Stimulation of the subthalamic nucleus in Parkinson's disease: cognitive and affective changes are not linked to the motor outcome.

Background: Subthalamic nucleus deep brain stimulation (STN0 DBS) is a widely performed surgical treatment in PD. However, the relationship between motor results and cognitive/behavioural modifications is unclear.

Objective: This study investigated the correlation patterns of the motor, cognitive and behavioural consequences of STN DBS with respect to positioning of the active contact.

Methods: Fifty-eight consecutive PD patients having undergone STN DBS were assessed pre-operatively and 12 months after surgery.

Results: Motor, cognitive and behavioural results were neither correlated to each other nor linked to the position of the active contact. Three patients with a history of pre-operative, dopaminergic psychosis or post-surgical confusion became demented. Age and a distant history of depression were associated with the occurrence of post-surgical depression.

Conclusion: Correct screening of patients for STN DBS remains an important issue, since the current implantation procedure is not able to take account of potential functional heterogeneity within the target.