Longitudinal patterns of semantic and episodic memory in frontotemporal lobar degeneration and Alzheimer's disease.
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.
Xie
Sharon X
SX
Department of Biostatistics and Epidemiology, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104-6021, USA. sxie@mail.med.upenn.edu
Libon
David J
DJ
Wang
Xingmei
X
Massimo
Lauren
L
Moore
Peachie
P
Vesely
Luisa
L
Khan
Alea
A
Chatterjee
Anjan
A
Coslett
H Branch
HB
Hurtig
Howard I
HI
Liang
Tsao-Wei
TW
Grossman
Murray
M
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