Deep brain stimulation - effects on swallowing function in Parkinson's disease

In patients with Parkinson's disease (PD), deep brain stimulation of the subthalamic nucleus (STN DBS) is well recognized in improving limb function, but the outcome on swallowing function has rarely been studied. The aim of this work was to evaluate the effect of STN DBS on pharyngeal swallowing function in patients with PD using self-estimation and fiberoptic endoscopic evaluation of swallowing.

Eleven patients (aged 41-72, median 61 years) were evaluated preoperatively and at 6 and 12 months after STN DBS surgery. All patients were evaluated with self-estimation on a visual analogue scale, and eight of them with a fiberoptic endoscopic examination with a predefined swallowing protocol including Rosenbek's Penetration-Aspiration Scale, Secretion Severity Scale, preswallow spillage, pharyngeal residue, and pharyngeal clearance.

The self-assessments of swallowing function revealed a subjective improvement with STN DBS stimulation, whereas the data from the swallowing protocol did not show any significant effect of the STN DBS treatment itself. The prevalence of aspiration was not affected by the surgery.

The results show that swallowing function was not negatively affected by STN DBS and the risk of aspiration did not increase. Self-estimation of swallowing function showed a subjective improvement due to stimulation.