rsfMRI based evidence for functional connectivity alterations in adults with developmental stuttering

Abstract

Persistent developmental stuttering (PDS) is defined as a speech disorder mainly characterized by intermittent involuntary disruption in normal fluency, time patterning, and rhythm of speech. Although extensive functional neuroimaging studies have explored brain activation alterations in stuttering, the main affected brain regions/ networks in PDS still remain unclear. Here, using functional magnetic resonance imaging (fMRI), we investigated resting-state whole-brain functional connectivity of 15 adults who stutter (PDS group) and 15 age-matched control individuals to reveal the connectivity abnormalities associated with stuttering. We were also interested in exploring how the severity of stuttering varies across individuals to understand the compensatory mechanism of connectivity pattern in patients showing less symptoms. Our results revealed decreased connectivity of left frontal pole and left middle frontal gyrus (MidFG) with right precentral/postcentral gyrus in stuttering individuals compared with control participants, while less symptomatic PDS individuals showed greater functional connectivity between left MidFG and left caudate. Additionally, our finding indicated reduced connectivity in the PDS group between the left superior temporal gyrus (STG) and several brain regions including the right limbic lobe, right fusiform, and right cerebellum, as well as the left middle temporal gyrus (MTG). We also observed that PDS individuals with less severe symptoms had stronger connectivity between right MTG and several left hemispheric regions including inferior frontal gyrus (IFG) and STG. The connectivity between right fronto-orbital and right MTG was also negatively correlated with stuttering severity. These findings may suggest the involvement of right MTG and left MidFG in successful compensatory mechanisms in more fluent stutterers.

Examining resting state functional connectivity and frequency power analysis in adults who stutter compared to adults who do not stutter

“…Functional magnetic resonance imaging (fMRI) studies have examined functional connectivity patterns in adults who stutter (AWS), revealing widespread connectivity differences compared to fluent speakers, though findings are inconsistent. For instance, reduced functional connectivity in specific brain regions and increased functional connectivity within speech-associated regions have been reported ( Xuan et al, 2012 ; Shojaeilangari et al, 2021 ). Some studies find certain connectivity patterns correlate with stuttering severity ( Lu et al, 2012 ) or improve after interventions ( Yang et al, 2016 ).…”