Global cognitive scores do not predict outcome after subthalamic nucleus deep brain stimulation

Background: Presence of dementia is a contraindication for DBS treatment of Parkinson's disease. Recent evidence suggests that borderline cognitive function, as measured with a common screening measure, the Mattis Dementia Rating Scale, has a negative impact on quality of life (QoL) after DBS of the STN. Methods: We attempted to replicate and extend this finding in a larger group of patients with a wider range of preoperative global cognitive performance. Results: Our data indicate that performance on the screening measure is not associated with QoL or medical outcomes, even with scores well below the cutoff for identifying dementia. Conclusions: This cognitive screening measure lacks sufficient sensitivity to warrant its use in predicting which patients will show QoL benefit from DBS.