Effect of transcranial direct current stimulation on post-stroke fatigue

Abstract

Background: Fatigue is one of the most commonly reported symptoms post-stroke, which has a severe impact on the quality of life. Post-stroke fatigue is associated with reduced motor cortical excitability, specifically of the affected hemisphere.

Objective: The aim of this exploratory study was to assess whether fatigue symptoms can be reduced by increasing cortical excitability using anodal transcranial direct current stimulation (tDCS).

Methods: In this sham-controlled, double-blind intervention study, tDCS was applied bilaterally over the primary motor cortex in a single session in thirty stroke survivors with high severity of fatigue. A questionnaire-based measure of trait fatigue (primary outcome) was obtained before, after a week and 5 weeks post stimulation. Secondary outcome measures of state fatigue, motor cortex neurophysiology and perceived effort were also assessed pre, immediately post, a week and 5 weeks post stimulation.

Results: Anodal tDCS significantly improved fatigue symptoms a week after real stimulation when compared to sham stimulation. There was also a significant change in motor cortex neurophysiology of the affected hemisphere and perceived effort, a week after stimulation. The degree of improvement in fatigue was associated with baseline anxiety levels.

Conclusion: A single session of anodal tDCS improves fatigue symptoms with the effect lasting up to a week post stimulation. tDCS may therefore be a useful tool for managing fatigue symptoms post-stroke.

Trial registration: NCT04634864 DATE OF REGISTRATION: 17/11/2020-"retrospectively registered".

Keywords: Effort; Fatigue; Perception; Stroke; tDCS.

Fig. 1

Study Design indicating the sequence in which procedures were done for each of the sessions at the 4 different time points (pre tDCS, immediately post-tDCS, week and month time points). PE perceived effort; TMS transcranial magnetic stimulation; RMT resting motor threshold; IO recruitment curves; tDCS transcranial direct current stimulation

Fig. 2

a Study recruitment and b randomisation (HADS Hospital Anxiety and Depression Scale; FSS Fatigue Severity Scale; tES transcranial Electrical Stimulation; TMS Transcranial magnetic stimulation)

Fig. 3

Changes in trait fatigue (a), state fatigue (b), resting motor threshold of the affected and unaffected hemisphere (c, d), slope of the recruitment curve of the affected and unaffected hemisphere (e, f), implicit perceived effort (g) and explicit perceived effort (H) compared to baseline (pre-stimulation time point) across the different time points for both the real (red) and sham (blue) stimulation group. Error bars represent standard error of the means. Significance levels are indicated by * (p < 0.05). FSS-7 = Fatigue Severity Scale-7; RMT-A = Resting motor threshold of affected hemisphere; RMT-U = Resting Motor threshold of Un-affected hemisphere; IO_Slope-A recruitment curve slope of affected hemisphere; IO_Slope-U recruitment curve slope of Un-affected hemisphere; PE Perceived Effort

Fig. 4

Correlation between baseline FSS-7 and the change in FSS-7 at the week time point for the real (red) and sham (blue) stimulation groups with the 95% confidence interval (A). The association between the baseline HADS-Anxiety levels and the change in FSS-7 at the week time point for the real stimulation group with its associated 95% confidence interval (B). FSS-7 Fatigue Severity Scale-7; HADS Hospital Anxiety and Depression Scale