Practice Parameters: Diagnosis, Treatment, and Early Detection of Dementia
The American Academy of Neurology (AAN) periodically releases Practice Parameters -- extensively referenced, evidence-based reviews that give 4 levels of recommendations, from "standards" to "advisories." Three recent Practice Parameters deal with dementia, revising the 1994 Practice Parameter for the Diagnosis of Dementia (see Neurology 1994; 44:2203) and providing new parameters for management of dementia and for early detection of dementia (mild cognitive impairment).
The growth of the dementia literature has been exponential: Of the approximately 35,000 articles on dementia or Alzheimer's disease (AD) published in the last 40 years, more than 80 percent were published after 1985. Unlike Moses, who, after a few days on Mount Sinai, returned with 10 rules cast in stone that would last for millennia, the AAN committees came up with 3 standards, 29 guidelines, and 11 options, any of which may be obsolete within weeks or months.
The recommendations for the diagnosis of dementia update those from 1994 and lean heavily on those recommendations, on the NINCDS-ADRDA definitions of AD (see Neurology 1984; 34:939), and on the DSM-III-R criteria of the American Psychiatric Association. Key changes include upgrading noncontrast CT or MRI studies from an "option" to a "guideline," no longer recommending routine serologic screening for syphilis, and recommending that CSF 14-3-3 protein be obtained for the diagnosis of Creutzfeldt-Jakob disease. SPECT and PET imaging are not recommended, nor is routine screening for genetic markers or the use of other spinal fluid, blood, or urine biomarkers for AD. Use of published diagnostic criteria for vascular dementia, Lewy body dementia, and frontotemporal dementia are considered "options," but of limited reliability.
Comment: The primary causes of progressive degenerative dementias remain obscure, and age is by far the most important risk factor. Clinical evaluation, including psychometric testing, is the best way to recognize the presence of a progressive dementia; etiologies are distinguished largely on clinical grounds, but laboratory tests may identify some causal or contributory factors that would not otherwise be recognized. Despite the relative rarity of unexpected causal or contributing factors, the costs -- both human and financial -- of missing treatable conditions are great. A physician with expertise in this area should always do a detailed dementia evaluation, and appropriate laboratory studies should be obtained before accepting the diagnosis of one of these presently incurable conditions.
Recommendations for the management of dementia include using anticholinesterase medications (donepezil, galantamine, rivastigmine) for cognitive symptoms in patients with mild to moderate AD and using vitamin E to slow disease progression. Evidence for using anti-inflammatories or antioxidants was insufficient, and estrogen was found to have no place in treating dementia. Antipsychotics are recommended for treating agitation or psychosis in patients with dementia, and antidepressants for treating these patients' depression. Educational programs for caregivers and for staff of long-term care facilities, support groups, and environmental modifications also were recommended.
Comment: The many recommendations for managing dementia reflect the fact that currently available treatments are of limited benefit. Progressive dementias severely disrupt the lives of patients and their families, and the available drugs produce minimal improvements. Atypical antipsychotics for severe behavioral problems are the most effective treatments at present, although without cognitive benefit. The role of vitamin E remains equivocal. The nonpharmacologic strategies are useful to help patients and their caregivers cope with the unrelenting decline in function and quality of life that inevitably occurs.
Patients with mild cognitive impairment who do not meet criteria for dementia are noted to be at increased risk for developing dementia over time. Follow-up with evaluation for progression to more severe impairment is recommended. Screening instruments, such as the Mini-Mental State Examination, and more detailed neuropsychological batteries could serve this purpose; interview-based screening tests were considered less reliable. No recommendations are made for screening asymptomatic populations for early dementia.
Comment: The benefit of identifying progressive dementing processes from their earliest symptoms is not clear at present. If and when early diagnosis leads to effective treatment or prevention of progression, it could become of major importance. Early identification of dementia may be useful for personal, social, and financial reasons: to plan for the future, to alert caregivers regarding driving competence, and to understand and anticipate expected cognitive and behavioral changes. Conversely, misdiagnosing early dementia in elderly individuals with only the usual cognitive changes of advancing age can be devastating. Our practice is to carefully assess elderly individuals who are concerned about their cognitive function to rule out any treatable disorders and then to follow their cognition over time before reaching any decision about possible dementia.
Progressive dementia is not a monolith and may be caused or exaggerated by many underlying disorders; its effects on thinking, memory, and behavior range from minimal to profound. Physicians caring for patients with cognitive issues must (1) first be certain that they accurately determine whether dementia is present, (2) make sure they do not miss a treatable condition, and (3) use the limited armamentarium of pharmacologic, behavioral, and educational treatments at our disposal. When the issue of progressive dementia arises, specialists with expertise in this area should be consulted. The Practice Parameters of the AAN provide useful recommendations; at some future time, the prevention, diagnosis, and treatment of these disorders will become both simpler and far more effective.
David A. Drachman, MD, is Professor and Chairman, Department of Neurology, University of Massachusetts Medical School, Worcester, MA.
Published in Journal Watch Neurology August 9, 2001
Knopman DS et al. Practice parameter: Diagnosis of dementia (an evidence-based review). Report of the Quality Standards Subcommittee of the American Academy of Neurology. Neurology 2001 May 8 56 1143-1153.
Doody RS et al. Practice parameter: Management of dementia (an evidence-based review). Report of the Quality Standards Subcommittee of the American Academy of Neurology. Neurology 2001 May 8 56 1154-1166.
Petersen RC et al. Practice parameter: Early detection of dementia: mild cognitive impairment (an evidence-based review). Report of the Quality Standards Subcommittee of the American Academy of Neurology. Neurology 2001 May 8 56 1133-1142.
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