Individuals are living longer now than they have in the past. As a result, there is an increased incidence in illnesses that are more prevalent in later life. One group of illnesses that is more prevalent is age related dementia. Alzheimer's disease (AD) and vascular dementia (VaD) are two common types of dementia found in the older adult population. Recent research suggests that these two types of dementia may both have a vascular component that is instrumental in their development. Not only may this vascular component be present in both these illnesses, but also it may be related to a more severe cognitive decline in the aging process. Results indicate that both cardiovascular disease and general and spousal social support in middle age are all three independent significant predictors of mild cognitive impairment and other non-normative cognitive impairment in later life. However, results do not indicate that social support moderates the relationship between cardiovascular disease and cognition.

The number of adults in the United States who are age 65 or older is rapidly increasing. With longer lifespan comes an increase in chronic diseases such as dementia, diabetes, and depression. This study used archival data from a larger study conducted at the Memory Clinic at John Peter Smith County Hospital in Ft. Worth, Texas to examine several hypotheses and research questions related to the influence of type of dementia, presence of Type II diabetes, and presence of depression on neuropsychological test performance. First, this study attempted to identify specific patterns of performance on neuropsychological measures for those with Alzheimer's dementia (AD), vascular dementia (VaD), or mild cognitive impairment (MCI). The results indicated that those with MCI perform better than those with AD or VaD on all neuropsychological measures, and that those with VaD perform better than those with AD on a measure of verbal memory. Another purpose of the study was to determine how the presence of Type II diabetes affects this pattern of functioning; the overall finding in this study was that the presence or absence of diabetes did not affect performance on measures of cognitive functioning. Additionally, the study attempted to add to literature examining the influence of depression on older adults with diabetes and/or dementia; no significant differences emerged.

Indiana University-Purdue University Indianapolis (IUPUI) / Dementia studies often collect multiple longitudinal neuropsychological measures in order to examine patients' decline across a number of cognitive domains. Dementia patients have shown considerable heterogeneities in individual trajectories of cognitive decline, with some patients showing rapid decline following diagnoses while others exhibiting slower decline or remain stable for several years. In the first part of this dissertation, a multivariate finite mixture latent trajectory model was proposed to identify longitudinal patterns of cognitive decline in multiple cognitive domains with multiple tests within each domain. The expectation-maximization (EM) algorithm was implemented for parameter estimation and posterior probabilities were estimated based on the model to predict latent class membership. Simulation studies demonstrated satisfactory performance of the proposed approach. In the second part, a simulation study was performed to compare the performance of information-based criteria on the selection of the number of latent classes. Commonly used model selection criteria including the Akaike information criterion (AIC), Bayesian information criterion (BIC), as well as consistent AIC (CAIC), sample adjusted BIC (SABIC) and the integrated classification likelihood criteria (ICLBIC) were included in the comparison. SABIC performed uniformly better in all simulation scenarios and hence was the preferred criterion for our proposed model. In the third part of the dissertation, the multivariate finite mixture latent trajectory model was extended to situations where the true latent class membership was known for a subset of patients. The proposed models were used to analyze data from the Uniform Data Set (UDS) collected from Alzheimer's Disease Centers across the country to identify various cognitive decline patterns among patients with dementia.

Thesis (M.S.)--University of Michigan, 1993.

Thesis (M.S.)--University of Michigan, 1993.

Thesis (M.S.)--University of Michigan, 1993.

Thesis (M.S.)--University of Michigan, 1993.

The Aronson Cognitive Residual Evaluation Scale (ACRES) is a new, relatively short neuropsychological test which attempts to measure residual cognitive skills. This study evaluated the ACRES test-retest reliability over a one to twelve month interval. The Trail Making Test (TMT) was included as a validation measure. Subjects were 58 males and females, aged 68 to 94, living in a retirement center or in the community. The ACRES exhibited moderate to strong reliability correlations and the TMT demonstrated low to moderate correlations with the ACRES. There was no time interval effect. Age had a negative effect on four of five ACRES subtests and gender was significant for one ACRES subtest and the TMT Part B. Percent of subjects classified as brain impaired using traditional cutoffs was higher than when age-corrected norms were used. Clinical utility of the ACRES and the TMT is discussed regarding need for age-corrected norms.

The present study investigated the criterion-based validity of the Mini-Mental State Examination (MMSE), the Cognitive Capacity Screening Examination (CCSE), and the Neurobehavioral Cognitive Status Examination (NCSE) in a sample of older adults with suspected cognitive impairment. As cognitive screening tests, the MMSE, CCSE, and NCSE should predict performance relative to a more thorough testing procedure. In the present study, performance on the Halstead-Reitan Neuropsychological Test Battery (HRNTB) was employed as the criterion measure. Scores on the General Neuropsychological Deficit Scale (G-NDS), a global performance measure computed from the HRNTB, served as the standard by which to judge the presence of cognitive impairment. The sensitivity, specificity, and predictive value of each screening test, as well as how well each screening test correlated with the G-NDS, were investigated. Results of this investigation found that, although the MMSE, CCSE, and NCSE were all significantly correlated with the G-NDS, only the NCSE demonstrated an appropriate balance between high sensitivity and specificity. When a rigorous neuropsychological evaluation was employed as the criterion standard, the NCSE accurately detected the presence of cognitive impairment: in 82% of the cases. The MMSE and CCSE, however, failed to detect cognitive deficits in approximately 80% of the cases. These findings strongly suggest that the MMSE and CCSE may have limited utility in the identification of cognitive impairment in older adults. The heightened sensitivity of the NCSE appears to be the result of several unigue features of the instrument, including a multidimensional scoring system and a graded series of increasingly difficult items within each ability area. Future studies need to examine the utility of the NCSE in other geriatric settings, as well as with more diverse populations suffering from a variety of organic mental syndromes.

The presence of cognitive deficits in obstructive sleep apnea (OSA) is well-documented. Specifically, short- and long-term memory, attention/vigilance, and executive function (e.g. processing speed, mental flexibility, and problem solving) are affected. Cognitive deficits in aging occur in similar areas (i.e., memory and processing speed). Given that a greater percentage of older adults experience sleep-disordered breathing as compared to middle-aged adults, it is possible that OSA may account for some of the deficits typically attributed to aging. This study investigated this hypothesis by comparing middle-aged and older adults with and without OSA on computer-based measures of cognitive performance. No effect of OSA or an interaction between OSA and age on cognitive function was found; an effect of age on processing speed, distinguishing stimuli rapidly, attention, spatial ability/mental flexibility, and both working memory and short-term visual memory was found. This study also explored whether or not cognitive function may be improved in persons with OSA by re-assessing those participants one month after treatment. An effect of treatment on improvements on processing speed, distinguishing stimuli rapidly, mental flexibility, and short term memory was found. Overall, findings reflect the ability of treatment to improve cognitive function among OSA patients, regardless of lack of deficits when compared to those without OSA.