Do children and adults with developmental stuttering manifest proton magnetic resonance spectroscopy neurometabolite alterations in the same brain regions and circuits where other neuroimaging modalities have detected effects of stuttering?
In this case-control study, proton magnetic resonance spectroscopy of the brain was acquired in a cohort of pediatric and adult people who stutter and matched nonstuttering control individuals. Consistent with prior neuroimaging studies, significant effects of stuttering diagnosis on the metabolite ratios N-acetyl-aspartate plus N-acetyl-aspartyl-glutamate and choline compounds to creatine were found in brain structures belonging to speech-production, default-mode, and emotional-memory networks.
These findings are consistent with models of stuttering as a disorder in self-regulation of motor control (speech production), attention (default mode), and emotion.
Developmental stuttering is a neuropsychiatric condition of incompletely understood brain origin. Our recent functional magnetic resonance imaging study indicates a possible partial basis of stuttering in circuits enacting self-regulation of motor activity, attention, and emotion.
To further characterize the neurophysiology of stuttering through in vivo assay of neurometabolites in suspect brain regions.
Design, Setting, and Participants
Proton chemical shift imaging of the brain was performed in a case-control study of children and adults with and without stuttering. Recruitment, assessment, and magnetic resonance imaging were performed in an academic research setting.
Main Outcomes and Measures
Ratios of N-acetyl-aspartate plus N-acetyl-aspartyl-glutamate (NAA) to creatine (Cr) and choline compounds (Cho) to Cr in widespread cerebral cortical, white matter, and subcortical regions were analyzed using region of interest and data-driven voxel-based approaches.
Forty-seven children and adolescents aged 5 to 17 years (22 with stuttering and 25 without) and 47 adults aged 21 to 51 years (20 with stuttering and 27 without) were recruited between June 2008 and March 2013. The mean (SD) ages of those in the stuttering and control groups were 12.2 (4.2) years and 13.4 (3.2) years, respectively, for the pediatric cohort and 31.4 (7.5) years and 30.5 (9.9) years, respectively, for the adult cohort. Region of interest–based findings included lower group mean NAA:Cr ratio in stuttering than nonstuttering participants in the right inferior frontal cortex (−7.3%; P = .02), inferior frontal white matter (−11.4%; P < .001), and caudate (−10.6%; P = .04), while the Cho:Cr ratio was higher in the bilateral superior temporal cortex (left: +10.0%; P = .03 and right: +10.8%; P = .01), superior temporal white matter (left: +14.6%; P = .003 and right: +9.5%; P = .02), and thalamus (left: +11.6%; P = .002 and right: +11.1%; P = .001). False discovery rate–corrected voxel-based findings were highly consistent with region of interest findings. Additional voxel-based findings in the stuttering sample included higher NAA:Cr and Cho:Cr ratios (regression coefficient, 197.4-275; P < .001) in the posterior cingulate, lateral parietal, hippocampal, and parahippocampal cortices and amygdala, as well as lower NAA:Cr and Cho:Cr ratios (regression coefficient, 119.8-275; P < .001) in the superior frontal and frontal polar cortices. Affected regions comprised nodes of the Bohland speech-production (motor activity regulation), default-mode (attention regulation), and emotional-memory (emotion regulation) networks. Regional correlations were also observed between local metabolites and stuttering severity (r = 0.40-0.52; P = .001-.02).
Conclusions and Relevance
This spectroscopy study of stuttering demonstrates brainwide neurometabolite alterations, including several regions implicated by other neuroimaging modalities. Prior ascription of a role in stuttering to inferior frontal and superior temporal gyri, caudate, and other structures is affirmed. Consistent with prior functional magnetic resonance imaging findings, these results further intimate neurometabolic aberrations in stuttering in brain circuits subserving self-regulation of speech production, attention, and emotion.
O’Neill J, Dong Z, Bansal R, Ivanov I, Hao X, Desai J, Pozzi E, Peterson BS. Proton Chemical Shift Imaging of the Brain in Pediatric and Adult Developmental Stuttering. JAMA Psychiatry. Published online November 23, 2016. doi:10.1001/jamapsychiatry.2016.3199