Projections of Alzheimer's disease in the United States and the public health impact of delaying disease onset

CNS stem cell transplantation: clinical and ethical perspectives

Central nervous system disorders evoke special fear though their varied and unrelenting threats to memory, cognition, mobility, and every aspect of personal integrity and independence. Understandably, neurologic patients and their families become desperate for help, making fully free, informed consent problematic but not impossible. This desperation mandates our anticipatory attention to ethical questions related to any aggressive new therapy, including central nervous system grafting. In the United States, the right-to-life issue dominates ethical discussions on neural grafting. A variety of alternative tissue sources may permit technically suitable preparations, at least for some uses. If plentiful supplies of grafting cells can be made commercially, this should reduce problems related to allocating scarce resources, although financial and other scarcity barriers may still raise ethical problems. Many contemporary conceptions of selfhood depend on the identity and intactness of the mind and, by implication, the brain as substrate of mind. How much can we reweave the cerebral tapestry without creating a new self, a new identity? These philosophical questions will probably be approached pragmatically and incrementally, in the context of many other developments in human genetics and biomedicine. Our vision of the self will evolve amidst conflicting religious, ethical and pragmatic perspectives.

Case management guideline: Alzheimer disease and other dementias

Case management guidelines are an integration of information obtained from research, observations, clinical experience, and judgments of expert clinicians, scientists, and clients. This guideline integrates information from multiple practice guidelines in order to guide the case manager in managing clients with Alzheimer disease and other dementias. The guideline provides direction in recognition of symptoms or triggers, risk factors, possible complications, case management outcomes, barriers to effective outcomes, goals, providers/practitioners, treatment options, location of treatment, estimated cost of treatment, psychosocial issues, life planning and long-term planning, vocational issues and teaching protocols. In addition, resource contacts and sources for major instruments used in measuring Alzheimer disease and dementia are presented.

Multimodal behavior management for people with dementia

Various psychological approaches are effective in maintaining and maximizing functioning in Alzheimer's disease. The most efficacious approaches have been based on a combination of individualized, interdisciplinary, and holistic treatment. Such a treatment approach is comparable to Lazarus's multimodal model, which has also been referred to as "systematic eclecticism." The multimodal model is especially well suited for people experiencing dementia, a progressive disorder

Plasma homocysteine as a risk factor for dementia and Alzheimer's disease

BACKGROUND

In cross-sectional studies, elevated plasma homocysteine levels have been associated with poor cognition and dementia. Studies of newly diagnosed dementia are required in order to establish whether the elevated homocysteine levels precede the onset of dementia or result from dementia-related nutritional and vitamin deficiencies.

METHODS

A total of 1092 subjects without dementia (667 women and 425 men; mean age, 76 years) from the Framingham Study constituted our study sample. We examined the relation of the plasma total homocysteine level measured at base line and that measured eight years earlier to the risk of newly diagnosed dementia on follow-up. We used multivariable proportional-hazards regression to adjust for age, sex, apolipoprotein E genotype, vascular risk factors other than homocysteine, and plasma levels of folate and vitamins B12 and B6.

RESULTS

Over a median follow-up period of eight years, dementia developed in 111 subjects, including 83 given a diagnosis of Alzheimer's disease. The multivariable-adjusted relative risk of dementia was 1.4 (95 percent confidence interval, 1.1 to 1.9) for each increase of 1 SD in the log-transformed homocysteine value either at base line or eight years earlier. The relative risk of Alzheimer's disease was 1.8 (95 percent confidence interval, 1.3 to 2.5) per increase of 1 SD at base line and 1.6 (95 percent confidence interval, 1.2 to 2.1) per increase of 1 SD eight years before base line. With a plasma homocysteine level greater than 14 micromol per liter, the risk of Alzheimer's disease nearly doubled.

CONCLUSIONS

An increased plasma homocysteine level is a strong, independent risk factor for the development of dementia and Alzheimer's disease.

Incidence of AD may decline in the early 90s for men, later for women: The Cache County study

OBJECTIVES

To characterize the incidence of AD among the elderly population of Cache County, UT, noted for its longevity and high response rates; to explore sex differences; and to examine whether AD incidence plateaus or declines in extreme old age.

METHODS

Using a multistage screening process in 1998 and 1999, and re-examining 122 individuals who had been identified 3 years earlier as cognitively compromised but not demented, the authors found 185 individuals with incident dementia (123 with AD) among 3,308 participants who contributed 10,541 person-years of observation. Adjusting for nonresponse and screening sensitivity, the authors estimated the incidence of dementia and of AD for men and women in 3-year age intervals. Multivariate discrete time survival analysis was used to examine influences of age, sex, education, and genotype at APOE, as well as interactions of these factors.

RESULTS

The incidence of both dementia and AD increased almost exponentially until ages 85 to 90, but appeared to decline after age 93 for men and 97 for women. A statistical interaction between age and the presence of two APOE-epsilon 4 alleles indicated acceleration in onset of AD with this genotype; the interaction of age and one epsilon 4 suggested more modest acceleration. A statistical interaction of sex and age indicated greater incidence of AD in women than in men after age 85.

CONCLUSIONS

The incidence of AD in the Cache County population increased with advancing age, but then peaked and declined among the extremely old. The presence of APOE-epsilon 4 alleles accelerated onset of AD, but did not appreciably alter lifetime incidence apparent over a span of 100 years.

Assessment of Health Economics in Alzheimer's Disease (AHEAD): treatment with galantamine in Sweden

BACKGROUND

Like other developed countries with aging populations, Sweden is expecting large increases in the prevalence of Alzheimer's disease and corresponding escalations in the cost of care for patients with this disease. Galantamine, a new acetylcholinesterase inhibitor and nicotinic modulator, has proved effective in managing patients with Alzheimer's disease in clinical trials.

