Åke Wahlin

Selective adult age differences in an age-invariant multifactor model of declarative memory.

Confirmatory factor analysis was used to test competing models of declarative memory. Data from middle-aged participants provided support for a model comprised of 2 2nd-order (episodic and semantic memory) and 4 1st-order (recall, recognition, fluency, and knowledge) factors. Extending this model across young-old and old-old participants established support for age invariance. Tests of group differences showed an age deficit in episodic memory that was more pronounced for recall than for recognition. For semantic memory, there was an increase in knowledge from middle to young-old age and thereafter a decrease. Overall, the results support the view that episodic memory is more age sensitive than semantic memory, but they also indicate that aging has differential effects within these 2 forms of memory.

Episodic memory change in late adulthood: Generalizability across samples and performance indices

Younger adults recall more information from episodic memory tasks than do older adults. Because longitudinal studies are rare and often incompatible, the extent of actual late-life memory change is not well established. We assemble two different longitudinal samples of normal older adults, each of which is tested twice at a 3-year interval, using a large battery of episodic memory indicators. Together, two-wave data from both the Victoria Longitudinal Study in Canada (n=400) and the Kungsholmen Project in Sweden (n=168) cover a 40-year span of adulthood, ranging from 54 to 94 years of age. Principal memory tasks include categorizable word lists, story recall, and random word lists, as well as indicators of cognitive support. Overall, an examination of performance on sets of common and complementary episodic tasks reveals that, for both samples, actual 3-year changes are modest and that, when decline occurs, it is gradual. The exception—greater decline for more supported tasks—suggests that these may be especially sensitive to late-life changes.

Effects of serum vitamin B12 and folate status on episodic memory performance in very old age : A population-based study

We examined the relationship between low levels of serum vitamin B12 (< 200 pmol/L) and folic acid (< 11 nmol/L), separately or combined, and episodic memory performance in very old age. Participants with low serum vitamin values were compared with a control group matched for age and educational level. Participants (N = 250) were selected from a group of nondemented, community-dwelling persons ages 75-96. Episodic memory was tested by means of free recall and recognition of slowly and rapidly presented words. Results indicated a deterioration in both free recall and recognition as a function of serum vitamin status. However, no linear effects of vitamin levels on memory were observed, indicating that vitamin B12 and folic acid status may effect memory only among individuals at the low end of the distribution. We speculate that the vitamin-related memory deficit may reflect encoding problems, possibly due to alterations in brain metabolism.

Further evidence on the effects of vitamin B12 and folate levels on episodic memory functioning: a population-based study of healthy very old adults

BACKGROUND The relationship between vitamin status and cognitive functioning has been addressed in several recent studies with inconclusive results. The purpose of this study was to examine separate and combined effects of serum vitamin B12 and folic acid on episodic memory functioning in very old age. METHODS Four study groups were selected from a population-based sample of healthy very old adults (90-101 years of age): normal B12/normal folic acid, low B12/normal folic acid, normal B12/low folic acid, and low B12/low folic acid. Cutoff levels were set at 180 pmol/L for vitamin B12 and at 13 nmol/L for folic acid. Subjects completed two episodic recall tasks (objects and words) and two episodic recognition tasks (faces and words). RESULTS Neither vitamin affected recognition or primary memory. Most interesting, although B12 was unrelated to recall performance, subjects with low folic acid levels showed impairment in both word recall and object recall. CONCLUSIONS These results replicate and extend previous findings that folic acid may be more critical than B12 to memory functioning in late life. The selective effects of folic acid on episodic recall were discussed in terms of encoding and retrieval mechanisms, as well as in relation to brain protein synthesis.

How do health and biological age influence chronological age and sex differences in cognitive aging: moderating, mediating, or both?

Much research on cognitive competence in normal older adults has documented age and sex differences. The authors used new cross-sectional data from the Victoria Longitudinal Study (VLS) (n=386; age 61 to 95 years) to examine how health and biological age influence age and sex differences in cognitive aging. The authors found evidence for both moderating and mediating influences. Age differences were moderated by health status, such that the negative effects of age were most pronounced among participants of relatively better health. Sex differences were moderated by health and were more pronounced among participants reporting comparatively poorer health. Although health mediated a notable amount of age-related cognitive variation, BioAge mediated considerably more variance, even after statistical control for differences in health. A complex pattern emerged for the mediation of sex differences: Although BioAge accounted for sex-related variation in cognitive performance, health operated to suppress these differences. Overall, both health and BioAge predicted cognitive variation independently of chronological age.

