Search

This study reports the validation of the Hong Kong version of Oxford Cognitive Screen (HK-OCS). Seventy Cantonese-speaking healthy individuals participated to establish normative data and 46 chronic stroke survivors were assessed using the HK-OCS, Albert’s Test of Visual Neglect, short test of gestural production, and Hong Kong version of the following assessments: Western Aphasia Battery, MMSE, MoCA, Modified Barthel Index, and Lawton Instrumental Activities of Daily Living scale. The validity of the HK-OCS was appraised by the difference between the two participant groups. Neurologically unimpaired individuals performed significantly better than stroke survivors on the HK-OCS. Positive and significant correlations found between cognitive subtests in the HK-OCS and related assessments indicated good concurrent validity. Excellent intra-rater and inter-rater reliabilities, fair test–retest reliability, and acceptable internal consistency suggested that the HK-OCS had good reliability. Specific HK-OCS subtests including semantics, episodic memory, number writing, and orientation were the best predictors of functional outcomes. [ABSTRACT FROM PUBLISHER]

We present an associative recognition experiment comparing three samples of healthy people (young people, older people with high cognitive reserve [HCR], and older people with low cognitive reserve [LCR], with each sample consisting of 40 people), manipulating stimuli repetition during the study phase. The results show significant differences among the three samples in their overall performance. However, these differences are not due to a different use of familiarity, but rather due to a different way of using recollection: although there are no differences in the hit rates between the HRC and LRC samples, the LCR group makes significantly more recollective false alarms than the HCR group. Moreover, repetition provokes an increase in the recollective false alarms in the LCR group, but this does not occur in the group of young people or in the HCR group. These findings are explained in terms of recollection-based monitoring errors and seem to provide support for the cognitive reserve hypothesis. [ABSTRACT FROM AUTHOR]

We compared the accuracy of the Brief Cognitive Assessment Tool—Short Form (BCAT-SF) and AD8 in identifying mild cognitive impairment (MCI) and dementia among long-term care residents. Psychometric analyses of 357 long-term care residents (n = 228, nursing home;n = 129, assisted living) in Maryland referred for neuropsychological evaluation evidenced robust internal consistency reliability and construct validity for the BCAT-SF. Furthermore, hierarchical logistic regression and receiver operating characteristic curve analyses demonstrated superior predictive validity for the BCAT-SF in identifying MCI and dementia relative to the AD8. In contrast, previously reported psychometric properties or cut scores for the AD8 could not be cross-validated in this long-term care sample. Based on these findings, the BCAT-SF appears to be a more reliable and valid screening instrument than the AD8 for rapidly identifying MCI and dementia in long-term care residents. [ABSTRACT FROM PUBLISHER]

Everyday memory lapses experienced by older adults (OAs) were examined using a daily-diary checklist and retrospective questionnaire. In Experiment 1, 138 younger and 138 OAs indicated the frequency of forgetting of 16 memory lapses, and whether each occurred daily during the course of a week. OAs reported more memory lapses on the questionnaire, but not the daily diary. OAs reported more frequently forgetting names and words, while younger adults had more difficulty with appointments and personal dates. Fewer memory lapses on the daily diary were related to better performance on a laboratory-memory measure for OAs. In Experiment 2, 62 OAs returned for a five-year follow-up and endorsed experiencing more memory lapses on the daily diary compared to baseline, specifically forgetting more names and words, but not the retrospective questionnaire. Daily checklist memory lapses again correlated with the laboratory-memory measure. A daily checklist may be a viable way to assess everyday memory lapses. [ABSTRACT FROM AUTHOR]

