Dementia 21

21 ^Dementia

William McCarberg, ^MD

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INTRODUCTION

As the US population ages, the incidence and prevalence of various demen- tias will increase in the absence of new methods for preventing or reversing dementia. With 4 million individuals with Alzheimer’s disease (AD) in 1990, the National Institutes of Health estimates that there will be 8.5 million Americans with this disease by the year 2030, and an unknown number of peo- ple with other dementias. In 1998, the annual cost for the care of patients with AD in the Unites States was approx $40,000 per patient. If one were able to suc- cessfully identify and treat mild cognitive impairment (MCI) such that the pro- gression of these individuals to AD could be delayed by 1 yr, there would be significant savings.

In 1994, the Quality Standards Subcommittee of the American Academy of Neurology (AAN) published the Diagnosis and Evaluation of Dementias. This practice parameter was designed for use by neurologists in the evaluation of patients with possible dementia and was based on evidence. Since 1994, con- siderable progress has been made prompting an updated report from the Quality Standards Subcommittee. The 2001 guideline was published in three parts:

early detection of dementia: MCI; diagnosis of dementia; and management of dementia (1–3).

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From: Current Clinical Practice: Essential Practice Guidelines in Primary Care Edited by: N. S. Skolnik © Humana Press, Totowa, NJ

All three reports follow a similar format:

• Clinical question statement: strategic questions are asked about each topic.

• Analysis of evidence: the clinical questions are analyzed presenting the quality of available evidence.

• Practice recommendations: grouped into three categories of patient manage- ment recommendations based on the quality of the evidence: (a) standard—

high degree of clinical certainty; (b) guidelines—moderate clinical certainty;

(c) option—clinical utility is uncertain.

The databases searched for the analysis of evidence comprised of MED- LINE, EMBASE, Excerpta Medica, BIOSIS, Current Contents, Psychological Abstract, Psycho Info, Cochrane Database and CINAHL. Each identified arti- cle was classified on the quality of evidence (classes I–IV; Table 1). When available, data on specificity and sensitivity were used. Inclusion of articles was dependent on a consensus of the Quality Standards Subcommittee and the Practice Committee of the AAN.

EARLY DETECTION OF DEMENTIA: MCI

Epidemiological studies of aging and dementia have demonstrated three groups of subjects—those who are demented, those who are not demented, and individuals who cannot be classified because of cognitive (memory) impair- ment but do not meet criteria for dementia. MCI (Table 2) refers to the state of cognitive and functional ability between normal aging and very mild AD. It is characterized by a memory complaint corroborated by a close friend or partner, objective memory impairment, and generally normal cognitive function with intact activities of daily living.

Table 1

Classification of the Evidence

Class Description

I Highest quality, well-designed prospective study in broad group of patients

II Well-designed prospective study of a narrow spectrum of patients with the condition, or a well-performed retrospective study of a broad group of patients

III Evidence from a retrospective study in which a narrow spectrum of patients are studied, and in which tests were applied in a blinded fashion

IV Evidence from studies that were not blinded or recommendation

provided by expert opinion

Clinical Question Statement

1. Does the presence of MCI predict the development of dementia?

Four class II studies, three in the United States and one in Canada, showed con- version from MCI to AD of 6 to 15% per year. Taken together, these studies indicate that individual as being cognitively impaired but not meeting the clin- ical criteria for dementia and has a high risk of progressing to dementia or AD.

2. Does screening at-risk subjects lead to the diagnosis of dementia?

The Mini-Mental Status Examination (MMSE) is a widely recognized instru- ment for the detection of cognitive impairment. Two large class I and several class II studies provide data on this instrument. The MMSE, originally designed as a bedside screening tool, appears to have limitations as a gen- eral population screening tool. It is still useful in examining patients with MCI. Other less-studied tools including Kokmen Short Test of Mental Status, 7-min screen, and memory impairment screen are useful for the detection of dementia when used in patient populations with elevated prevalence. Brief focused screening instruments such as drawing the face of a clock with a des- ignated time, the subject’s ability to tell time, and ability to make change are less useful.

Neuropsychological batteries include nonverbal memory, confrontational naming, recall of prose passages, calculation, visuomotor function, construction memory, attention, and other tests. Class II and III studies showed good predictive value. A close observer such as a significant other often is the first to complain of the patient’s cognitive decline. Several tools (informant-based instruments) emphasize the history from such observers. Not enough work has been done to recommend these tools.

Practice Recommendations

• There were sufficient data to recommend the evaluation and clinical monitor- ing of person with MCI because of the person’s increased risk for developing dementia (guideline).

• Screening instruments such as the MMSE were found to be useful to the clini- cian for assessing the degree of cognitive impairment (guideline), as were neuropsychological batteries (guideline).

• Brief focused cognitive instruments and structured informant interviews were not thought to be as helpful (option).

DIAGNOSIS OF DEMENTIA

Dementia describes a variety of diseases with resultant loss of cognitive

functioning. These include AD, vascular dementia (VAD), dementia with Lewy

bodies (DLB), frontotemporal dementia (FTD), prion diseases, and others.

