Grey matter volume differences in the left caudate nucleus of people who stutter.
The cause of stuttering has many theoretical explanations. A number of research groups have suggested changes in the volume and/or function of the striatum as a causal agent. Two recent studies in children and one in adults who stutter (AWS) report differences in striatal volume compared that seen in controls; however, the laterality and nature of this anatomical volume difference is not consistent across studies. The current study investigated whether a reduction in striatal grey matter volume, comparable to that seen in children who stutter (CWS), would be found in AWS. Such a finding would support claims that an anatomical striatal anomaly plays a causal role in stuttering. We used voxel-based morphometry to examine the structure of the striatum in a group of AWS and compared it to that in a group of matched adult control subjects. Results showed a statistically significant group difference for the left caudate nucleus, with smaller mean volume in the group of AWS. The caudate nucleus, one of three main structures within the striatum, is thought to be critical for the planning and modulation of movement sequencing. The difference in striatal volume found here aligns with theoretical accounts of stuttering, which suggest it is a motor control disorder that arises from deficient articulatory movement selection and sequencing. Whilst the current study provides further evidence of a striatal volume difference in stuttering at the group level compared to controls, the significant overlap between AWS and controls suggests this difference is unlikely to be diagnostic of stuttering.
Department of Cognitive Science, Macquarie University, New South Wales 2109, Australia; Australian Research Council Centre of Excellence in Cognition and Its Disorders, Australia; Perception and Action Research Centre, Faculty of Human Sciences, Macquarie University, New South Wales 2109, Australia. Electronic address: paul.sowman@mq.edu.au.
Paul F
PF
Sowman
Department of Cognitive Science, Macquarie University, New South Wales 2109, Australia; Australian Research Council Centre of Excellence in Cognition and Its Disorders, Australia.
Margaret
M
Ryan
Department of Cognitive Science, Macquarie University, New South Wales 2109, Australia; Australian Research Council Centre of Excellence in Cognition and Its Disorders, Australia.
Blake W
BW
Johnson
Australian Research Council Centre of Excellence in Cognition and Its Disorders, Australia; Department of Psychology, Macquarie University, New South Wales 2109, Australia.
Greg
G
Savage
Australian Research Council Centre of Excellence in Cognition and Its Disorders, Australia; Department of Linguistics, Macquarie University, New South Wales 2109, Australia.
Stephen
S
Crain
Department of Linguistics, Macquarie University, New South Wales 2109, Australia.
Elisabeth
E
Harrison
Department of Cognitive Science, Macquarie University, New South Wales 2109, Australia.
Erin
E
Martin
Centre for Advanced Imaging, The University of Queensland, Queensland 4072, Australia.
Hana
H
Burianová
D016022:Case-Control Studies; D002421:Caudate Nucleus / Q000473:pathology* / Q000503:physiopathology; D015331:Cohort Studies; D005260:Female; D007839:Functional Laterality; D066128:Gray Matter / Q000473:pathology* / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009068:Movement; D013342:Stuttering / Q000473:pathology* / Q000503:physiopathology*