title: Longitudinal patterns of semantic and episodic memory in frontotemporal lobar degeneration and Alzheimer's disease.
abstract: The longitudinal assessment of episodic and semantic memory was obtained from 236 patients diagnosed with Alzheimer's disease (AD, n = 128) and with frontotemporal lobar degeneration (FTLD, n = 108), including patients with a social comportment/dysexecutive (SOC/EXEC) disorder, progressive nonfluent aphasia (PNFA), semantic dementia (SemD), and corticobasal syndrome (CBS). At the initial assessment, AD patients obtained a lower score on the delayed free recall test than other patients. Longitudinal analyses for delayed free recall found converging performance, with all patients reaching the same level of impairment as AD patients. On the initial evaluation for delayed recognition, AD patients also obtained lower scores than other groups. Longitudinal analyses for delayed recognition test performance found that AD patients consistently produced lower scores than other groups and no convergence between AD and other dementia groups was seen. For semantic memory, there were no initial between-group differences. However, longitudinal analyses for semantic memory revealed group differences over illness duration, with worse performance for SemD versus AD, PNFA, SOC/EXEC, and CBS patients. These data suggest the presence of specific longitudinal patterns of impairment for episodic and semantic memory in AD and FTLD patients suggesting that all forms of dementia do not necessarily converge into a single phenotype.
authors.affiliation: Department of Biostatistics and Epidemiology, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104-6021, USA. sxie@mail.med.upenn.edu
authors.forename: Sharon X
authors.initials: SX
authors.lastname: Xie
authors.forename: David J
authors.initials: DJ
authors.lastname: Libon
authors.forename: Xingmei
authors.initials: X
authors.lastname: Wang
authors.forename: Lauren
authors.initials: L
authors.lastname: Massimo
authors.forename: Peachie
authors.initials: P
authors.lastname: Moore
authors.forename: Luisa
authors.initials: L
authors.lastname: Vesely
authors.forename: Alea
authors.initials: A
authors.lastname: Khan
authors.forename: Anjan
authors.initials: A
authors.lastname: Chatterjee
authors.forename: H Branch
authors.initials: HB
authors.lastname: Coslett
authors.forename: Howard I
authors.initials: HI
authors.lastname: Hurtig
authors.forename: Tsao-Wei
authors.initials: TW
authors.lastname: Liang
authors.forename: Murray
authors.initials: M
authors.lastname: Grossman
mesh_terms: D000368:Aged; D000544:Alzheimer Disease / Q000453:epidemiology*; D001921:Brain / Q000000981:diagnostic imaging / Q000473:pathology; D003072:Cognition Disorders / Q000175:diagnosis / Q000453:epidemiology*; D005260:Female; D005500:Follow-Up Studies; D057174:Frontotemporal Lobar Degeneration / Q000453:epidemiology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D011939:Mental Recall; D009483:Neuropsychological Tests; D020774:Pick Disease of the Brain / Q000453:epidemiology; D049268:Positron-Emission Tomography; D012660:Semantics; D012720:Severity of Illness Index; D015899:Tomography, Emission-Computed, Single-Photon; D014057:Tomography, X-Ray Computed