Decomposing the within-person and between-person sources of variation in physical activity-cognition associations for low-active older adults.

OBJECTIVES: To examine within-person and between-person sources of variation in the relationship between physical activity and cognition in older adults participating in a walking program. To explore whether demographic, health and fitness variables, and their interactions with activity, are significant predictors of cognition. DESIGN: Brief longitudinal burst design. PARTICIPANTS: 118 participants (91 females, mean age = 72.81 + 5.24 years). MAIN OUTCOME MEASURES: Cognition, self-reported moderate-to-vigorous walking and self-reported moderate-to-vigorous physical activity were assessed at baseline and 6, 9, 12 and 16 weeks follow-up. Attendance at weekly walks was also recorded. RESULTS: Within-persons, changes in physical activity were related to select measures of executive functioning, with increased activity predictive of better cognition (three of four cognitive functions, p<.05). Between-persons, activity was also associated with cognition (two of four cognitive functions, p<.05). Younger age and higher education were related to better cognition. Interactions of demographic, health, and fitness variables with changes in within-person activity were generally non-significant. CONCLUSION: The results highlight the importance of distinguishing within- from between-person effects in longitudinal analyses of the association between physical activity and cognition. This stringent within-person test of association underscores the potential value of simple physical activity interventions for improving cognitive function.

Do Demographics and Functional Abilities Influence Vehicle Type Driven by Older Canadians?

In this study, we examined the Candrive baseline data (n = 928; aged 70 to 94; 62% were men) to determine whether driver characteristics (i.e., age, gender, height, weight, BMI) and certain functional abilities (i.e., Rapid Paced Walk, Timed Up and Go) influenced the types of vehicles driven. There were significant differences with respect to type of vehicle and mean driver age (F = 3.58, p = 0.003), height, (F = 13.32, p < 0.001), weight (F = 14.31, p < 0.001), and BMI (F = 4.40, p = 0.001). A greater proportion of drivers with osteoporosis (χ2 = 21.23, p = 0.020) and osteo/rheumatoid arthritis (χ2 = 21.23, p = 0.020) drove small and medium-sized cars compared to larger ones. Further research is needed to examine older driver-vehicle interactions, and the relationship to demographics and functional abilities, given the vulnerability of this age group to automotive-related injuries.

Seasonal and Weather Effects on Older Drivers' Trip Distances.

The purpose of this study was to determine if season or weather affected the objectively measured trip distances of older drivers (≥ 70 years; n = 279) at seven Canadian sites. During winter, for all trips taken, trip distance was 7 per cent shorter when controlling for site and whether the trip occurred during the day. In addition, for trips taken within city limits, trip distance was 1 per cent shorter during winter and 5 per cent longer during rain when compared to no precipitation when controlling for weather (or season respectively), time of day, and site. At night, trip distance was about 30 per cent longer when controlling for season and site (and weather), contrary to expectations. Together, these results suggest that older Canadian drivers alter their trip distances based on season, weather conditions, and time of day, although not always in the expected direction.

Driving Task: How Older Drivers' On-Road Driving Performance Relates to Abilities, Perceptions, and Restrictions.

This study examined a cohort of 227 older drivers and investigated the relationship between performance on the electronic Driver Observation Schedule (eDOS) driving task and: (1) driver characteristics; (2) functional abilities; (3) perceptions of driving comfort and abilities; and (4) self-reported driving restrictions. Participants (male: 70%; age: M = 81.53 years, SD = 3.37 years) completed a series of functional ability measures and scales on perceived driving comfort, abilities, and driving restrictions from the Year 2 Candrive/Ozcandrive assessment protocol, along with an eDOS driving task. Observations of participants' driving behaviours during the driving task were recorded for intersection negotiation, lane-changing, merging, low-speed maneuvers, and maneuver-free driving. eDOS driving task scores were high (M = 94.74; SD = 5.70) and significantly related to participants' perceived driving abilities, reported frequency of driving in challenging situations, and number of driving restrictions. Future analyses will explore potential changes in driving task scores over time.

Older driver estimates of driving exposure compared to in-vehicle data in the Candrive II study.