Clinical Question Statement

1. Are the current criteria for the diagnosis of dementia reliable?

The diagnostic criteria most widely used in the United States are based on def- initions contained in the Diagnostic and Statistical Manual, 3rd edition, revised (DSM-IIIR). DSM-IIIR states:

The essential feature of Dementia is impairment in short- and long-term mem- ory, associated with impairment in abstract thinking, impaired judgment, other disturbances of higher cortical function, or personality change. The disturbance is severe enough to interfere significantly with work or usual social activities and relationship with others. The diagnosis of Dementia is not made if these symptoms occur in Delirium.

The DSM-IIIR definition of dementia has good to very good reliability. The DSM-IV definition, which is identical to DSM-IIIR, has not been subjected to assessment but presumably would have similar reliability.

2. Are current diagnostic criteria sufficiently accurate to establish a diagnosis for the prevalent dementias in the elderly?

AD: Three class I and 10 class II studies addressed the diagnostic accuracy of AD using neuropathological confirmation. DSM-IIIR of “probable” AD achieved good sensitivity (81%) and average specificity (70%) across studies.

VAD: The diagnosis of VAD is difficult using current criteria. Recent studies dis- tinguished between “some or any” vascular lesions against “pure” vascular pathology (the circumstance in which vascular pathology was both sufficient to account for cognitive symptoms and unaccompanied by other pathology). Some vascular pathology existed in 29–41% of dementia cases coming to autopsy with pure vascular pathology accounting for about only 10%. The Hachinski ischemic score is the most suitable for identifying the majority of patients with VAD.

DLB: DLB has been defined clinically by the presence of dementia, gait/

balance disorder, prominent hallucinations and delusions, sensitivity to tradi- tional antipyschotics, and fluctuations in alertness. Multiple class I and II stud- ies have investigated the diagnostic criteria for DLB and all either demonstrate low sensitivity and/or specificity. Current neuropsychological tests do not reli- ably differentiate DLB from either AD or VAD. Neuroimaging is also unsuc- cessful in differentiating DLB from AD despite reported less atrophy of the temporal lobe in AD.

FTD: Early loss of social awareness, hyperorality, and stereotyped, persevera- tive behavior were somewhat sensitive (63–73%) and highly specific (>96%) in diagnosing FTD. Neuropsychological test profiles of patients with FTD typ- ically reveal deficits in verbal fluency, abstraction, and executive function;

however, patients with AD demonstrate substantial impairment in all of these functions as well. Neither the clinical nor neuropsychological profile of the frontotemporal syndrome is specific for FTD.

Prion disease: The diagnostic criteria of Masters were used in a class I study

of 188 patients with Creutzfeldt-Jakob disease (CJD). Autopsy-proven dis-

ease was found in 97% of the “probable” and 44% of the “possible” cases.

3. Do laboratory tests improve the accuracy of the clinical diagnosis of dement- ing illness?

Given the goal of minimal undetected structural lesions, the data supports the use of a neuroimaging examination—either a noncontrast computed tomogra- phy (CT) or magnetic resonance imaging (MRI) scan—usually at the time of the initial dementia assessment to identify pathology such as brain neoplasms or subdural hematomas. Normal pressure hydrocephalus, which might be detected by CT or MRI and might be responsive to treatment, is very rare.

Genetic biomarkers—the genetics of dementing illness is a maturing field.

Although autosomal-dominant transmission is not evident, advances in the identification of genetic markers for dementia of the familial nature increases awareness of these disorders. One large pathologically confirmed class II study using apolipoprotien (APO) E4 found only a slight increase in positive-predic- tive value. In patients with a clinical diagnosis of AD, APO E testing increased predictive value by only 4% with the presence of APO E4. No genetic testing is recommended for AD, DLB, or CJD. The CSF 14-3-3 protein is recom- mended in the diagnosis of CJD.

4. What comorbidities should be evaluated in elderly patients undergoing an initial assessment for dementia?

Up to 12% of demented patients were also depressed. Screening with the appro- priate office-based tool is recommended.

Vitamin B

deficiency is common in elderly patients; however, improved cog- nition with treatment is uncertain. As a cause of dementia, vitamin B

defi- ciency is unusual, but ease of screening and treatment warrant monitoring for this disorder.

Hypothyroidism is also common in the elderly. The link between decreased thy- roid function and cognition is unclear, with variable results from several stud- ies. In population-based studies, increased thyroid-stimulation hormone carried an increased risk of dementia; however, this risk is small and often not reversible with treatment. However, screening is recommended for this comorbidity.

No other testing, including testing for syphilis, hypoparathyroidism, or hepatic encephalopathy, is recommended by current evidence.

Practice Recommendations

• DSM-IIIR definition of dementia is reliable and should be used in diagnosis of AD and CJD (guideline).

• Diagnostic criteria for VAD, DLB, FTD is imprecise with current evidence (option).

• Structural neuroimaging with noncontrast CT or MRI is appropriate (guideline).

