Grace J. Petot

Patients with Alzheimer's disease have reduced activities in midlife compared with healthy control-group members

The development of Alzheimers disease (AD) later in life may be reflective of environmental factors operating over the course of a lifetime. Educational and occupational attainments have been found to be protective against the development of the disease but participation in activities has received little attention. In a case-control study, we collected questionnaire data about 26 nonoccupational activities from ages 20 to 60. Participants included 193 people with probable or possible AD and 358 healthy control-group members. Activity patterns for intellectual, passive, and physical activities were classified by using an adaptation of a published scale in terms of “diversity” (total number of activities), “intensity” (hours per month), and “percentage intensity” (percentage of total activity hours devoted to each activity category). The control group was more active during midlife than the case group was for all three activity categories, even after controlling for age, gender, income adequacy, and education. The odds ratio for AD in those performing less than the mean value of activities was 3.85 (95% confidence interval: 2.65–5.58, P < 0.001). The increase in time devoted to intellectual activities from early adulthood (20–39) to middle adulthood (40–60) was associated with a significant decrease in the probability of membership in the case group. We conclude that diversity of activities and intensity of intellectual activities were reduced in patients with AD as compared with the control group. These findings may be because inactivity is a risk factor for the disease or because inactivity is a reflection of very early subclinical effects of the disease, or both.

Validity of Portion-Size Measurement Aids: A Review

A review of research studies that focus on the validity of portion-size measurement aids (PSMAs) was undertaken because guidelines for the use of PSMAs in studies of food intake have not been developed. Also, the accuracy of food quantity estimates may greatly influence the quality of dietary intake data. Generally, the review indicated that differences between the food quantity estimates obtained from different PSMAs were not statistically significant. Research on PSMA accuracy was lacking in several areas. Additional information is needed on the validity of PSMAs, particularly as it relates to PSMA use by different socio-demographic groups. Little research has focused on the specific effects that PSMAs have on quantity estimates or on subject perceptions of PSMA use. Improved reporting of PSMAs in the literature is also needed. Future research should be directed toward these issues so that PSMA guidelines can be developed. Until there is a more complete research base, it is not possible at this time to establish guidelines for use of PSMAs in clinical practice or in research settings.

INTEGRATING CASE-BASED AND RULE-BASED REASONING TO MEET MULTIPLE DESIGN CONSTRAINTS

Although case‐based reasoning (CBR) was introduced as an alternative to rule‐based reasoning (RBR), there is a growing interest in integrating it with other reasoning paradigms, including RBR. New hybrid approaches are being piloted to achieve new synergies and improve problem‐solving capabilities. In our approach to integration, CBR is used to satisfy multiple numeric constraints, and RBR allows the performance of “what if” analysis needed for creative design.

A Metabolic Basis for Alzheimer Disease

Most studies of Alzheimers disease (AD) have focused on a single precipitating alteration as the etiological event rather than global changes closely linked to aging. Recent evidence suggests that the most significant of these global changes are metabolic. Here we present data indicating that metabolic rate, nutrition, and neuronal size are all early indicators of AD. Understanding the cellular and molecular basis for these changes may open a new dimension to understanding AD.

Participation in novelty-seeking leisure activities and Alzheimer's disease

The objective was to study the associations between participation in different types of mentally stimulating leisure activities and status as Alzheimer’s disease (AD) case or normal control. Research suggests that participation in leisure activities, especially mentally stimulating activities, is associated with a lower risk for AD. However, no study has yet evaluated associations between AD and different types of mental leisure activities, especially those involving “novelty seeking.” The authors used a case-control design to compare participation in activities across the life span in persons with AD and normal controls. Cases (n = 264) were recruited from clinical settings and from the community. Controls were drawn from 2 populations. Control group A members (n = 364) were the friends or neighbors of the cases or members of the same organizations to which the cases belonged. Control group B members (n = 181) were randomly drawn from the community. The 2 control groups did not differ in their responses to most activity questions, so they were combined. Factor analysis of activity questions identified 3 activity factors: (1) novelty seeking; (2) exchange of ideas; and (3) social. Logistic regression analysis indicated that, adjusting for control variables, greater participation in novelty-seeking and exchange-of-ideas activities was significantly associated with decreased odds of AD. The odds of AD were lower among those who more often participated in activities involving exchange of ideas and were lower yet for those who more frequently participated in novelty-seeking activities. We conclude that participation in a variety of mental activities across the life span may lower one’s chances of developing AD.

