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Purpose Quality of life (QoL) decreases in very old age, and is strongly related to health outcomes and mortality. Understanding the predictors of QoL and change in QoL amongst the oldest old may suggest potential targets for intervention. This study investigated change in QoL from age 79 to 90 years in a group of older adults in Scotland, and identified potential predictors of that change. Method Participants were members of the Lothian Birth Cohort 1921 who attended clinic visits at age 79 (n = 554) and 90 (n = 129). Measures at both time points included QoL (WHOQOL-BREF: four domains and two single items), anxiety and depression, objective health, functional ability, self-rated health, loneliness, and personality. Results Mean QoL declined from age 79 to 90. Participants returning at 90 had scored significantly higher at 79 on most QoL measures, and exhibited better objective health and functional ability, and lower anxiety and depression than non-returners. Hierarchical multiple regression models accounted for 20.3–56.3% of the variance in QoL at age 90. Baseline QoL was the strongest predictor of domain scores (20.3–35.6% variance explained), suggesting that individual differences in QoL judgements remain largely stable. Additional predictors varied by the QoL domain and included self-rated health, loneliness, and functional and mood decline between age 79 and 90 years. Conclusions This study has identified potential targets for interventions to improve QoL in the oldest old. Further research should address causal pathways between QoL and functional and mood decline, perceived health and loneliness. Electronic supplementary material The online version of this article (10.1007/s11136-018-2056-4) contains supplementary material, which is available to authorized users.

Objective Mean speed of responding is the most commonly used measure in the assessment of reaction time (RT). An alternative measure is intraindividual variability (IIV): the inconsistency of responding across multiple trials of a test. IIV has been suggested as an important indicator of central nervous system functioning, and as such, there has been increasing interest in the associations between IIV and brain imaging metrics. Results however, have been inconsistent. The present seeks to provide a comprehensive evaluation of the associations between a variety of measures of brain white matter integrity and individual differences in choice RT (CRT) IIV. Method MRI brain scans of members of the Lothian Birth Cohort 1936 were assessed to obtain measures of the volume and severity of white matter hyperintensities, and the integrity of brain white matter tracts. CRT was assessed with a 4 CRT task on a separate occasion. Data were analyzed using multiple regression (N range = 358-670). Results Greater volume of hyperintensities and more severe hyperintensities in frontal regions were associated with higher CRT IIV. White matter tract integrity, as assessed by both fractional anisotropy and mean diffusivity, showed the smallest effect sizes in associations with CRT IIV. Associations with hyperintensities were attenuated and no longer significant after controlling for M CRT. Conclusions Taken together, the results of the present study suggested that IIV was not incrementally predictive of white matter integrity over mean speed. This is in contrast to previous reports, and highlights the need for further study. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Obesity and low cognitive function are associated with multiple adverse health outcomes across the life course. They have a small phenotypic correlation (r=-0.11; high body mass index (BMI)-low cognitive function), but whether they have a shared genetic aetiology is unknown. We investigated the phenotypic and genetic correlations between the traits using data from 6815 unrelated, genotyped members of Generation Scotland, an ethnically homogeneous cohort from five sites across Scotland. Genetic correlations were estimated using the following: same-sample bivariate genome-wide complex trait analysis (GCTA)-GREML; independent samples bivariate GCTA-GREML using Generation Scotland for cognitive data and four other samples (n=20 806) for BMI; and bivariate LDSC analysis using the largest genome-wide association study (GWAS) summary data on cognitive function (n=48 462) and BMI (n=339 224) to date. The GWAS summary data were also used to create polygenic scores for the two traits, with within- and cross-trait prediction taking place in the independent Generation Scotland cohort. A large genetic correlation of -0.51 (s.e. 0.15) was observed using the same-sample GCTA-GREML approach compared with -0.10 (s.e. 0.08) from the independent-samples GCTA-GREML approach and -0.22 (s.e. 0.03) from the bivariate LDSC analysis. A genetic profile score using cognition-specific genetic variants accounts for 0.08% (P=0.020) of the variance in BMI and a genetic profile score using BMI-specific variants accounts for 0.42% (P=1.9 × 10(-7)) of the variance in cognitive function. Seven common genetic variants are significantly associated with both traits at P

OBJECTIVE To investigate whether and to what extent mortality is predictable from facial photographs of older people. METHODS High-quality facial photographs of 292 members of the Lothian Birth Cohort 1921, taken at the age of about 83 years, were rated in terms of apparent age, health, attractiveness, facial symmetry, intelligence, and well-being by 12 young-adult raters. Cox proportional hazards regression was used to study associations between these ratings and mortality during a 7-year follow-up period. RESULTS All ratings had adequate reliability. Concurrent validity was found for facial symmetry and intelligence (as determined by correlations with actual measures of fluctuating asymmetry in the faces and Raven Standard Progressive Matrices score, respectively), but not for the other traits. Age as rated from facial photographs, adjusted for sex and chronological age, was a significant predictor of mortality (hazard ratio = 1.36, 95% confidence interval = 1.12-1.65) and remained significant even after controlling for concurrent, objectively measured health and cognitive ability, and the other ratings. Health as rated from facial photographs, adjusted for sex and chronological age, significantly predicted mortality (hazard ratio = 0.81, 95% confidence interval = 0.67-0.99) but not after adjusting for rated age or objectively measured health and cognition. Rated attractiveness, symmetry, intelligence, and well-being were not significantly associated with mortality risk. CONCLUSIONS Rated age of the face is a significant predictor of mortality risk among older people, with predictive value over and above that of objective or rated health status and cognitive ability.

