FATIGUE AS VIEWED BY THE NEUROLOGIST

Fatigue is a highly polymorphic symptom associated with many etiologic factors, whose exact role in the pathophysiologic cascade that result s in the sensation of fatigue remains unclear. Three points relevant t o fatigue in neurologic practice deserve to be emphasized. First, it i s clear that sleep deprivation results in fatigue, and that fatigue in patients with hypersomnia is often closely related to the degree of d rowsiness. Second, fatigue is an extremely common symptom of multiple sclerosis (MS). Specific scales have been developed to evaluate fatigu e in MS because this symptom has a major impact on functional performa nce even in patients with little neurological loss. Empirical treatmen ts have been proposed, including amantadine. Regular physical activity may be beneficial. Third, fatigue, or rather easy fatigability, is a symptom of peripheral nervous system or muscle disease, in which it of ten heralds motor loss. However, the place of fatigue in neurology ext ends far beyond these three areas, whose diversity could serve as a st arting point for a semantic discussion of the terms <<fatigue>>, <<sle ep>>, <<fatigability>>, <<asthenia>>, etc. In clinical practice, fatig ue is often difficult to analyze and should be evaluated based on the nosologic context, mode of onset, functional impact, quality of sleep. mood, and presence of organic disease.