Sheng Huang Lin

Neuropsychological effects after chronic subthalamic stimulation and the topography of the nucleus in Parkinson's disease

OBJECTIVEThe neuropsychological effects of chronic subthalamic nucleus (STN)-deep brain stimulation (DBS) as a treatment for Parkinsons disease are variable. Whether these side effects result from the target per se or current diffusion into neighboring structures is uncertain. In this study, the relationship between clinical outcomes and coordinates of active contact are analyzed and compared between patients with and without neuropsychological sequelae. METHODSThirty-eight Parkinsonian patients who underwent bilateral STN-DBS were enrolled in this retrospective cohort study. They were followed for at least 12 months. During the follow-up period, they were divided into two groups for comparison; Group A included patients with neuropsychological side effects and Group B was composed of patients without neuropsychological side effects. The position of the active contact of the electrode was defined with postoperative magnetic resonance imaging scans according to the midcommissural line. Active contact coordinates and clinical outcomes were compared for the two groups. RESULTSAmong the 38 Parkinsonian patients who underwent STN-DBS, eight patients who had neuropsychological side effects were assigned to Group A; the other 30 patients were assigned to Group B. In Groups A and B, the mean follow-up periods were 13.9 and 12.1 months, respectively, the Unified Parkinsons Disease Rating Scale motor score was improved by 53.4 and 45.2% (P = 0.24), respectively, and the levodopa equivalent daily dosage was decreased by 68.4 and 46.4% (P = 0.16), respectively. The mean coordinates of active contact in both Groups A and B were x = 10.1 and 10.5 mm, respectively, y = −2.8 and −3.9 mm, respectively, and z = −6.3 and −6.2 mm, respectively, relative to the midcommissural point. A significant difference was observed on the y axis (P = 0.01). CONCLUSIONWhen taking spatial influence into consideration, the neuropsychological effects of chronic STN-DBS were related to a significant anteriorly located active contact within the ventral STN in this preliminary study. This might suggest the existence of topography of STN in patients with Parkinsons disease concerning limbic and associative circuits.

Subthalamic deep brain stimulation after anesthetic inhalation in Parkinson disease: a preliminary study

OBJECT The authors of this preliminary study investigated the outcome and feasibility of intraoperative microelectrode recording (MER) in patients with Parkinson disease (PD) undergoing deep brain stimulation of the subthalamic nucleus (STN) after anesthetic inhalation. METHODS The authors conducted a retrospective analysis of 10 patients with PD who received a desflurane anesthetic during bilateral STN electrode implantation. The MERs were obtained as an intraoperative guide for final electrode implantation and the data were analyzed offline. The functional target coordinates of the electrodes were compared preoperatively with estimated target coordinates. RESULTS Outcomes were evaluated using the Unified Parkinsons Disease Rating Scale 6 months after surgery. The mean improvement in total and motor Unified Parkinsons Disease Rating Scale scores was 54.27 +/- 17.96% and 48.85 +/- 16.97%, respectively. The mean STN neuronal firing rate was 29.7 +/- 14.6 Hz. Typical neuronal firing patterns of the STN and substantia pars nigra reticulata were observed in each patient during surgery. Comparing the functional target coordinates, the z axis coordinates were noted to be significantly different between the pre- and postoperative coordinates. CONCLUSIONS The authors found that MER can be adequately performed while the patient receives a desflurane anesthetic, and the results can serve as a guide for STN electrode implantation. This may be a good alternative surgical method in patients with PD who are unable to tolerate deep brain stimulation surgery with local anesthesia.

Subthalamic deep brain stimulation in Parkinson's disease under different anesthetic modalities: a comparative cohort study.

Background: The efficacy and feasibility of bilateral subthalamic deep brain stimulation (STN-DBS) for Parkinson’s disease (PD) under general anesthesia (GA) has not been evaluated. Objective: We compared the outcome of patients under GA with those who were operated on under local anesthesia (LA). Material and Methods: Thirty-three patients were assigned to the GA group (desflurane) and 19 patients were assigned to the LA group. Microelectrode recording (MER) was performed in both groups. The surgical outcomes of the patients were evaluated using the Unified Parkinson’s Disease Rating Scale (UPDRS) after at least 12 months after surgery. Results: Postoperatively, there was no significant difference on the UPDRS scores in either groups. A significant deterioration in cognitive function in the GA group was observed (p = 0.017). The recorded electrode coordinates, the average tracts for the MER, and STN depth were comparable in both groups. The overall incidence of adverse effects did not show any difference except that the incidence of sialorrhea and dysarthria was significantly higher in the GA group. Conclusion: Desflurane GA was shown to be a good alternative anesthetic method for PD patients undergoing DBS. Although the motor outcomes were comparable, a significant cognitive decline may be seen in the GA group with a higher occurrence of stimulation side effects.

Surgical and hardware complications in subthalamic nucleus deep brain stimulation

OBJECTIVE To assess the surgical and hardware complications in 26 consecutive patients with movement disorders undergoing subthalamic deep brain stimulation (STN-DBS) in early practice at our institute. METHODS The 26 patients in our institute were analyzed retrospectively. Group A included the first eight patients treated while we had no facility for microelectrode recording (MER), 16 intracranial procedures were performed and 8 batteries were implanted. Group B (with MER) included 18 patients, 35 intracranial procedures were performed and 18 batteries were implanted. RESULTS The intracranial morbidity was 18.75% in group A and 5.71% in group B. The extracranial morbidity was 37.5% in group A and 16.67% in group B. There was no hardware-related infection in our study. The overall mortality rate was 7.69%, and deaths were not surgical related. CONCLUSIONS The associated morbidity is significant in STN-DBS. The use of MER may improve the clinical outcome while decreasing the morbidity.

