Dementia is a syndrome in which progressive deterioration in intellectual abilities is so severe that it interferes with the person's usual social and occupational functioning. An estimated 5 to 10 percent of the U.S. adult population ages 65 and older is affected by a dementing disorder, and the incidence doubles every 5 years among people in this age group.
Alzheimer's disease is the most common form of dementia in the United States. It and related dementias affect at least 2 million, and possibly as many as 4 million, U.S. residents. Despite its prevalence, dementia often goes unrecognized or is misdiagnosed in its early stages. Many health care professionals, as well as patients and family members, mistakenly view the early symptoms of dementia as inevitable consequences of aging.
Some disorders that result in dementia are "reversible or potentially reversible," which means that they can be treated effectively to restore normal or nearly normal intellectual function. Among the most frequent reversible causes of dementia are depression, alcohol abuse, and drug toxicity. In elderly persons, drug use—particularly drug interactions caused by "polypharmacy" (simultaneous use of multiple drugs)—is a common cause of cognitive decline. Depression also is an underdiagnosed condition in this population.
The majority of dementias, including Alzheimer's disease, are considered nonreversible. Even for these conditions, correct diagnosis of the problem in its early stages can be beneficial. Correct recognition can prevent costly and inappropriate treatment resulting from misdiagnosis, and give patients and families time to prepare for the challenging financial, legal, and medical decisions that may lie ahead. In addition, many of the nonreversible dementias such as Alzheimer's disease include symptoms that can be treated effectively (for example, incontinence, wandering, depression).
According to the National Institute on Aging, an estimated $90 billion is spent annually for Alzheimer's disease alone, and the noneconomic toll is incalculable. Although State and local governments and the Federal Government bear some of the economic burden, largely through Medicare and Medicaid, a substantial proportion is borne by families that provide unpaid care. Changes caused by dementia may advance relentlessly over many years, creating not only deep emotional and psychological distress but practical problems related to caregiving that can overwhelm affected families.
In 1992, the Agency for Health Care Policy and Research, a Federal Government agency within the Public Health Service, convened a panel of private-sector experts to develop a clinical practice guideline on screening for Alzheimer's disease and related dementias. This topic was selected because:
After extensive literature searches and meta-analyses, the panel decided to focus on early detection of dementia in persons exhibiting certain characteristics or triggers that signal the need for further assessment, rather than recommend general screening of segments of the population, such as those over a certain age. The panel made this decision after concluding that:
The panel subsequently limited its scope specifically to the subject of recognition and initial assessment and therefore did not address differential diagnosis, management, or treatment issues after diagnosis.
The panel's principal objective was to increase the likelihood of early recognition and assessment of a potential dementing illness so that (1) concern can be eliminated if it is not warranted; (2) treatable conditions can be identified and addressed appropriately; and (3) nonreversible conditions can be diagnosed early enough to permit the patient and family to plan for contingencies such as long-term care.
Specifically, the panel's goals were to:
The panel's major findings include:
In asymptomatic persons who have possible risk factors (e.g., family history and Down syndrome for Alzheimer's disease), the clinician's judgment and knowledge of the patient's current condition, history, and social situation (living arrangements, support services, isolation) should guide the decision to initiate an assessment for dementia.
For a diagnosis of dementia, current criteria in the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV), require evidence of decline from previous levels of functioning and impairment in multiple cognitive domains, not solely memory. Because evidence of decline in previous abilities is critical in establishing dementia, a personal knowledge of the patient is invaluable to the clinician in assessing symptoms and interpreting results of an initial assessment for dementia.
A focused history is critical in the assessment for dementia. It is particularly important to establish the symptoms' mode of onset (abrupt versus gradual); progression (stepwise versus continuous decline; worsening versus fluctuating versus improving), and duration.
A focused physical examination, including a brief neurological evaluation, is an essential component of the initial assessment. Special attention should be placed on assessing for those conditions that cause delirium, since delirium represents a medical emergency. During the focused physical examination, health care providers should be alert to signs of abuse and neglect of patients by caregivers and report suspected abuse to the proper authorities.
Informant reports (information obtained from family members or caregivers) can supplement information from patients who have experienced memory loss and may lack insight into the severity of their decline. Health care providers, however, should consider the possibility of questionable motives of informant reports, which may exaggerate, minimize, or deny symptoms.
