Search

Objective: Creation of normative data with regression corrections for demographic covariates reduces risk of small cell sizes compared with traditional normative approaches. We explored whether methods of correcting for demographic covariates (e.g., full regression models versus hybrid models with stratification and regression) and choice of covariates (i.e., correcting for age with or without sex and/or education correction) impacted reliability and validity of normative data. Method: Measurement invariance for sex and education was explored in a brief telephone-administered cognitive battery from the Canadian Longitudinal Study on Aging (CLSA; after excluding persons with neurological conditions N = 12,350 responded in English and N = 1,760 in French). Results: Measurement invariance was supported in hybrid normative models where different age-based regression models were created for groups based on sex and education level. Measurement invariance was not supported in full regression models where age, sex, and education were simultaneous predictors. Evidence for reliability was demonstrated by precision defined as the 95% inter-percentile range of the 5th percentile. Precision was higher for full regression models than for hybrid models but with negligible differences in precision for the larger English sample. Conclusions: We present normative data for a remotely administered brief neuropsychological battery that best mitigates measurement bias and are precise. In the smaller French speaking sample, only one model reduced measurement bias, but its estimates were less precise, underscoring the need for large sample sizes when creating normative data. The resulting normative data are appended in a syntax file. [ABSTRACT FROM AUTHOR]

Semantic memory is stable in healthy older adults but shows decline in mild cognitive impairment (MCI). Current measures of semantic function do not assess multiple aspects of semantic function and/or are time-consuming to administer. Here we report the psychometric properties of a battery to detect semantic impairment that we recently developed and published. Study 1 determined the face validity of the battery; interviews were conducted with five professionals with expertise in MCI and language. Face validity interviews suggested the battery appropriately assesses semantic impairments. Study 2 assessed convergent validity and reliability (inter-rater reliability, test-retest reliability, and internal consistency). Participants included 102 healthy older adults and 60 people with MCI who completed a four-task semantic battery. Results demonstrate that performance on the semantic battery correlates with traditional measures of semantic function, inter-rater reliability and internal consistency was high, and there was no significant change in mean scores between participants' first and second testing sessions. The present findings suggest that the semantic battery is a reliable and valid assessment of semantic function. It is currently recommended for research use only. [ABSTRACT FROM AUTHOR]

Most research investigating neurocognitive changes in participants with PTSD has focused on young adults. Numerous studies have recognized the crucial role of social support in diminishing the likelihood of developing PTSD. The current study evaluates the cognitive performance of middle-aged and older adults with symptoms of PTSD, and examines if perceived social support can act as a cognitive reserve factor. The study was conducted using data from the Canadian Longitudinal Study on Aging, a nationwide study on health and aging. The current study included 1,096 participants in the PTSD group and 22,158 participants in the comparison group, all between the ages of 45 and 85. Participants completed the MOS (Medical Outcomes Study) Social Support Survey as well as neuropsychological tests in the domains of executive functioning, declarative memory, and prospective memory. The PTSD group had worse performance in the domains of executive functioning and prospective memory than the comparison group. Furthermore, when examining global cognitive impairments (impairment was defined as scoring 1.5 or more standard deviations below age and education adjusted comparison group), the PTSD group demonstrated greater impairment rates than the comparison group on two or more tests. Moderation analyses revealed that greater social support was associated with better executive functioning for the comparison group, although this was not found to be true for the PTSD group. The PTSD group experienced greater cognitive deficits compared to the comparison group. Higher levels of perceived social support were associated with better performance on neurocognitive measures for the comparison group. However, social support did not appear to moderate this relationship for the PTSD group. [ABSTRACT FROM AUTHOR]

Recall of story materials is a primary way to assess episodic memory. However, the standard scoring method may not be maximally sensitive to cognitive decline. We developed a set of 24 stories, and younger and older adults heard these stories and recalled them immediately and after a delay (Study 1). Twelve of these stories were then selected, and older adults and people with MCI completed immediate and delayed recall of these stories (Study 2). Responses were classified as veridical, gist, or distorted, and were scored by number of units and number of propositions recalled. Younger adults had higher veridical recall than older adults, and proposition-based scoring revealed higher gist recall in older than younger adults. Gist and distortion recall increased over time in older adults, but decreased in MCI. Using proposition-based scoring and distinguishing between veridical and gist responses may discriminate better between healthy older adults and people with MCI. [ABSTRACT FROM AUTHOR]

