Dr Peter Connelly explains how the updated SIGN guideline will help GPs to diagnose dementia and keep patients and carers informed about the disease


   

Alois Alzheimer presented the first known case of his eponymous disease in 1907. We now know it is the most prevalent cause of dementia in the UK.1

Over the past 30 years the feeling of therapeutic nihilism surrounding dementia has begun to lift, first with a recognition that improving the ability of carers to manage people with dementia could lead to their successful maintenance at home, and second with the advent of therapies that were of direct benefit to patients.

The previous SIGN guideline on dementia (SIGN 22) concentrated only on the management of behavioural problems.2

The recommendations were due to be updated, but the advent of cholinesterase inhibitors has changed the face of dementia treatment and has made it essential that dementia is recognised early, at a point where the patient as well as the carer will appreciate the benefits of intervention.

The new guideline (SIGN 86), published in February, covers both recognition and management and focuses on interventions that are of direct benefit to patients.3

Recommendations in SIGN 86 are graded according to the strength of evidence (Figure 1).

Subtypes of dementia

Alzheimer's disease is the most common subtype. In Alzheimer's there is a progressive deterioration in the ability of the patient to perform basic activities of daily living and behavioural changes tend to occur as the illness worsens.

Vascular dementia may present abruptly following a stroke and is often characterised by periods of sudden decline and others of relative stability. However, cerebrovascular disease commonly co-exists with Alzheimer's disease and such patients tend to have increased physical problems such as urinary incontinence, decreased mobility and balance problems.

Dementia with Lewy bodies (DLB) is less common and new consensus criteria have been produced recently.4 Fluctuation in awareness, Parkinsonian symptoms and visual hallucinations are characteristic features of DLB.

Fronto-temporal dementia is uncommon but is seen in a significant proportion of people who present with dementia under the age of 65 years. Changes in behaviour, e.g. disinhibition, lack of judgement, loss of social awareness and loss of insight, are much more common than memory problems. A positive family history is not uncommon.

Figure 1: Key to evidence statements and grades of recommendations
Figure 1: Key to evidence statements and grades of recommendations of SIGN
Reproduced from Management of patients with dementia by kind permission of SIGN

Diagnosis

Dementia is a clinical diagnosis made when acquired cognitive deficits in more than one area interfere with activities of daily living and represent a decline from a previous higher level of functioning. All the major diagnostic criteria, i.e. American Psychiatric Association Diagnostic and Statistical Manual 4th edition (DSM-IV),5 the McKhann Criteria6 and ICD-107 refer to these crucial areas.

The guideline highlights the importance of taking a careful history. Increasing memory impairment is common as people age but rapid change in memory is not a normal feature of old age. A change in the rate of decline in memory must not be ignored, especially if the duration of decline is in excess of 6 months.

Carers may be more forthcoming about the mode of onset and degree of memory impairment shown by the patient and information from the carer is vital. Vascular risk factors, family history and depression need to be assessed. Factors that should raise the suspicion that dementia might be present include evidence of declining ability to:

  • use the telephone
  • manage medication
  • manage money
  • use a list for shopping
  • undertake a journey alone.

An objective assessment of change, such as the Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE, see Box 1),8 which can be completed by the carer in less than 10 minutes, can be a valuable source of information.

The Mini-Mental State Examination (MMSE)9 (Box 2) contains elements that test key areas of intellectual deficit as defined in Box 1, although in a very basic fashion.

Nonetheless, errors in the MMSE coupled with features suggestive of dementia should trigger the need for further evaluation.

Excluding alternative causes

Truly reversible causes of dementia are very rare. However, hypothyroidism, B12 or folate deficiency, anxiety and depression can all co-exist with dementia and treating these physical or mental problems can improve cognition, function and behaviour.

Good practice suggests screening for co-morbid physical conditions should be undertaken according to history and clinical circumstances, but the presence of co-morbid depression should always be considered.

Box 1: Diagnostic criteria for dementia of the Alzheimer’s type
Box 1: Diagnostic criteria for dementia of the Alzheimer’s type
Reproduced by kind permission of Professor Anthony Jorm, University of Melbourne

Specialist investigations

Specialists normally perform more detailed cognitive tests, including memory testing (such as word learning and recall) and assessment of frontal lobe functioning using verbal fluency tests, finger tap or motor sequencing. Many of these tests are fairly brief and simple to perform, and GPs could undertake administration of the tests following suitable training.

Tests such as the Addenbrookes Cognitive Examination10 are more extensive than the MMSE but are still relatively brief.

More intensive assessments such as detailed neuropsychological testing can be extremely helpful in identifying complex presentations of dementia but the added value of neuropsychological testing in patients who have already received simple but comprehensive cognitive testing has not been established. Functional assessment may involve detailed evaluation of daily living skills by an occupational therapist.

