Post-stroke Fatigue and Brain Excitability: An Exploratory TMS Study

The purpose of this study was to explore the relationship between brain excitability indexed using different transcranial magnetic stimulation (TMS) measures and post-stroke fatigue (PSF) in individuals with mild to moderate motor impairment. We used single- and paired-pulse TMS to obtain various TMS outcomes from 24 participants with chronic stroke: resting motor threshold (RMT), motor evoked potential amplitude (MEP), Input-Output Curve (IOC) slope, short-interval intracortical inhibition (SICI), and intracortical facilitation (ICF). IO curve slope (ρ = -0.61, p = 0.02) and SICI (ρ = -0.51, p = .03) measured from the ipsilesional hemisphere correlated with PSF. Other TMS measures were not significantly correlated with PSF measures. Findings suggest that higher levels of fatigue were associated with lower brain excitability. Together with previous studies, our findings suggest that level of motor impairment and the tool used to assess fatigue might influence the relationship between brain excitability and PSF.