Objective: We examined the extent to which loss of consciousness (LOC) following mild traumatic brain injury (mTBI) may be associated with impairments in executive functions and declarative memory more than a year after brain injury. Method: Analyses were run on 548 participants who had self-reported LOC of <1 min, 441 with LOC of 1–20 min, and 13,609 no brain injury comparison participants, taken from the Canadian Longitudinal Study on Aging (CLSA), a nationwide study on health and aging. Results: Those that had mTBI with LOC of 1–20 min were more likely than no head injury comparisons to be impaired on measures of executive functioning and declarative memory. Impairments were evident when examining for single- and two-test impairment rates on measures of executive functioning and declarative memory. Conclusions: A subset of people that had reported a single mTBI with LOC more than 12 months ago may experience impairments in executive functioning and declarative memory, particularly those who spent more time unconscious. [ABSTRACT FROM AUTHOR]

Objective: We present descriptive information on the cognitive measures used in the Canadian Longitudinal Study on Aging (CLSA) Comprehensive Cohort, relate this to information on these measures in the extant literature, and identify key considerations for their use in research and clinical practice. Method: The CLSA Comprehensive Cohort is composed of 30,097 participants aged 45–85 years at baseline who provided a broad range of sociodemographic, physical, social, and psychological health information via questionnaire and took part in detailed physical and cognitive assessments. Cognitive measures included: the Rey Auditory Verbal Learning Test – immediate and 5-min delayed recall, Animal Fluency, Mental Alternation Test (MAT), Controlled Oral Word Association Test (COWAT), Stroop Test – Victoria Version, Miami Prospective Memory Test (MPMT), and a Choice Reaction Time (CRT) task. Results: CLSA Comprehensive Cohort sample sizes were far larger than previous studies, and performances on the cognitive measures were similar to comparable groups. Within the CLSA Comprehensive Cohort, main effects of age were observed for all cognitive measures, and main effects of language were observed for all measures except the CRT. Interaction effects (language × age) were observed for the MAT, MPMT Event-based score, all time scores on the Stroop Test, and most COWAT scores. Main effects of education were observed for all measures except for the MPMT Time score in the French sample, and interaction effects (age × education) were observed for the RAVLT (immediate and delayed) for the English sample and the Stroop Dot time for the French sample. Conclusion: This examination of the cognitive measures used in the CLSA Comprehensive Cohort lends support to their use in large studies of health and aging. We propose further exploration of the cognitive measures within the CLSA to make this information relevant to and available for clinical practice. [ABSTRACT FROM AUTHOR]

Variations in brain activation may lead to individual differences in working memory (WM) performance. Such differences may account for contradictory findings in the literature relating to age-related changes in neural activation during WM tasks. In the present study, 39 young adults (aged 18–30) and 34 older adults (aged 65+) completed an n-back task while their electroencephalography, accuracy, and reaction time was recorded. They were then categorized as high or low performers. High performers had larger P3b and parietal P200 amplitudes and smaller parietal N200 amplitudes than low performers. High-performing older adults exhibited larger parietal P200 amplitudes than low-performing older adults, and similar P3bs to young adults during the 2-back. Low-performing older adults, in contrast, exhibited smaller parietal P3bs than young adults during the 2-back. These findings suggest that brain activity during a WM task is influenced by individual differences in performance level. Moreover, some older adults can maintain high WM performance and capacity through recruitment of additional brain regions. [ABSTRACT FROM AUTHOR]

Objective: The aim of this study was to verify the effect of age, education and sex on Miami Prospective Memory Test (MPMT) performance obtained at baseline of the Canadian Longitudinal Study on Aging (CLSA) by neurologically healthy French- and English-speaking subsamples of participants (N = 18,511). Method: The CLSA is a nation-wide large epidemiological study with participants aged 45-85 years old at baseline. The MPMT is an event- and time-based measure of prospective memory, with scores of intention, accuracy and need for reminders, administered as part of the Comprehensive data collection. Participants who did not self-report any conditions that could impact cognition were selected, which resulted in 15,103 English- and 3408 French-speaking participants. The samples are stratified according to four levels of education and four age groups (45-54; 55-64; 65-74; 75+). Results: There is a significant age effect for English- and French-speaking participants on the Event-based, Time-based, and Event- + Time-based scores of the MPMT. The effect of the education level was also demonstrated on the three MPMT scores in the English-speaking group. The score 'Intention to perform' was the most sensitive to the effect of age in both the English and French samples. Sex had no impact on performance on the MPMT. Conclusions: This study confirms the impact of age and level of education on this new prospective memory task. It informs future research with this measure including the development of normative data in French- and English-speaking Canadians on the Event-based and Time-based MPMT. [ABSTRACT FROM AUTHOR]