OBJECTIVE: Most studies on older adults' driving practices have relied on self-reported information. With technological advances it is now possible to objectively measure the everyday driving of older adults in their own vehicles over time. The purpose of this study was to examine the ability of older drivers to accurately estimate their kilometers driven over one year relative to objectively measured driving exposure. METHODS: A subsample (n = 159 of 928; 50.9% male) of Candrive II participants (age ≥ 70 years of age) was used in these analyses based on strict criteria for data collected from questionnaires as well as an OttoView-CD Autonomous Data Logging Device installed in their vehicle, over the first year of the prospective cohort study. RESULTS: Although there was no significant difference overall between the self-reported and objectively measured distance categories, only moderate agreement was found (weighted kappa = 0.57; 95% confidence interval, 0.47-0.67). Almost half (45.3%) chose the wrong distance category, and some people misestimated their distance driven by up to 20,000 km. Those who misjudged in the low mileage group (≤5000 km) consistently underestimated, whereas the reverse was found for those in the high distance categories (≥ 20,000); that is, they always overestimated their driving distance. CONCLUSIONS: Although self-reported driving distance categories may be adequate for studies entailing broad group comparisons, caution should be used in interpreting results. Use of self-reported estimates for individual assessments should be discouraged.

BioAge: toward a multi-determined, mechanistic account of cognitive aging.

The search for reliable early indicators of age-related cognitive decline represents a critical avenue for progress in aging research. Chronological age is a commonly used developmental index; however, it offers little insight into the mechanisms underlying cognitive decline. In contrast, biological age (BioAge), reflecting the vitality of essential biological systems, represents a promising operationalization of developmental time. Current BioAge models have successfully predicted age-related cognitive deficits. Research on aging-related cognitive function indicates that the interaction of multiple risk and protective factors across the human lifespan confers individual risk for late-life cognitive decline, implicating a multi-causal explanation. In this review, we explore current BioAge models, describe three broad yet pathologically relevant biological processes linked to cognitive decline, and propose a novel operationalization of BioAge accounting for both moderating and causal mechanisms of cognitive decline and dementia. We argue that a multivariate and mechanistic BioAge approach will lead to a greater understanding of disease pathology as well as more accurate prediction and early identification of late-life cognitive decline.

Influence of negative stereotypes and beliefs on neuropsychological test performance in a traumatic brain injury population.

The impact of stereotype threat and self-efficacy beliefs on neuropsychological test performance in a clinical traumatic brain injury (TBI) population was investigated. A total of 42 individuals with mild-to-moderate TBI and 42 (age-, gender-, educationally matched) healthy adults were recruited. The study consisted of a 2 (Type of injury: control, TBI) × 2 (Threat Condition: reduced threat, heightened threat) between-participants design. The purpose of the reduced threat condition was to reduce negative stereotyped beliefs regarding cognitive effects of TBI and to emphasize personal control over cognition. The heightened threat condition consisted of an opposing view. Main effects included greater anxiety, motivation, and dejection but reduced memory self-efficacy for head-injured-groups, compared to control groups. On neuropsychological testing, the TBI-heightened-threat-group displayed lower scores on Initial Encoding (initial recall) and trended toward displaying lower scores on Attention (working memory) compared to the TBI-reduced-threat-group. No effect was found for Delayed Recall measures. Memory self-efficacy mediated the relation between threat condition and neuropsychological performance, indicating a potential mechanism for the threat effect. The findings highlight the impact of stereotype threat and self-referent beliefs on neuropsychological test performance in a clinical TBI population.

An evaluation of the roadwise review: a mixed methods approach.

OBJECTIVE: The objective of this mixed methods study was to perform an evaluation of the Roadwise Review CD-ROM (RWR), a self-screening tool for older drivers. METHODS: Ninety-six older drivers (67 to 91) used the RWR with a research assistant at two different sites, and then completed written surveys (closed and open-ended questions) immediately after the session as well as two weeks later. In addition, RWR test results by these 96 older drivers were compared to the results of the original sample that was used to establish normative data for the RWR. RESULTS: When test scores were evaluated, almost all participants (96%) were found to have at least one impairment. The rates of impairment varied dramatically between tests from 3 percent (visual acuity) to 75 percent (visual search). Several average test scores were found to be different from the original samples upon which the normative data were derived. Several factors were found that influenced these older drivers' scores on the various components of the RWR, although the explanatory power was very low. Participants reported that the RWR was useful, they made changes to their driving, and talked to their family and friends about driving. Participants also provided many good suggestions for improvements of this tool. CONCLUSION: The RWR offers promise for older drivers to self-screen their ability to drive as well as provide education on safe driving, however modifications are recommended for this tool.

Evidence-based risk assessment and recommendations for physical activity clearance: cognitive and psychological conditions.

