What if the touch of a button was enough to reduce the alienating speech symptoms of Parkinson’s? Health Sciences graduate student Thea Knowles is seeking just that kind of ‘better button.’
Affecting more than 3 per cent of the population over the age of 60, Parkinson’s brings to mind symptoms like instability, slowness of movement, rigidity and tremors. But a large majority of sufferers also have difficulty with their speech.
“Difficulty speaking is often reported to be one of the most disabling aspects of the disease and can lead to things like social withdrawal and overall decrease in the quality of life,” said Knowles, who is completing a combined MClSc/PhD program in Speech Language Pathology. “Whether or not they are completely aware of the speech output is one thing. But if it is difficult for others to understand them, or if constant attempts to communicate are shut down or ignored, asking them to ‘say it again,’ it can get very frustrating.”
While there is no cure for Parkinson’s, doctors have been successful in developing interventions targeting motor symptoms of the disease, Knowles said. Once such intervention is deep-brain stimulation (DBS), considered a standard surgical treatments for Parkinson’s. The surgery involves implanting an electrode deep within the brain where neurologists are then able to control the amount of electrical current sent to the brain by adjusting frequency, voltage and pulse width.
“Once programmed, it really is as simple as the touch of a button – the button controlling the stimulator – for the patient to see a major improvement in many of the motor symptoms of the disease,” Knowles said.
Deep-brain stimulation’s impact on speech is not as clear – it may, in fact, lead to a worsening effect. However, Knowles is exploring ways to fine-tune those traditional deep-brain stimulation settings to better combat speech issues.
In her research, Knowles had 13 Parkinson’s patients who received DBS provide speech samples. She found optimal DBS levels were associated with lower frequency and higher pulse, and the combination of these settings yielded higher intelligibility than the standard setting chosen for the individual.
“There does seem to be a trend that frequency may play a bigger role. It may be that a lower frequency may be better for speech than what it is normally set at,” Knowles said. “Right now, it’s finding what’s working for speech and what’s not, and then look at how this works into the bigger picture of treatment for Parkinson’s.
“Every person responds to the stimulation differently. The question is, the setting that is chosen for that person, how does it affect speech and can there be a different setting that is better?”
Once a setting, or combination of settings, is determined, Knowles added a person, theoretically, could use a particular setting that is better for speech but not so good for the major motor symptoms, depending on the situation. Going to dinner, for example, knowing they were going to be seated, and the focus was going to be on conversation, they could use a specific setting for that, she said.
“When the neurologists are programming these settings, they are doing so in order to reduce the major symptoms. They’re not thinking speech,” she added. “In fact, the clinical settings the neurologists use when optimizing these parameters may be suboptimal for speech.
“The hope is, one day we’ll be able to provide individuals with Parkinson’s, who receive DBS, an alternative setting – a better speech button, if you will – they can use when they need. While good health is never going to be as simple as the touch of a button, the more we know about the affects of DBS on speech, the better we can fine tune our interventions to address all of an individual’s needs.”