August 20, 2019
The frequency of subthalamic deep brain stimulation as well as the location of electrode contacts can affect speech in patients with Parkinson’s disease, according to a study published online in Parkinsonism & Related Disorders.
“Speech disorders, including stuttering and hypophonia, have been reported in patients with Parkinson's disease after subthalamic deep brain stimulation,” researchers explained.
After comparing vocal intensities and perceptual speech ratings for 50 patients with Parkinson’s disease who received subthalamic deep brain stimulation and 100 patients with Parkinson’s disease who did not, researchers reported lower vocal intensities, lower United Parkinson's Disease Rating Scale speech section scores, and more stuttering-impeded communication with subthalamic deep brain stimulation.
During high-frequency stimulation of 130 Hz, vocal intensity was significantly lower compared with low-frequency stimulation of 80 Hz, according to the study. In addition, communication impeded by stuttering was greatest during high-frequency stimulation.
The study also found vocal intensity was lower when active electrode contacts were in the dorsal zone compared with the ventral zone.
“High-frequency subthalamic deep brain stimulation with dorsal zone contacts can aggravate certain speech problems in Parkinson’s disease patients,” researchers wrote. “Therefore, it is important to balance between motor control and speech impairments in these patients.”
Phokaewvarangkul O, Boonpang K, Bhidayasiri R. Subthalamic deep brain stimulation aggravates speech problems in Parkinson's disease: objective and subjective analysis of the influence of stimulation frequency and electrode contact location [published online July 16, 2019]. Parkinsonism Relat Disord. doi: 10.1016/j.parkreldis.2019.07.020