Thalamic DBS is a safe and effective treatment of ET and the tremor of PD. In PD, its use should be limited to patients in whom high-amplitude tremor results directly in significant functional disability.

Background: Deep brain stimulation (DBS) has proven to be an effective treatment for Parkinson’s disease (PD) and other movement disorders, but its usefulness is limited by complications related to the hardware. Methods: We reviewed the records of all our patients treated with DBS from January 1996 to August 2010 and analyzed those with hardware complications and reasons for surgical revision. Results: A total of 512 patients underwent 856 electrode implantations during the study period. A total of 297 (58%) patients had PD, 127 (24.8%) had essential tremor (ET), 40 (7.8%) had dystonia, and 48 (9.37%) had another movement disorder. The mean age at the first electrode implantation was 57.6 ± 14 years and patients were followed for a mean of 3.9 ± 2.8 years. A total of 44 patients (8.6%) had a hardware complication or system revision. Lead fracture was the most common complication and occurred in 13 (2.5%) patients, followed by infections (n = 10, 1.9%), electrode misplacement (n = 10, 1.9%), electrode migration (n = 9, 1.75%), and other complications (n = 2 , 0.39%). Patients with ET had a higher risk of hardware complications compared to those with PD, 13 vs. 7% (OR 2.03; p = 0.042). Conclusions: DBS is a safe intervention with a relatively low rate of hardware complications.

The safety and efficacy of subthalamic nucleus (STN) deep brain stimulation (DBS) in patients who have had a previous unilateral pallidotomy is not clear. We identified 10 patients (9 male) at the Baylor College of Medicine Parkinson's Disease Center who underwent STN DBS after prior unilateral pallidotomy. Demographics, efficacy as determined by off Unified Parkinson's Disease Rating Scale (UPDRS) part III scores, and levodopa equivalent dosing were analyzed. We then compared these to an age- and sex-matched group of 25 DBS patients who had no prior pallidotomy. After their initial pallidotomy (mean age, 51.8 +/- 10.8 years), the mean UPDRS motor off medicine scores improved from 51.3 +/- 14.3 to 34.9 +/- 12.8, and the UPDRS dyskinesia score improved from 1.8 +/- 1.0 to 0.8 +/- 0.7. Their STN DBS off UPDRS motor scores (mean age, 56.0 +/- 10.2 years) improved by 16.0% from 53.1 +/- 9.7 (range, 42-68) to 44.6 +/- 11.1 (range, 25-67). In contrast, the UPDRS off motor scores in a control group of 25 DBS patients improved by 49.9%, from 49.7 +/- 11.1 to 25.7 +/- 18.9, (16.0% vs. 49.9%; P < 0.001). Changes in UPDRS dyskinesia scores were similar in both groups. AE thought to be related to the STN DBS following pallidotomy included worse dysarthria (three) and worse balance (two). STN DBS patients with prior pallidotomy had less improvement in UPDRS off motor score compared to other STN DBS patients, despite relatively good outcomes immediately after their pallidotomy. This may be partially due to a selection bias, but it may also indicate that prior pallidotomy is a negative predictor of outcome of STN DBS and should be considered in patient selection.

Bilateral ventralis intermedius nuclei (Vim) deep brain stimulation (DBS) improves tremor in patients with both essential tremor (ET) and Parkinson's disease (PD). In each condition, patients have individually noted both subjective improvement and worsening in balance. Computerized posturography (CP) is able to quantify some aspects of balance. Twenty-one patients (8 with PD and 13 with ET) with bilateral Vim DBS were recruited to undergo randomized-order identical CP testing (EquiTest system) while their DBS devices were both activated and deactivated. One PD patient could not complete any OFF assessment and is not included. Three PD patients could not tolerate portions of the OFF testing. Overall, sensory organization testing was improved by DBS activation in conditions that involved quiet standing with eyes open with no motion of the support surface, or with sway-referenced support surface motion, but worsened during quiet standing with eyes closed only in ET patients. Falls lessened with activation in ET patients. Motor control testing was not changed. Bilateral Vim DBS activation mostly improved balance, but may modestly worsen other specific features.

Dysphagia is a frequent complication in Parkinson's disease (PD). 1 There is evidence that deep brain stimulation (DBS) improves PD motor symptoms, such as tremors and rigidity, but there is little research evaluating DBS on dysphagia improvement in PD. 2 We report a case of a PD patient with severe dysphagia, relieved with percutaneous endoscopic gastrostomy (PEG). The patient showed remarkable improvement in swallowing after bilateral subthalamic nucleus (STN) DBS. Swallowing function was evaluated by videofluoroscopy (VF) before and after operation.The patient was a 43-year-old man whose initial symptoms were right hand tremors and gait disturbance at 32 years. Symptoms such as rigidity and akinesia gradually became aggravated, and he had pronounced swallowing disability. PEG was performed at age 43 years, because of aspiration pneumonia due to dysphagia. Myocardial scintigraphy (99mTc-metaiodobenzylguanidine [MIBG]) showed decreased uptake compatible with PD. Since the symptoms were uncontrollable with various medications, the patient was considered for DBS. Preoperative Unified Parkinson's Disease Rating Scale (UPDRS) motor score was 31/58 in the on/off period, respectively. He could not swallow solid foods or liquids, and medicine and nutrition were given through PEG. However, pharyngeal and palatal reflex were normal. L-Dopa equivalent dose (LED) 3 was 842 mg. Swallowing abnormality was evaluated by VF before DBS (see Video Segment 1, $41 seconds). Piecemeal deglutition, residue in the oral cavity, and tongue tremors were observed in the oral phase, and residue in the vallecula of the epiglottis and piriform recesses, delay of laryngeal elevation, aspiration, coughing, and insufficient opening of the esophageal orifice were observed in the pharyngeal phase. Bilateral STN-DBS was performed, and motor function and swallowing ability were noticeably improved. The effect of DBS lasted beyond 3 years; the UPDRS motor score decreased to 11/17 in the on/off period, respectively, and the LED was 525 mg. The patient could eat anything he wanted. In the VF findings, after 3 years from DBS, the swallowing abnormal-ities were noticeably improved (see Video Segment 2, 41 seconds $).Various swallowing abnormalities associated with PD were found with VF examination. 4,5 Nagaya et al. 4 evaluated swallowing function by VF in 16 PD patients. They suggested that disturbed motility in the oral phase may be due to bradykinesia. Ali et al. 5 showed that incomplete upper esophageal sphincter (UES) relaxation and reduced UES opening are prevalent in PD. Dysphagia was reported as an occasional side effect of DBS, 6 whereas improvement of deglutition after STN-DBS was observed by VF, performed 3 to 6 months after DBS. 2 The pharyngeal composite score and pharyngeal transit time were significantly improved with DBS on compared with DBS off. However, the degree of hyoid bone excursion and oral stage measures did not improve. The mechanism of dysphagia in PD was hypothesized to be due to degeneration of cholinergic neurons of the p...