Does deep brain stimulation induce apathy in Parkinson's disease?

Chronic deep brain stimulation (DBS) is an important therapeutic advancement for the treatment of motor symptoms in Parkinson's disease (PD). However, its effects on non-motor symptoms are not well understood. Several studies have reported motivational disturbances and apathy after DBS surgery. Recent studies are beginning to more carefully examine the relationship between DBS and apathy. This review summarizes and evaluates the current state of the literature on apathy after DBS surgery, discusses methodological limitations in the literature, and makes suggestions for future research.