Physical activity has established mental and physical health benefits, but related adverse events have not received attention. The purpose of this paper was to review the documented adverse events occurring from physical activity participation among individuals with psychological or cognitive conditions. Literature was identified through electronic database (e.g., MEDLINE, psychINFO) searching. Studies were eligible if they described a published paper examining the effect of changes on physical activity behaviour, included a diagnosed population with a cognitive or psychological disorder, and reported on the presence or absence of adverse events. Quality of included studies was assessed, and the analyses examined the overall evidence by available subcategories. Forty trials passed the eligibility criteria; these were grouped (not mutually exclusively) by dementia (n = 5), depression (n = 10), anxiety disorders (n = 12), eating disorders (n = 4), psychotic disorders (n = 4), and intellectual disability (n = 15). All studies displayed a possible risk of bias, ranging from moderate to high. The results showed a relatively low prevalence of adverse events. Populations with dementia, psychological disorders, or intellectual disability do not report considerable or consequential adverse events from physical activity independent of associated comorbidities. The one exception to these findings may be Down syndrome populations with atlantoaxial instability; in these cases, additional caution may be required during screening for physical activity. This review, however, highlights the relative paucity of the reported presence or absence of adverse events, and finds that many studies are at high risk of bias toward reporting naturally occurring adverse events.

Partial measurement equivalence of French and English versions of the Canadian Study of Health and Aging neuropsychological battery.

Neuropsychological batteries are often translated for use across populations differing in preferred language. Yet, equivalence in construct measurement across groups cannot be assumed. To address this issue, we examined data from the Canadian Study of Health and Aging, a large study of older adults. We tested the hypothesis that the latent variables underlying the neuropsychological battery administered in French or English were the same (invariant). The best-fitting baseline model, established in the English-speaking Exploratory sample (n = 716), replicated well in the English-speaking Validation sample (n = 715), and the French-speaking sample (FS, n = 446). Across the English- and FSs, two of the factors, Long-term Retrieval and Visuospatial speed, displayed invariance, that is, reflected the same constructs measured in the same scales. In contrast, the Verbal Ability factor showed only partial invariance, reflecting differences in the relative difficulty of some tests of language functions. This empirical demonstration of partial measurement invariance lends support to the continued use of these translated measures in clinical and research contexts and illustrates a framework for detailed evaluation of the generality of models of cognition and psychopathology, across groups of any sort.

A review of the stereotype threat literature and its application in a neurological population.

Stereotype threat is a situational phenomenon, leading to test performance decrements, in which a member of a stigmatized group feels pressured by the possibility of confirming or being judged by a negative stereotype. This review article highlights the progression of research in the stereotype threat field, and its relevance to neurological populations. Early studies focused on demonstrating this effect in African American, women, and elderly populations. Since this time, research has continued to focus on these populations but has moved to elucidating stereotype threat's mediating psychological factors, studying the impact of individual differences in response to stereotype threat, and attempting to reduce its overall effect. A proposal for further study in neurological populations, under the framework of stereotype threat, comprises the last portion of the paper. It is argued that this social psychological phenomenon may, at least in part, account for poor neuropsychological test performance for neurologically compromised individuals.

Health conditions, health symptoms and driving difficulties in older adults.

OBJECTIVES: Previous research has indicated that age-related medical or health conditions can affect driving performance in older adults but little, if any, research has examined the mechanisms through which health conditions affect driving difficulties in older adults. DESIGN: Cross-sectional, correlational study. SETTING: Random sample from the community. We examined the nature of the relations among health conditions, health-related symptoms, physical fitness levels and specific types of self-reported driving difficulties in a random sample of older adults. PARTICIPANTS: Three hundred eighteen adults 60 years of age or older. INTERVENTION: None. MEASUREMENTS: General health, health-related symptoms, driving-related difficulties and physical activity. RESULTS: Our findings support the position that health-related symptoms are more clearly associated with driving difficulties than are health conditions, and mediate the relations between health conditions and driving difficulties. Health-related symptoms involving the spine and lower body appeared to be particularly relevant to difficulties with driving experienced in those body areas (i.e. spine and lower body). CONCLUSION: These findings are encouraging, in that the most frequently reported symptoms are in areas highly amenable to modification and, in that most of our respondents indicated a willingness to engage in exercise if an association between fitness and driving was demonstrated.

Perception, attitudes and beliefs, and openness to change: implications for older driver education.

