Age Limits for Deep Brain Stimulation of Subthalamic Nuclei in Parkinson's Disease

Clinical pre-operative predictive factors of optimal STN-DBS motor outcome in Parkinson's disease (PD) have been previously reported. However, available data involving elderly patients are conflicting.

To compare early post-operative outcomes in parkinsonian patients younger than 65 years old (group 1) vs patients 65 years old or older (group 2) at the time of surgery.

The cognitive and motor effects of DBS were evaluated by comparison of different scores obtained before (baseline) and 6 months after surgery using a repeated measures analysis of variance.

Post-operative motor improvement (UPDRS part III and UPDRS part IV scores) and drug reduction were not statistically different between groups 1 and 2 (P > 0.05). Axial motor score which was significantly worse in group 2 in the on-drug condition before surgery was also significantly worse both in off-drug/on-stimulation and on-drug/on-stimulation conditions (P < 0.05). Similarly, cognitive performances (Wisconsin Card Sorting Test, Stroop interference test, Free and Cued Selective Reminding Test with Immediate Recall, Verbal Fluency) significantly worsened post-operatively ingroup 2.

Although effective and safe, STN-DBS has a more negative impact on cognitive functions in elderly patient, requiring a careful preoperative selection.