In a community-based sample of older, medically complicated patients with dementia, there are neuropsychological differences between dementia subtypes at the time of diagnosis. In particular, patients with Alzheimer disease (AD) alone and AD/Lewy body pathology (LBP) had more severe memory impairment than patients with LBP. LBP alone was associated with more severe executive dysfunction. Patients with AD/LBP had the most rapid rate of cognitive decline.

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The ability to engage in instrumental activities of daily living (IADLs) is known to rely on cognitive abilities, primarily executive functioning and memory. There is also evidence that good self-awareness, which facilitates the use of compensatory strategies, may prolong functionality and delay the diagnosis of dementia. However, little is known about the mechanisms that mediate self-awareness among healthy elderly. The present study examined the correlates of discrepancies between self-report and performance-based measures of IADLs in a sample of 75 community-dwelling elderly. The results indicate that even among independently living individuals, there is still variability in functionality (i.e., 35% of the sample made IADL performance errors) and self-awareness (i.e., 38% of the sample demonstrated a discrepancy between IADL self-report and performances). Better awareness of IADL weaknesses was associated with higher levels of cognitive reserve but, unexpectedly, lower levels of executive abilities. Additionally, consistent with prior research, better IADL performances were associated with better cognition.

Self-reports of the ability to engage in instrumental activities of daily living (IADLs) among older adults are known to be related to personality traits. However, self-reports are sometimes discrepant with performance-based IADL assessments, and little is known about personality associations with objective functionality or with poor insight about functional deficits. This study examined the NEO Personality Inventory-Revised profiles associated with (a) self-report of functional problems, (b) functional errors evidenced on performance-based IADL assessment, and (c) discrepancies between self-report and performance. Participants were 65 community-dwelling individuals ranging in age from 60 to 87 years. The results showed that self-report of IADL problems are associated with higher neuroticism and lower conscientiousness, actual IADL difficulties with higher neuroticism and lower agreeableness and openness to experience, underreporting of problems with higher conscientiousness, and overreporting of problems with higher extraversion and neuroticism. These relationships were partly mediated by age, education, and cognitive status. When unique personality associations with self-report and performance were examined, neuroticism and agreeableness, respectively, emerged as the strongest predictors.

The relationship between executive functioning and three components of motor programming (motor control, motor planning, and motor learning) was examined. Participants were 54 adults aged 18 to 68 years. Instruments included the Push-Turn-Taptap task from the Behavioral Dyscontrol Scale-Electronic Version and a battery of traditional neuropsychological measures. The results showed that, after controlling for age, processing speed, and motor speed, all three components of motor programming accounted for additional 12 to 19% of variance in executive functioning. Additionally, task complexity, but not task novelty, accounted for the relationship between executive functioning and motor learning and motor control, but not motor planning.

Practice Effects (PE) have been gaining interest as an early marker of pathological cognitive decline among older adults, with cognitively compromised individuals exhibiting diminished or absent PE, presumably due to reduced ability to learn. However, the opposite pattern has also been observed, with MCI participants showing larger PEs than controls. In this prospective cohort study, we examined the possibility that individuals with incipient cognitive decline may be more "thrown" by task novelty, which may inflate PE due to diminished performance during the first exposure to the task. We assessed Novelty Effect (NE) and Learning (LRN) on a motor task in 50 community-dwelling independent older adults who expressed a concern about their cognition. Results showed that larger NE was associated with greater cognitive decline 17 months later, reliably classifying participants into decliners and nondecliners. LRN did not independently explain any variance in future cognitive change, but moderated the relationship between NE and decline and correlated with the level of cognition at baseline and follow-up. These findings highlight the differing contributions of NE and LRN to PE, and demonstrate that NE may be sensitive to depletion of cognitive reserve among individuals who are on the verge of exhibiting a reliable cognitive decline.

Design Fluency (DF) is typically assumed to assess planning, cognitive flexibility, and fluency in generation of visual patterns, above and beyond contributions from motor speed (Delis, Kaplan, & Kramer, 2001; Ruff, 1998). The present study examined these assumptions, as little construct validation research has been done in the past. Sixty one community-dwelling elderly participants were administered the DF, Trail Making, and Letter Fluency tests from the Delis-Kaplan Executive Function System (D-KEFS), as well as electronically administered measures of motor planning and motor sequence fluency. Hierarchical regressions were used to parse out unique variance contributions to DF performance. The results showed that generation of novel designs (i.e., the first two trials on the D-KEFS DF) relied primarily on motor planning, the ability to generate novel motor actions, and, to a lesser extent, speed of drawing with a writing implement. In contrast, generation of unique designs while switching (i.e., the third trial on the D-KEFS DF) relied primarily on visual scanning and perhaps visual-attentional resources. These findings highlight the wisdom of interpreting the switching trial of the D-KEFS DF separately. Interestingly, cognitive flexibility did not contribute to performance on any of the three D-KEFS DF trials.

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