Longitudinal and cross-sectional twin data on cognitive abilities in adulthood: the Swedish Adoption/Twin Study of Aging.

Division of Social Sciences, Indiana University Southeast, New Albany 47150, USA.
Developmental Psychology (Impact Factor: 3.21). 12/1998; 34(6):1400-13. DOI: 10.1037//0012-1649.34.6.1400
Source: PubMed

ABSTRACT Cross-sequential methods of analysis, designed to separate age and cohort effects, were applied to data from the Swedish Adoption/Twin Study of Aging. Thirteen cognitive variables were collected at 3 times of measurement separated by 3-year intervals. Data were available from 85 individuals from monozygotic (MZ) pairs reared apart, 132 from MZ pairs reared together, 207 from dizygotic (DZ) pairs reared apart, and 178 from DZ pairs reared together (age range at first assessment: 41-84 years). Time x Cohort interactions were found for mean performance on 8 of the measures, revealing stable mean performance in the younger cohorts and longitudinal decreases in mean performance in the older cohorts. Cohort and time effects for total variance were mixed; little evidence was found for increases in variance with age. Age changes and cohort differences in genetic and environmental components of variance were test-specific; several Cohort x Time interactions attained significance. Heritability of the general cognitive ability factor showed significant longitudinal decreases over time in the older cohorts.

  • [Show abstract] [Hide abstract]
    ABSTRACT: Total brain volume (BV) and the volumes of brain substructures are influenced by genes, the magnitude of which changes with age. One approach to the examination of genetic influences on the volumes of brain structures is to determine their heritability using twin and family studies. We reviewed published cross-sectional studies which examined heritability in healthy subjects at different ages. We identified 32 studies, which examined a total of 77 brain volumetric measures. The findings of our review showed that BVs are under significant genetic influence at all ages, although different brain regions showed different heritability levels. Furthermore, the cross-sectional approach of our review found that heritability factor for the majority of BVs declined with age, such as in the total brain and cerebrum, followed by subsequent increment of environmental influences. Overall, this study identified for the first time a cross-sectional pattern for brain structures' heritability changes with age, and suggests the potential for longitudinal investigations in the future.
    Ageing research reviews 11/2013; · 5.62 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Processing speed, inhibitory control and working memory have been identified as the main possible culprits of age-related cognitive decline. This article describes a study of their interrelationships and dependence on age, including exploration of whether any of them mediates between age and the others. We carried out a LISREL analysis of the performance of 79 participants of low educational level aged 40-91 years in six cognitive tasks. In the best mediational model the effects of age on inhibitory control and working memory are largely mediated by its effect on processing speed. However, in the best-fitting model age has only direct effects on processing speed, working memory, and inhibitory control.
    The International Journal of Aging and Human Development 02/2008; 66(2):115-30. · 0.62 Impact Factor
  • Zeitschrift für Urologie. 02/1953; 46(5):337-9.

Full-text (2 Sources)

Available from
May 30, 2014