Planum temporale asymmetry in people who stutter.
Patricia M Gough, Emily L Connally, Peter Howell and 3 others
PMID 28648465WHAT IT FOUND
Brain scans of 130 people showed no difference in the size or left-right asymmetry of a speech-processing brain region between those who stutter and those who do not.
This finding does not support the theory that atypical brain structure causes stuttering.
Key findings
01Manual measurement of brain scans found no significant difference in the size or asymmetry of the planum temporale between people who stutter and fluent controls.
02Automated analysis confirmed the manual results, showing no significant group differences in brain asymmetry in any area after correcting for multiple comparisons.
03There was no significant relationship between the severity of stuttering and the asymmetry of this brain region in either the manual or automated analyses.
STILL TO COME
How it was doneWhat they foundWhat it means for SLPs
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What it does not show
The study is cross-sectional, so it cannot determine if any brain differences are a cause or a consequence of stuttering. Scans were collected from different studies using different MRI machines (1.5T and 3T) and sequences, which may have added noise to the data. The sample included fewer females who stuttered compared to males, limiting the generalisability of gender-specific findings. The study failed to replicate previous findings that suggested reduced asymmetry in stuttering, but the authors note that if a difference exists, it is likely too small to be clinically significant.
Declared interests
The authors declare no known conflicts of interest and no significant financial support that could have influenced the outcome.
The easy way to misread this
Do not conclude that the brain structure of people who stutter is identical to controls in all respects. While this specific region (planum temporale) showed no group difference, the study found a difference in how this region changes with age between the groups, and other brain areas or functional networks were not the focus of this analysis.