Commingling analysis of memory performance in elderly men

✍ Scribed by Christina G. S. Palmer; Bonnie H. Wolkenstein; Asenath La Rue; Gary E. Swan; Susan L. Smalley

• Book ID: 102221043
• Publisher: John Wiley and Sons
• Year: 1994
• Tongue: English
• Weight: 406 KB
• Volume: 11
• Category: Article
• ISSN: 0741-0395
• DOI: 10.1002/gepi.1370110506

✦ Synopsis

Smalley et al. [(

1992

) Genet Epidemiul 9:333-3451 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 = 7 1.4 2 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.