OBJECTIVE: This study aimed to investigate the effects of high altitude on reaction time (RT) mean and intra-individual variability. METHOD: Ten students (6 men, 4 women) took a 4-choice RT test and had their vital signs and Lake Louise (LL) score measured on 21 occasions during the Edinburgh Altitude Research Expedition of 2008 to the Western Himalayas (max. altitude 5,565 m). RESULTS: Linear mixed modeling revealed that mean RT was significantly impaired at altitudes above 4,000 m (p < .001), but relatively unaffected below that threshold. An estimated increase in RT between 4,000 and 5,000 m was 15.5 ms, 95% CI [11.1, 19.9]. LL score was related to slower RTs (B = 1.97, 95% CI [0.70, 3.23], p < .01), while number of errors was associated with faster RTs (B = -1.50, 95% CI [-2.60, -0.39], p < .01). There were persistent practice effects in mean RT (B = -2.16, 95% CI [-2.49, -1.83], p < .001. Log-transformed intra-individual variability in RT increased with higher LL scores (B = 0.01801, 95% CI [0.0049, 0.0311], p < .01) and decreased with rising temperature (B = -0.00754, 95% CI [-0.0119, -0.0032], p < .001). However, after controlling for mean RT, these effects were no longer significant. CONCLUSIONS: RTs become significantly impaired above a threshold of 4,000 m. Altitude-related changes in RT intra-individual variability were accounted for by mean RT.

In longitudinal studies data is collected in a series of waves. Each wave after the first suffers from attrition. Therefore it can be difficult to discriminate between changes in sample parameters due to a longitudinal process (e.g. ageing) and changes due to attrition. The problem is particularly vexing if one of the purposes is to compare differences between two or more groups over time, because there may be differential attrition across groups. We refer to this as a recruitment problem, because the sample studied in any wave after the first can be thought of as having been recruited from a preceding wave. We present a mathematical model of the recruitment process. We then apply it to two large longitudinal studies, the British Cohort Survey 1970 and the National Child Development Study (1958), to demonstrate how we can identify effects expected from recruitment alone. As an illustration we show that differential recruitment would predict increasing differences between estimates of men's and women's intelligence as the studied sample ages.

This study investigated the possibility that apparent sex differences in IQ are at least partly created by the degree of sample restriction from the baseline population. We used a nationally representative sample, the 1970 British Cohort Study. Sample sizes varied from 6518 to 11,389 between data-collection sweeps. Principal components analysis of scores obtained on four cognitive tests administered at age 10 was used to obtain estimates that we name ‘IQ’. These age-10 scores were then used to estimate the sex differences at age 10, and also among participants in the two later waves, at age 26 and 30. At age 10, there was a small but significant advantage for boys (Cohen’s d = 0.081). Boys had greater variability in these IQ scores. We then investigated how this very small male advantage at 10 changed with sample restriction. We used the same IQs obtained at age 10, but considered only those subjects who returned for data-collection sweeps at ages 26 and 30 years. Subjects returning at age 26 and 30 were more likely to be females and to have higher age-10 IQ scores. Attrition at age 30 was 28% and the male advantage in IQ scores increased by 15%. Attrition at age 26 was 43% and the male advantage in IQ scores increased by 48%. The findings underline the importance of monitoring attrition in longitudinal studies, as well as emphasising the need for representative samples in studying sex differences in intelligence. A proportion of the apparent male advantage in general cognitive ability that has been reported by some researchers might be attributable to the combination of greater male variance in general cognitive ability and sample restriction, though this remains to be tested in a sample with an appropriate mental test battery.

Greater cognitive ability in childhood is associated with increased longevity, and speedier reaction time (RT) might account for much of this linkage. Greater bodily symmetry is linked to both higher cognitive test scores and faster RTs. It is possible, then, that differences in bodily system integrity indexed by symmetry may underlie the associations of RT and intelligence with increased longevity. However, RT and symmetry have seldom been examined in the same study, and never in children. Here, in 2 large samples aged 4 to 15 (combined n = 856), we found that more symmetrical children had significantly faster mean choice RT and less variability in RT. These associations of faster and less variable RT with greater symmetry early in life raise the possibility that the determinants of longevity in part originate in processes influencing bodily system integrity early in the life-course.

