Purpose: The purpose of this SBU project was to use systematic database searches and a review of the scientific literature as a starting point to assess the current state of knowledge about dementia disorders from various perspectives. Those perspectives included occurrence, risk factors for development, diagnostics, care, ethical considerations, ethnicity and drug therapies, as well as the health economic aspects.
Objective of the report: The objective of the report is to:
Analyse current knowledge and values about caregiving in order to help caregivers of dementia patients.
Support nurses and caregivers in diagnosing and treating people with dementia disorders.
Describe the key role of family members in caring for people with dementia.
Provide public officials and other decision makers with a scientific basis for formulating dementia care policy.
Occurrence, risk and prevention:
Two thirds of the approximately 140,000 Swedes with a dementia disorder have Alzheimer’s disease. The other two leading disorders are vascular dementia (10%) and frontotemporal dementia (5%). Other disorders occur in various combinations with non-dementia conditions, such as the frequent comorbidity of Lewy body dementia and Parkinson’s disease.
A common denominator of all dementia disorders is that memory and cognitive function is impaired due to neuron death.
Age is the primary risk factor for developing dementia (strong scientific evidence). Rising life expectancies are increasing the number of people who develop dementia disorders. Approximately 1% of 65-year-olds and more than 50% of 90-year-olds have a dementia disorder.
Among people older than 85, a greater percentage of women than men have Alzheimer’s disease (moderately strong scientific evidence).
Although known genetic changes that cause Alzheimer’s disease are rare, the Apolipoprotein E (ApoE) ε4 allele is known to increase the risk (strong scientific evidence).
Currently, there is no specific preventive treatment for dementia, but blood pressure monitoring in middle age reduces the risk of developing it later in life (moderately strong scientific evidence).
Treatment with antihypertensives reduces the risk of developing vascular dementia later in life (moderately strong scientific evidence).
The progression of dementia can be delayed among older people who continue to lead active lives (moderately strong scientific evidence).
Relationship to other diseases:
Cognitive deterioration due to hypothyroidism or hyperthyroidism is unrelated to dementia but needs to be diagnosed and treated.
Existing studies show contradictory results with respect to the cor- relation between low vitamin B12 (cobalamin) levels and impaired cognitive function or Alzheimer’s disease. There is a moderate corre- lation between low folic acid levels and impaired cognitive function.
There is a strong correlation between high homocysteine levels and impaired cognitive function.
Treatment with vitamins such as cobalamin or folic acid that lower homocysteine levels does not lead to any improvement in impaired cognitive function.
Diagnosis:
Currently, there is no simple, reliable test for identifying dementia at an early stage. In their present form, no diagnostic instruments are sufficiently developed to be used for dementia screening.
A gold standard is lacking for identifying dementia and ruling out other diseases. Imprecise definitions of the various dementia disorders limit the ability of caregivers to distinguish one disorder from another.
Many methods (scales and indices) are used to measure the severity of various symptoms of dementia, such as cognitive deterioration, functional decline and behavioural changes. The insufficient evaluation to which most methods have been subjected makes it more difficult to assess the efficacy of specific care and treatment approaches.
Family, friends and caregivers (knowledgeable informants/collateral sources) can provide valuable information to supplement diagnosis and the patient’s narrative. Standardised interviews with collateral sources (moderately strong scientific evidence), as well as the clock drawing test and other simple exercises (moderately strong scientific evidence), allow general practitioners to perform an initial selection of patients for possible further diagnosis.
After a baseline assessment, detection of atrophy of the medial temporal lobe by computer tomography (CT scan) and magnetic resonance imaging (MRI scan), respectively can identify people who have Alzheimer’s disease with a high degree of certainty (strong scientific evidence).
After a baseline assessment, biochemical diagnostic markers such as cerebrospinal fluid analysis (strong scientific evidence) and neuropsychological testing (strong scientific evidence) effectively identify people with Alzheimer’s disease.
Functional diagnosis – positron emission tomography (PET scan) and single photon emission computed tomography (SPECT scan) – has moderate value (moderately strong scientific evidence), while neurophysiological testing – EEG brain mapping and quantitative EEG – has limited value (limited scientific evidence) for identifying dementia disorders.
The apoliprotein E ε4 is a poor marker for the ApoE ε4 allele for identifying Alzheimer’s disease or for differential diagnosis.
Studies are lacking that have combined different types of testing. As a result, which approaches are most cost-effective is not known with certainty.
