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Semantic memory and language dysfunction in early Alzheimer's disease: a review
Author(s) -
Verma M.,
Howard R. J.
Publication year - 2012
Publication title -
international journal of geriatric psychiatry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.28
H-Index - 129
eISSN - 1099-1166
pISSN - 0885-6230
DOI - 10.1002/gps.3766
Subject(s) - verbal fluency test , psychology , disease , semantic memory , fluency , cognition , alzheimer's disease , cognitive reserve , cognitive psychology , cognitive impairment , medicine , neuroscience , neuropsychology , pathology , mathematics education
Background Language impairment in Alzheimer's disease occurs early, and language function deteriorates with progression of the illness to cause significant disability. This review focuses on language dysfunction in Alzheimer's disease and the contribution of semantic memory impairment. Methods Electronic publication databases were searched for literature relevant to the review. Additionally, individual references were examined to elicit further studies not found by online search. Results Language impairment in Alzheimer's disease initially affects verbal fluency and naming before breakdown in other facets. Naming and fluency require integrity of semantic concepts, and dysfunction may be a marker of primary semantic memory impairment rather than overall cognitive decline. Research suggests the presence of semantic loss several years prior to diagnosis. Imaging studies indicate an altered connectivity state with respect to language networks, and this is associated with potential semantic failure. This state may also be present in individuals with established risk factors for Alzheimer's disease. Compensatory recruitment of alternative cortical areas to supplement language function appears to occur and may be a target for future intervention. Conclusions Identifying and classifying the nature and degree of language impairment more closely could aid in developing targeted therapies. Treatments already established in other aphasic states, such as post‐stroke, may be especially relevant. The nature of these and the protective nature of cognitive reserve are potential therapeutic avenues. Copyright © 2012 John Wiley & Sons, Ltd.