Search Abstracts | Symposia | Slide Sessions | Poster Sessions
Repetitive Negative Thinking Differentiates and Specifies Left Hemisphere Speech and Language Activation in Adults who Stutter
Poster Session F, Friday, October 2, 2:45 - 4:45 pm, Wangari Maathai
Seth Tichenor1, Amanda Hampton Wray2, Hendrik Santosa2; 1Duquesne University, 2University of Pittsburgh
Introduction: Repetitive Negative Thinking (RNT) is the habit of engaging in thought patterns that are repetitive, passive, automatic, and negative. RNT arises from a difficulty in redirecting attention away from one’s negative thoughts, resulting in aberrant activation and functional connectivity within the frontoparietal network (FPN). As a group, adults who stutter (AWS) demonstrate decreased left hemisphere activation in speech motor areas, though significant group variation exists in the strength and consistency of this effect. Given the crucial role of the FPN in initiating volitional goal-oriented motor behaviors, accounting for sub-group differences in RNT is critical for characterizing speech neurophysiology in AWS. Furthermore, identifying FPN activity during ecologically valid speaking tasks is necessary to enhance understanding of neural processes underlying stuttering. Given the high occurrence of RNT in AWS, this study determined whether differences in RNT in AWS specifies frontal activation patterns during speech. Methods: 22 AWS and 22 matched controls completed a hierarchy of stress-inducing speech tasks. Subjects completed two picture description tasks (PD1 and PD2), and the mock Interview Task of the Trier Social Stress Task, a well-validated social stress task. PD2 and the Interview Tasks were conducted in the presence of a simulated audience, increasing social stress and ecological validity. Functional near-infrared spectroscopy (fNIRS) data were recorded using a NIRSport2 (NIRx). A total of 56-channels (48 channels for long-distance and eight channels for short-separation) were distributed across bilateral speech-motor and frontal regions. Raw light intensities for each wavelength and channel were converted to optical density via the Modified Beer-Lambert Law. For connectivity analysis, a short-separation (SS) filter was applied to remove signals related to non-neural sources. For the first level statistics, a GLM and functional connectivity (FC) analyses were performed using robust regressors and robust correlation, respectively, on whitened fNIRS data. In the GLM, SS channels were included as regressors of no-interest. For the second level (group-level) statistics, mixed-effects models examined whether RNT, measured by Perseverative Thinking Questionnaire (PTQ) Total Scores, predicted brain activity between (a) PD2 and PD1 and (b) in the Interview Task. Results: AWS with the higher RNT demonstrated significantly lower activation in left dlPFC (HbO, t=-2.301, p=.027) and higher activation in left SMA (HbO, t=2.207 p=.034) between PD2 and PD1 compared to controls. Left SMA and dLPFC showed differing patterns of FC during the Interview task to left hemisphere motor regions, with left SMA showing significantly reduced FC to left IFG, PMC, and STG and left dlPFC showed significantly increased FC to these areas. Behaviorally, this higher SMA activation in AWS with higher RNT significantly correlated with increased avoidance/concealment behaviors. Conclusion: Findings suggest that AWS who engage in higher RNT demonstrate insufficient inhibition of, and reduced ability to adapt to, stress-related and cognitive-affective responses that accompany difficult speaking contexts. Left SMA contributes to speech initiation, sequencing, and timing and AWS with greater RNT exhibit higher SMA activation levels. This may suggest that, in AWS, engaging in a greater concealment/avoidance behaviors interferes with fluent speech production, contributing to impaired left hemisphere speech motor network functioning.
Topic Areas: Disorders: Developmental, Control, Selection, and Executive Processes