Dementing Illnesses in Rural Populations: The Need for Research and Challenges Confronting Investigators

Expansion of the world's elderly populations has increased concerns about aging-related medical disorders like Alzheimer's disease and other dementias. In the United States, one fourth of those older than age 65 and at greatest risk for developing dementia live in rural environments that may influence its manifestation. The objectives of this study were to determine the need for and potential benefits of further epidemiological research concerning dementia and similar disorders in rural U.S. populations and to identify pertinent methodological issues related to rural dementia research. This study employed a National Library of Medicine (MEDLINE) document search based on the key words "cognitive disorders," "dementia," "Alzheimer's disease," and "rural," followed by recovery of literature resources references in the bibliographies of selected articles. Nineteen studies focusing on dementia or related disorders in rural settings have been reported from around the world. While four of these were conducted in the United States, only one rural dementia prevalence study has been undertaken in this country. Because of methodological variability, comparisons of prevalence estimates between these rural studies, as well as with those from urban investigations, is difficult. Nonetheless, there is reason to believe that certain potentially dementing illnesses are more common in rural populations. There is also evidence to suggest that the screening instruments commonly used in such studies tend to misclassify rural elders as "false positive" dementia cases. Information regarding dementing disorders, particularly Alzheimer's disease, in rural populations is scarce. Preliminary observations that dementia may be more common in rural settings and that rural families are more likely to maintain their dementing elders in the community imply that further rural dementia research could yield important insights into the risk factors for these illnesses, the variables influencing their course, and the methods by which they can be more effectively managed. A determination of the reliability and validity of commonly used dementia screening instruments in rural populations would represent an important advancement in this area of research.     

Empirical comparison of alternate forms of the Boston Naming Test

Abstract

Various short forms of the Boston Naming Test (BNT) are compared including an empirically derived 30-item form, odd and even items split-half forms, four 15-item forms, and a rationally derived 15-item form used in conjunction with the Consortium to Establish a Registry in Alzheimer's Disease (CERAD). The present analysis was conducted using a sample of 320 individuals with diagnoses including dementia (n = 194), thought disorder (n = 46), depression (n = 16), general neuropsychiatric disorders (n = 12), and cerebral tumors (n = 52). Results indicated that all forms possess adequate, although variable internal consistency, and correlations between forms were reasonable. Average item difficulty indices also differed with the CERAD version being least desirable. Finally, classification rates were different by forms, indicating limitations on the extent to which the forms may be used interchangeably.     

Alzheimer's disease as a diagnosis of exclusion

Although dementia is frequent among the elderly, and usually the result of Alzheimer's disease, other illnesses may be responsible. A diagnostic approach to discover such treatable disorders is detailed in this paper.     

Clinical assessment of family caregivers in dementia.

Development of an integrated family assessment inventory based on the Double ABCX and Circumplex models of family functioning and its clinical utility was evaluated with 121 primary family caregivers from a cognitive disorders program. The proposed model predicted a significant proportion of the variance associated with caregiver stress and strain. Several aspects of the caregiving arrangement also emerged as key features in predicting caregiver depression. These findings supported the model's central premise that both dyadic (caregiver-patient) and systemic (caregiver-family) variables are salient in assessing the impact of family caregiving with dementia.     

Effects of Methylphenidate on Stimulus Evaluation and Response Processes: Evidence from Performance and Event-Related Potentials

This study investigated the effects of methylphenidate in a memory scanning task with two levels of high cognitive load (memory set sizes 2 and 4 presented in displays of size 4) and two response requirements (simple mapping or rotation). Twenty young adults were tested under placebo and methylphenidate (0.3 mg/Kg) in a double-blind protocol. As expected, memory load increased misses, false alarms, confusions, and failures to respond by the deadline. In turn, the rotation requirement increased confusions and nonresponses. Reaction time (RT) was slowed by both factors. P3b latency also was increased by memory load and, to some extent, by the rotation requirement. These results are consistent with the proposition that P3b latency reflects largely evaluation, rather than response processes. Misses and reaction time were decreased in response to targets presented in the center vs. the periphery of the display. Confusions, however, showed the opposite trend. The display position did not affect P3b latency. These results can be explained by assuming that the subject was focusing on the center of the display and that accuracy diminished when stimuli were presented toward the periphery of the display. The stimulant challenge speeded up reaction times overall and specifically reduced the slowing effect of rotation. However, P3b latency was not affected by methylphenidate, so that the speeding of reaction time by the stimulant can be attributed to post-evaluation processes.