• No genetic markers are recommended for routine diagnostic purposes. CSF 14-3-3 protein is useful for confirming the diagnosis of CJD (guideline).

• Depression, vitamin B

, and hypothyroidism, but not syphilis, should be

screened (guideline).

MANAGEMENT OF DEMENTIA

The previously identified databases were searched and revealed 2548 articles identified with 380 meeting predefined inclusion criteria to help answer the fol- lowing questions. Drugs that were reviewed are shown in Table 3.

Clinical Question Statement

1. Does pharmacotherapy improve outcomes in patient with dementia compared with no therapy?

AD—multiple drugs were identified in the cholinesterase inhibitors category for the 2001 study. All were approved for use in AD: tacrine, donepezil, rivastigmine, and galantamine (Note: since issue of the guideline: Memantine, an N-methyl-

-aspartate receptor antagonist [a newer drug], was not reviewed but has been approved by the Food and Drug Administration).

Cholinesterase inhibitors as a class are consistently better than placebo.

However, the disease eventually continues to progress and the average treat- ment effect is modest. The main difference between the multiple agents is in side-effect profile and ease of administration.

One study of vitamin E or selegiline showed a possible benefit. These agents should not be combined.

A wide group of agents with diverse mechanisms of action have been tested in at least one class I trial but there is incomplete or conflicting evidence for these agents. Nonsteroidal anti-inflammatory agents show a slight decline with high drop-out rates. Two well-designed trials failed to show that Premarin

slowed decline in AD.

2. Does pharmacotherapy for noncognitive symptoms improve outcomes in patients with dementia compared with no therapy?

Behavioral disturbances including agitation, psychosis, anxiety, disinhibition, sleep disturbances, wandering, shadowing, compulsive behaviors, apathy, and others are common in dementia. Pain or environmental triggers may be associated with these disturbances. Treatment of these behaviors can improve quality of life for patients and caregivers. When nonpharmacological strategies for environmen- tal triggers are not apparent, class I evidence supports the use of both traditional and atypical antipyschotics in the treatment of both agitation and psychosis.

Atypical agents are better tolerated. Anticonvulsants, benzodiazepines, antihista- mines, monoamine oxidase (MOA) inhibitors, and selective serotonin reuptake inhibitors (SSRI) lack evidence of efficacy. Other behavioral disturbances also lack convincing evidence in any drug trials. Depression is also commonly found in the patient with dementia. Selected tricyclics, SSRIs, and MAO-B inhibitors offer benefit in treatment of depression in the demented patient.

3. Do educational interventions improve outcomes in patient and/or caregivers of

patients with dementia compared with no such interventions?

Trials comparing educational programs to no program or a support group, showed impact only on patients and caregivers without effect on disease sever- ity or patient outcome. Short-term improvement in caregivers’ disease knowl- edge and ability to cope occurs, but decision-making skills and perceived burden did not improve. Intensive long-term education and support delayed time to nursing home placement by 12–24 mo.

4. Do nonpharmacological interventions other than education improve outcomes in patients and/or caregivers of patients with dementia compared with no such interventions?

Interventions to improve functional performance: Two class I studies show that behavior modification, scheduled toileting, and prompted voiding can reduce urinary incontinence. Graded assistance, skills practice, and positive reinforce- ment can increase functional independence.

Nonpharmacological interventions for problem behaviors: Sensory stimulation of various types (music, bright lights, verbal cues, walking, light, exercise) are usu- ally studied in a multifaceted approach to treatment of patients with dementia and make it difficult to judge any one treatment; however, they may have a beneficial impact on agitation.

Psychosocial interventions for caregivers: Psychosocial interventions directed toward caregivers, which may include education, support, and respite care, may improve caregivers’ emotional well-being and quality of life as well as delay nursing home placement.

Practice Recommendations

• Cholinesterase inhibitors (and memantine) benefit patients with AD, although the benefit appears small (standard). Vitamin E delays the time to clinical worsening (guideline). Selegiline, other antioxidants, anti-inflammatories, and estrogen are not supported by current evidence.

• Antipyschotics are effective for agitation and psychosis in which environmen- tal manipulation fails (standard). Antidepressants are effective in depressed patients (guideline).

• Staff at long-term care facilities should be educated about AD to minimize the unnecessary use of antipsychotic medications (guideline).

• Behavior modification, scheduled toileting, and prompted voiding reduce uri- nary incontinence (standard). Functional independence can be increased by graded assistance, skills practice, and positive reinforcement (guideline).

More evidence-based studies must explore the early detection of dementia,

better methods of diagnosis including biogenetic markers and earlier treat-

ments that include preventative strategies. These should include prospective

studies of elderly at-risk individuals prior to the development of dementia.

Studies must be designed to guide routine clinical care and research involving patient with dementia. Guidance in these areas is critical for therapeutic research to continue effectively.

SOURCES

1. Early Detection of Dementia: Mild Cognitive Impairment (2001) Neurology 56:113.

2. Diagnosis of Dementia (2001) Neurology 56:1143.

3. Management of Dementia (2001) Neurology 56:1154.