Amnestic stroke caused by a left temporo-occipital parahippocampal unilateral infarct
Abstract
A persistent amnesia regarding the episodic memory often occurs for bilateral hippocampal and parahippocampal lesions. However there are reports of transient or persistent global amnesic syndrome from left unilateral lesions in the posterior cerebral artery territory. We report the case of a 81 years old male patient with severe and persistent global (retro-anterograde) amnesia, with a sudden onset in October 2000, from a left temporo-occipital parahippocampal infarction, in a subject with non-valvular chronic atrial fibrillation, associated with right lateral hemianopia and behavioural problems as irritability and verbal aggressiveness. The neuropsychological assessment showed both an anterograde amnesia and a long period of retrograde amnesia which regarded autobiographic and historical events from the age of 15 years old onwards. The tests for intellectual level, language, ideomotor and constructional praxis, and attention were in the normal range for age and education. Neither prosopoagnosia nor color anomia were found in our patient. In the clinical evaluation of acute amnesic patients we underline the possibility of an amnesic stroke, in which a transient as well as persistent amnesia, anterograde or global, may be the sole manifestation of a stroke that is limited to the temporomesial region (in the territory of the infero-posterior temporal branches of the posterior cerebral artery), even only unilaterally in the dominant hemisphere.