ABSTRACT
AIM: To assess the long-term cognitive and behavioural outcome after bilateral deep brain stimulation (DBS) of the subthalamic nucleus (STN) in patients affected by Parkinson's disease, with a 5-year follow-up after surgery. METHODS: 11 patients with Parkinson's disease treated by bilateral DBS of STN underwent cognitive and behavioural assessments before implantation, and 1 and 5 years after surgery. Postoperative cognitive assessments were carried out with stimulators turned on. RESULTS: A year after surgery, there was a marginally significant decline on a letter verbal fluency task (p = 0.045) and a significant improvement on Mini-Mental State Examination (p = 0.009). 5 years after surgery, a significant decline was observed on a letter verbal fluency task (p = 0.007) and an abstract reasoning task (p = 0.009), namely Raven's Progressive Matrices 1947. No significant postoperative change was observed on other cognitive variables. No patient developed dementia 5 years after surgery. A few days after the implantation, two patients developed transient manic symptoms with hypersexuality and one patient developed persistent apathy. CONCLUSION: The decline of verbal fluency observed 5 years after implantation for DBS in STN did not have a clinically meaningful effect on daily living activities in our patients with Parkinson's disease. As no patient developed global cognitive deterioration in our sample, these findings suggest that DBS of STN is associated with a low cognitive and behavioural morbidity over a 5-year follow-up, when selection criteria for neurosurgery are strict.
Subject(s)
Cognition Disorders , Deep Brain Stimulation , Parkinson Disease/therapy , Subthalamic Nucleus/physiology , Aged , Bipolar Disorder/etiology , Deep Brain Stimulation/adverse effects , Female , Follow-Up Studies , Humans , Male , Mental Status Schedule , Middle Aged , Mood Disorders/etiology , Patient SelectionSubject(s)
Deep Brain Stimulation/adverse effects , Deep Brain Stimulation/psychology , Depressive Disorder/psychology , Movement Disorders/psychology , Movement Disorders/therapy , Suicide/psychology , Adult , Antiparkinson Agents/adverse effects , Causality , Clinical Trials as Topic/standards , Comorbidity , Dementia/epidemiology , Dementia/psychology , Depressive Disorder/epidemiology , Female , Humans , Hypothalamus, Posterior/physiopathology , Hypothalamus, Posterior/surgery , Male , Middle Aged , Parkinsonian Disorders/psychology , Parkinsonian Disorders/therapy , Patient Selection , Retrospective Studies , Risk Factors , Subthalamic Nucleus/physiopathology , Subthalamic Nucleus/surgery , Suicide/statistics & numerical data , Switzerland/epidemiology , Suicide PreventionABSTRACT
OBJECTIVE: To investigate cognitive and behavioural effects of bilateral lead implants for high frequency stimulation (HFS) of the subthalamic nucleus in patients with Parkinson's disease; and to discriminate between HFS and the effects of surgical intervention on cognitive function by carrying out postoperative cognitive assessments with the stimulators turned on or off. METHODS: Motor, cognitive, behavioural, and functional assessments were undertaken in 20 patients with Parkinson's disease before implantation and then at three, six, and 12 months afterwards. Nine patients were also examined 18 months after surgery. Postoperative cognitive assessments were carried out with stimulators turned off at three and 18 months, and turned on at six and 12 months. RESULTS: Cognitive assessment showed a significant postoperative decline in performance on tasks of letter verbal fluency (across all postoperative assessments, but more pronounced at three months) and episodic verbal memory (only at three months, with stimulators off). At three, six, and 12 months after surgery, there was a significant improvement in the mini-mental state examination and in a task of executive function (modified Wisconsin card sorting test). On all postoperative assessments, there was an improvement in parkinsonian motor symptoms, quality of life, and activities of daily living while off antiparkinsonian drugs. A significant postoperative decrease in depressive and anxiety symptoms was observed across all assessments. Similar results were seen in the subgroup of nine patients with an 18 month follow up. Following implantation, three patients developed transient manic symptoms and one showed persistent psychic akinesia. CONCLUSIONS: Bilateral HFS of the subthalamic nucleus is a relatively safe procedure with respect to long term cognitive and behavioural morbidity, although individual variability in postoperative cognitive and behavioural outcome invites caution. Stimulation of the subthalamic nucleus does not per se appear to impair cognitive performance in patients with Parkinson's disease and may alleviate the postoperative decline in verbal fluency.
Subject(s)
Cognition Disorders/therapy , Electric Stimulation Therapy , Neuropsychological Tests , Parkinson Disease/therapy , Social Behavior Disorders/therapy , Subthalamic Nucleus/physiopathology , Aged , Cognition Disorders/diagnosis , Cognition Disorders/physiopathology , Disability Evaluation , Dominance, Cerebral/physiology , Female , Follow-Up Studies , Humans , Male , Middle Aged , Neurologic Examination , Outcome and Process Assessment, Health Care , Parkinson Disease/diagnosis , Parkinson Disease/physiopathology , Social Behavior Disorders/diagnosis , Social Behavior Disorders/physiopathology , Verbal Behavior/physiologyABSTRACT
Twenty-two patients with PD received bilateral implants for high frequency stimulation of the subthalamic nucleus. The patients were treated for more than 1 year (up to 36 months). At the last visit, the Unified Parkinson Disease Rating Scale (UPDRS) motor score without medication improved by 50.2% (p < 0.001) and the UPDRS activities of daily living score improved by 68.4% (p < 0.001). The most common long-lasting adverse events were hypophonia and dysarthria; transient events were increased sexuality and mania. The surgical procedure induced transient intraoperative psychosis in seven patients.
