Differential decline in word generation from phonemic and semantic categories during the course of Alzheimer's disease: Implications for the integrity of semantic memory

Abstract

The ability to generate words from phonemic (i.e., words beginning with 'F,' 'A,' and 'S') and semantic (i.e., animals, fruits, and vegetables) categories was assessed longitudinally in patients with Alzheimer's disease (AD; N 5 59) and normal controls (NC; N 5 59). Patients with AD performed worse than NC participants on both tasks at each of 4 annual evaluations and exhibited greater impairment relative to controls on the semantic-category task than on the phonemic-category task. In addition, the performance of the patients with AD declined over time on both tasks, but the rate of decline was faster on the semantic-category than on the phonemic-category task. Examination of individual responses across the annual evaluations revealed that patients with AD were more consistent than NC participants in failing to generate previously produced semantic-category, but not phonemic-category, items in all years following the 1st year in which the item was not produced. These results are consistent with the notion that patients with AD suffer a gradual deterioration of the organization and content of semantic memory as the disease progresses. (JINS, 1999, 5, 692-703.)

Distinct cognitive profiles and rates of decline on the Mattis Dementia Rating Scale in autopsy-confirmed frontotemporal dementia and Alzheimer's disease

“…In the case of Initiation0Perseveration, this less than robust discriminability may be because the subscale is heavily weighted toward a semantically based verbal fluency task that could be adversely affected by either frontal lobe mediated executive processes (e.g., initiation, strategic search, and retrieval) prominently affected in FTD (Ruff et al, 1997) or by the deterioration of semantic knowledge that characterizes AD (Butters et al, 1987;Chertkow & Bub, 1990;Martin & Fedio, 1983;Monsch et al, 1994;Salmon et al, 1999). The relatively low discriminating power of the MDRS Construction subscale, in contrast, most likely reflects the cursory evaluation provided by this subscale.…”

Semantic memory in Alzheimer's disease and the frontotemporal dementias: A longitudinal study of 236 patients.

“…demands similar to those of CF but depends less on the integrity of the semantic system (Monsch et al, 1992;Salmon et al, 1999). Participants were assessed on the letters F, A, and S, and data were summed across these.…”

A longitudinal study of semantic memory impairment in patients with Alzheimer’s disease

“…In this study, the patients were first asked to name pictures and subsequently to perform a "same category word to picture matching" task. There was a reliable overlap between loss of name production and name comprehension such that pictures named correctly were more likely to be chosen in a word-to-picture matching task than pictures not named correctly (see also Alathari et al, 2004;Bayles et el., 1999;Binetti et al, 1995;Garrard et al, 2005;Hodges and Patterson, 1995;Hornberger et al, 2009;Martin and Fedio, 1983;Salmon et al, 1999a for similar procedures). Several other researchers have described a breakdown in the structure and organization of semantic memory in patients with Alzheimer's disease (for review see Salmon et al, 1999b).…”