Plasticity in Parkinson's: Adapting to speech is always possible
by Elizabeth Teskey
It’s pretty common to call your best friend after a long day, so much so that most people don’t think twice about it. However, for people struggling with Parkinson’s Disease, a progressive disease that makes movements difficult and stochastic, such a simple conversation can be pretty challenging. For these people, it can be difficult to talk during everyday interactions, such as checking out at a grocery store, speaking to a coworker, or even ordering a coffee.
Although tremors, shaking, and loss of coordination are the primary symptoms of Parkinson’s, this disease impacts more than large movements. Unfortunately, fine motor skills are also affected. These delicate skills help us plan the movements of our lips and tongue, which are necessary for our ability to produce speech. Over time, the loss of fine control can result in slurred or slowed speech, caused by weakness in the muscles used to produce speech, which is called dysarthria.
Beyond movement, Parkinson’s disease also impacts the way they understand spoken language. Concerning language, most studies focus on the motor impact of perceptual phonetic plasticity in Parkinson’s disease. This may be because deficits in the ability to talk are more noticeable in conversation than comprehension is. However, we know that these people also have trouble understanding speech during conversations. It is extremely important that we understand how people understand speech so that we can better assist the Parkinson’s community to improve their quality of life. Luckily, groundbreaking research is racing to uncover more about how the disease affects the brain.
In 2022, Chris Heffner and Emily Myers at the University of Connecticut, along with Vincent Gracco of Haskins Laboratories, conducted a research study that looked closer at how people with Parkinson’s Disease perceive speech.
The team was most concerned with a phenomenon called “phonetic plasticity.” It refers to the ability of listeners to adjust to changing situations in speech perception. In their study, they measured behavior from three groups of people: young adults without Parkinson’s, older adults without Parkinson’s, and people with Parkinson’s. These people participated in four tasks designed to tap into different aspects of phonetic plasticity. Two tasks looked at the ability to learn new speech sounds (from another language) using two different strategies, the third task tested people’s ability to listen to extremely sped up speech (rate adaptation), and the fourth measured how well people can cope with accented speech.
The results showed that those with Parkinson’sperformed worse on being able to perceive spedup speech than older adults without Parkinson’s. In addition, people with Parkinson’s on medication performed worse on some of the phonetic plasticity tasks than those off medication.
The ability to adapt to different types of speech and taking into account medication status is especially important in clinical work, as it has such a significant impact on learning.
Heffner describes the real-world implications of these findings, stating,
“If learning is better off medication, [then] try to learn [new] things when you are just about to take your next dose. We can time things so that [when] you are low on your medication, then we can teach you something at a time when you are prime to learn.”
Understanding common deficits in this population will allow for a more effective treatment, and therefore higher quality of life. The ability to communicate is an extremely important, and complex, aspect that everyone deserves to have.
So, what does this mean? This study demonstrates that speech perception is impacted in people with Parkinson’s Disease, and that the disease is not limited to motor deficits. Encouraging other researchers to focus on speech perception when researching Parkinson’s will help change lives.
Everyone deserves the ability to communicate effectively, and researching any differences in how the brain perceives speech is essential in order for this goal to be reached. So next time you come across someone with Parkinson’s, keep this in mind and remember to be patient.
Source:
Heffner, C. C., Myers, E. B., & Gracco, V. L. (2022). Impaired language, most studies focus on the motor impact of perceptual phonetic plasticity in Parkinson’s disease. The Journal of the Acoustical Society of America, 152(1), 511–523. https://doi.org/10.1121/10.0012884
Stock photos from Pexels.com