Structural brain alterations in persistent developmental stuttering: a whole- brain voxel-based morphometry (VBM) analysis of grey and white matter

Persistent developmental stuttering (PDS), known as childhood-onset speech fluency disorder involves, significant involuntary problems in normal fluency such as repetition and prolongation of sounds, syllables, or words, as well as silence for certain syllables or words, or pauses within a word. Given the significance of brain morphological abnormalities in unraveling the origins of various neurological disorders, the scientific community has displayed a longstanding fascination with the advancement of structural neuroimaging methods like voxel-based morphometry (VBM). Despite numerous investigations using structural neuroimaging techniques to examine alterations in brain structure associated with stuttering, the precise brain regions predominantly affected by this speech disorder remain unclear. Here, adults with PDS (n = 15) and fluent speakers (n = 15) carefully matched based on age, sex, education, and hand preference were examined utilizing MRI scans to detect possible brain volumetric abnormalities in the stuttering group compared to the healthy control group. Using a whole-brain VBM technique, the brains of adults with PDS and normal subjects were compared concerning grey matter (GM) and white matter (WM) volume differences. Our investigation revealed a reduction in WM volume within the cerebellum. Moreover, we observed increased GM volumes in two specific regions: the right Superior Frontal Gyrus (SFG) and the left Middle Temporal Gyrus (MTG). Conversely, a decrease in GM volume was observed in the left SFG, bilateral paracentral lobule, the right cuneus and the right cerebellum. These findings strengthen the potential significance of brain structures in persistent stuttering.