Speaking up for Parkinson’s patients
The Role of Auditory Feedback for Speech Intensity Regulation in Parkinson's disease
Speaking at a near whisper is a hallmark of Parkinson’s disease, but the cause and effective treatment of this problem remain elusive. At Western University, Anita Abeyesekera, a doctoral candidate, is exploring why people with Parkinson’s often perceive their voice as louder than it is.
“I thought there was a huge opportunity in this particular area of research,” she explains.
Abeyesekera began focusing on how Parkinson’s affects speech while she was working on an academic program that combined speech language pathology with speech and language sciences. This led her into clinical research work with her supervisor, Scott Adams, where she encountered individuals dealing with hypophonia, the diminishing of one’s speaking voice.
What intrigued her was the way people with Parkinson’s regularly report that they believe they’re speaking at a typical conversational level, level, when in fact they’re often speaking at little more than a whisper. When asked to yell, they raise their voices to a level that sounds more normal, but they remain convinced that they’re now speaking too loudly.
Abeyesekera is distorting the way subjects hear their own voice in conditions that people experience in daily life. This includes experiments that vary the distance between a speaker and listener or simulating the ambient background noise in a busy restaurant. Abeyesekera then analyzes how patients misperceive the sound of their voices.
She links this research with other investigations into how Parkinson’s may affect vocal cords or the respiratory muscles involved in speech. There is also evidence of people with Parkinson’s are physically capable of speaking louder.
Abeyesekera has been touched by the impact of hypophonia on patients, who often stop socializing after constantly being asked to repeat themselves and speak up.
“I’ve seen how much it affects them,” she says. “There really is a lot we don’t know and I want to know how much of an auditory component — how they hear their voices — is related to this disease.”
Her current work builds on the potential of deep brain stimulation (DBS), a procedure where a surgically implanted electrical stimulator can improve the symptoms of Parkinson’s. Although DBS works wonders for most symptoms of the disease, it doesn’t work consistently to resolve hypophonia. In fact, the DBS settings that improve hypophonia may differ from those that improve other motor symptoms, an observation that raises further questions and complicates the application of DBS.
“It is a goal of mine to determine what is causing speech symptoms and look to find improved treatments,” she says. “The more we understand about the mechanisms involved, the better we will be able to treat speech symptoms.”
Above all, Abeyesekera is excited to be at the forefront of the emerging field of speech movement disorders within the well-established fields of speech language pathology and clinical neuroscience.
“Now that my last five years have been dedicated to Parkinson’s disease, I can’t imagine doing anything else,” she says.