Alleviation of dysphagia after deep brain stimulation: results from a Parkinson's disease patient

Dysphagia is a frequent complication in Parkinson’s disease (PD). 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. 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) 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 abnormalities were noticeably improved (see Video Segment 2, 41 seconds ). Various swallowing abnormalities associated with PD were found with VF examination. Nagaya et al. 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. 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, whereas improvement of deglutition after STN-DBS was observed by VF, performed 3 to 6 months after DBS. 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 pedunculopontine tegmental nucleus (PPN), which is involved in the pathophysiology of dysphagia in PD. STN-DBS may improve the actions of the PPN, or simply mitigate bradykinesia of oropharyngeal movements. There are no long-term evaluations of DBS against deglutition. Here, we report pronounced improvement in swallowing, which lasted 3 years post-DBS.