OBJECTIVE

To estimate the long-term health and economic impact of galantamine from the perspective of the public health payer in Sweden.

DESIGN AND SETTING

The Assessment of Health Economics in Alzheimer's Disease (AHEAD) model compares galantamine treatment with no pharmacologic treatment. It consists of a module based on trial data followed by a projection module that uses the trial results to predict the time until patients require full-time care (FTC) or until their death. Forecasts were made for up to 10 years. The model was customised to Sweden by using Swedish resource use profiles obtained from the literature.

RESULTS

Galantamine is predicted to reduce the time patients require FTC by almost 10%. Approximately 5.6 patients with mild-to-moderate disease would need to be treated to avoid one year of FTC. This would result in savings averaging 27 436 Swedish kronas (SEK) [3131 euros (EUR)] per patient over 10 years (1998 values). To avoid one year of FTC, 3.9 patients with moderate disease would need to be treated, with savings averaging SEK49 019 (EUR 5594) per patient over 10.5 years. Sensitivity analyses of key parameters, such as proportion of patients needing FTC treated in the community, cost of care in an institution, cost of FTC care in the community, the price of galantamine, and the discount rate, found savings with galantamine would occur under most circumstances.

CONCLUSION

Galantamine can increase the time before patients require FTC, and may also lead to savings as treatment costs are offset by reductions in other healthcare expenditures and the costs associated with FTC.

Smoking as a risk factor for Alzheimer's disease: contrasting evidence from a systematic review of case-control and cohort studies

AIMS

To investigate the risk of Alzheimer's disease (AD) associated with smoking.

DESIGN

Meta-analyses of case-control and cohort studies.

DATA SOURCE

Index Medicus-Medline (1966-April 2000) and PsycINFO (1984-April 2000) databases were systematically consulted for the retrieval of references. This search was supplemented by manual search of relevant references quoted by other studies and reviews.

STUDY SELECTION

Irrelevant abstracts and articles were identified by one of the authors. These papers were retrieved and examined by at least two of the authors, who initially assessed them for the relevance of the exposure (smoking), outcome (AD) and study-design (case-control or cohort study).

DATA EXTRACTION

Two reviewers rated independently the quality of selected papers. Whenever possible, raw data were extracted and the crude odds ratio (OR) calculated using the Cornfield method. The pooled risk ratios were estimated using a fixed-effects model.

FINDINGS

Twenty-one case-control studies reported data on 5323 subjects. The estimated pooled odds ratio (OR) was 0.74 [95% confidence interval (CI) = 0.66-0.84]. In another analysis incorporating ORs adjusted for confounding variables (such as age, sex, schooling and alcohol use), the pooled odds ratio was 0.82 (95% CI = 0.70-0.97). Finally, in a analysis that included only the four case-control studies that used matched design the pooled odds ratio was 0.82 (95% CI = 0.53-1.27). Eight cohort studies reported data on 43 885 people at risk-the overall relative risk (RR) of AD among ever smokers was 1.10 (95% CI = 0.94-1.29). Restricting the analysis to the two cohort studies that described the number of subjects who were smokers at baseline and later developed AD produced a RR of 1.99 (95% CI = 1.33-2.98).

CONCLUSIONS

Case-control and cohort studies produce conflicting results as to the direction of the association between smoking and AD. Survival bias and other methodological problems associated with case-control studies may partly explain this difference. Access to information collected by ongoing follow-up studies may contribute to clarify the role of smoking in AD. If new results confirm that smoking is associated with increased risk of AD, then smoking prevention and cessation should become public health priorities in the fight against dementia.

New concepts in the drug therapy of Alzheimer's disease

There are currently four compounds approved for use in the treatment of Alzheimer's disease (AD). These drugs are all cholinesterase (ChE) inhibitors, which are thought to provide predominantly symptomatic benefits by increasing the level of acetylcholine (ACh) in the synapse. Although there are slight differences in the mechanisms of action of these compounds, it remains to be determined whether any one of them has a significant therapeutic advantage over the others. Several other drugs have also been investigated for their potential use as either symptomatic or disease-modifying agents in the treatment of AD, with mixed results. Current therapeutic research is focused on addressing the underlying pathology of AD, in the hope of arresting or reversing the course of the disease. This review will provide an overview of the ChE inhibitors and other drugs used for treating the symptoms of AD, summarise the results of recent therapeutic trials, discuss directions of future research and outline the current treatment recommendations for AD.

National estimates of the quantity and cost of informal caregiving for the elderly with dementia

OBJECTIVE

Caring for the elderly with dementia imposes a substantial burden on family members and likely accounts for more than half of the total cost of dementia for those living in the community. However, most past estimates of this cost were derived from small, nonrepresentative samples. We sought to obtain nationally representative estimates of the time and associated cost of informal caregiving for the elderly with mild, moderate, and severe dementia.

DESIGN

Multivariable regression models using data from the 1993 Asset and Health Dynamics Study, a nationally representative survey of people age 70 years or older (N = 7,443).

SETTING

National population-based sample of the community-dwelling elderly.

MAIN OUTCOME MEASURES

Incremental weekly hours of informal caregiving and incremental cost of caregiver time for those with mild dementia, moderate dementia, and severe dementia, as compared to elderly individuals with normal cognition. Dementia severity was defined using the Telephone Interview for Cognitive Status.

RESULTS

After adjusting for sociodemographics, comorbidities, and potential caregiving network, those with normal cognition received an average of 4.6 hours per week of informal care. Those with mild dementia received an additional 8.5 hours per week of informal care compared to those with normal cognition (P < .001), while those with moderate and severe dementia received an additional 17.4 and 41.5 hours (P < .001), respectively. The associated additional yearly cost of informal care per case was 3,630 dollars for mild dementia, 7,420 dollars for moderate dementia, and 17,700 dollars for severe dementia. This represents a national annual cost of more than 18 billion dollars.

