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1.  Recent Clinical History and Cognitive Dysfunction for Attention and Executive Function among Human Immunodeficiency Virus-Infected Patients 
This study examined the association between recent trends in CD4 and viral loads and cognitive test performance with the expectation that recent history could predict cognitive performance. Eighty-three human immunodeficiency virus (HIV)-infected patients with a mean CD4 count of 428 copies/ml were examined in this study (62% with undetectable plasma viral load [PVL]). We investigated the relationships between nadir CD4 cell count, 1-year trends in immunologic function/PVLs, and cognitive performance across several domains using linear regression models. Nadir CD4 cell count was predictive of current executive function (p = .004). One year clinical history for CD4 cell counts and/or PVLs were predictive of executive function, attention/working memory, and learning/memory measures (p < .05). Models that combined recent clinical history trends and nadir CD4 cell counts suggested that recent clinical trends were more important in predicting current cognitive performance for all domains except executive function. This research suggests that recent CD4 and viral load history is an important predictor of current cognitive function across several cognitive domains. If validated, clinical variables and cognitive dysfunction models may improve our understanding of the dynamic relationships between disease evolution and progression and CNS involvement.
doi:10.1093/arclin/acr065
PMCID: PMC3243921  PMID: 21873325
HIV; Cognition; Neuropsychology; Executive function; Recent clinical history
2.  Category and letter verbal fluency across the adult lifespan: relationship to EEG theta power 
The purpose of this study was to examine the impact of age, sex, and education on category and letter verbal fluency task performance. A secondary goal was to examine whether resting EEG theta power in bilateral frontal and temporal lobes impacts age-associated decline in verbal fluency task performance. A large sample (N=471) of healthy, normal participants, age 21–82, was assessed for letter fluency (i.e., FAS), and for category fluency (i.e., Animal Naming), and with a 32-channel EEG system for ‘eyes-open’ resting theta power. The effects of age, sex, and education were examined using analyses of variance. Correlation analyses were used to test the impact of theta power on age and fluency performance by controlling for the effects of theta when examining the relationship between the other two variables. The results indicated that performance on both fluency tests declined linearly with age, but that the rate of decline was greater for category fluency. These age changes were not associated with education level, and there were no sex differences. While theta power was negatively associated with age and positively associated with Animal Naming performance, it did not moderate the relationship between the two. The differential age-associated decline between category and letter fluency suggests separate neurobiological substrates underlying the two domains of performance, which is not related to theta activity.
doi:10.1016/j.acn.2004.12.006
PMCID: PMC2758771  PMID: 15939182
Normal aging; Category fluency; Letter fluency; EEG; Theta
3.  Evaluating elements of executive functioning as predictors of instrumental activities of daily living (IADLs) 
OBJECTIVE
Executive functioning has been repeatedly linked to the integrity of instrumental activities of daily living (IADL). The present study examined the association of multiple executive functioning elements (i.e., working memory, generation, inhibition, planning, and sequencing) to IADLs among an older adult cohort at risk for future cognitive and functional decline.
METHODS
Seventy-two participants with prevalent but stable cardiovascular disease completed a neuropsychological protocol assessing multiple elements of executive functioning, including COWA, PASAT, DKEFS Color-Word Interference Test, DKEFS Trail-Making Test, DKEFS Tower Test, and Ruff Figural Fluency Test. Reliable informants completed a measure of IADLs.
RESULTS
Stepwise logistic regression selected a model involving a single significant predictor, a measure of inhibition (i.e., DKEFS Color-Word Interference Test), which had a significant regression coefficient. Subsequent correlation analyses confirmed an association between the inhibition measure and multiple IADL items. Inter-item comparisons among the IADLs revealed significant differences, such that telephone use and laundry were significantly more intact than most other IADLs while shopping and housekeeping were most compromised.
CONCLUSIONS
Our data suggest that inhibition, also known as susceptibility to interference, is most strongly related to IADL impairment among patients at risk for future cognitive and functional decline.
doi:10.1016/j.acn.2006.03.007
PMCID: PMC2746400  PMID: 16814980
Cardiovascular disease; Neuropsychology; Cognition; Executive functioning; Instrumental activities of daily living (IADLs); Delis-Kaplan Executive Function System (D-KEFS); Inhibition; Geriatric
4.  Subcortical hyperintensities impact cognitive function among a select subset of healthy elderly 
Previous studies have examined the impact of subcortical hyperintensities (SH), a proxy measure of cerebrovascular disease, on the cognitive abilities of otherwise healthy older adults. However, there remains a limited understanding as to what extent this MRI marker of pathological processes explains the decline in specific cognitive functions that occur nearly ubiquitously with advanced age, especially in relation to other age-related imaging markers. In the present study we compared cognitive abilities between a sample of 53 older healthy adults (age range = 50–79) and a sample of 53 younger adults (age range = 21–40). As expected, the older group performed significantly worse on most cognitive measures compared to the younger group. Frontal volume and total grey matter volume were also significantly reduced among the older individuals compared to the younger individuals. SH volume was consistently associated with cognitive function in older adults, though, this relationship was evident only for a relatively small subset of older individuals with the most severe SH. These data suggest that the relationship between SH and cognition in the elderly is driven by a subset of individuals who may be in the earliest stages of vascular cognitive impairment. Further, the findings suggest that cognitive aging is largely determined by factors other than SH for most older adults.
doi:10.1016/j.acn.2005.02.004
PMCID: PMC2733246  PMID: 15941646
Subcortical hyperintensities; Cognition; Elderly; MRI

Results 1-4 (4)