The purpose of this study was to estimate and examine ways to improve the reliability of change scores on the Alzheimer’s Disease Assessment Scale, Cognitive Subtest (ADAS-Cog). The sample, provided by the Alzheimer’s Disease Neuroimaging Initiative, included individuals with Alzheimer’s disease (AD) (n = 153) and individuals with mild cognitive impairment (MCI) (n = 352). All participants were administered the ADAS-Cog at baseline and 1 year, and change scores were calculated as the difference in scores over the 1-year period. Three types of change score reliabilities were estimated using multivariate generalizability. Two methods to increase change score reliability were evaluated: reweighting the subtests of the scale and adding more subtests. Reliability of ADAS-Cog change scores over 1 year was low for both the AD sample (ranging from .53 to .64) and the MCI sample (.39 to .61). Reweighting the change scores from the AD sample improved reliability (.68 to .76), but lengthening provided no useful improvement for either sample. The MCI change scores had low reliability, even with reweighting and adding additional subtests. The ADAS-Cog scores had low reliability for measuring change. Researchers using the ADAS-Cog should estimate and report reliability for their use of the change scores. The ADAS-Cog change scores are not recommended for assessment of meaningful clinical change. [ABSTRACT FROM PUBLISHER]

Exercise “stress tests” are widely used to assess cardiovascular function and to detect abnormalities. In line with the view of exercise as a stressor, the present study examined the relationship between cognitive function and cardiovascular activity before and after light physical exercise in a sample of 84 non-demented community-dwelling older adults. Based on known relationships between hypertension, executive function and cerebral white matter changes, we hypothesized that greater post-exercise reactivity, as indexed by higher pulse pressure, would be more related to worse performance on frontal-executive tasks than pre-exercise physiologic measures. All participants were administered a comprehensive neuropsychological battery and underwent a Six Minute Walk Test (6MWT), with blood pressure (BP) measures obtained immediately before and after the walk. Pulse pressure (PP) was derived from BP as an indicator of vascular auto-regulation and composite scores were computed for each cognitive domain assessed. As predicted, worse executive function scores exhibited a stronger relationship with post-exercise PP than pre-exercise PP. Results suggest that PP following system stress in the form of walking may be more reflective of the state of vascular integrity and associated executive dysfunction in older adults than baseline physiologic measures. [ABSTRACT FROM PUBLISHER]

This study examined the effects of executive control and working memory on older adults’ sentence-final word recognition. The question we addressed was the importance of executive functions to this process and how it is modulated by the predictability of the speech material. To this end, we tested 173 neurologically intact adult native English speakers aged 55–84 years. Participants were given a sentence-final word recognition test in which sentential context was manipulated and sentences were presented in different levels of babble, and multiple tests of executive functioning assessing inhibition, shifting, and efficient access to long-term memory, as well as working memory. Using a generalized linear mixed model, we found that better inhibition was associated with higher accuracy in word recognition, while increased age and greater hearing loss were associated with poorer performance. Findings are discussed in the framework of semantic control and are interpreted as supporting a theoretical view of executive control which emphasizes functional diversity among executive components. [ABSTRACT FROM PUBLISHER]

The purpose of the current study was to determine the microlinguistic processes that contribute to picture description in healthy adults across the life span. Two-hundred forty healthy adults were separated into three groups, young (n = 80; 20–39), middle (n = 80; 40–69), and older (n = 80; 70–89). Participants provided language samples in response to two single and two sequential pictures analyzed for total number of words, informativeness, lexical diversity, syntactic complexity, and main events. The older group produced a significantly lower proportion of main events for the single and sequential pictures compared to the other groups. Group differences on the microlinguistic measures varied depending on the measure and the stimulus type. Further, regardless of task, total number of words significantly related to main event production for the young and middle aged groups, but not the older group. Results of the current study extend previous findings by researchers who have investigated discourse production in cognitively healthy, older adults. Using a multi-level approach, we found that linguistic processes across different levels interact; however, the relationship is age-dependent. By including a middle-aged group we identify the potential course of documented change and our results indicate that the changes in language processes with age may not be linear. [ABSTRACT FROM PUBLISHER]

Cognitive training programs that instruct specific strategies frequently show limited transfer. Open-ended approaches can achieve greater transfer, but may fail to benefit many older adults due to age deficits in self-initiated processing. We examined whether a compromise that encourages effort at encoding without an experimenter-prescribed strategy might yield better results. Older adults completed memory training under conditions that either (1) mandated a specific strategy to increase deep, associative encoding, (2) attempted to suppress such encoding by mandating rote rehearsal, or (3) encouraged time and effort toward encoding but allowed for strategy choice. The experimenter-enforced associative encoding strategy succeeded in creating integrated representations of studied items, but training-task progress was related to pre-existing ability. Independent of condition assignment, self-reported deep encoding was associated with positive training and transfer effects, suggesting that the most beneficial outcomes occur when environmental support guiding effort is provided but participants generate their own strategies. [ABSTRACT FROM PUBLISHER]