CONCLUSION

The quantity and associated economic cost of informal caregiving for the elderly with dementia are substantial and increase sharply as cognitive impairment worsens. Physicians caring for elderly individuals with dementia should be mindful of the importance of informal care for the well-being of their patients, as well as the potential for significant burden on those (often elderly) individuals providing the care.

Should a diagnosis of Alzheimer's disease be disclosed?

There is evidence that some health practitioners may be reluctant to disclose a diagnosis of Alzheimer's disease (AD) to patients. However, this reluctance towards disclosure may not be in accordance with patient expectation. This study examined the attitudes of 100 undergraduate psychology students towards disclosure practices in relation to AD, before and after exposure to AD education. After AD education, 93% of participants indicated a desire to be informed of a diagnosis of AD, and 95% of participants were in favour of telling a close relative a diagnosis of AD. Results are discussed in terms of the relationship between age and attitudes towards AD diagnosis. It is concluded that the high rate of support for disclosure of AD diagnoses to patients among younger adults may reflect a change in the information preferences of patients brought about by a shift away from a patriarchal medical model, toward a more autonomous model of health.

Interventions to reduce the burden of caregiving for an adult with dementia: a meta-analysis

Because of conflicting results, in order to clarify the state of the science it was necessary to do a systematic analysis of the literature on research testing the effect of interventions on the burden of persons caring for family members with dementia. The purpose of this study was to evaluate, using meta-analytic techniques, those intervention strategies (support group, education, psychoeducation, counseling, respite care, and multicomponent) designed to help caregivers cope with the burden of caregiving. Using meta-analytic methods developed by Glass, McGraw, and Smith (1981) and Hedges and Olkin (1985), 24 published research reports testing 27 treatments for caregivers of adults with dementia were synthesized. Overall, the analysis showed that collectively the interventions had no effect on caregiver burden. Only the category of multicomponent interventions significantly reduced caregiver burden. Burden may be too global an outcome to be affected consistently by intervention. Better and more precise measures are needed to evaluate the effects of caregiver interventions properly.

Frequency of Alzheimer's disease and other dementias in a community outreach sample of Hispanics

OBJECTIVES

To determine the proportion of Alzheimer's disease (AD) and other dementia types in a community sample of Hispanics.

DESIGN

This is a descriptive diagnostic study of a nonrandom community outreach sample utilizing established criteria for the diagnosis of dementia type. Recruitment involved direct community outreach with diagnostic evaluations conducted at a university-affiliated outpatient clinic.

SETTING

Hispanic Neuropsychiatric and Memory Research Clinic at the Olive View-UCLA Medical Center in Sylmar, California.

PARTICIPANTS

One hundred community-dwelling Hispanics age 55 and older without prior diagnosis or treatment of their cognitive symptoms.

MEASUREMENTS

Each subject underwent a complete medical diagnostic evaluation, in Spanish, including neuropsychological tests, neurological examination, laboratory tests, and brain imaging (computed tomography or magnetic resonance imaging) to establish dementia type. Presence of dementia was established according to Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) criteria. Diagnosis for probable or possible AD and vascular dementia (VascD) was established using criteria from the National Institute of Neurological and Communicative Disorders and Stroke and the Alzheimer's Disease and Related Disorders Association for probable AD and by research criteria from the National Institute of Neurological Disorders and Stroke and the Association Internationale pour la Recherche et l'Enseignement en Neurosciences for VascD, respectively. Frontotemporal dementia was diagnosed using recommendations set forth by the Lund and Manchester groups.

RESULTS

Subjects were poor, with low acculturation levels despite long years of U.S. residence. Forty percent of subjects had had undiagnosed cognitive symptoms for 3 or more years. Of those demented, 38.5% had AD and 38.5% met criteria for VascD. The best predictors of VascD were hypertension and cerebrovascular disease, whereas apolipoprotein E4 allele best predicted AD. Other forms of dementia were also present. Twenty percent of the sample was clinically depressed but not demented.

CONCLUSIONS

In comparison with data from predominantly white populations, our proportion of AD cases was lower and that of VascD cases was considerably higher than anticipated. The percentage of clinically depressed older individuals was also high. These findings could have implications for differential cultural and genetic risk factors for dementia among diverse ethnic/racial groups. Further studies are needed to obtain accurate prevalence estimates of dementing disorders among the different U.S. Hispanic populations.

Annual incidence of Alzheimer disease in the United States projected to the years 2000 through 2050

Alzheimer disease will affect increasing numbers of people as baby boomers (persons born between 1946 and 1964) age. This work reports projections of the incidence of Alzheimer disease(AD) that will occur among older Americans in the future. Education adjusted age-specific incidence rates of clinically diagnosed probable AD were obtained from stratified random samples of residents 65 years of age and older in a geographically defined community. These rates were applied to U.S. Census Bureau projections of the total U.S. population by age and sex to estimate the number of people newly affected each year. The annual number of incident cases is expected to more than double by the midpoint of the twenty-first century: from 377,000 (95% confidence interval = 159,000-595,000) in 1995 to 959,000 (95% confidence interval = 140,000-1,778,000) in 2050. The proportion of new onset cases who are age 85 or older will increase from 40% in 1995 to 62% in 2050 when the youngest of the baby boomers will attain that age. Without progress in preventing or delaying onset of Alzheimer disease, both the number of people with Alzheimer disease and the proportion of the total population affected will increase substantially.

Brain aging research at the close of the 20th century: from bench to bedside

Remarkable and continued growth in the field of brain aging research has been fueled by a confluence of factors. Developments in molecular biology, imaging, and genetics coupled with the imperative caused by the aging of the population has created fertile ground for improved understanding of the interaction between brain function and behavior. Aging changes in neurochemical systems may account for the spectrum of cognitive and behavioral states of successfully aged pen sons, but may also contribute to enhanced vulnerability to depressive or dementing illness. In particular, the refinement of in vivo imaging approaches to investigating the structure and function of the aging brain has provided the opportunity to strengthen our knowledge of the biological substrate of the aging brain and neuropsychiatrie disorders, and translate these into therapeutics.

