Reporting source bias in estimating prevalence of cognitive impairment.

Reporting source bias was examined using cognitive data from a probability sample of adult day health care (ADHC) clients. Data were obtained from four sources: client, family, staff, and chart. These data suggest that prevalence estimates are influenced by the reporting source and method of assessment, with chart diagnoses yielding the least convergent estimates. Examination of agreement summary statistics and bias indices show that both staff and family underreport prevalence of cognitive impairment, but that more bias is associated with staff than is with family sources. Such bias should be considered in studies of prevalence estimation of cognitive impairment.

Item bias in cognitive screening measures: comparisons of elderly white, Afro-American, Hispanic and high and low education subgroups.

A study of item bias in standard cognitive screening measures was conducted in a sample of Afro-American, Hispanic and non-Hispanic white elderly respondents who were part of a dementia case registry study. The methods of item-response theory were applied to identify biased items. Both cross-cultural and high and low education groups were examined to determine which items were biased. Out of 50 cognitive items examined from six widely used cognitive screening measures, 16 were identified as biased for either high and low education groups or ethnic/racial group membership.

Increased serum mitogenic activity for arterial smooth muscle cells associated with relaxation and low educational level in human subjects with high but not low hostility traits: implications for atherogenesis.

Proliferation of arterial smooth muscle cells (aSMC) is a key component of atherogenesis. A sample of 225 volunteers, aged 21-65 years, was exposed to "frustration," "harassment," or "relaxation," after completing the 50-item Hostility subscale of the Minnesota Multiphasic Personality Inventory (MMPI). Whole blood was measured before and after exposure for platelet-derived growth factor (PDGF), and sera were evaluated for total and HDL cholesterol concentrations and PDGF-independent mitogenic activity (SMA). Blood pressure and pulse rate were also evaluated. Analyses of SMA (i.e., serum independent of PDGF) revealed an increase in mitogenic effect for cultured human aSMC when hostility was treated as a dichotomous modifier. Among high-hostility subjects, surprisingly, those in the relaxed group and those with a lower educational level were found to have a significant mitogen response; no significant effects were observed for the low-hostility groups. The data suggest that endogenous stresses may occur in high-hostility individuals when "relaxed," to influence proliferation of arterial smooth muscle cells, as a contribution to atherogenesis. In individuals with lower educational levels and higher hostility scores, lifestyle changes may play a role.

An evaluation of the effects of commingling cognitively and noncognitively impaired individuals in long-term care facilities.

A sample of 77 noncognitively impaired individuals residing in integrated long-term care units housing both demented and nondemented residents were assessed in terms of morale and satisfaction with their environment and with life. One third of these individuals lived near and/or shared a bathroom with a cognitively and/or behaviorally impaired individual. Residents placed next to demented individuals had significantly fewer kin contacts, were more likely to be unmarried or never married, and were more dissatisfied with their roommate/living situation.

Factors differentiating hospital transfers from long-term care facilities with high and low transfer rates.

This paper examines the factors that account for differences among nursing homes in terms of the rates at which they transfer patients to hospitals. Data from nursing staff and charts were collected on the 286 most recent transfers from 10 nursing homes. Discriminant function analyses indicated that from relatively equivalent patient populations, high-rate facilities tended to transfer the more chronically ill, physically frail patients; patients with infection (a potentially treatable condition within the long-term care facility); and to make transfers because of lack of resources such as a lab and X-ray equipment. Lack of IV therapy, while a frequently cited primary nonmedical reason for transfer, did not discriminate between high- and low-transfer-rate facilities.

Prevalence of behavior disorder and disturbance to family and staff in a sample of adult day health care clients.

Latent class-derived prevalence estimates of behavior disorder are provided for adult day health care (ADHC) clients; informal and formal caregivers reported 11% and 14%, respectively, of these clients as engaging in severe disturbed behavior (95% confidence intervals across sources are from 7% to 18%). The prevalences, estimated for informal and formal caregivers respectively, were 12% and 16% for affective disorder, 15% and 18% for cognitive disorders, 16% and 13% for verbal-vocal agitation, and 6% and 8% for socially inappropriate behavior. These rates can be contrasted with those of the institutional population which, while higher, overlap with the distribution of behavior disorder for ADHC community residents. The degree of reported disturbance to family and staff was similar across items.

Depression in nursing home residents.

