White matter correlates of sensorimotor synchronization in persistent developmental stuttering.
Sivan Jossinger, Anastasia Sares, Avital Zislis and 3 others
PMID 34856426WHAT IT FOUND
Adults who stutter showed different brain wiring for timing tasks than fluent speakers.
In those who stuttered, better synchronization to a beat was linked to cerebellar connections, whereas in fluent speakers it was linked to frontal-temporal connections. This suggests stutterers may rely more on the cerebellum for timing.
Key findings
01In adults who stutter, better synchronization to an auditory beat was significantly correlated with lower mean diffusivity in the left inferior cerebellar peduncle, a pattern not seen in fluent speakers.
02In fluent speakers, better synchronization was correlated with higher fractional anisotropy in the left arcuate fasciculus, but this association was absent in adults who stutter.
03Adults who stutter had significantly reduced fractional anisotropy in the left arcuate fasciculus and the left middle cerebellar peduncle, and elevated mean diffusivity in the frontal aslant tract, compared to fluent speakers.
STILL TO COME
How it was doneWhat they foundWhat it means for SLPs
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What it does not show
The sample size was very small (27 participants total), which limits the statistical power and generalizability of the findings. The study was cross-sectional, so it cannot determine whether the brain differences cause stuttering or are a result of living with it for years. The group of adults who stutter had an atypical gender distribution (more females than males), whereas stuttering is generally more prevalent in males. The task involved finger tapping, not speech production, so the direct link to speech fluency is inferred rather than measured.
Declared interests
The authors declare that they have no conflict of interest.
The easy way to misread this
Do not interpret these brain differences as a cause of stuttering or as a target for direct treatment. The study is cross-sectional and small, so it shows an association between brain structure and tapping timing, but it does not prove that altering these brain pathways will improve speech fluency.