Mini Nutritional Assessment of rural elderly people in Bangladesh: the impact of demographic, socio-economic and health factors.

OBJECTIVE In stating the Millennium Development Goals, the United Nations aims to halve malnutrition around the world by 2015. Nutritional status of the elderly population in low-income countries is seldom focused upon. The present study aimed to evaluate the magnitude of malnutrition among an elderly population in rural Bangladesh. DESIGN AND SETTING Data collection for a multidimensional cross-sectional study of community-based elderly people aged 60 years and over was conducted in a rural area in Bangladesh. SUBJECTS Of 850 randomly selected elderly individuals, 625 participated in home interviews. Complete nutritional information was available for 457 individuals (mean age 69+/-8 years, 55% female). Nutritional status was assessed using an adapted form of the Mini Nutritional Assessment (MNA) including body mass index (BMI). Age, sex, education, household expenditure on food and self-reported health problems were investigated as potential predictors of nutritional status. RESULTS BMI<18.5 kg m(-2), indicating chronic energy deficiency, was found in 50% of the population. MNA revealed a prevalence of 26% for protein-energy malnutrition and 62% for risk of malnutrition. Health problems rather than age had a negative impact on nutritional status. Level of education and food expenditure were directly associated with nutritional status. CONCLUSION In order to reduce world hunger by half in the coming decade, it is important to recognise that a substantial proportion of the elderly population, particularly in low-income countries, is undernourished.

Free recall and recognition of slowly and rapidly presented words in very old age: a community-based study

This study addressed the effects of study time on episodic recall and recognition of words in a community-based sample of healthy older adults ranging from 75 to 96 years of age (N = 221). Results indicated a slight but reliable age-related deterioration of free-recall performance that was attributable to age deficits in secondary memory. The size of the age-related impairment in recognition was reduced relative to that in recall. As well, for all age groups, recall and recognition were higher when items were slowly as opposed to rapidly presented, indicating proficient utilization of study time in very old age. Finally, multiple regression analyses indicated that, although a variety of demographic (i.e., age and education), psychometric (i.e., Mini-Mental State Exam [MMSE] and Block Design scores), and biological (i.e., thyroid-stimulating hormone) variables were related to free-recall performance, only Block Design and MMSE scores made independent contributions to recognition performance.

Cognitive functioning in aging and dementia : the Kungsholmen Projekt

The Kungsholmen Project (KP) is a community-based longitudinal study of aging and dementia targeting the 75+ population. In this article, we review empirical studies with a cognitive focus from the KP. The main findings indicate that (a) there is an age-related decline for some cognitive domains (e.g., episodic memory, verbal fluency, visuoconstructive skill, psychomotor speed), but not for others (e.g., primary memory, visuoperceptive skill, motor-hand coordination), (b) multiple individual-difference variables within demographic (e.g., sex, education) life-style (e.g., activity levels), genetic (e.g., apolipoprotein E genotype), and health-related (e.g., vitamin B deficiency, depression, diabetes) domains are related to late-life cognitive functioning, (c) a potential for improving cognitive performance – a reserve capacity – is present also among very old adults, (d) the 2 most common dementia diseases, Alzheimer’s disease (AD) and vascular dementia (VaD), affect cognition in a strikingly similar manner, (e) the role of individual-difference variables in cognitive functioning is markedly reduced in dementia – the pathogenesis itself may overshadow the influence of other variables, and (f) there is a long preclinical period in dementia during which cognitive deficits are detectable. As is true with the other projects represented in this issue, the KP portrays a rather diversified picture of cognitive aging, although systematic patterns are evident with regard to the variability of late-life cognitive functioning.

Low episodic memory performance as a premorbid marker of depression: evidence from a 3‐year follow‐up

Objective:  To examine low episodic memory scores as a potential risk factor for depression.

Longitudinal evidence of the impact of normal thyroid stimulating hormone variations on cognitive functioning in very old age

The purpose of this study was to examine longitudinal associations among thyroid stimulating hormone (TSH) levels and cognitive performance. Data collected at the first three assessment times, approximately 3 years apart, are reported for the survivors (n=45) from a previously published cross-sectional study. Participants were aged 75-93 years at baseline, and data reported were collected in the Kungsholmen Project, a longitudinal project investigating aging and dementia. Analyses revealed that although declining verbal fluency and visuospatial abilities were accompanied by simultaneously declining TSH levels, the pattern of cross-sectional and longitudinal results are interpreted such that declining TSH levels may have caused episodic memory deficits later on. These results were obtained in the examination of 6-year but not 3-year change, and after removal of the cognitive variation associated with depressive mood symptoms.