Clinical-anatomical correlation in a selective phonemic speech production impairment

Although phonemic paraphasias are common in aphasic disorders, including Broca's aphasia, conduction aphasia and transcortical motor aphasia, selective phonemic speech production impairment, or phonemic disintegration, is unusual. A patient with a selective phonemic speech production disorder underwent clinical, neuropsychological and structural neuroradiological assessment over a period of 6 years. The disorder was characterised by phonemic paraphasias (phonemic disintegration) with preserved comprehension and naming. Imaging showed a focal lesion in the white matter of the left precentral gyrus and, to a lesser extent, the posterior part of the left middle frontal gyrus, with overlying cortical atrophy. Biopsy of the lesion, after several years of observation, showed a calcified haemangioma. Clinical-anatomical correlation in this case suggests the importance of primary motor cortex of the inferior precentral (pre-Rolandic) gyrus and subjacent white matter in phoneme production, with sparing of the posterior inferior frontal gyrus (Broca's area).