A recent study found that increased grey matter volume in the left putamen is significantly associated with stuttering severity, suggesting a shared neuroanatomy across stuttering types.

Published in Brain, the study investigates the neuroanatomical basis of stuttering, which affects 1 in 100 adults. Researchers examined three datasets: case reports of stroke-induced neurogenic stuttering (n=20), a clinical cohort of stroke patients with neurogenic stuttering (n=20), and adults with developmental stuttering (n=20). Using lesion network mapping, they identified a common brain network associated with stuttering, centered on the left putamen, claustrum, and amygdalostriatal transition area.

Lesions causing stuttering were found in multiple brain regions but were all functionally connected to a network centered around the left putamen (PFWE < 0.05). This finding was reproduced in the independent clinical cohort of stroke patients with neurogenic stuttering (PFWE < 0.05). In both stroke-related datasets, connectivity to the left putamen was specifically associated with stuttering, distinguishing it from other stroke-induced speech disorders.

In the developmental stuttering cohort, increased grey matter volume in this network was significantly associated with the severity of stuttering (PFWE < 0.05), suggesting a shared neuroanatomy across different forms of stuttering. The researchers stated that the study supports the role of the basal ganglia, particularly the left putamen, in stuttering and indicates that specific brain circuits involving the left putamen are crucial.

"The additional findings implicating the ventral claustrum and amygdalostriatal transition area in stuttering provide an important new direction in mapping the neural basis of stuttering, and ensuring the best possible diagnostic and treatment approaches can be developed," the researchers concluded.

Full disclosures can be found in the study.