Abstract

Fatigue and increased fatigability occur as symptoms in almost every medical and psychiatric condition, as well as being common reactions to non pathological physical and psychological strain and stress. We will attempt to clarify the semantics of the terms "fatigue" and "fatigability", and we will put forward the hypothesis that the special kind of mental fatigability which characterises many cases of mild to moderate dysfunction of the brain is functional in a sense that it represents an overload of pathological information (from the injured area) to higher cognitive mechanisms which may themselves be anatomically and physiologically intact