Studying Fatigue and Movement After Stroke

Stroke is a leading cause of long-term disability worldwide. Although many stroke survivors can initiate movement, sustaining motor performance during everyday activities often becomes progressively difficult, suggesting abnormal development of neuromuscular fatigue. Neuromuscular fatigue, defined as an exercise-induced reduction in force-generating capacity, arises through interactions between central neural and peripheral muscular mechanisms. However, despite extensive investigation in healthy populations, the neurophysiological mechanisms underlying neuromuscular fatigue after stroke remain poorly understood. Existing studies have focused predominantly on peripheral manifestations of fatigue, with limited investigation of cortical oscillatory dynamics and brain-muscle communication. Here, we propose a multimodal neurophysiological study combining electroencephalography (EEG), electromyography (EMG), and corticomuscular coherence analyses to determine whether fatigability after stroke is driven predominantly by altered central neural processes rather than peripheral muscle failure. Stroke survivors and age-matched healthy controls will perform sustained isometric contractions while neural and muscular activity are recorded across progressive fatigue stages. We hypothesize that stroke survivors will exhibit earlier and greater fatigability, accompanied by altered cortical oscillatory activity, peripheral muscular changes, and disrupted corticomuscular coherence, consistent with a predominant contribution of central oscillatory dysfunction.

Inclusion criteria

Stroke survivors will be recruited from Brussels University Hospital (Brussels, Belgium). Patients who have a first-ever stroke, ≥18 years, subacute phase: 1 week to 6 months post-stroke, quadriceps (hemiplegic side) strength ≤3/5 (Medical Research Council (MRC)), and Montreal Cognitive Assessment (MoCA) ≥21 will be included.

Exclusion criteria

Exclusion criteria

include a history of a previous stroke, severe spasticity (Modified Ashworth Scale (MAS) 3-4 in quadriceps/hamstrings), other neurological, motor, musculoskeletal, or orthopedic conditions affecting trunk stability and lower limb mobility, non-cerebral strokes (e.g., brainstem, cerebellar), or dementia (MoCA ≤20), and current or former athletes. Athletes are defined as individuals who participated in organized competitive sports and engaged in structured training ≥3 sessions per week for ≥1 year within the 5 years preceding stroke. Control participants will be excluded if they meet the same exclusion criteria.