Brief mental status tests can be used but they are not diagnostic. They are used to (1) develop a multidimensional clinical picture; (2) provide a baseline for monitoring the course of cognitive impairment over time; (3) reassess mental status in persons who have treatable delirium or depression on initial evaluation; and (4) document multiple cognitive impairments as required for a diagnosis of dementia.
Depression can be difficult to distinguish from dementia, and it can coexist with dementia. Changes in memory, attention, and the ability to make and carry out plans suggest depression, the most common psychiatric illness in older persons. Marked visuospatial or language impairment suggests a dementing process. The clinical interview is the mainstay for evaluating and diagnosing depression in older adults. Two self-report instruments with established reliability and validity are the Geriatric Depression Scale (GDS) and the Center for Epidemiological Studies Depression Scale (CES-D).
Three results are possible from the combination of findings from assessments of mental and functional status: (1) normal, (2) abnormal, and (3) mixed.
When results of both mental and functional status tests are normal and there are no other clinical concerns, reassurance and suggested reassessment in 6 to 12 months are appropriate. If concerns persist, referral for a second opinion or further clinical evaluation should be considered.
When both mental and functional status tests yield findings of abnormality, further clinical evaluation should be conducted. However, a laboratory test should not be used as a screening procedure or part of an initial assessment. Laboratory tests should be conducted only after (1) it has been confirmed that the patient has impairment in multiple domains that is not lifelong and represents a decline from previous levels of functioning; (2) delirium and depression have been excluded; (3) confounding factors such as educational level have been considered; and (4) medical conditions have been be ruled out.
Mixed results—abnormal findings on the mental status test with no abnormalities in functional assessment or vice versa—call for further evaluation. For example:
Neuropsychological tests can examine performance across different domains of cognition. This broad battery of tests can help in identifying dementia among persons with high premorbid intellectual functioning, discriminating patients with a dementing illness from those with focal cerebral disease, and differentiating among certain causes of dementia.
Followup, with assessment of declining mental function, may be the most useful diagnostic procedure for differentiating Alzheimer's disease from normal aging. For this reason, the mental status test should be repeated over a period of 6 to 12 months. In cases of referral, it is important to make sure that test results and medical records follow the patient from the specialist back to the referring clinician.
Does the person have increased difficulty with any of the activities listed below? Positive findings in any of these areas generally indicate the need for further assessment for the presence of dementia.
The Agency for Health Care Policy and Research convened an 18-member private-sector, interdisciplinary panel composed of psychologists, psychiatrists, neurologists, an internist, geriatricians, nurses, a social worker, and consumer representatives. The panel conducted extensive literature searches to identify empirical studies of assessment of mental status instruments for differentiating persons with and without dementia and instruments used in the assessment of persons with Alzheimer's disease. It conducted additional literature searches related to assessment of functional impairment and risk factors for dementia and conducted meta-analyses. The panel also held a public hearing to give interested organizations, individuals, and agencies an opportunity to present oral or written testimony for the panel's consideration.
The results of the literature reviews and meta-analyses were used to develop a draft guideline. Copies were distributed for two peer review cycles. Reviewers were selected to represent a broad range of disciplines and clinical practice areas. A total of 109 reviewers submitted comments, which were collated and reviewed by the panel co-chairs and used to develop the final guideline.
Additional guideline information will be available later this year (Winter 1996) in several forms:
To obtain further information on the availability of the Quick Reference Guide or Consumer Version, call the AHCPR Publications Clearinghouse at (800) 358-9295.
Single and bulk copies of the Clinical Practice Guideline, Recognition and Initial Assessment of Alzheimer's Disease and Related Dementias, may be purchased, when available, from the U.S. Government Printing Office by calling (202) 512-1800.
The Clinical Practice Guideline, Quick Reference Guide, and Consumer Version will also be available on the Internet through the AHCPR Home Page. You can access the guideline products by using a Web browser, specifying the URL www.ahrq.gov/clinic/, and clicking on Clinical Practice Guidelines Online.
AHCPR, a part of the U.S. Public Health Service, is the lead agency charged with supporting research designed to improve the quality of health care, reduce its costs, and broaden access to essential services.
U.S. Department of Health and Human Services
Public Health Service
Agency for Health Care Policy and Research
2101 East Jefferson Street, Suite 501
Rockville, MD 20852
Current as of September 1996
AHCPR Publication No. 97-R123
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