Neuropsychiatric side effects of deep brain stimulation in Parkinson’s disease

Abstract

Parkinson’s disease (PD) is a neurodegenerative movement disorder characterized by akinesia, tremor, rigidity, and postural instability, but also by nonmotor symptoms, including olfactory loss, autonomic failure, and psychiatric symptoms. Deep brain stimulation (DBS) of the subthalamic nucleus has been established as a highly effective treatment option for motor fluctuations and dyskinesia in advanced PD. However, psychiatric side effects after a DBS operation are a common finding and have a high impact on quality of life. In this chapter we give an overview of the main neuropsychiatric symptoms that may occur after a DBS operation in PD. In this context, one has to distinguish between neuropsychiatric symptoms in the adjustment phase of medication and stimulation and in the long-term treatment phase. Psychiatric symptoms in the early postoperative period often reflect the complex interaction between drug and neurostimulation treatment. In the long term, however, psychiatric symptoms are more likely the result of the ongoing neurodegenerative process. In practice, the assignment of a neuropsychiatric symptom to any single cause is often complicated by additional contributing factors such as the exact electrode location, lesion effects, preoperative neuropsychiatric status, individual personality traits, and the need for adjustment to a new life situation with less Parkinsonian motor disability.