Why do 90% of people afflicted with Parkinson’s develop speech and voice impairments?

Cara Stepp and colleagues win a $3.5M NIH grant to uncover the causes

By Maureen Stanton, Hariri Institute for Computing

Parkinson’s disease (PD) is the fastest growing neurological disease, with 10 million people affected worldwide. It is a progressive, degenerative brain condition that affects the nervous system and a person’s control of their body movement.

While speech and voice impairments affect close to 90% of people living with the disease, research into what is physiologically causing these problems has been incomplete. This can make understanding and treating PD-related speech problems somewhat of a black box.

“When an individual with PD comes for treatment for a speech problem, it is not clear where the speech problems are coming from,” explains Cara Stepp, Sargent College professor and director of the BU Stepp Lab for Sensorimotor Rehabilitation Engineering, and faculty affiliate of Hariri Institute. “Is it respiratory? Is it laryngeal? Is it the way they move their tongue or their jaw? All those things are implicated but what is causing the speech problem? Population heterogeneity also creates complexity. It is not clear if an individual with a speech problem has all three of these problems or whether different individuals are getting different symptoms.”

Stepp and colleagues have received a five-year $3.5M grant from the National Institute of Health (NIH) for a comprehensive, large population sample study that examines and compares changes in speech in individuals with Parkinson’s disease. The study will also compare and quantitatively measure these physiological and acoustics changes with what is clinically referred to as “patient-centered outcomes” (PCOs), which include quality of life metrics as well as standard clinical measures.

This work will guide the future development of personalized treatment for individuals with PD, providing a roadmap for future evidence-based treatment, and empowering clinicians with knowledge and tools to target specific speech subsystems to improve speech clarity and quality of life for patients.

The study is expected to provide novel outcomes for clinical translation, particularly since there have been no studies that have examined all the specific subsystems that can cause PD-related speech impairments in a single cohort. This study will undertake that work, obtaining quantitative metrics looking at changes over time, both as a group and at the individual level.

“Currently, the only available treatment for individuals with PD is behavioral speech therapy, which focuses on training people to speak louder,” says Stepp. “It’s pretty one size fits all. Also, when examined over time, most of the benefit doesn’t last longer than seven months.”

A major thrust of the work will serve to help treating clinicians pinpoint the causes of PD-related speech problems in individuals. The work will include developing and evaluating acoustic measurements of speech decline in PD based on their relationships with respiratory, laryngeal, and articulatory physiology. This is expected to significantly benefit patients at point of care since many clinical settings lack the resources to implement physiological measures.

Tracking measurements over time is essential for use in clinical or research applications. To comprehensively assess sensitivity to change, the study will examine speech clarity, both decreasing, due to disease progression, and improving, with behavioral cueing.

“This is the first comprehensive study to quantitatively ascertain the source of specific PD-related speech problems, and track the impacts of those problems, and subsystem assessment tools over time. We expect that the results of this study and information gained will dramatically serve to improve quality of life for the tens of millions of patients and caregivers impacted by this disease.

Joining Stepp as a principal investigator is Daryush Mehta, director of the Voice Science and Technology Laboratory at the Mass General Hospital Center for Laryngeal Surgery and Voice Rehabilitation. Collaborators include Stepp’s PhD student Daria Dragicevic, who is also a Hariri Institute Graduate Student Fellow, and coinvestigators Pieter Noordzij, professor of otolaryngology-head & neck surgery at the BU Chobanian & Avedisian School of Medicine; Marie Helene Saint-Hillaire, professor of neurology at the BU Medical Center and medical director of the American Parkinson Disease Association Center for Advanced Research at BU; and Lauren Tracy, an otolaryngologist at the Boston Medical Center specializing in voice care.

The researchers have already begun screening individuals with PD who are interested in becoming part of the study. Individuals interested should complete this form.