Predictor index of mortality in dementia patients upon entry into long-term care

BACKGROUND

The purpose of this study was to develop an algorithm that predicts survival in patients with dementia upon entry into long-term care. There are, as yet, no predictive equations developed for those in the late stages of Alzheimer's disease (AD).

METHODS

This was a prospective, observational study of 132 patients with dementia (61% with AD) followed for up to 5.0 years (median of 41.0 months) after admission to a long-term care facility for dementia patients. Information on demographic characteristics, physical health, and cognitive, emotional, and behavioral characteristics was collected shortly after admission and entered as predictors of time until death in Cox regressions. Findings were used to derive an index predicting mortality.

RESULTS

There were 60 deaths among the 132 patients (45.4% mortality), with an average survival of 22.4 months in those who died. Better physical health and the presence of delusions were associated with longer survival. These two variables were aggregated into the Copper Ridge Index (CRI). Each one-point increase on the CRI was associated with a four-fold greater likelihood of death over 5 years.

CONCLUSIONS

A predictive equation incorporating measures of general physical health and delusions accurately predicted time to death in dementia patients in long-term care.

Brain aging research at the close of the 20th century: from bench to bedside

Remarkable and continued growth in the field of brain aging research has been fueled by a confluence of factors. Developments in molecular biology, imaging, and genetics coupled with the imperative caused by the aging of the population has created fertile ground for improved understanding of the interaction between brain function and behavior. Aging changes in neurochemical systems may account for the spectrum of cognitive and behavioral states of successfully aged pen sons, but may also contribute to enhanced vulnerability to depressive or dementing illness. In particular, the refinement of in vivo imaging approaches to investigating the structure and function of the aging brain has provided the opportunity to strengthen our knowledge of the biological substrate of the aging brain and neuropsychiatrie disorders, and translate these into therapeutics.

Therapeutic approaches to age-associated neurocognitive disorders

The United Nations projects that the number of individuals with dementia in developed countries alone will be approximately 36,7 million by the year 2050. International recognition of the significant emotional and economic burden of Alzheimer's disease has been matched by a dramatic increase in the development of pharmacological and nonpharmacological approaches to this illness in the past decade. Changing demographics have underscored the necessity to develop similar approaches for the remediation of the cognitive impairment associated with more benign syndromes, such as mild cognitive impairment (MCI) and age-associated cognitive decline (AACD). The present article aims to provide an overview of the most current therapeutic approaches to age-associated neurocognitive disorders. Additionally, it discusses the conceptual and methodological issues that surround the design, implementation, and interpretation of such approaches.

Current perspectives on benefits and risks of hormone replacement therapy

Hormone replacement therapy with estrogen alone or with added progestin relieves menopausal symptoms and physical changes associated with depleted endogenous estrogen levels. Estrogen replacement has also demonstrated a clear benefit in the prevention of osteoporosis. Hormone replacement therapy with added progestin maintains spinal bone density, protects against postmenopausal hip fractures, and provides these benefits even when therapy is started after age 60. More recently, additional benefits have emerged. Current estrogen and hormone replacement therapy users have a 34% reduction in the risk of colorectal cancer and a 20% to 60% reduction in the risk of Alzheimer's disease. Until recently, the body of evidence indicated that hormone replacement therapy with estrogen only reduced cardiovascular disease risk by 40% to 50% in healthy patients; whether the findings of 3 ongoing trials will change this conclusion is pending availability of the final results. The many benefits of estrogen and hormone replacement therapy must be weighed against a slight increase in the risk of breast cancer diagnosis with use for 5 or more years, but which disappears following cessation of therapy. Overall, estrogen and hormone replacement therapy improves the quality of life and increases life expectancy for most menopausal women.

A critique of research on the use of activities with persons with Alzheimer's disease: a systematic literature review

TOPIC

The topic of this paper concerns the use of therapeutic activities with persons with Alzheimer's disease (AD).

PURPOSE

The purpose is to present a critique of the research on these activities, with an emphasis on methodology. ORGANIZING CONSTRUCT AND SCOPE: Nursing literature identifies a number of purposes for activities for persons with AD. Activities should be therapeutic, enhance quality of life, arrest mental decline, and generate and maintain self-esteem. Other purposes of activities for this population are to create immediate pleasure, re-establish dignity, provide meaningful tasks, restore roles, and enable friendships. Activities may be more important to the psychological state of well-being of persons with dementia than the general physical and social environments in which they live.

SOURCES

The literature reviewed was identified with the use of computer data bases (Medline - 1991-March 2001; Cumulative Index of Nursing and Allied Health Literature (CINAHL) - 1991-March 2001; and PsychLit - 1988-March 1999). In addition, data bases of Science Citation Index and Social Science Citation Indexes as they appear in the computer base, Web of Science, were searched for 1992-2001. The time period for each search was determined by the manner in which the literature was grouped for inclusion in the particular database. Hand searches of 11 selected journals included the years 1993-2001. The search dates were selected to reflect the time period when the largest number of studies on activities and AD have appeared in the professional literature. We critique a total of 33 studies.

CONCLUSIONS

While researchers have demonstrated interest in the use of activities with persons with AD, theoretical and methodological difficulties, unclear findings and gaps exist, including a lack of emphasis on gender, ethnic, racial or cultural differences. Sampling issues involving diagnosis and staging complicate the research on individuals with AD. Case studies, single subject experimental designs, and tightly controlled quasi-experimental and experimental designs are needed to advance knowledge in this important area.

