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Commingling analysis of memory performance in elderly men
Author(s) -
Palmer Christina G. S.,
Wolkenstein Bonnie H.,
La Rue Asenath,
Swan Gary E.,
Smalley Susan L.
Publication year - 1994
Publication title -
genetic epidemiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.301
H-Index - 98
eISSN - 1098-2272
pISSN - 0741-0395
DOI - 10.1002/gepi.1370110506
Subject(s) - offspring , skewness , dementia , population , psychology , audiology , biology , medicine , statistics , genetics , mathematics , disease , pregnancy , environmental health
Abstract Smalley et al. [(1992) Genet Epidemiol 9:333–345] found evidence of a mixture of two distributions in memory performance among offspring of patients with dementia of the Alzheimer type (DAT), suggesting that these groups reflect genotypic subgroups of carriers and non‐carriers of a putative DAT gene. One prediction of this hypothesis is that, in the general population, two distributions of memory performance are present, with a smaller proportion of subjects in the low‐scoring cluster than that found among the offspring sample, but similar to the prevalence of DAT in the elderly community‐at‐large. Memory performance was investigated in a large sample of normal elderly males ( N = 1,149; mean age = 71.4 ± 4.7 years) to test this hypothesis. Commingling analyses of performance on the Benton visual retention test demonstrated significant negative skewness in the distribution of memory performance, requiring a transformation to fit a single normal distribution. In the absence of a transformation, two distributions fit better than one, with 6% of subjects falling into a “low”‐scoring cluster. These findings are consistent with the hypothesis that memory performance may represent a premorbid or morbid difference in those who go on to develop, or currently have, DAT, possibly allowing identification of at‐risk carriers of a putative single major gene for DAT. © 1994 Wiley‐Liss, Inc.