Objective. In the amnesic syndrome associated with mesial temporal lobe lesions, the dissociation between episodic and semantic memory is not unanimously recognized, and this debate parallels the debate about the anatomical substrates of memory processes. One hypothesis is that the hippocampus subserves the retrieval of semantic information, as well as of past experiences. This study was aimed to evaluate semantic compromise in mesial temporal lobe amnesia. Methods. We evaluated two male patients who developed global amnesia following bilateral hippocampal lesion. Patient 1, 33 years old, became amnesic after heart block, while patient 2, 23 years old, was affected by bilateral thrombosis of the posterior cerebral arteries. In both cases, magnetic resonance showed bilateral lesion of the hippocampus and normal findings in the remaining temporal lobe regions. Results. The neuropsychological assessment showed that reasoning, language, visual perception, and immediate memory were well retained. Verbal and non-verbal long-term memory and learning were seriously impaired. Remote autobiographical memory was normal. Semantic memory was well retained on tests using either verbal or nonverbal stimuli and responses. Conclusions. These findings highlight the preservation of semantic memory in mesial temporal lobe amnesia associated with bilateral hippocampal lesions. We suggest that the hippocampus does not necessarily contribute to the retrieval of semantic information.
|Issue number||4 SUPPL.|
|Publication status||Published - 2000|
ASJC Scopus subject areas
- Clinical Neurology