Gene identification in Alzheimer's disease

Alzheimer's disease (AD) is the most common cause of dementia in the elderly population. Three genes have been identified that cause the less common early-onset, familial cases of the disease: the amyloid precursor (APP) protein gene on chromosome 21, the presenilin 1 (PSEN1) gene on chromosome 14 and the presenilin 2 (PSEN2) gene on chromosome 1. Mutations in these genes account for << 2% of the total number of AD cases. More than 50% of the cases are late-onset and related to the apolipoprotein E (APOE) gene on chromosome 19. The apolipoprotein E locus is a susceptibility gene, with polymorphisms affecting both risk and age-of-onset of the disease. Intense efforts are underway to identify additional susceptibility genes and promising regions on chromosomes 6, 9, 10 and 12 have been identified through whole genome scans. In addition, the genetic basis of several other non-AD inherited dementias has been unravelled. Discovery of the genetically relevant genes will aid in the elucidation of the pathogenesis of AD. The high-throughput tools of pharmacogenomics for gene-to-function-to-target studies can provide a quicker means of monitoring how mutations and polymorphisms affect model systems' adaptations to the altered genes, possibly identifying signal transduction or biochemical pathways. This relevant information can then be used for drug target selection and pharmacogenetics.

How proxies make decisions about research for patients with Alzheimer's disease

We examined the proxy decision-making and informed consent processes for clinical research involving 49 patient-subjects with dementia in an outpatient setting by performing serial in-depth, structured, open-ended telephone interviews. Interviews were tape recorded and transcribed. Transcripts were then coded and analyzed. Although in all cases proxy consent was obtained for research from a legally authorized representative, proxies reported considerable ambiguity regarding who made the decision to participate in research, or to what degree the decision was that of the proxy or of the patient. Reasons proxies gave for participating in research included: hope of direct or indirect benefits to the patient, caregiver, or patient's descendents; desperation; trust in the investigator; belief in the goodness of research; and altruism. These reasons varied according to the type of research. For instance, in drug trials hope of direct benefit prevailed; in studies not evaluating a potential therapy more altruistic concerns predominated. Being a proxy decision maker for research can be burdensome. The degree of burden related to making a decision to participate in research seems influenced by a number of intersecting factors, most importantly, the risk and nature of the study, the extent to which patients were able to participate in the decision, and the duration and severity of dementia. Proxy decision-making concerning participation in research for patients with dementia can be a difficult task. The process might be improved by emphasizing that proxy consent is being sought because the nature of the patient's underlying medical condition can preclude the ability to make meaningful decisions. In addition, clinical researchers should recognize that giving proxy consent might place additional burdens on caregivers and discuss this explicitly when proxy consent is solicited.

Midlife vascular risk factors and Alzheimer's disease in later life: longitudinal, population based study

OBJECTIVE

To examine the relation of midlife raised blood pressure and serum cholesterol concentrations to Alzheimer's disease in later life.

DESIGN

Prospective, population based study.

SETTING

Populations of Kuopio and Joensuu, eastern Finland.

PARTICIPANTS

Participants were derived from random, population based samples previously studied in a survey carried out in 1972, 1977, 1982, or 1987. After an average of 21 years' follow up, a total of 1449 (73%) participants aged 65-79 took part in the re-examination in 1998.

MAIN OUTCOME MEASURES

Midlife blood pressure and cholesterol concentrations and development of Alzheimer's disease in later life.

RESULTS

People with raised systolic blood pressure (>/=160 mm Hg) or high serum cholesterol concentration (>/=6.5 mmol/l) in midlife had a significantly higher risk of Alzheimer's disease in later life, even after adjustment for age, body mass index, education, vascular events, smoking status, and alcohol consumption, than those with normal systolic blood pressure (odds ratio 2.3, 95% confidence interval 1.0 to 5.5) or serum cholesterol (odds ratio 2.1, 1.0 to 4.4). Participants with both of these risk factors in midlife had a significantly higher risk of developing Alzheimer's disease than those with either of the risk factors alone (odds ratio 3.5, 1.6 to 7.9). Diastolic blood pressure in midlife had no significant effect on the risk of Alzheimer's disease.

CONCLUSION

Raised systolic blood pressure and high serum cholesterol concentration, and in particular the combination of these risks, in midlife increase the risk of Alzheimer's disease in later life.

Alzheimer's disease: insights from epidemiology

While a complete understanding of the pathogenesis of Alzheimer's disease (AD) remains elusive, many conclusions can be drawn from the numerous epidemiological studies undertaken to date. Prevalence and incidence estimates show consistency, following a roughly exponential pattern with a doubling of both parameters roughly every five years after age 65. Roughly 7% of the population aged 65 and over has AD. The clinical course of the disease is reasonably well established and mortality rates rise with increasing levels of cognitive deficit. Four risk factors for AD are firmly established: increasing age, the presence of the apolipoproteinE-epsilon4 allele, familial aggregation of cases, and Down's syndrome. Numerous other associations have been shown in some studies, but not in others. For example, women generally appear at higher risk than men, as do people with lower levels of education; depression is probably prodromal; head injury is an established risk factor, and may interact with the apoE gene; several occupational exposures appear hazardous, and exposure to aluminum in the water supply confers excess risk. Hypertension and other vascular symptoms appear to predispose to AD, which is now seen as nosologically closer to vascular dementia than was previously believed. Several apparently protective factors have been identified, although preventive trials based on these have so far shown minimal effectiveness. The use of non-steroidal anti-inflammatory drugs to treat arthritis is associated with a reduced risk of AD, as is estrogen use by post-menopausal women. Physical activity appears beneficial, as does a diet with high levels of vitamins B6, B12 and folate. while red wine in moderate quantities appears protective. This review concludes with a discussion of the strengths and limitations of current epidemiological methods for studying Alzheimer's disease.

