NIH Awards $3.1M to Study Speech in Patients Given DBS Surgery

A branch of the National Institutes of Health has awarded a $3.1 million, multiyear grant to a research team to study changes in speech, and look at movement, in Parkinson’s patients given bilateral deep brain stimulation (DBS).

The grant from the National Institute on Deafness and other Communication Disorders (NIDCD) was given to a collaborative team of researchers led by Jeremy Greenlee, MD, a neurosurgeon at the University of Iowa. It runs through June 2025.

DBS is an established treatment for people with Parkinson’s disease who do not adequately respond to medication. It is a surgical procedure in which electrodes are implanted in certain areas of the brain, generating electrical impulses to control abnormal brain activity and lessen motor symptoms.

After DBS treatment, however, patients usually have varied and unpredictable speech outcomes, showing either a worsening, no change, or a slight improvement in speaking abilities, while most “properly selected patients” show consistent limb motor benefits.

“An estimated 40% of STN-DBS [subthalamic nucleus DBS] patients notice worsened speech and with declines significant enough to reduce quality of life,” Greenlee wrote in the project proposal.

Understanding the source of these varied speech outcomes is important for identifying factors likely to predict functional communication changes, and in further identifying patients most likely to respond well to this treatment approach.

In this research project, titled “Role of Subthalamic nucleus in Speech and Movement among people with Parkinson’s as Revealed by Intraoperative Recordings and Deep Brain Stimulation (DBS),” Greenlee’s team will be responsible for the DBS surgeries.

A separate team led by Kris Tjaden, PhD, at the Motor Speech Laboratory, part of the State University of New York at Buffalo, will analyze the patients’ speech.

“In order to optimize and develop better treatments for those living with PD [Parkinson’s disease], it is necessary to better understand the role of STN in speech as contemporary mechanistic models of human speech production omit STN,” Greenlee wrote. (The subthalamic nucleus is a small collection of neurons, part of the brain’s basal ganglia that affect movement and are thought to also have roles in cognitive and emotional functions. )

Specifically, the Buffalo researchers will analyze audio recordings taken pre-surgery, and again at six and 12 months post-surgery, of 80 Parkinson’s patients to measure voice quality, pitch and intensity, as well as articulation precision and speech durations. Findings will be compared with recordings of 40 patients who have not had DBS surgery, serving as a control group.

Recordings will also be obtained during DBS surgery, with patients awake and talking, to compare brain activity during both speech and limb motor tasks.

“One of the most exciting aspects of the project is that we are studying neural activity in the brain while patients are awake and talking as they are undergoing DBS surgery,” Tjaden said in a press release.

The team will also measure functional communication skills through perceptual judgments of speech intelligibility given by people listening to the recordings.

“We have reason to hypothesize that differences in brain activity during speaking versus the limb task will help to predict, along with other factors, those patients whose functional speech ability — for example, intelligibility — declines substantially within a year post-surgery,” Tjaden said.

“To our knowledge, this data will be the first of its kind to evaluate patients before, during, and after surgery with the goals of both directly defining the role of STN in speech and predicting speech outcome after STN-DBS,” the proposal concluded. “Such knowledge will provide mechanistic insights that cannot be obtained using other techniques and will guide development of new treatments of impaired speech in PD.”

The study is scheduled to restart this month, after surgeries were suspended due to the COVID-19 pandemic.