With a rapidly aging population, strategies for improving driver safety are beginning to emerge that focus on changing driving behaviors and knowledge. We examined the perceptions of risk, beliefs and attitudes, and openness to change of 86 older participants voluntarily attending a driver education program. It appeared that most people attending these sessions were not necessarily concerned about their own driving, safety or abilities, but were interested in maintaining mobility. They were conservative and reasonably consistent in their attitudes toward traffic regulations and safe driving practices. Some gender differences emerged with more men than women being resistant to changing their driving habits, more men than women reporting that they drive after consuming alcohol and more women than men identifying a role for their families in decision-making regarding driving cessation. This suggests that educational material may need to be targeted differently for men and women. It is anticipated that psychosocial factors related to driving such as driver perception, beliefs and openness to change will be useful for maximizing the fit between education program content and outcomes.

Neuropsychological detection of cognitive impairment: inter-rater agreement and factors affecting clinical decision-making.

The agreement between neuropsychologists identifying cognitive impairment (CI) in older adults was examined, as were factors influencing the classification process. Twenty four neuropsychologists in 18 study centers classified cases with or without CI after reviewing neuropsychological findings and other relevant information. All cases were participants in the third wave of the Canadian Study of Health and Aging, a study of CI in later life. For 117 randomly selected cases, a second neuropsychologist reviewed the same material and reclassified the cases. Cases given the same (concordant) or different (discordant) classifications were compared with respect to patient and rater characteristics. The inter-rater agreement was moderate (77.7% agreement, kappa = .49). On all measures of cognitive functioning, the concordant group without impairment obtained a higher mean score than the discordant group, and the discordant group obtained a higher mean score than the concordant group with impairment. For 5 out of 8 cognitive measures, the concordant group with impairment differed from the concordant group without impairment and the discordant group, but the latter two groups did not differ significantly. The findings are comparable to others in the field and highlight the need for neuropsychologists to further clarify procedures for identifying subtle, or mild, forms of cognitive impairment.

Reliable change scores and their relation to perceived change in memory: implications for the diagnosis of mild cognitive impairment.

The relation between the subjective report of memory problems and objective evidence of the same has been debated with mixed results appearing in the literature. Less is known about the relation between objective change in test performance and the perceptions of cognitive change from family members/friends and trained clinicians. These relations were explored using 5-year longitudinal data from the population-based Canadian Study of Health and Aging. Statistically reliable deterioration in memory test performance was determined using a standardized regression-based (SRB) approach and a Reliable Change Index (RCI) that accounts for aging and practice effects. Among a subsample of persons with no cognitive impairment (NCI) at baseline, there was a moderate relation between reliable test score decline and ratings made by clinicians and informants. No relation, however, was found with the subjective reports of memory difficulties. These findings hold implications for current mild cognitive impairment (MCI) criteria which include subjective, informant and/or clinician ratings of cognitive decline.

A comparison of methods for measuring cognitive change in older adults.

Well-researched statistical methods are required to guide clinicians in determining the significance of test score changes in serial neuropsychological assessment of older adults. The following six change score methods were examined using five-year test-retest data from the Canadian Study of Health and Aging: the standard deviation method, three reliable change indices (RCIs), and two standardized regression-based methods. Changes in scores on four memory measures were examined in cognitively healthy older adults, and the RCI with a correction for practice/aging effects most accurately classified this normal variability. Diagnostic change (i.e., developing dementia versus remaining cognitive healthy) was also examined in relation to memory test score changes. All change score methods were significantly associated with diagnostic change, though the strength of association varied by measure and method. In contrast to some previous research, RCIs were found to be useful when making diagnostic discriminations in older adults.

Psychometric properties of an abridged version of The Zarit Burden Interview within a representative Canadian caregiver sample.

PURPOSE: Given the exponential increase in dementia prevalence anticipated in the coming years, measurement of caregiver burden has become common in gerontological research and clinical practice. The Zarit Burden Interview (BI) has emerged as the most widely utilized burden measure. The current study examines the psychometric properties of responses to an abridged, 12-item version of this scale. DESIGN AND METHODS: Data were derived from a national epidemiological study of dementia incidence and patterns of care (N = 1,095). Informal caregivers of surviving institutionalized and community-dwelling index subjects were interviewed 5 years subsequent to initial recruitment (n = 770). RESULTS: Results of both the exploratory and confirmatory factor analyses support a two-factor structure of responses to this abridged scale. Subsequent to control for demographic variables, dementia illness features, and baseline depressive symptoms at baseline, responses to this brief BI provide a significant increase to prediction of depressive symptoms at Time 2 (R(2) =.24, p <.01) with no additional variance provided by the 10 remaining items from the complete BI (deltaR(2) = 0, ns). IMPLICATIONS: The results of this study are discussed relative to theory and the operational definition of caregiver burden. Findings can be generalized with greater confidence given the representative and national composition of caregivers recruited for this study.