Prognostic Factors of Subthalamic Stimulation in Parkinson's Disease: A Comparative Study between Short- and Long-Term Effects

Background/Aims: Bilateral subthalamic nucleus deep brain stimulation (STN-DBS) has been shown to have long-term benefits in Parkinson’s disease (PD). Through analyzing different variables, this study identified prognostic factors for the short- and long-term effects of STN-DBS. Methods: Thirty-six PD patients underwent bilateral STN-DBS. Clinical evaluations were performed 1 month before and 3 months after surgery, with additional follow-up examinations for a mean of 31.3 months. Results: There was a trend for long-term STN-DBS-induced improvements in the Unified Parkinson’s Disease Rating Scale (UPDRS) part II and part III measures to be greater in younger patients. Preoperative levodopa responsiveness only led to consistent UPDRS part III improvement from STN-DBS at 3 months, and this predictive value did not exist in the long term. The preoperative levodopa response of tremor and axial symptoms in motor disability predicted long-term DBS effect only. Preoperative cognitive function positively correlated with postoperative improvement from DBS in UPDRS part III during long-term follow-up only. Conclusions: The prognostic factors for STN-DBS benefit were different for short- and long-term follow-ups. Good prognostic factors for long-term STN-DBS for PD patients were good cognitive function and tremor dominance. Poor prognostic factors were related to older age and non-dopaminergic-responsive axial disability.

Targeting the Subthalamic Nucleus for Deep Brain Stimulation—A Comparative Study Between Magnetic Resonance Images Alone and Fusion with Computed Tomographic Images

BACKGROUND The aim of this study is to determine whether stereotactic computed tomographic (CT) images fused with magnetic resonance images (MRI) is superior to stereotactic MRI alone in accuracy for targeting the subthalamic nucleus (STN) in deep brain stimulation (DBS). METHODS During 2006 to 2007, 21 consecutive patients with Parkinsons disease were enrolled in this retrospective cohort study. CT Fusion group included 10 patients who underwent 20 procedures of STN-DBS under MRI-directed targeting in which the MRIs were fused to stereotactic CT images for surgical coordinates. MRI group included 11 patients who underwent 20 procedures under MRI-directed targeting alone. RESULTS After DBS surgery, in comparison to baseline levodopa (L-dopa) OFF, Unified Parkinson Disease Rating Scale, Part III scores improved by 43.6% ± 20.3% and 39.0% ± 15.6% (P = 0.60) in CT Fusion group and MRI group, respectively (L-dopa OFF/DBS ON). The mean decrease in L-dopa equivalent daily dose was 38.9% ± 26.3% and 36.7% ± 30.5% (P = 0.87), respectively. Single microelectrode recording (MER) trajectory procedure was experienced in 65% of patients in the CT Fusion group (13/20) and 45% of patients in the MRI group (9/20). The mean recorded STN length from initial to final MER trajectory in the CT Fusion and MRI groups was 4.3 mm (standard deviation [SD] = 1.8 mm)/5.1 mm (SD = 0.5 mm) and 3.6 mm (SD = 1.7 mm) (P = 0.214)/4.5 mm (SD = 0.7 mm) (P = 0.006), respectively. The final recorded STN length was significantly longer in the CT Fusion group. CONCLUSIONS In-frame-based stereotactic STN targeting, an image fusion technique between stereotactic CT and MRI, can record a significantly longer STN length through limited MER compared with MRI alone. Whether this could translate into better clinical outcome and less morbidity still need a large and randomized trial.

Long-term outcome of young onset Parkinson's disease after subthalamic stimulation - A cross-sectional study

OBJECTIVE Age of onset is considered a poor prognostic factor for subthalamic deep brain stimulation (STN-DBS) outcome in the case of Parkinsons disease (PD). The goal of current study is to identify the long-term impact of STN-DBS for young onset PD (YOPD) patients. METHODS 17 YOPD patients with a mean disease onset at 32.3 years were prospectively followed up at 1, 2, 5 and 7 years after STN-DBS. Unified Parkinsons disease rating scale (UPDRS) was evaluated in 4 combinations of Med/DBS on/off. RESULTS UPDRS part II-IV improved significantly 7 years after operation. While a slowly progressive worsening of levodopa response on part III, synergistic effect of medication and stimulation consistently improves motor disabilities. STN-DBS could remarkably reduce levodopa equivalent daily dose at 7 years. The morbidity rates were low. However, these patients seem to have more transient stimulation dyskinesia (47.1%) and dopamine dysregulation syndrome (11.8%) after surgery. CONCLUSIONS STN-DBS remains effective to improve motor disabilities over 7 years for YOPD and is a safe procedure concerning cognitive outcome and morbidity. However, stimulation dyskinesia and dopamine dysregulation syndrome deserve attention for the causal relationship between DBS surgery and behavioral outcomes.