What Causes Fatigue in Parkinson Disease?

This article is a brief review of the literature on fatigue in Parkinson disease (PD). The authors struggle with the difficult issue of defining and measuring fatigue. Even the Fatigue Severity Scale (FSS) and the Fatigue Questionnaire, which have been validated in the Norwegian population (of particular interest to these authors), give substantially varied results. The authors try to focus on fatigue that is primary and not secondary (i.e., caused by other diseases, sleep disorders, medications, or depression). They view physical exhaustion with low energy as peripheral fatigue and label mental exhaustion with great effort to concentrate, speak, and perform memory tasks as central fatigue.

The studies reviewed indicate a 37% to 56% prevalen…