Semantic Memory impairment : a neuropsychological hallmark of Late Onset Alzheimer Disease. (P6.205)

Neurology(2015)

Cited 23|Views17
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Abstract
OBJECTIVE : To examine if patients with sporadic early-onset Alzheimer’s disease (EOAD) and those with late-onset Alzheimer’s disease (LOAD) exhibit distinct patterns of impairment across memory subdomains. METHOD : One group of EOAD patients (n=20, MMSE = 21, mean age: 60.6), one group of LOAD patients (n=20, MMSE = 22, mean age: 77.9) and two groups of matched younger and older controls (n=40) participated. All patients presented with mild dementia (CDR=1). The diagnosis of AD was supported by evidence of both amyloidopathy and neuronal injury from CSF biomarkers (Innotest). All participants underwent a detailed neuropsychological assessment, a MRI scan and a FDG-PET scan. For each neuropsychological test, individual z-scores were calculated and then averaged into a global patient group z-score (EOAD/LOAD) for each cognitive domain. RESULTS : Both EOAD and LOAD groups were impaired in all the cognitive domains when compared to their respective control groups. Concerning memory domains both groups were similarly affected on measures of verbal episodic memory, short term memory and working memory. The EOAD group was not more affected than the LOAD group in any memory domain. By contrast LOAD patients showed significantly poorer performance than EOAD patients in semantic memory (p < 0.0001). VBM analysis with MRI and SPM with PET-FDG showed that impaired semantic performance in patients was associated with reduced gray matter volume in the anterior temporal lobe region bilaterally and greater hypometabolism in the left temporoparietal region, both areas being key regions of the semantic network. DISCUSSION : Contrary to previous studies, our results do not support the view that EOAD patients show a preservation of memory in the early stage of the disease. EOAD and LOAD patients present with distinct patterns of memory impairment, and LOAD patients show a prominent semantic memory impairment Disclosure: Dr. Ceccaldi has received personal compensation for activities with Novartis, Eli Lilly, Ipsen, Nutricia, Pharnext, and Piramal as a consultant, scientific advisory board member and/or speaker. Dr. Joubert has nothing to disclose. Dr. Gour has nothing to disclose. Dr. Koric has nothing to disclose. Dr. Didic has nothing to disclose. Dr. Gueriot has nothing to disclose. Dr. Ranjeva has nothing to disclose. Dr. Guedj has nothing to disclose. Dr. Felician has nothing to disclose.
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Key words
semantic memory impairment,late onset alzheimer disease,neuropsychological hallmark
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