Stuttering is not well understood, but a new study from the University of Alberta’s Institute for Stuttering Treatment and Research (ISTAR) is filling in the blanks. The researchers analyzed the brains of adults and children who stutter. They found that Broca’s area, a part of the brain responsible for speech production, develops abnormally in children who stutter and that this abnormality persists into adulthood. The study is the first of its kind to review the long-term brain effects of stuttering.
The researchers conducted MRI scans of the brains of 116 males aged 6 to 48. Roughly half of the participants had a stutter and half served as the control group. The researchers reviewed the imaging results of multiple brain regions.
Of the 30 brain regions they evaluated, only Broca’s area exhibited abnormal development in the participants with a stutter. In the stuttering group, Broca’s area had abnormal grey matter patterns. This abnormality was present in children and adults with a stutter.
Derky Beal, ISTAR executive director and assistant professor in the Faculty of Rehabilitation Medicine explains, “In every other region of the brain we studied, we saw a typical pattern of brain matter development. These findings implicate Broca’s area as a crucial region associated with stuttering.”
The MRI results also depicted a normal, steady decline in the cortical thickness of grey matter in the control group, suggesting that the brain becomes more efficient with age. It is possible that, for those who stutter, the brain is not as efficient in Broca’s area as the brain of a person with typical brain development.
The findings are consistent with ISTAR’s previous work demonstrating that children who stutter have a lower volume of grey matter. The current study offers more perspective into the same area of brain development. Although the findings confirm that Broca’s area is impacted by stuttering, the researchers report that they cannot say for sure whether Broca’s area is implicated as the cause of stuttering.
This research is published in the journal Frontiers in Human Neuroscience.
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