Modulation of cortical excitability to normalise brain function and improve cognition in multiple sclerosis

Efficacy of non-invasive brain stimulation on cognitive and motor functions in multiple sclerosis: A systematic review and meta-analysis

Objective

In this study, we aimed to investigate the effects of non-invasive brain stimulation (NIBS) on cognitive and motor functions in patients with multiple sclerosis (pwMS).

Methods

A literature search was performed in the Cochrane Library, Embase, PubMed, Web of Science, Medline, CNKI, and Wan fang. The time interval used for database construction was up to December 2022, and the language was not limited. The collected trials were subsequently screened, the data were extracted, the quality was evaluated, and the effect sizes were computed using STATA/MP Version 13 for outcome analysis. Standard mean difference (SMD) and 95% confidence interval (CI) were calculated for domain of interest.

Results

In total, 17 articles that examined 364 patients with multiple sclerosis were included in this analysis. Non-invasive brain stimulation did not improve the overall cognitive function [SMD = 0.18, 95% CI (-0.32, 0.69), P = 0.475] but helped improve motor function in patients [SMD = 0.52, 95% CI (0.19, 0.85), P = 0.002]. Moreover, this study specifically indicated that non-invasive brain stimulation improved alerting [SMD = 0.68, 95% CI (0.09, 1.26), P = 0.02], whereas non-invasive brain stimulation intervention improved motor function in patients aged <45 years [SMD = 0.67, 95% CI (0.23, 1.10), P = 0.003] and in patients with expanded disability status scale scores (EDSS) <3.5 [SMD = 0.82, 95% CI (0.22, 1.42), P = 0.007]. In particular, NIBS contributed to the improvement of spasticity in pwMS [SMD = 0.68, 95% CI (0.13, 1.23), P = 0.015].

Conclusion

These results of this present study provide evidence that non-invasive brain stimulation could improve alertness in pwMS. Furthermore, NIBS may help pwMS with motor function and those who are under 45 years of age or with EDSS < 3.5 improve their motor function. For the therapeutic use of NIBS, we recommend applying transcranial magnetic stimulation as an intervention and located on the motor cortex M1 according to the subgroup analysis of motor function. These findings warrant verification.

Systematic review registration

https://www.crd.york.ac.uk/PROSPERO/, identifier CRD42022301012.

Bipedal hopping timed to a metronome to detect impairments in anticipatory motor control in people with mild multiple sclerosis

BACKGROUND

People with mild multiple sclerosis (MS) often report subtle deficits in balance and cognition but display no measurable impairment on clinical assessments. We examined whether hopping to a metronome beat had the potential to detect anticipatory motor control deficits among people with mild MS (Expanded Disability Status Scale ≤ 3.5).

METHODS

Participants with MS (n = 13), matched controls (n = 9), and elderly subjects (n = 13) completed tests of cognition (Montreal Cognitive Assessment (MoCA)) and motor performance (Timed 25 Foot Walk Test (T25FWT)). Participants performed two bipedal hopping tasks: at 40 beats/min (bpm) and 60-bpm in random order. Hop characteristics (length, symmetry, variability) and delay from the metronome beat were extracted from an instrumented walkway and compared between groups.

RESULTS

The MS group became more delayed from the metronome beat over time whereas elderly subjects tended to hop closer to the beat (F = 4.52, p = 0.02). Delay of the first hop during 60-bpm predicted cognition in people with MS (R = 0.55, β = 4.64 (SD 4.63), F = 4.85, p = 0.05) but not among control (R = 0.07, p = 0.86) or elderly subjects (R = 0.17, p = 0.57). In terms of hopping characteristics, at 60-bpm, people with MS and matched controls were significantly different from the elderly group. However, at 40-bpm, the MS group was no longer significantly different from the elderly group, even though matched controls and elderly still differed significantly.

CONCLUSIONS

This new timed hopping test may be able to detect both physical ability, and feed-forward anticipatory control impairments in people with mild MS. Hopping at a frequency of 40-bpm seemed more challenging. Several aspects of anticipatory motor control can be measured: including reaction time to the first metronome cue and the ability to adapt and anticipate the beat over time.