Of the more than 10 million people with Parkinson’s disease (PD) worldwide, nearly 89% will develop speech and voice problems over the course of their illness.
New research suggests a specific gene called alpha-synuclein – which is commonly linked with Parkinson’s – could be a reason behind some of those voice-related changes and issues. It’s a finding researchers say could help lead to earlier diagnoses and treatments.
“Very little focus has been placed on understanding the genetics of the non-peripheral and motor symptoms of Parkinson’s, such as changes in voice, reduced amplitude, hoarse voice and monotonous tone as well,” César Medina, lead author, told Seasons. “We were particularly interested in how changes in the brain reflect the changes that a person might experience as they start to develop symptoms.”
Using zebra finch birds to study human speech
Medina and other researchers at the University of Arizona used an animal model – specifically zebra finches, a songbird originally from Central Australia – to find any connection between alpha-synuclein and vocal changes.
According to Julie Miller, PhD, senior author, the researchers used zebra finches because they have well-characterized brain regions for song learning and production. Particularly in males, the way their brain circuitry is wired for producing a song is very similar to the human brain.
“In zebra finches, there are brain regions whose anatomy and wiring are very similar to our own brain regions that help control speech, language and hearing,” she said. “Researchers over many years have done a lot of studies where they’ve compared the anatomy of the finch brain to the human brain in terms of vocal production. Looking at how neurons are wired together, they found that a lot of the genes are the same.”
Similarities in behavior, anatomy and genetics allowed the researchers to use the zebra finches to study and analyze human speech and voice, Medina said.
What the researchers found
To test alpha-synuclein and the effect it would have on the vocal production in the zebra finches, the researchers first measured standard recordings of their songs. Secondly, Miller said they introduced a copy of the alpha-synuclein gene into a specific region of the bird’s brain.
After the gene was introduced, the researchers immediately recorded all the birds’ songs again and repeated that process one, two and three months later.
“We chose one specific region because it’s part of the motor control system in humans. When we introduce that gene and it gets expressed, it makes a lot of this alpha-synuclein protein, too much of the protein,” Miller said. “If you have too much of this protein in the brain, as is the case in humans with Parkinson’s, it can change the output; in this case, it changes the bird’s song.”
Medina said after analyzing the birds’ songs over time, they found birds that received the alpha-synuclein gene had changes in song production. The Parkinsonian birds at two months reduced their amount of singing compared to the beginning.
“What that means is that it likely reflects what we see in Parkinson’s patients, where in some cases, patients with Parkinson’s will present with vocal fatigue,” he said. “As a person is speaking, it becomes harder for them to continue speaking or they have problems initiating speech.”
…in some cases, patients with Parkinson’s will present with vocal fatigue… As a person is speaking, it becomes harder for them to continue speaking or they have problems initiating speech.
The researchers also found changes in syllable duration, which reflects the changes in the length of an “utterance” a person might make. Medina also found there were changes in the variability of tone (the bird’s vocalizations were softer and shorter), the amplitude of the zebra finches’ song and other measures like hoarseness, which can all be seen in Parkinson’s patients.
What you need to look for
Even though it can be challenging to identify if you or a loved one has Parkinson’s, anyone experiencing changes, especially in their voice or with stringing words together, should seek care from a primary care physician, neurologist or speech pathologist, Medina said.
Early signs of Parkinson’s disease include:
- Small handwriting
- Loss of smell
- Trouble sleeping
- Difficulty moving or walking
- Constipation/bowel imbalance
- A soft or low voice
- Masked face
- Dizziness or fainting
- Stopping or hunching over
“Regardless of whatever they notice, if they’re having problems communicating, the first step is to seek out the appropriate care and specialists,” Miller said. “They will then come up with ways for treatment and also diagnoses.”
Miller added while a change in a person’s voice is normal and part of the aging process, some things can help identify if a loved one should see a doctor, including family history of the disease and significant changes in voice.
“It’s about awareness, making people aware that there are vocal changes, voice and speech changes that can occur in Parkinson’s and other diseases early and also just as a matter of aging,” Miller added. “The goal of our research is to spread awareness of this and to have caregivers pay attention to their loved ones’ communication. The second step is to then support people, being aware of their family history or being aware of how those vocal changes can impact their communication, and that’s their opportunity to seek out help.”
It’s about awareness, making people aware that there are vocal changes, voice and speech changes that can occur in Parkinson’s and other diseases early and also just as a matter of aging.
Miller and Medina plan to identify a list of other potential genes that may be correlated with the changes seen in the Parkinsonian zebra finch model.
“Identifying these genes will help us in developing therapeutics and pharmaceuticals that we can use to target these early phenomena that we think we’re capturing in our model,” Medina said. “Hopefully leading to the development of new therapeutics for people with Parkinson’s disease and specifically these changes in voice.”