Mild cognitive impairment: clinical features and review of screening instruments

Clinical criteria to recognize subjects with cognitive impairment in the pre-dementia stage are becoming available. These are frail subjects, at risk of adverse outcomes, such as death, institutionalization, and functional and cognitive deterioration. Early identification of these subjects has a great importance in order to start rehabilitative or pharmacological interventions that could slow the progression of cognitive impairment, and the onset of disability. In this regard, cognitive screening tests might be helpful in different clinical settings (general practice, acute care, rehabilitation, and nursing home). We describe the most frequent clinical presentations of cognitive impairment in the pre-dementia stage, and review eleven screening tests to provide recommendations on which should be preferred in each setting.

Treatment of alzheimer's disease with cholinesterase inhibitors

The cholinergic system is the most severely affected neurotransmitter system in patients with Alzheimer's disease, and therapeutic strategies have been developed to restore cholinergic function in these patients. This article reviews the present status of cholinesterase inhibitors for the treatment of Alzheimer's disease. It then discusses treatment approaches and current and future issues regarding efficacy and safety.

Declining brain activity in cognitively normal apolipoprotein E epsilon 4 heterozygotes: A foundation for using positron emission tomography to efficiently test treatments to prevent Alzheimer's disease

Cross-sectional positron emission tomography (PET) studies find that cognitively normal carriers of the apolipoprotein E (APOE) epsilon4 allele, a common Alzheimer's susceptibility gene, have abnormally low measurements of the cerebral metabolic rate for glucose (CMRgl) in the same regions as patients with Alzheimer's dementia. In this article, we characterize longitudinal CMRgl declines in cognitively normal epsilon4 heterozygotes, estimate the power of PET to test the efficacy of treatments to attenuate these declines in 2 years, and consider how this paradigm could be used to efficiently test the potential of candidate therapies for the prevention of Alzheimer's disease. We studied 10 cognitively normal epsilon4 heterozygotes and 15 epsilon4 noncarriers 50-63 years of age with a reported family history of Alzheimer's dementia before and after an interval of approximately 2 years. The epsilon4 heterozygotes had significant CMRgl declines in the vicinity of temporal, posterior cingulate, and prefrontal cortex, basal forebrain, parahippocampal gyrus, and thalamus, and these declines were significantly greater than those in the epsilon4 noncarriers. In testing candidate primary prevention therapies, we estimate that between 50 and 115 cognitively normal epsilon4 heterozygotes are needed per active and placebo treatment group to detect a 25% attenuation in these CMRgl declines with 80% power and P = 0.005 in 2 years. Assuming these CMRgl declines are related to the predisposition to Alzheimer's dementia, this study provides a paradigm for testing the potential of treatments to prevent the disorder without having to study thousands of research subjects or wait many years to determine whether or when treated individuals develop symptoms.

Dementia in rural primary care practices in Lake County, Oregon

Procedures used in assessing patients with dementia in rural settings are little studied. Among all patients aged 65 years and older in the four primary care practices in Lake County, Oregon, dementia cases were identified from computerized office databases using preselected International Classification of Diseases, Ninth Edition, codes. A semi-structured chart review determined (1) a dementia diagnosis, (2) cognitive and functional domains assessed, and (3) diagnostic studies performed. Of 1540 available records, 30 had dementia. Nineteen of them met National Institute of Neurological and Communicative Diseases and Stroke-Alzheimer's Disease and Related Disorders Association criteria for Alzheimer's disease (AD). Cognitive impairment was documented in 73% of the 51 identified charts and all with AD. Laboratory studies were recorded in 33% overall and in 42% with AD. Neuroimaging was documented in 18% overall and in 16% with AD. The prevalence of documented dementia in these rural practices may be low, possibly because cases of mild dementia may not be labeled as such. Laboratory studies were performed in a minority of cases of dementia.

The recognition, assessment and management of dementing disorders: conclusions from the Canadian Consensus Conference on Dementia

OBJECTIVE

i) To develop evidence based consensus statements on which to build clinical practice guidelines for primary care physicians towards the recognition, assessment and management of dementing disorders; ii) to disseminate and evaluate the impact of these statements and guidelines built on these statements.

OPTIONS

Structured approach to assessment, including recommended laboratory tests, choices for neuroimaging and referral; management of complications (especially behaviour problems and depression) and use of cognitive enhancing agents. POTENTIAL OUTCOMES: Consistent and improved clinical care of persons with dementia; cost containment by more selective use of laboratory investigations, neuroimaging and referrals; appropriate use of cognitive enhancing agents.

EVIDENCE

Authors of each background paper were entrusted to: perform a literature search, discover additional relevant material including references cited in retrieved articles; consult with other experts in the field and then synthesize information. Standard rules of evidence were applied. Based upon this evidence, consensus statements were developed by a group of experts, guided by a steering committee of eight individuals from the areas of Neurology, Geriatric Medicine, Psychiatry, Family Medicine, Preventive Health Care and Health Care Systems.

VALUES

Recommendations have been developed with particular attention to the context of primary care and are intended to support family physicians in their ongoing assessment and care of patients with dementia.

BENEFITS, HARMS AND COSTS

Potential for improved clinical care of individuals with dementia. A dissemination and evaluation strategy will attempt to measure the impact of the recommendations.

RECOMMENDATIONS

See text.

VALIDATION

Four other sets of consensus statements and/or guidelines have been published recently. These recommendations are generally congruent with our own consensus statements. The consensus statements have been endorsed by relevant bodies in Canada.

Alcohol use and the risk of developing Alzheimer's disease

Some of the detrimental effects of heavy alcohol use on brain function are similar to those observed with Alzheimer's disease (AD). Although alcohol use may be a risk factor for AD, it is difficult to study this relationship because of similarities between alcoholic dementia and AD and because standard diagnostic criteria for alcoholic dementia have not yet been developed. Similar biological mechanisms may be involved in the effects of AD and alcohol abuse on the brain. Epidemiologic studies have investigated the relationship between alcohol use and AD but have not provided strong evidence to suggest that alcohol use influences the risk of developing AD. Further research is needed before the effect of alcohol use on AD is understood fully.

