Finding out what causes speech production problems

Scanning the brain to understand stuttering.


Over the past decades, brain imaging studies in fluently speaking participants have enormously propelled our insight into the brain areas associated with speech generation. Moreover, complementary data has been given by examinations of brain activation patterns related to disordered speech.

A new study sought to examine the effects of simulating disfluencies on the brain activation patterns of fluent speakers during overt and covert speech production.

There is no known cure for stuttering and other speech disorders such as dysarthria and apraxia of speech. According to this study, understanding the neural basis of speech production problems will lead to effective and personalized treatment approaches.

Dr. Catherine Theys, a senior lecturer in UC’s School of Psychology, Speech, and Hearing, said“My research in the Speech-Language Neuroscience Lab at UC focuses on how we produce speech, and what happens at the level of the brain when people have speech difficulties, especially in people who stutter. I work with people who started to stutter as a child, but also with adults who started to stutter following brain injuries or neurodegenerative diseases.”

Scientists used fMRI scanners to identify differences at the level of the brain that cause stuttering. They scanned the brains of fluent speakers and looked at what happens when asked to change the way they usually speak.

Dr. Theys said, “This helps us to understand the brain networks that we use to produce speech. It also helps us to understand what happens when we ask people to change the way they speak during speech treatment, for example, by asking people to speak slower or stutter voluntarily.”

The participants were asked to repeat the first letter of a word. Strikingly, talking this way prompted increments in activation in the brain networks we use to produce speech. This included brain areas answerable for the planning and starting mechanisms of speech, and also areas that screen your movements to distinguish errors.

This information enabled scientists to identify the causes of speech production problems. It shows what is happening in our brains when we produce speech in a novel manner.

Dr. Theys said, “Changing someone’s speech pattern is a tool that is often used during the assessment and treatment of people with speech disorders, including stuttering, dysarthria, and apraxia of speech. These speech disorders can be developmental, but also affect people following stroke, traumatic brain injury, or neurodegenerative diseases such as Parkinson’s disease.”

“Having speech production problems can have a big impact on the health and wellbeing of the speaker, but also their whānau. Understanding the changes in brain functioning that cause these speech problems will help us to create more effective treatment approaches for these people.”

The study is published in the journal PLOS ONE.


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