This study examines age-associated changes in retrieval on a picture-naming task, phonemic and semantic fluency tasks, and the Homophone Meaning Generation Test (HMGT). The sample included 152 Hebrew-speaking adults, half young (mean age 22.75) and half old (mean age 76.05). Groups differed on the picture-naming task and on both verbal fluency tasks, but not on the HMGT. Age explained a greater share of the variance than did education level on these three tests, whereas the opposite pattern of results was seen on the HMGT. We suggest that age-related word finding difficulties are attenuated when performance allows for semantic rather than phonological access. [ABSTRACT FROM AUTHOR]

Recent research has suggested that age-related positivity effects are eliminated under conditions of dual-task load (Knight et al., 2007, Emotion, 7, 705; Mather & Knight, 2005, Psychology and Aging, 20, 554), because the cognitive control resources necessary to enact such preferences are not available when individuals are distracted by competing information. We further examined how older adults' emotional information processing preferences are affected by distracting information by utilizing a within-subjects dual-task measure. Younger and older adults viewed a series of positive, negative, and neutral images both in conditions of full and divided attention. Fixation preferences to valenced images were assessed through eye tracking. Regardless of whether images were viewed in full or divided attention conditions, older adults demonstrated a preference in their fixation for positive and neutral in comparison to negative images. These results provide evidence that older adults' positive fixation preferences may not always necessitate full, cognitive control. [ABSTRACT FROM AUTHOR]

Impairments in visual attention and visual information processing have been identified as part of the neuropsychological features of Alzheimer's disease (AD), even in its earliest stages. There is increasing recognition that these deficits may be selective rather than global, with some attentional subtypes being more vulnerable than others. The few studies that have investigated attentional deficits in mild cognitive impairment (MCI), a putatively prodromal phase of AD, have not satisfactorily addressed the possible selectivity in attentional deficits in MCI. This study examined potential dissociations in visual attention deficits in MCI using a measure that assesses simple, divided, and selective attention. The results indicated a hierarchy of attentional impairments, with divided attention being the most affected and simple attention the least. Among participants with MCI, 53% showed evidence of impairment in divided attention compared to 19% of controls (OR = 4.81, p < .001). Poorer visual attention was also associated with poorer overall cognitive status. The implications of these findings for early identification of MCI, prevention of functional decline in MCI, and delay/reversal of cognitive degradation in MCI are discussed. [ABSTRACT FROM AUTHOR]

In cognitive skill learning, shifts to better strategies for obtaining solutions often occur while associations between problems and solutions are being strengthened. In two skill learning experiments, we examined the effects of item difficulty on the retrieval of solutions and the learning of problem-solution associations in younger and older adults. The results of both experiments demonstrated an 'easy effect' in both younger and older adults, such that the retrieval of solutions as well recognition memory for problems was best for the easier items. In addition, a 'hard effect' was found in younger adults, but not in older adults, whereby the retrieval of solutions as well as recognition memory for problems was better for harder items than for medium-difficulty items. The finding that increased computational demands at the item level delayed item memorization and the retrieval of solutions in older adults but not younger adults is consistent with a general-resources account of age-related differences in skill learning. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the relationship between force control and cognitive performance under dual-task conditions in younger (18–22 years) and older adults (65–77 years). Cognitive (n-back test) and motor performance (force-tracking) was measured independently and simultaneously. Results indicated overall age-related differences for the n-back and the force-tracking task. Age-related differences increased during dual-task conditions. While younger adults exhibited no decrease in cognitive or motor performance during dual-task conditions, older adults showed a decrease in motor and cognitive performance. Additionally, when older adults made an error in the cognitive task they tended to show greater variability in the force-tracking task. These results suggest that cognitive motor deficits are responsible for older adults' performance decrements under dual-task conditions. [ABSTRACT FROM AUTHOR]