Causes of Alzheimer's disease: paracetamol (acetaminophen) today? Amphetamines tomorrow?

Phenacetin was implicated as a causative factor in Alzheimer's disease (AD) in 1971. Although the chief metabolite, paracetamol, was earlier identified as responsible for its analgesic and antipyretic properties, a link with senile plaque formation does not appear to have been previously suspected. In common with paracetamol, so-called recreational drugs (RDs) likewise stimulate free radical activity, and might therefore pose a similar danger in terms of causing AD later in life. The case for regarding the brain as an even more delicate and vulnerable structure than currently believed, at risk especially from substances untested in man but of proven neurotoxicity in rodents and non-human primates, needs to be taken more seriously than at present.

Identification of novel genes in late-onset Alzheimer's disease

Four genes affecting Alzheimer's Disease (AD)(AP, PS1, PS2, and APOE) have been identified and a fifth potential gene localized to chromosome 12. Collectively, these genes explain at most half of the genetic effect in AD. Understanding the genetics of AD is critical to developing new treatments. The quest to find the remaining AD genes led us to undertake a large genomic screen using over 466 families (730 affected sibpairs) in late-onset AD. In conjunction with this increase in power, we initiated several novel approaches to identify potential AD-related genes. This included stratification of the data into an autopsy-confirmed subset of 199 AD families. Each of these targeted analyses resulted in the identification of novel regions containing potential AD genetic risk factors. Our most significant finding was on chromosome 9 in the autopsy-confirmed subset where we obtained an MLS of 4.31. These approaches, together with new methodologies such as conditional linkage analysis, generalized family-based association tests (PDT), and a new generation of genetic markers (SNPs), opens the door for additional AD gene discovery. Such strategies are necessary if we are to understand the subtle and complex threads that, woven together, create the intricate tapestry of AD.

Treatment of sleep disturbance in Alzheimer's disease

The prevalence of Alzheimer's disease (AD) is rapidly increasing as growing numbers of people around the world are living to old age. Sleep disturbances are a common, and often highly disruptive, behavioral symptom associated with AD. Nevertheless, the study of sleep in AD is relatively new. Little is known about the moderating factors that may alter a given patient's risk for developing sleep problems, or that may influence severity of presentation and persistence. Current treatments for improving sleep in AD fall into three broad categories: (i) pharmacological; (ii) cognitive-behavioral or psycho-educational strategies; and (iii) biological/circadian therapies. There are few studies demonstrating the efficacy of these treatments with community-dwelling AD patients, although studies with persons in institutional settings are promising. In this review, it is suggested that sleep problems in AD are multi-factorial, and influenced by a variety of demographic, physical, psychiatric and situational factors. These factors vary in how readily they can be modified and in how relevant they are to any individual case. Thus, when developing a treatment plan for sleep problems in a dementia patient, it is important to evaluate the underlying causes as well as the context in which the problems are occurring, and to target the intervention accordingly.

Vascular dementia, a new beginning: shifting focus from clinical phenotype to ischemic brain injury

Dementia may result from complete or incomplete infarction of brain regions subserving memory and cognition. Several effective treatments reduce the risk of initial and recurrent stroke. Presumably, these interventions reduce the risk of vascular cognitive impairment. Incomplete infarction caused by recurrent, chronic, or subclinical ischemia appears to represent another important cause of ischemic brain injury, but has been relatively neglected. A shift in focus from the serendipitous clinical phenotype of vascular dementia to preventing and ameliorating the broad spectrum of ischemic brain injury is recommended.

The role of routine laboratory studies and neuroimaging in the diagnosis of dementia: a clinicopathological study

OBJECTIVE

To determine the neuropathological diagnoses of longitudinally followed patients with potentially reversible causes of dementia and to examine the results of the "dementia work-up," especially neuroimaging, by comparison with the pathological diagnosis.

DESIGN

A neuropathologic series of 61 consecutive patients, with review of clinical, laboratory, neuroimaging, and pathological results.

RESULTS

Of the 61 patients, forty-eight (79%) had a clinical diagnosis of probable or possible Alzheimer's disease (AD). Compared with the pathological diagnosis, the sensitivity and specificity of the clinical diagnosis of AD were 96% and 79%, respectively. Of the 61 patients, 9 had abnormal laboratory tests, the correction of which did not improve the subsequent course. These patients were found to have AD8 and frontotemporal dementia on pathology. In two patients, neuroimaging was helpful in the clinical diagnoses of frontotemporal dementia and progressive supranuclear palsy (PSP). Neuroimaging revealed cerebrovascular disease in 18 patients, only two of whom were suspected clinically. Pathology confirmed AD in 17 and PSP in 1 of these patients. Sensitivity and specificity for the clinical diagnosis of cerebrovascular disease in comparison with pathology were 6% and 98%, respectively. With the added information from neuroimaging, that sensitivity increased to 59% and specificity decreased to 81%.

CONCLUSIONS

All cases with abnormal laboratory or neuroimaging results had AD or some other neurodegenerative disease on pathology. The "dementia work-up" did not reveal any reversible causes for dementia in this group of patients. Neuroimaging may have a role, especially in the diagnosis of possible AD with concomitant cerebrovascular disease.

Cost-effectiveness of functional imaging tests in the diagnosis of Alzheimer disease

PURPOSE

To evaluate the cost-effectiveness of functional neuroimaging in the work-up of patients at specialized Alzheimer disease clinics.

