit was motor performance. In addition, we found that disability score was associated with fatigue improvement. Thus, these findings support the idea that NIBS could have some promising effects on specific MS symptoms. It is also important to underscore that studies are very heterogeneous regarding the parameters of stimulation, and this may also have influenced the effects on some specific behavioral domains.