Site of penetrating brain lesions causing chronic acquired stuttering.

Ten subjects exhibited acquired stuttering that had persisted for 10 to 15 years following penetrating missile wounds sustained during the Vietnam War. None had a history of developmental or chronic adult stuttering. In comparison with other head-injured subjects and normal control subjects, the subjects with acquired stuttering had significant deficits in skilled rapid hand movements and oral and speech movements, suggesting a motor control disorder. The identified brain lesions of the acquired stuttering group were on the right in 5 subjects, on the left in 4, and bilateral in 1. The internal and external capsules, the frontal white matter, and the striatum were more frequently involved in the acquired stuttering group than in other head-injured subjects (p less than or equal to 0.05). This speech rhythm and rate disorder was not associated with evident cortical lesions in either hemisphere but with predominantly unilateral lesions of the subcortical pyramidal and extrapyramidal systems.