title: Performance on neurocognitive tests by co-twins to dementia cases compared to normal control twins.
abstract: Nondemented co-twins of twins who were diagnosed as demented were compared to randomly selected members of normal control twin pairs in which both members of the pair were nondemented. Nondemented co-twins included 23 monozygotic and 62 dizygotic twins; there were 27 normal control twins. Both monozygotic and dizygotic nondemented co-twins of dementia cases scored significantly lower than normal control twins on 5 of 10 cognitive tests. Moreover, monozygotic co-twins of dementia cases had a generally lower score profile than dizygotic co-twins of dementia cases did. These findings show that being at greater genetic risk for dementia is reflected in cognitive performance even in the absence of a diagnosis of dementia.
authors.affiliation: Department of Psychology, University of Southern California, Los Angeles 90089-1061, USA. gatz@usc.edu
authors.forename: Margaret
authors.initials: M
authors.lastname: Gatz
authors.forename: Amy
authors.initials: A
authors.lastname: Fiske
authors.forename: Chandra A
authors.initials: CA
authors.lastname: Reynolds
authors.forename: Boo
authors.initials: B
authors.lastname: Johansson
authors.forename: Laura
authors.initials: L
authors.lastname: Fratiglioni
authors.forename: Nancy L
authors.initials: NL
authors.lastname: Pedersen
mesh_terms: D000368:Aged; D016022:Case-Control Studies; D003072:Cognition Disorders / Q000209:etiology / Q000235:genetics*; D003704:Dementia / Q000235:genetics* / Q000523:psychology*; D005260:Female; D020022:Genetic Predisposition to Disease; D006801:Humans; D008297:Male; D008609:Mental Status Schedule; D012307:Risk Factors; D014429:Twins, Dizygotic; D014430:Twins, Monozygotic