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[Crossed aphasia disclosed by central auditory disorder]
C Nedelec-Ciceri1, A Anguenot, M P Rosier
1Service de Médecine B-Neurologie, Centre Hospitalier, La Rochelle.
Revue Neurologique
|November 1, 1996
Summary
A stroke affecting the right temporo-parietal region caused crossed aphasia and right hemianacousia in an 80-year-old woman. While language deficits improved, the hearing loss in the left ear persisted, indicating distinct auditory processing pathways.
Area of Science:
- Neuroscience
- Neurology
- Audiology
Background:
- Crossed aphasia is rare, occurring when the dominant hemisphere (typically left) is not affected by a lesion causing aphasia.
- Auditory processing involves complex integration between hemispheres, with distinct pathways for linguistic and non-linguistic information.
Observation:
- An 80-year-old right-handed woman presented with sudden deafness and transcortical sensory aphasia, diagnosed as crossed aphasia.
- MRI revealed a right temporo-parietal infarct. Initial symptoms included language deficits and subjective hearing loss.
- Auditory evaluations confirmed right hemianacousia, characterized by left ear hearing loss in dichotic listening and reduced right cortical auditory potentials.
Findings:
- The patient's aphasic symptoms partially resolved, but the left ear hearing deficit remained.
- Neuroacoustic tests, auditory gnosia studies, and evoked potentials demonstrated specific disturbances consistent with right hemianacousia.
- The findings suggest a dissociation between linguistic auditory processing and general auditory processing after right hemispheric damage.
Implications:
- This case highlights the distinct neural substrates for linguistic and non-linguistic auditory processing.
- It supports theories of bilateral hemispheric representation for general auditory functions, where right hemisphere damage can lead to hemianacousia.
- Understanding these pathways is crucial for diagnosing and managing complex neurological auditory deficits.