Interacting effects of age and time of day on verbal fluency performance and intraindividual variability.

We explored the effects of age and time of day (TOD) on verbal fluency ability with respect to performance level and intraindividual variability (IIV). Verbal fluency, which involves complex cognitive operations, was examined in 20 older (mean age = 72.8 years) and 20 younger (mean age = 24.2 years) adults with test start time alternating between morning and evening across four days. Older adults generated more words in the morning and younger adults more in the evening, corresponding with self-report peak TOD. Age by TOD interactions were also observed across fluency tasks on the number of switches among subcategory exemplars during word generation and on the IIV observed in switching behavior. Older adults exhibited greater variability in switching in the evening than in the morning, whereas younger adults showed the opposite pattern. These findings demonstrate that processes involving energization (initiating and sustaining) and attentional control may be particularly sensitive to age differences in TOD influences on cognition.

The role of working memory and divided attention in metaphor interpretation.

Although several types of figurative language exist, neuropsychological tests of non-literal language have focused on proverbs. Metaphors in the form X is (a) Y (e.g., The body's immunological response is a battle against disease.) place a lower demand on language skills and are more easily manipulated for novelty than proverbs. Forty healthy participants completed the Metaphor Interpretation Test (developed by the authors). The task includes 20 items chosen from a list of metaphors that were rated on several scales (e.g. imagery, aptness) in a study by Katz et al. (Metaphor Symb Act 3(4):191-214, 1988). Participants were asked to rate the familiarity and provide an explanation of each metaphor. A scoring system was developed to categorize answers into: abstract complete (AC), abstract partial (AP), concrete (CT), and other/unrelated (OT) types. Participants also completed short-term memory and divided attention tests. Overall, participants produced 56 % AC, 25.38 % AP, 7.88 % CT, and 10.88 % OT responses. It was found that a measure of verbal short-term memory span was the best predictor of performance on this task (adjusted R(2) = .369). It appears that short-term memory span, not working memory or divided attention, contributes most to providing abstract responses in explaining metaphors. This is in line with the idea that when one accesses the semantic network associated with a novel metaphor, one must hold this information in mind long enough to search for and link similar cognitive networks.

Adult chronic kidney disease: neurocognition in chronic renal failure.

In recent years there has been a keen interest in the neurocognitive sequelae of renal failure and subsequent end-stage renal disease given its increasing prevalence and incidence. This review article summarizes the relevant information on cognitive functioning in chronic kidney disease in adults before the initiation of dialysis, after the initiation of dialysis, and after renal transplantation. In general, compared to pre-dialysis, there is an improvement in cognitive function after the institution of dialysis and further improvement after renal transplantation. Throughout the paper an attempt is made to highlight the importance of considering disease related variables in the neuropsychological assessment of individuals with chronic kidney disease. The paper concludes with a discussion of future avenues of research.

Developing a spatial analogue of the reliable digit span.

It is recommended that performance validity be assessed in all neuropsychological cases involving external incentive. The present study sought to develop an embedded performance validity measure based on the Spatial Span task of the Wechsler Memory Scale-III in a sample of litigating persistent postconcussion complainants. The Reliable Spatial Span (RSS) calculation had specificity, sensitivity, and predictive power values within the range of other embedded measures. This finding suggests that RSS is able to distinguish between persistent postconcussion complainants demonstrating valid and invalid performance. Other calculations involving Spatial Span scores had lower classification accuracy. Reliable Digit Span (RDS) classification accuracy within the present sample was lower than that of previous research, as well as of RSS. Potential reasons for lack of RDS replication are discussed, along with the potential use of RSS as an embedded validity performance indicator.

Older adults and capacity-related assessment: promise and caution.

Data from 30 cognitively intact and emotionally stable Canadian elders provided support for the construct validity of the Hopemont Capacity Assessment Instrument and the Independent Living Scales. Subscale scores in the health or financial domains on these two capacity-related instruments were moderately correlated; weaker correlations were observed between ILS and HCAI subscales tapping discrepant domains. Training in thinking aloud and responding to hypothetical questions did not affect scores on these measures, nor were scores on brief depression and anxiety scales statistically associated with standing on capacity-related measures. Reading comprehension was associated with scores on the Hopemont Capacity Assessment Instrument.

Early cognitive outcome after neonatal stroke.

The purpose of this study was to assess the cognitive development of 27 children with nonhemorrhagic neonatal stroke (occurring within the first 28 days of life). The cognitive evaluation consisted of the Bayley Scales of Infant Development, administered at 12 and/or 24 months poststroke. Compared with the normative sample, children with neonatal stroke obtained significantly lower scores on the Bayley Psychomotor Development Index at 12 months poststroke and on the Bayley Mental and Psychomotor Development Indices at 24 months poststroke. Outcome did not differ based on stroke type or laterality of infarct. However, there was a trend toward higher scores on the Bayley Psychomotor Development Index at 24 months in the left hemisphere group compared to the right hemisphere group. Overall, children with neonatal stroke evidenced significant impairment within the first 2 years poststroke. Further research is required to confirm whether cognitive impairments in these children resolve, remain in the low-average range, or increase with development as more complex skills are learned.

Standard measures of executive function in predicting instrumental activities of daily living in older adults.

OBJECTIVE: The purpose of this study was to examine the ability of specific, commonly used neuropsychological tests of executive function to predict functional status among a group of elderly subjects. METHODS: Fifty study participants underwent a brief neuropsychological evaluation of executive functions and assessment of instrumental activities of daily living (IADL). RESULTS: A multiple stepwise regression analysis indicated that executive function tests accounted for 54% of the variance in functional status. An examination of the standardized regression coefficients revealed that Trail Making Test-Part B and the Wisconsin Card Sorting Test were the only two of the five executive function tests that significantly predicted functional status. These executive function measures contributed significantly to the prediction of functional status even after statistically controlling for age, sex, and education. CONCLUSION: Thus, the common clinical measures of executive function are useful in predicting functional status in older adults.