Lipids, diet and Alzheimer disease: an extended summary

A number of dietary elements and foods have been reported to be either risk or protective factors for the development of dementia and Alzheimer disease (AD). These include fat, fatty acids, antioxidants, fish, homocysteine/methionine, vitamins and alcohol. We propose that brain diseases with aging are not be only the result of pathogenic processes, but also due to the failure of protective mechanisms, and that diet influences the success of these protective mechanisms. Both animals and humans with genetic forms of AD do not get the disease until a certain time in mid or late life. Therefore, there must be protective factors responsible for the delayed onset of disease.

Plasma homocysteine, vitamin B12 and folate in Alzheimer's patients and healthy Arabs in Israel

High plasma homocysteine (tHcy) is a risk factor for cardiovascular disease and stroke and Alzheimers disease (AD). An inverse relationship has been reported between tHcy and plasma B12 and folate levels. Seventy-nine AD patients and 156 controls from three Arab villages in northern Israel participated. Plasma tHcy, B12 and folate levels were determined. Data were analyzed using univariate statistical tests and logistical regression with confounders. tHcy was significantly higher in AD patients (20.6+/-8.7 micromol/l) than in controls (16.4+/-6.5 micromol/l) (p=0.03) after correction for year of birth, gender and smoking status. Plasma B12 (322.9+/-136.0/350.5+/-175.3 pmol/l) and plasma folate (4.5+/-3.8/4.9+/-2.6 nmol/l) levels did not differ significantly between AD patients and controls. Subjects in the highest tHcy tertile or in the lowest B12 and folate tertiles did not have greater risk to develop AD. In this population residing in Arab villages in northern Israel, tHcy levels were significantly higher among AD patients than in controls. Plasma B12 and folate levels were lower among cases but were not significant. There was not a significant association between plasma tHcy, B12 and folate levels in controls or AD patients. High levels of tHcy may suggest the need for folate and vitamin B12 supplementation in this population.

An Artificial Intelligence System for Computer-Assisted Menu Planning

Planning nutritious and appetizing menus is a complex task that researchers have tried to computerize since the early 1960s. We have attempted to facilitate computer-assisted menu planning by modeling the reasoning an expert dietitian uses to plan menus. Two independent expert systems were built, each designed to plan a daily menu meeting the nutrition needs and personal preferences of an individual client. One system modeled rule-based, or logical, reasoning, whereas the other modeled case-based, or experiential, reasoning. The 2 systems were evaluated and their strengths and weaknesses identified. A hybrid system was built, combining the best of both systems. The hybrid system represents an important step forward because it plans daily menus in accordance with a persons needs and preferences; the Reference Daily Intakes; the Dietary Guidelines for Americans; and accepted aesthetic standards for color, texture, temperature, taste, and variety. Additional work to expand the systems scope and to enhance the user interface will be needed to make it a practical tool. Our system framework could be applied to special-purpose menu planning for patients in medical settings or adapted for institutional use. We conclude that an artificial intelligence approach has practical use for computer-assisted menu planning.

Effects of educational attainment on the clinical expression of Alzheimer's disease: Results from a research registry:

The “reserve” hypothesis suggests that education should affect the clinical expression of Alzheimers disease (AD), but results from studies examining this idea are not consistent. In a single study, we evaluated the effects of educational attainment on three aspects of the clinical expression of AD: age at symptom onset, rate of cognitive decline, and survival. Subjects were 258 persons with mild-or moderate-stage Alzheimers, drawn from our AD Research Registry. With statistical adjustment for confounding variables present in a clinic-based design, we found that higher educational attainment was associated with slightly earlier reports of symptom onset and a slower rate of cognitive decline on the Mini-Mental State Exam (MMSE). Education did not affect time of survival until death. We conclude that, for subjects in our sample, education had modest effects on aspects of the clinical expression of AD. These effects were not fully consistent with predictions derived from the “reserve” hypothesis.

Indices of Metabolic Dysfunction and Oxidative Stress

Metabolic alterations are a key player involved in the onset of Alzheimer disease pathophysiology and, in this review, we focus on diet, metabolic rate, and neuronal size differences that have all been shown to play etiological and pathological roles in Alzheimer disease. Specifically, one of the earliest manifestations of brain metabolic depression in these patients is a sustained high caloric intake meaning that general diet is an important factor to take in account. Moreover, atrophy in the vasculature and a reduced glucose transporter activity for the vessels is also a common feature in Alzheimer disease. Finally, the overall size of neurons is larger in cases of Alzheimer disease than that of age-matched controls and, in individuals with Alzheimer disease, neuronal size inversely correlates with disease duration and positively associates with oxidative stress. Overall, clarifying cellular and molecular manifestations involved in metabolic alterations may contribute to a better understanding of early Alzheimer disease pathophysiology.