Beyond production: Brain responses during speech perception in adults who stutter

Abstract

Developmental stuttering is a speech disorder that disrupts the ability to produce speech fluently. While stuttering is typically diagnosed based on one's behavior during speech production, some models suggest that it involves more central representations of language, and thus may affect language perception as well. Here we tested the hypothesis that developmental stuttering implicates neural systems involved in language perception, in a task that manipulates comprehensibility without an overt speech production component. We used functional magnetic resonance imaging to measure blood oxygenation level dependent (BOLD) signals in adults who do and do not stutter, while they were engaged in an incidental speech perception task. We found that speech perception evokes stronger activation in adults who stutter (AWS) compared to controls, specifically in the right inferior frontal gyrus (RIFG) and in left Heschl's gyrus (LHG). Significant differences were additionally found in the lateralization of response in the inferior frontal cortex: AWS showed bilateral inferior frontal activity, while controls showed a left lateralized pattern of activation. These findings suggest that developmental stuttering is associated with an imbalanced neural network for speech processing, which is not limited to speech production, but also affects cortical responses during speech perception.

EEG Mu ( µ ) rhythm spectra and oscillatory activity differentiate stuttering from non-stuttering adults

“…It seems possible that even lower noise levels might be sufficient to induce motor activity in PWS, especially in light of observed differences in auditory processing that may alter auditory-motor interactions (Hampton and Weber-Fox, 2008;Kikuchi et al, 2011;Mock et al, 2015;Kikuchi et al, 2017). Referencing other developmentally disordered populations (e.g., autism and dyslexia), Halag-Milo et al (2016) address this possibility in a cautionary note following a recent fMRI speech perception study in PWS. Clues to how motor systems in PWS might be impacted by white noise come from studies demonstrating enhancement of fluency under masking (Andrews et al, 1983;Martin et al, 1985;Bloodstein and Ratner, 1995).…”

“…These include evidence that PWS rely more heavily on the right hemisphere for speech processing (Weber-Fox et al, 2004;Liotti et al, 2010; Robb et al, 2013;Halag-Milo et al, 2016) and exhibit differences in left hemisphere activity patterns for complex speech processing but not for simple tone processing (Biermann-Ruben et al, 2005;Corbera et al, 2005). ERP responses to speech stimuli in adults (Beal et al, 2010) and children (Beal et al, 2011;Jansson-Verkasalo et al, 2014) who stutter also suggest evidence of auditory-motor integration deficits.…”

Children who stutter show reduced action-related activity in the rostral cingulate zone

“…Interestingly, this study showed that activity in the 15 ACC was negatively correlated with the severity of stuttering symptoms, possibly reflecting a 16 failure to recruit conflict related regions to resolve stuttering (Liu et al, 2014). 17 Even though almost no studies examined functional brain activation in children who 18 stutter, some hypotheses can be derived from studies that related stuttering in children to showing less inhibitory control in CWS (Eggers et al, 2009(Eggers et al, , 2010(Eggers et al, , 2013 time, they were shown a feedback screen with the marble at the point at which they had 14 stopped it. These trials measured stimulus-driven action and were called Green-Go trials.…”

How Stuttering Develops: The Multifactorial Dynamic Pathways Theory

“…Differences in brain activity patterns between AWS and adults who do not stutter can also be observed in speech perception tasks with both auditory and visual linguistic stimuli (Biermann-Ruben, Salmelin, & Schnitzler, 2005;Cuadrado & Weber-Fox, 2003;Halag-Milo et al, 2016;Weber-Fox, 2001, Weber-Fox & Hampton, 2008WeberFox et al, 2004). Using magnetoencephalography, BiermannRuben et al (2005) observed differences in brain activation in the left inferior frontal and right Rolandic regions in AWS compared with fluent adults in a language perception task that required no speech production.…”