Objective: We aimed to examine the extent to which loss of consciousness (LOC) following mild traumatic brain injury (mTBI) may be associated with impairments in time- and event-based prospective memory (PM). PM is thought to involve executive processes and be subserved by prefrontal regions. Neuroimaging research suggests alterations to these areas of the brain several years after mTBI, particularly if LOC was experienced. However, it remains unclear whether impairments in time- or event-based functioning may persist more than a year after mTBI, and what the link with duration of LOC may be. Method: Analyses were run on data from the Canadian Longitudinal Study on Aging, a nationwide study on health and aging involving individuals between the ages of 45-85. The present study consisted of 1937 participants who experienced mTBI more than 12 months prior, of whom 1146 reported spending less than 1 min unconscious, and 791 had LOC between 1 and 20 min, and 13,525 cognitively healthy adults. Participants were administered the Miami Prospective Memory Test, and tests of retrospective memory and executive functioning. Results: Both mTBI groups were impaired in time-based PM relative to people with no history of TBI. Time- and event-based impairments were predicted by older age, and executive dysfunction among those who spent more time unconscious. Conclusions: Those with mTBI with LOC may experience impairments in PM, particularly in conditions of high demand on executive processes (time-based PM). Implications for interventions aimed at ameliorating PM among those who have experienced mTBI are discussed. [ABSTRACT FROM AUTHOR]

Objective:We detail a new approach to the creation of normative data for neuropsychological tests. The traditional approach to normative data creation is to make demographic adjustments based on observations of correlations between single neuropsychological tests and selected demographic variables. We argue, however, that this does not describe the implications for clinical practice, such as increased likelihood of misclassification of cognitive impairment, nor does it elucidate the impact on decision-making with a neuropsychological battery.Method:We propose base rate analyses; specifically, differential base rates of impaired scores between theoretical and actual base rates as the basis for decisions to create demographic adjustments within normative data. Differential base rates empirically describe the potential clinical implications of failing to create an appropriate normative group. We demonstrate this approach with data from a short telephone-administered neuropsychological battery given to a large, neurologically healthy sample aged 45–85 years old. We explored whether adjustments for age and medical conditions were warranted based on differential base rates of spuriously impaired scores.Conclusions:Theoretical base rates underestimated the frequency of impaired scores in older adults and overestimated the frequency of impaired scores in younger adults, providing an evidence base for the creation of age-corrected normative data. In contrast, the number of medical conditions (numerous cardiovascular, hormonal, and metabolic conditions) was not related to differential base rates of impaired scores. Despite a small correlation between number of medical conditions and each neuropsychological variable, normative adjustments for number of medical conditions does not appear warranted. Implications for creation of normative data are discussed. [ABSTRACT FROM PUBLISHER]

Objective:We describe the implementation of cognitive measures within the Canadian Longitudinal Study on Aging (CLSA), a nationwide, epidemiological study of aging, and relate CLSA Tracking cohort data (n over 20,000) to previous studies using these measures.Method:CLSA participants (aged 45–85,nover 50,000) provided demographic, social, physical/clinical, psychological, economic, and health service utilization information relevant to health and aging through telephone interviews (Tracking cohort,nover 20,000) or in-person (i.e. Comprehensive cohort,nover 30,000) in both official languages (i.e. English, French). Cognitive measures included: the Rey Auditory Verbal Learning Test (RAVLT) – Trial 1 and five-minute delayed recall; Animal Fluency (AF), the Mental Alternation Test (MAT) (both cohorts); Controlled Oral Word Association Test, Stroop Test, Prospective Memory Test, and Choice reaction times (Comprehensive Cohort).Results:Performance on the RAVLT Trial 1 and AF were very similar to comparable groups studied previously; CLSA sample sizes were far larger. Within the CLSA Tracking cohort, main effects of age and language were observed for all cognitive measures except RAVLT delayed recall. Interaction effects (language × age) were observed for AF.Conclusion:This preliminary examination of the CLSA Tracking cognitive measures lends support to their use in large studies of aging. The CLSA has the potential to provide the ‘best’ comparison data for adult Canadians generated to date and may also be applicable more broadly. Future studies examining relations among the psychological, biological, health, lifestyle, and social measures within the CLSA will make unique contributions to understanding aging. [ABSTRACT FROM AUTHOR]

Mild cognitive impairment (MCI) manifests as memory impairment in the absence of dementia and progresses to Alzheimer's disease (AD) at a rate of around 15% per annum, versus 1-2% in the general population. It thus constitutes a primary target for investigation of early markers of AD. Language deficits occur early in AD, and performance on verbal tasks is an important diagnostic criterion for both AD and MCI. We review language performance in MCI, compare these findings to those seen in AD, and identify the primary issues in understanding language performance in MCI and selecting tasks with diagnostic and prognostic value. [ABSTRACT FROM AUTHOR]