Crossed aphasia in a dextral: a clinicopathological study

Area of Science:

• Neuroscience
• Neurology
• Clinical Neuroanatomy

Background:

• Cerebral dominance for speech and motor control is typically lateralized to the left hemisphere in right-handed individuals.
• Understanding brain lateralization is crucial for diagnosing and treating neurological disorders.
• Previous research has largely assumed a consistent left-hemisphere dominance for both speech and limb praxis in right-handed people.

Observation:

• A right-handed man experienced sudden severe Broca aphasia and left hemiplegia.
• Neurological examination revealed no right limb apraxia.
• Postmortem analysis identified a right hemisphere infarction, primarily affecting the precentral gyrus.

Findings:

• The patient exhibited right-hemisphere dominance for speech.
• Limb praxis dominance was localized to the left hemisphere.
• This dissociation challenges established models of cerebral lateralization.

Implications:

• This case demonstrates that cerebral dominance for speech and handedness can be dissociated in right-handed individuals.
• Lesions in the precentral gyrus may play a significant role in the development of Broca aphasia.
• Findings suggest a more complex and potentially variable pattern of brain lateralization than previously understood.