Comparison of dysphagia before and after deep brain stimulation in Parkinson's disease.

Although dysphagia is a common problem for many Parkinson's disease (PD) patients, the effect of deep brain stimulation (DBS) on swallowing is unclear. Fourteen subjects with advanced PD underwent videofluorographic swallowing studies prior to bilateral DBS of the subthalamic nucleus (STN) and at 3 and 12 months postprocedure. They were tested under several stimulation and medication conditions. Subjects completed the Dysphagia Handicap Index at each time. There was a strong trend toward improved swallowing response for solid intake in the medication-free condition with the stimulator on compared with the stimulator off (P = .0107). Also, there was a trend toward improved oral preparation of thin liquids (P = .0368) in the medication-free condition when the stimulator was on versus off 12 months later. The remaining swallowing parameters showed no change or worsening of swallowing function regardless of stimulator or medication status. Results of the Dysphagia Handicap Index revealed significant improvement in subject self-perception of swallowing 3 and 12 months following the procedure compared with baseline on the functional subscale (P = .020 and P = .010, respectively), the emotional subscale (P = .013 and P = .003, respectively), and the total score (P = .025 and P = .003, respectively). These data suggest that bilateral STN-DBS does not substantively impair swallowing in PD. In addition, it may improve motor sequencing of the oropharyngeal swallow for solid consistencies (which are known to provide increased sensory feedback to assist motor planning of the oropharyngeal swallow). Subjects with advanced PD who are undergoing DBS may perceive significant improvement in swallowing ability despite the lack of objective improvements in swallowing function.

Subthalamic deep brain stimulation with a constant-current device in Parkinson's disease: an open-label randomised controlled trial.

BACKGROUND: The effects of constant-current deep brain stimulation (DBS) have not been studied in controlled trials in patients with Parkinson's disease. We aimed to assess the safety and efficacy of bilateral constant-current DBS of the subthalamic nucleus. METHODS: This prospective, randomised, multicentre controlled trial was done between Sept 26, 2005, and Aug 13, 2010, at 15 clinical sites specialising in movement disorders in the USA. Patients were eligible if they were aged 18-80 years, had Parkinson's disease for 5 years or more, and had either 6 h or more daily off time reported in a patient diary of moderate to severe dyskinesia during waking hours. The patients received bilateral implantation in the subthalamic nucleus of a constant-current DBS device. After implantation, computer-generated randomisation was done with a block size of four, and patients were randomly assigned to the stimulation or control group (stimulation:control ratio 3:1). The control group received implantation without activation for 3 months. No blinding occurred during this study, and both patients and investigators were aware of the treatment group. The primary outcome variable was the change in on time without bothersome dyskinesia (ie, good quality on time) at 3 months as recorded in patients' diaries. Patients were followed up for 1 year. This trial is registered with ClinicalTrials.gov, number NCT00552474. FINDINGS: Of 168 patients assessed for eligibility, 136 had implantation of the constant-current device and were randomly assigned to receive immediate (101 patients) or delayed (35 patients) stimulation. Both study groups reported a mean increase of good quality on time after 3 months, and the increase was greater in the stimulation group (4·27 h vs 1·77 h, difference 2·51 [95% CI 0·87-4·16]; p=0·003). Unified Parkinson's disease rating scale motor scores in the off-medication, on-stimulation condition improved by 39% from baseline (24·8 vs 40·8). Some serious adverse events occurred after DBS implantation, including infections in five (4%) of 136 patients and intracranial haemorrhage in four (3%) patients. Stimulation of the subthalamic nucleus was associated with dysarthria, fatigue, paraesthesias, and oedema, whereas gait problems, disequilibrium, dyskinesia, and falls were reported in both groups. INTERPRETATION: Constant-current DBS of the subthalamic nucleus produced significant improvements in good quality on time when compared with a control group without stimulation. Future trials should compare the effects of constant-current DBS with those of voltage-controlled stimulation. FUNDING: St Jude Medical Neuromodulation Division.