Prosopagnosia: Anatomic and Physiologic Aspects
The early descriptions of prosopagnosia indicated that the condition was associated with bilateral damage to the occipital lobes. In the 1960’s when fresh neuropsychological investigations revealed the major role of right hemisphere in visual processing, it appeared reasonable to assume that the right hemisphere might possess the key to facial recognition (Meadows, 1974). Hecaen and Angelergues (1962) added strength to this hypothesis by noting that most prosopagnosic patients had left visual field defects, and suggesting that this was due to exclusive right hemisphere damage. The current view, however, is that bilateral lesions are generally necessary, although it would be unwise to rule out exceptions. This notion is based on: (1) critical review of the meaning of visual field data; (2) reassessment of post-mortem studies of prosopagnosic patients; (3) Computed Tomography (CT), Nuclear Magnetic Resonance (NMR) and Emission Tomography (ET) studies of patients with and without prosopagnosia; (4) study of patients with cerebral hemispherectomy, callosal surgery and amnesic syndromes.
KeywordsFacial Recognition Bilateral Lesion Unilateral Lesion Contextual Memory Visual Agnosia
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