Although their extent remains unclear, major and minor depressions are widespread in the nursing home population. This statement appears intuitively to be correct when consideration is given to the inactivity, decline in functional competence, loss of personal autonomy, and unavoidable confrontation with the process of death and dying that are associated with nursing home placement. In addition, some nursing home residents have had previous episodes of depression or are admitted to the facility already dysthymic or with other chronic forms of the illness. Such circumstances provide a favorable culture for the development and persistence of depressive illness. When the high frequency of other psychiatric disorders among nursing home residents is factored in, it is not surprising that long-term health care facilities have come to be regarded as de facto psychiatric hospitals. Nursing homes largely lack the treatment resources of psychiatric hospitals, however. Nursing home physicians are often unprepared to make psychiatric diagnoses, and a perfunctory annual psychiatric evaluation is insufficient to manage the complex depression syndromes of nursing home residents. Because nursing home psychiatrists typically work on a consultation basis, recommendations are not necessarily acted upon by the primary physicians. The consequences of undiagnosed and untreated depression are substantial. From the psychiatric perspective, the possibility that depression increases the risk for eventual development of permanent dementia highlights the importance of early identification for cases of reversible dementia. From the rehabilitation point of view, persistent depression among individuals with physical dependency following a catastrophic illness is associated with failure to improve in physical functioning. Depression can probably be linked to increased medical morbidity in nursing home residents, a relationship that also has been suggested for elderly medical inpatients. If so, the use of nursing time and other health-care facility services would be greater for depressed than nondepressed residents, and financial costs would be higher as well. Finally, recent data point to increased mortality in nursing home residents with major depressive disorder. It is apparent that depression in long-term care facilities is a condition with doubtful prognosis and negative medical, social, and financial consequences. The highest costs of all may be paid by nursing home residents who experience the unrelieved suffering of depressive illness. Only epidemiologic research using standard diagnostic criteria and direct resident assessment will adequately establish the magnitude of the need for intervention among depressed residents in long-term care.(ABSTRACT TRUNCATED AT 400 WORDS)

Improved diabetes control in the elderly delays global cognitive decline.

OBJECTIVES: To examine whether improved diabetes control is related to better cognitive outcomes. DESIGN: Randomized control trial. SETTING: A randomized trial of telemedicine vs. usual care in elderly persons with type 2 diabetes. PARTICIPANTS: Participants were 2169 persons 55 years and older with type 2 diabetes from New York City and Upstate New York. INTERVENTION: The diabetes case management intervention was implemented by a diabetes nurse, via a telemedicine unit in the participant's home, and in coordination with the primary care physician. MEASUREMENTS: Hemoglobin A1c (HbA1c), systolic blood pressure (SBP), and low density lipoprotein cholesterol (LDL), were measured at a baseline visit and at up to 5 annual follow-up visits. Global cognition was measured at those visits with the Comprehensive Assessment and Referral Evaluation (CARE). RESULT: In mixed models the intervention was related to slower global cognitive decline in the intervention group (p = 0.01). Improvements in HbA1c (p = 0.03), but not SBP or LDL, mediated the effect of the intervention on cognitive decline. CONCLUSION: Improved diabetes control in the elderly following existing guidelines through a telemedicine intervention was associated with less global cognitive decline. The main mediator of this effect seemed to be improvements in HbA1c.

Reading ability, education, and cognitive status assessment among older adults in Harlem, New York City.

OBJECTIVES: This study examined reported level of education and current reading ability as predictors of cognitive status among older African Americans in central Harlem, New York City. METHODS: A probability sample of 164 noninstitutionalized older African Americans was assessed. Mini-Mental State Examination (MMSE) scores were regressed on education and reading ability measures. RESULTS: Reading ability and educational attainment were significant, independent predictors of MMSE performance. Within any level of education, subjects whose grade-equivalent reading ability exceeded reported level of education scored significantly higher on the MMSE. CONCLUSIONS: Reading ability may be useful in interpreting the results of cognitive screening among low-educated and minority groups.

Methodological issues in cognitive assessment and their impact on outcome measurement.

Assessment of cognitive impairment in chronic care populations is complicated by several factors that may interfere with the assessment process: physical frailty and disability; comorbid conditions such as depression; and decrements in vision, hearing, speech, and general communication. Moreover, cognitive impairment itself affects assessment of outcome domains such as depression, behavior, and function, thus contributing to several sources of measurement bias. Sources of bias are discussed in the context of findings from the literature relating individual and cognitive factors to outcome measurement. Recommendations for further methodological research are provided.

The physical well-being of old homeless men.

This study addressed a variety of issues related to the etiology, prevalence, and treatment of physical disorders among aging homeless men. The sample consisted of 195 nonstreet dwellers (177 residing in flophouses, 18 in apartments) and 86 street dwellers on the Bowery in New York City. The sample comprised men aged 50 and older. Bowery men scored worse than an aged-matched sample of community men on all physical health scales, with the greatest differences occurring in the respiratory, gastrointestinal, edema, hearing, hypertension, and ambulatory scales. Frequency of visits to doctors by the Bowery men was comparable to that of the community men, and the Bowery men rated their health substantially better than did their counterparts of two decades ago. Poor physical health often appeared to antedate arrival on the Bowery. However, a hierarchical regression analysis identified several variables--stress, unfulfilled needs, being relatively young, institutional/agency contacts--that were associated with current levels of poor health. Identification of these variables pointed to areas that warrant closer attention by clinicians and service providers.

Modelling the decline pattern in functional measures from a prevalent cohort study.

