Clinical-anatomical correlation in a selective phonemic speech production impairment

Area of Science:

• Neuroscience
• Neurolinguistics
• Speech Pathology

Background:

• Phonemic paraphasias are common in various aphasia types.
• Selective phonemic speech production impairment (phonemic disintegration) is rare.

Observation:

• A patient presented with selective phonemic disintegration, showing phonemic paraphasias but preserved comprehension and naming.
• Longitudinal clinical, neuropsychological, and neuroradiological assessments were conducted over six years.
• A focal lesion in the left precentral gyrus white matter and adjacent middle frontal gyrus was identified, with overlying cortical atrophy.

Findings:

• A biopsy revealed a calcified haemangioma as the cause of the lesion.
• Clinical-anatomical correlation indicated the inferior precentral gyrus's primary motor cortex and subjacent white matter are crucial for phoneme production.
• Broca's area (posterior inferior frontal gyrus) function was spared.

Implications:

• This case underscores the specific role of the precentral gyrus in phoneme articulation.
• It differentiates the neural substrates for phoneme production from those involved in language comprehension and naming.
• Understanding these distinct pathways advances the diagnosis and treatment of speech production disorders.