Optimal target localization for subthalamic stimulation in patients with Parkinson disease.

OBJECTIVE: To further determine the causes of variable outcome from deep brain stimulation of the subthalamic nucleus (DBS-STN) in patients with Parkinson disease (PD). METHODS: Data were obtained from our cohort of 309 patients with PD who underwent DBS-STN between 1996 and 2009. We examined the relationship between the 1-year motor, cognitive, and psychiatric outcomes and (1) preoperative PD clinical features, (2) MRI measures, (3) surgical procedure, and (4) locations of therapeutic contacts. RESULTS: Pre- and postoperative results were obtained in 262 patients with PD. The best motor outcome was obtained when stimulating contacts were located within the STN as compared with the zona incerta (64% vs 49% improvement). Eighteen percent of the patients presented a postoperative cognitive decline, which was found to be principally related to the surgical procedure. Other factors predictive of poor cognitive outcome were perioperative confusion and psychosis. Nineteen patients showed a stimulation-induced hypomania, which was related to both the form of the disease (younger age, shorter disease duration, higher levodopa responsiveness) and the ventral contact location. Postoperative depression was more frequent in patients already showing preoperative depressive and/or residual axial motor symptoms. CONCLUSION: In this homogeneous cohort of patients with PD, we showed that (1) the STN is the best target to improve motor symptoms, (2) postoperative cognitive deficit is mainly related to the surgery itself, and (3) stimulation-induced hypomania is related to a combination of both the disease characteristics and a more ventral STN location.

Are parkin patients particularly suited for deep-brain stimulation?

Patients with parkin mutations are known to have slower PD progression and a better response to levodopa at lower doses than patients with idiopathic Parkinson's disease. To determine the effects of deep brain stimulation (DBS) on such patients, we have compared the follow-up after surgery of 7 patients with one parkin mutation, 7 patients with two parkin mutations, and 39 patients without parkin mutations. Twelve to 24 months after neurosurgery, the daily doses of levodopa equivalent were significantly lower in patients with two parkin mutations, indicating that these patients benefit from DBS, and they might have more durable results.

Mortality in patients with Parkinson's disease treated by stimulation of the subthalamic nucleus.

Subthalamic nucleus (STN) stimulation improves motor disability and quality of life in patients with advanced Parkinson's disease (PD). Short-term mortality is low, but little is known about long-term mortality. We assessed mortality and causes of death in 171 consecutive PD patients treated by STN stimulation. Surgery was performed after a median lagtime of 13 years from PD onset at a median age of 57 years. The median follow-up after surgery was 41 months. Sixteen patients died 8 to 83 months after neurosurgery. Poorer cognitive function was the only predictive factor for mortality (standardized mortality ratio = 2.9; 95% confidence interval [CI], 1.6-4.7; P < 0.0001). Based on a historical comparison of 118 operated patients with 39 nonoperated patients from a different population, survival among operated patients was not better (hazard ratio = 1.2; 95% CI, 0.7-2.1).

Subthalamic stimulation in Parkinson disease: behavior and social adaptation.

BACKGROUND: Bilateral subthalamic high-frequency stimulation significantly improves motor functions in patients with advanced forms of Parkinson disease (PD). This favorable effect contrasts with a growing number of reports that the treatment may result in psychiatric complications. OBJECTIVE: To analyze the presence of behavioral disorders and social maladjustment in PD patients successfully treated with continuous bilateral subthalamic stimulation. DESIGN: Prospective study. SETTING: University hospital. METHODS: Twenty PD patients underwent prospective evaluation for behavioral and personality changes, quality of life, and social functioning, 6 and 24 months after surgery to implant bilateral stimulating electrodes within the subthalamic nucleus. RESULTS: At 6 and 24 months after surgery, parkinsonian motor disability (on-stimulation/off-medication) was improved by 81% and 67%, respectively, and the severity of levodopa-related motor complications was improved by 84% and 70%, respectively. Levodopa-equivalent dosage was decreased by 79% and 66%, respectively; severity of depression was improved by 21% and 33%, respectively; and severity of anxiety was improved by 43% and 64%, respectively. The patients' personality traits were unmodified. Twenty-four months after surgery, the global score for quality of life was improved by 28%, whereas scores for social adjustment remained stable. CONCLUSIONS: Provided that patients with PD are rigorously selected for neurosurgery, subthalamic stimulation (1) improves mood, anxiety, and quality of life; (2) does not result in severe permanent psychiatric disorders or modify patients' personality; and (3) does not ameliorate social adaptation.

Subthalamic stimulation in Parkinson disease: with or without anesthesia?

OBJECTIVE: To study the effects of general anesthesia on the postoperative outcome of patients with Parkinson disease (PD) who underwent surgery using bilateral placement of stimulating electrodes within the subthalamic nucleus (STN). DESIGN: Retrospective analysis. SETTING: Hôpital de la Salpêtrière, Paris, France. PATIENTS: Fifteen PD patients who underwent bilateral implantation of electrodes within the STN received general anesthesia because of severe anxiety, poorly tolerated off-period dystonia, or respiratory difficulties. These patients were compared with 15 patients matched for age, disease duration, and parkinsonian motor disability who underwent the same neurosurgical procedure under local anesthesia. MAIN OUTCOME MEASURE: Motor disability scores. RESULTS: After surgery, the severity of parkinsonian motor disability was markedly improved in both groups of patients. Compared with patients who were under local anesthesia during the operation, the residual parkinsonian motor score under stimulation (with ["on"] or without ["off"] levodopa) and the intensity of stimulation were higher in patients who were under general anesthesia during the operation. CONCLUSIONS: Although the improvement of parkinsonian motor disability is greater in PD patients who receive local anesthesia during surgery, general anesthesia can be performed in patients unable to tolerate prolonged states without levodopa.

Subthalamic stimulation in Parkinson disease: intraoperative predictive factors.

BACKGROUND: High-frequency stimulation of the subthalamic nucleus (STN) is an effective treatment for advanced forms of Parkinson disease. Postoperative improvement of motor parkinsonian disability is known to depend on patient selection and surgical targeting. OBJECTIVE: To determine which clinical and electrophysiological variables evaluated during the operation predict the postoperative clinical outcome of patients with Parkinson disease treated by bilateral high-frequency stimulation of the STN. METHODS: Intraoperative clinical and electrophysiological data obtained in 41 patients with Parkinson disease who underwent bilateral implantation of electrodes for STN stimulation were correlated with the improvement in parkinsonian disability assessed 6 months after the operation. RESULTS: The extent of STN neuronal activity recorded along the trajectory of the therapeutic electrode had no effect on the postoperative clinical outcome. The intraoperative improvement in segmental akinesia, but not rigidity, was predictive of the postoperative improvement in parkinsonian motor disability and reduction in daily levodopa-equivalent dosage. Parkinsonian motor disability scores assessed after surgery were lower in patients with intraoperative stimulation-induced dyskinesias than in those without stimulation-induced dyskinesias. CONCLUSION: The improvement of segmental akinesia and the observation of dyskinesias provoked by stimulation during the operation predict the best postoperative effects of bilateral STN stimulation on parkinsonian motor disability.