In studying decline among cognitively impaired people, a prevalent cohort study design is commonly used to account for entry into the study at different levels of impairment. The data set typically consists of many short series of repeated measurements collected over time. However, the time origin, such as time of disease/impairment onset, is often uncertain. In order to model non-linear decline patterns in functional test scores and associated risk factors with such data, we propose two approaches as alternatives to Liu et al. One approach models change over adjacent visits with varying time intervals. The second models the change since baseline using a random effect for heterogeneity of change. We used these two approaches to examine the decline in cognitive test scores among special care unit (SCU) and non-SCU residents at the New York sites of the National Institute on Aging (NIA) collaborative studies of special dementia care. The analyses suggest that, controlling for several covariates, SCU residents experienced more rapid cognitive decline than did non-SCU residents. The relative advantages and disadvantages of the two models are discussed.

Modern psychometric methods for detection of differential item functioning: application to cognitive assessment measures.

Cognitive screening tests and items have been found to perform differently across groups that differ in terms of education, ethnicity and race. Despite the profound implications that such bias holds for studies in the epidemiology of dementia, little research has been conducted in this area. Using the methods of modern psychometric theory (in addition to those of classical test theory), we examined the performance of the Attention subscale of the Mattis Dementia Rating Scale. Several item response theory models, including the two- and three-parameter dichotomous response logistic model, as well as a polytomous response model were compared. (Log-likelihood ratio tests showed that the three-parameter model was not an improvement over the two-parameter model.) Data were collected as part of the ten-study National Institute on Aging Collaborative investigation of special dementia care in institutional settings. The subscale KR-20 estimate for this sample was 0.92. IRT model-based reliability estimates, provided at several points along the latent attribute, ranged from 0.65 to 0.97; the measure was least precise at the less disabled tail of the distribution. Most items performed in similar fashion across education groups; the item characteristic curves were almost identical, indicating little or no differential item functioning (DIF). However, four items were problematic. One item (digit span backwards) demonstrated a large error term in the confirmatory factor analysis; item-fit chi-square statistics developed using BIMAIN confirm this result for the IRT models. Further, the discrimination parameter for that item was low for all education subgroups. Generally, persons with the highest education had a greater probability of passing the item for most levels of theta. Model-based tests of DIF using MULTILOG identified three other items with significant, albeit small, DIF. One item, for example, showed non-uniform DIF in that at the impaired tail of the latent distribution, persons with higher education had a higher probability of correctly responding to the item than did lower education groups, but at less impaired levels, they had a lower probability of a correct response than did lower education groups. Another method of detection identified this item as having DIF (unsigned area statistic=3.05, p<0.01, and 2.96, p<0.01). On average, across the entire score range, the lower education group's probability of answering the item correctly was 0.11 higher than the higher education group's probability. A cross-validation with larger subgroups confirmed the overall result of little DIF for this measure. The methods used for detecting differential item functioning (which may, in turn, be indicative of bias) were applied to a neuropsychological subtest. These methods have been used previously to examine bias in screening measures across education and ethnic and racial subgroups. In addition to the important epidemiological applications of ensuring that screening measures and neuropsychological tests used in diagnoses are free of bias so that more culture-fair classifications will result, these methods are also useful for the examination of site differences in large multi-site clinical trials. It is recommended that these methods receive wider attention in the medical statistical literature.

The human element in survey research.

This paper addresses itself to issues related to data collection in survey research with a community population. Areas discussed related to practical human problems in conducting a community survey of a stratified random sample of people sixty-five years of age and over in New York City. Some of these problems occur in most large scale community surveys, but some are a result of special features of this particular study. Topics covered include difficulties encountered in obtaining interviews, maintaining the staff, and coordinating the research team in the ongoing U.S.-U.K. Cross-National Project.

Detection of dementia and depression cases with the Comprehensive Assessment and Referral Evaluation interview schedule.

The objective of this research was to develop two indicator-scales for detection of dementia and detection of depression for individuals aged sixty-five or over who are living in the community. Data were collected in two large surveys in London and New York City using a semistructured interview technique, the Comprehensive Assessment and Referral Evaluation. Each of the two indicator-scales were developed so as to meet criteria regarding content and construct validity and internal consistency reliability such as is required in geriatric epidemiological research. The advantage of simultaneously using both indicator-scales in the detection of dementia and depression cases and in the differential diagnosis of dementia and depression is demonstrated.

Some applications of latent trait analysis to the measurement of ADL.

The use of latent trait methods for detection of biased items used in scales is discussed and two examples given. In the first, items measuring functional impairment in elderly community residents are tested for possible sex bias, and items predicted on the basis of clinical judgment to be clearly sex-biased are correctly identified. In the second example, taken from a cross-national study of elderly residents in long-stay institutions in New York and London, scale items suspected of bias due to interviewer variability and to cross-national differences in institutional environments are identified. It is shown that estimated rates of impairment are affected by presence of variant (biased) items. We argue that latent trait methods are useful for identifying biased items and may have wide application in gerontological research.