Ethical considerations and attitudes:
Because dementia affects almost all areas of life, ethical issues often arise. Values and beliefs – including views about the human con- dition and the appropriateness of various interventions – influence diagnosis, care and treatment alike. The issues are rarely simple or uncomplicated, but tend to require active moral reflection based on both knowledge and subjective principles.
People with dementia are sometimes stigmatised. Greater under- standing and candour can lead to more objective and compassionate social attitudes.
Dementia care varies considerably from one Swedish county and municipality to another. The results of the literature search should be used, particularly by the municipalities, for the benefit of patients and their families.
Caring for people with dementia:
In addition to knowledge and objectivity, effective care requires a trusting relationship between the patient and caregiver. Because the studies that have assessed various kinds of care do not generally control for or evaluate the impact of that relationship, the benefits of a particular approach are difficult to determine. Substantial variations with regard to purpose, type of intervention and assessment instrument hamper attempts to summarise the studies as a single evidence grade. A number of studies, though with generally low internal validity, have demonstrated the efficacy of various interventions – such as multisensory stimulation (Snoezelen), music and reminiscence therapy – for improving the quality of life of individual patients.
Many studies have looked at training programmes and clinical guidance for nurses and caregivers. But given that the studies do not meet suitable criteria for assessing evidence, the most effective approach cannot be identified. Generally speaking, nurses and caregivers need support in the form of training.
Dementia affects the lives of family members as well as the patient. Psychosocial training programmes (moderately strong scientific evidence) for family members, along with instruction in dealing with the behavioural problems that accompany dementia (limited scientific evidence), can alleviate their anxiety and depression.
While good quality of life is a vital objective in caring for people with dementia, effective methods are lacking for evaluating quality of life from the patient’s point of view.
Existing studies have not found that respite care reduces the community resources that must be devoted to people with dementia or the anxiety experienced by family members. But it offers family members the opportunity to obtain some valuable relief.
Drug therapies:
Existing studies have not found that treatment with cholinesterase inhibitors (donepezil, galantamine and rivastigmine) affects the progress of mild to moderate Alzheimer’s disease. But it offers some improvement of global function and cognition (moderately strong scientific evidence). However, knowledge about effects for longer than one year is limited.
Treatment of mild to severe Alzheimer’s disease with memantine can lead to some cognitive improvement (limited scientific evidence). Knowledge about long-term effects is limited to therapy for six months.
Extract of Ginkgo biloba can provide some relief of cognitive and Activities of Daily Living (ADL) impairment (limited scientific evidence). Knowledge about long-term effects is limited to therapy for six months.
Cholinesterase inhibitors commonly cause the adverse effects of dizziness and nausea (moderately strong scientific evidence).
A number of drug groups, such as benzodiazepines and anticholi- nergics, have undesired effects on cognition (strong scientific evidence).
People with dementia disorders commonly develop depression. Selective serotonin reuptake inhibitors (SSRIs) can provide some relief. The scientific evidence for treating coexisting depression in people with dementia is however limited (limited scientific evidence).
Drug therapies for behavioural symptoms in people with dementia disorders have limited effectiveness (limited scientific evidence). Increased mortality has been demonstrated in people with dementia who have been treated with atypical antipsychotics. The impact on mortality has not shown up in individual studies but was identified by a meta-analysis (moderately strong scientific evidence). Corresponding data is lacking concerning older antipsychotics.
The health economic studies published so far suffer from methodological flaws and are not conclusive. Because only a few studies contain empirical data, determining whether drug therapy is cost-effective or not is difficult.
Social impact:
Approximately half of all people with dementia move to assisted living facilities within 2–3 years after diagnosis. Approximately half of all people with dementia are in assisted living facilities.
The burden of dementia in Sweden corresponds to approximately sek 40 billion (eur 4.36 billion) a year, a figure that is likely to grow as the size of the elderly population continues to increase. Municipalities bear more than 80% of the costs, which cover care at assisted living facilities and support for those who remain at home.
Additional research needs: Additional research on dementia disorders is required in several areas:
How the various disorders progress
Development of diagnostic methods
Better evaluation of instruments for identifying and measuring cognitive and related symptoms, as well as assessing the quality of life of people with dementia
Development of caregiving methods, such as guidance, training and studies that focus on the relationship between patient and caregiver
Clearer ethical guidelines for diagnosis, treatment and care of people with dementia
Drugs for all categories of dementia that are more effective and cause fewer adverse effects
Studies that examine the long-term effects and costs of drug therapies.
Copyright © 2008 by the Swedish Council on Health Technology Assessment.