Post-Stroke Motor Fatigability: Defining and Studying the Impairments That Emerge During Prolonged Motor Tasks

BackgroundFatigue, a complex and multidimensional complaint, is highly prevalent after stroke and contributes to adverse outcomes and impaired motor recovery. Here, we focus on post-stroke motor fatigability (PSMF), which refers to objective limitations in continuous motor performance post-stroke. PSMF can impair the performance of activities of daily living and may significantly hinder rehabilitation efforts, limiting progress and recovery.ObjectivesThe purpose of this review is to summarize the current understanding of PSMF and to evaluate various tools used to investigate its underlying mechanisms.ResultsPrior studies on PMSF differ significantly in their approaches, with some employing neurophysiology and neurostimulation to investigate neural mechanisms, while others focus on functional assessments. Inconsistent terminology and the lack of standardized methodology are key barriers to reaching meaningful conclusions. While there is some consensus that central factors in the neuromuscular pathway limit sustained motor activity more than peripheral factors, additional research is needed to understand the timing and pathophysiology of PSMF including its relationship with other impairments of motor control. We present several specific recommendations for future studies, including the use of proper taxonomy to demystify the patient complaint, consistent paradigms to evoke fatigability, and neurophysiological tools to locate its origin.ConclusionApplying these guidelines to future investigations will help researchers better identify stroke-specific limitations in continuous motor performance and develop tailored interventions to help patients adjust to the persistent, repetitive demands of daily life.