Fatigue and Fatigability in Persons With Multiple Sclerosis

We examine the hypothesis that in persons with multiple sclerosis, fatigue measured with a questionnaire is attributable to interactions between the central nervous system and the immune system, which exacerbate both perceived fatigability and performance fatigability. Performance fatigability is represented by the decline in voluntary force during sustained contractions as a consequence of the inability to maintain high levels of voluntary activation.