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Semantic memory and language dysfunction in early Alzheimer's disease: a review
1Dept. of Old Age Psychiatry, Institute of Psychiatry, King's College London, De Crespigny Park, London, SE5 8AF. mohit@doctors.org.uk
International Journal of Geriatric Psychiatry
|February 3, 2012
Summary
Early Alzheimer's disease language impairment, particularly word recall and fluency, may signal semantic memory decline. This semantic deficit can precede diagnosis and offers potential therapeutic targets.
Area of Science:
- Neuroscience
- Cognitive Psychology
- Linguistics
Background:
- Language impairment is an early and progressive symptom of Alzheimer's disease (AD), leading to significant disability.
- This review examines language dysfunction in AD, emphasizing the role of semantic memory impairment.
Purpose of the Study:
- To review the literature on language dysfunction in Alzheimer's disease.
- To explore the contribution of semantic memory impairment to language deficits in AD.
- To identify potential therapeutic targets for language impairment in AD.
Main Methods:
- Comprehensive literature search of electronic publication databases.
- Manual examination of references to identify additional relevant studies.
Main Results:
- Language deficits in AD initially impact verbal fluency and naming, reflecting semantic concept integrity.
- Semantic memory impairment may precede broader cognitive decline and can be detected years before AD diagnosis.
- Altered connectivity in language networks, observed via imaging, correlates with semantic failure and may be present in individuals at risk for AD.
- Evidence suggests compensatory mechanisms involving alternative cortical areas for language function.
Conclusions:
- Precise identification of language impairment in AD is crucial for developing targeted therapies.
- Treatments used for other aphasic conditions, like post-stroke aphasia, may be applicable to AD.
- Cognitive reserve and its protective effects present a potential avenue for therapeutic intervention.
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