Background Although bodily symmetry is widely used in studies of fitness and individual differences, little is known about how symmetry changes across development, especially in childhood. Aims To test how, if at all, bodily symmetry changes across childhood. Study design We measured bodily symmetry via digital images of the hands. Participants provided information on their age. We ran polynomial regression models testing for associations between age and symmetry. Subjects 887 children attending a public science event aged between 4 and 15 years old. Outcome measures Mean asymmetry for the eight traits (an average of the asymmetry scores for the lengths and widths of digits 2 to 5). Results Symmetry increases in childhood and we found that this period of development is best described by a nonlinear function. Conclusion Symmetry may be under active control, increasing with time as the organism approaches an optimal state, prior to a subsequent decline in symmetry during senescence. The causes and consequences of this contrasting pattern of developmental improvement in symmetry and reversal in old age should be studied in more detail.

In order to assess the degree of cognitive decline resulting from a pathological state, such as dementia, or from a normal aging process, it is necessary to know or to have a valid estimate of premorbid (or prior) cognitive ability. The National Adult Reading Test (NART; Nelson & Willison, 1991) and the Wechsler Test of Adult Reading (WTAR; Psychological Corporation, 2001) are 2 tests developed to estimate premorbid or prior ability. Due to the rarity of actual prior ability data, validation studies usually compare NART/WTAR performance with measures of current abilities in pathological and nonpathological groups. In this study, we validate the use of WTAR scores and extend the validation of the use of NART scores as estimates of prior ability, vis-à-vis the actual prior (childhood) cognitive ability. We do this in a large sample of healthy older people, the Lothian Birth Cohort 1936 (Deary, Gow, Pattie, & Starr, 2012; Deary et al., 2007). Both NART and WTAR scores were correlated with cognitive ability tested in childhood (r = .66-.68). Scores on both the NART and the WTAR had high stability over a period of 3 years in old age (r in excess of .90) and high interrater reliability. The NART accounted for more unique variance in childhood intelligence than did the WTAR.

BackgroundIntra-individual variability in reaction time (RT IIV) is considered to be an index of central nervous system functioning. Such variability is elevated in neurodegenerative diseases or following traumatic brain injury. It has also been suggested to increase with age in healthy ageing.ObjectivesTo investigate and quantify age differences in RT IIV in healthy ageing; to examine the effect of different tasks and procedures; to compare raw and mean-adjusted measures of RT IIV.Data sourcesFour electronic databases: PsycINFO, Medline, Web of Science and EMBASE, and hand searching of reference lists of relevant studies.Study eligibilityEnglish language journal articles, books or book chapters, containing quantitative empirical data on simple and/or choice RT IIV. Samples had to include younger (under 60 years) and older (60 years and above) human adults.Study appraisal and synthesisStudies were evaluated in terms of sample representativeness and data treatment. Relevant data were extracted, using a specially-designed form, from the published report or obtained directly from the study authors. Age-group differences in raw and RT-mean-adjusted measures of simple and choice RT IIV were quantified using random effects meta-analyses.ResultsOlder adults (60+ years) had greater RT IIV than younger (20-39) and middle-aged (40-59) adults. Age effects were larger in choice RT tasks than in simple RT tasks. For all measures of RT IIV, effect sizes were larger for the comparisons between older and younger adults than between older and middle-aged adults, indicating that the age-related increases in RT IIV are not limited to old age. Effect sizes were also larger for raw than for RT-mean-adjusted RT IIV measures.ConclusionsRT IIV is greater among older adults. Some (but not all) of the age-related increases in RT IIV are accounted for by the increased RT means.

Men are often found to have faster and less variable reaction times (RTs) than do women. However, it has not been established whether these differences occur in children. One suggestion is that sex differences in RT variability may be due to the effect of sex hormones on the brain and, by implication, may be expected in adults but not in children. The present study investigates sex differences in RT mean and intraindividual variability in a sample that includes both children and adults (age range = 4-75 years). Mean and intraindividual variability of simple RT (SRT) and 4-choice RT (CRT) were measured in 1,994 visitors to science festivals held in Edinburgh, Scotland, in 2008 and 2009 and in Cheltenham and Cambridge, England, in 2008. The commonly reported pattern of decreasing RT mean and variability in childhood and adolescence, followed by an increase in mean and variability through adulthood and into old age, was confirmed. Greater intraindividual variability for females in SRT and CRT was observed in adults but not in children. Males had significantly faster mean SRT than did females across the life span, but there were no sex differences in mean CRT.

Intra-individual variability (IIV), that is the inconsistency of responding across multiple trials of a test, has been suggested as a measure of cognitive performance alternative to the commonly-used mean level of performance. IIV in reaction time (RT) is a trait-like characteristic of an individual and has been purported as an index of the central nervous system functioning. In this study we investigated whether white matter integrity explains individual differences in RT IIV. Volume and severity of white matter lesions were assessed from MRI brain scans of 671 73-year-olds. Individuals with greater volume of lesions and more severe lesions in frontal regions had higher RT IIV. However, these associations were eradicated by controlling for mean RT. We conclude that white matter integrity does not explain variance in RT IIV that is independent of mean RT.