MATERIALS AND METHODS

A decision model was used to calculate costs and benefits (in quality-adjusted life-years [QALYs]) that accrued to hypothetical cohorts of patients at presentation to an Alzheimer disease center. Sensitivity analysis was performed to examine the effects of diagnostic test characteristics, therapeutic efficacy, disease severity, and costs on cost-effectiveness.

RESULTS

The incremental cost-effectiveness ratio of dynamic susceptibility contrast material-enhanced magnetic resonance (MR) imaging was $479,500 per QALY (compared with the usual diagnostic work-up), while visual or quantitative single photon emission computed tomography (SPECT) was dominated (higher costs, lower effectiveness) by the usual diagnostic work-up. These results depend critically on the sensitivity and specificity of the standard diagnostic work-up, the effectiveness of drug treatment, and the disease severity. Varying these parameters resulted in estimates of incremental cost-effectiveness for dynamic susceptibility contrast-enhanced MR imaging of $24,680 to $8.6 million per QALY. SPECT either was dominated by the usual diagnostic work-up or had cost-effectiveness ratios of $180,200 to $6 million per QALY.

CONCLUSION

The addition of functional neuroimaging to the usual diagnostic regimen at Alzheimer disease clinics is not cost-effective given the effectiveness of currently available therapies.

Do nutrition indicators predict death in elderly Canadians with cognitive impairment?

This study describes the independent association between nutritional risk and death in older adults diagnosed with cognitive impairment. Canadian Study of Health and Aging participants who completed a clinical exam and were diagnosed with cognitive impairment and had complete data for regression analyses were included (n = 735). Nutritional risk was defined as the presence of at least one abnormal nutrition indicator identified during the clinical exam (history of weight loss, abnormal serum albumin, poor appetite, body mass index < 20). Other covariates believed to influence mortality were modelled with nutritional risk using logistic regression. There were 373 deaths during the five-year follow-up period in this sample. Nutritional risk was found to independently increase the likelihood of death (OR = 1.6, 95% CI 1.1, 2.2) in these older adults suffering from cognitive impairment. Further work is required to determine if interventions can improve nutritional status and quality of life of these older adults.

Driving cessation in older men with incident dementia

OBJECTIVE

To determine the prevalence and cessation of driving among older men with incident dementia in the Honolulu-Asia Aging Study.

DESIGN

Retrospective cohort data from a community-based study of incident dementia.

SETTING

The Honolulu Heart Program and the Honolulu-Asia Aging Study.

PARTICIPANTS

A total of 643 men who were evaluated for the incidence of Alzheimer's disease or other dementia between the fourth and the fifth examination of the Honolulu Heart Program.

MEASUREMENTS

Driving history, diagnosis of dementia, grip strength, walking speed, standing balance test, interviewer's rating of vision status, and the neurologist's notes on mentions of driving behavior from informal interviews with a caregiver or family informant.

RESULTS

The prevalence of driving declined dramatically with level of cognitive functioning. Among 162 men evaluated and found to have normal cognitive functioning, 78% still drove, compared with 62% of 287 men with poor cognitive functioning but no clinical dementia, 46% of 96 men with a new diagnosis of very mild dementia (Clinical Dementia Rating = 0.5), and 22% of 98 men with a new diagnosis of mild dementia (CDR = 1). Only one of 23 men diagnosed with moderate or more severe staged incident dementia (CDR > 1) was driving. About 10% of the 59 demented persons still driving relied on co-pilots, and only one driver was reported as involved in a crash according to a review of the neurologists' notes.

CONCLUSIONS

Incident dementia is a major cause of driving cessation. Based on these data, we estimate that approximately 4% of male drivers aged 75 years and older nationwide (about 175,000 men) have dementia. This number will increase with the projected growth of drivers aged 75 years and older.

Prevalence of AD among whites: a summary by levels of severity

OBJECTIVE

To determine age- and sex-specific AD prevalence rates for whites using each of four severity-based definitions of a case: a person diagnosed as having at least questionable AD, one diagnosed as having at least mild AD, one diagnosed as having moderate or severe AD, and one diagnosed as having severe AD.

METHODS

Data from 21 studies of Europeans and North Americans were pooled.

RESULTS

Empirically, one study, from East Boston, is an outlier. Applied to the US population of 1996, the obtained estimates yield a prevalence of 1.7 to 1.9 million cases, depending on whether the outlier study is excluded or included.

CONCLUSIONS

With disease severity taken into account, estimates of AD prevalence from white populations are more consistent than is usually acknowledged. By including disease severity in the case definition, variations in reported rates are much reduced. The outlier status of the East Boston study appears to result from the use of a definition of AD that differs from that used in the other 20 studies. Alternative explanations of the discrepancy between these estimates and the common estimate of 4 million cases are discussed.

Barriers to healthcare access for cognitively impaired older Hispanics

This study describes the development of the Barriers to Healthcare Access Survey (BHAS) used to evaluate seven barrier factors believed to influence healthcare access for elderly Hispanics with memory or cognitive problems. This study further reports the results of the BHAS applied to a community sample of cognitively impaired older Hispanics and their caregivers. The study includes (1) The BHAS's development and procedures to establish instrument validity and reliability; (2) Interviews with the BHAS on 65 cognitively impaired Hispanics who were undergoing full diagnostic assessment for dementia and their caregivers. The most frequently perceived healthcare barriers reported in our study were related to (1) personal beliefs (38%), (2) language proficiency (33%), and (3) economic status (13%). The BHAS possesses the requisite psychometric properties to be an effective instrument for an initial survey of perceived barriers to access health care for low-education, cognitively impaired, elderly Hispanic patients. The findings suggest that perceptions regarding illness, health consequences of aging, and beliefs about the utility of medicine do, in fact, influence healthcare use by older Hispanic patients with dementia. Language proficiency and economic status remain common barriers among elderly Hispanic subgroups, but when these barriers are experienced by the cognitively impaired, serious healthcare implications ensue, especially delay in early diagnosis and treatment.