Computed tomography (CT) scanning is the most widely available neuro-imaging investigation and structural imaging using CT or magnetic resonance imaging (MRI) should ideally form part of the diagnostic work up of patients with suspected dementia.

Functional imaging, e.g. single photon emission computed tomography (SPECT), may aid the differential diagnosis of dementia when the diagnosis is in doubt.

Box 2: The Mini-Mental State Examination (MMSE)
Box 2: The Mini-Mental State Examination (MMSE)
Reproduced from Folstein MF, Folstein ME,McHugh PR. Psychiatry Research 1975; 12(3): 189-198,with permission from Elsevier.

Specific treatment

The most specific treatment of dementia is the use of cholinesterase inhibitors for Alzheimer's disease. Three of these drugs exist:

  • donepezil
  • rivastigmine
  • galantamine.

Systematic reviews confirm their effectiveness in treating cognitive decline in people with mild to moderate Alzheimer's disease;11-13 all three drugs seem equipotent.14 Each has an effect in maintaining cognition and function and reducing particular forms of behavioural disturbance such as apathy, irritability and visual hallucinations.

Current guidance recommends evaluation of response after 4-6 months but long-term usage is now commonplace and the ability of these drugs to maintain cognition and function over longer periods, e.g. more than 2 years needs further evaluation. Intolerance of one drug does not mean intolerance of the other two, but the value of switching drugs in cases where people have not responded remains uncertain.

At present there is limited published evidence for the benefits of memantine and its place in the treatment of dementia is consequently doubtful.

Ginkgo biloba is a popular complementary therapy but evidence would suggest that it is less potent in establishing cognitive improvement than cholinesterase inhibitors.15 Caution is required because of the possibility of interactions with other drugs. There is no evidence of the benefits of adding ginkgo biloba to a cholinesterase inhibitor, and this combination is best avoided.

Treating associated symptoms

Antidepressants should be used for the treatment of co-morbid depression in dementia providing their use is evaluated carefully for each patient.

Conventional antipsychotic drugs such as chlorpromazine and haloperidol have traditionally been used to treat behavioural problems associated with dementia. Side-effects such as sedation, movement disorder and increasing confusion are all recognised.

Atypical antipsychotics such as olanzapine and risperidone have a significant evidence base suggesting efficacy in managing behavioural problems associated with dementia especially psychotic phenomena and aggression.16 They have reduced sedation and extrapyramidal side-effects compared with conventional anti-psychotics although concern has been expressed about the risk of cerebrovascular adverse events including stroke.17

The risk of stroke associated with conventional antipsychotics has not been clearly established and practitioners are recommended to be cautious when assessing the risk of cerebrovascular disease, sedation and falls when choosing to prescribe any form of antipsychotic drug.

The ideal duration of treatment with antipsychotic drugs remains unclear. However, the guideline suggests that if a patient has been largely free from behavioural symptoms for a period of 3 months, reduction and withdrawal of the drug is unlikely to lead to a recurrence of behavioural problems.18

Non-pharmacological interventions

In recent years increasing weight has been given to the argument that in the treatment of dementia non-pharmacological interventions should be used first. However, there is little systematic evidence for the use of formal non-pharmacological therapies such as behaviour management, multi-sensory stimulation, light therapy or validation therapy in people with mild dementia.

Reality orientation therapy19 and possibly cognitive stimulation20 may be of benefit, although the amount and duration of each therapy necessary to maximise benefit is still to be evaluated.

There have been a greater number of studies on the role of non-pharmacological interventions in people with more severe dementia, but consistent benefits have not been found. Indeed, studies of non-pharmacological interventions often have lower baseline behaviour disturbance than those comparing antipsychotics with placebo.

The role of non-pharmacological interventions requires more careful evaluation and at present none can be recommended as a direct alternative to either cholinesterase inhibitors, antidepressants or antipsychotic medication.

A number of interventions lack evidence of clinical effectiveness including:

  • anti-convulsants for adverse behaviour
  • aspirin
  • benzodiazepines
  • memory books
  • reminiscence therapy.

Information for patients

Poor memory and language problems are key features of people with dementia. Consequently good communication between healthcare professionals, patients and their carers is essential. Patients and carers should be offered information tailored to the patient's perceived needs.

There is evidence that it is most helpful to give information at the point of diagnosis,21 although evidence for disclosure is inconsistent and limited in scale.

Currently it seems more common for carers to be routinely given information than the patients themselves but professionals need to be aware that many people with dementia can understand their diagnosis, receive information and remain involved in decision making.

Not all people with dementia wish to know their diagnosis and care must be taken to establish the patient's position before the diagnosis is given.

There are many methods of disseminating information to people with dementia, including written information, individual education, group education and counselling, although not everyone benefits from these interventions.

Sources of further information can be found in the section of the guideline entitled 'Information for discussion with patients and carers'.3

Carers

The guideline concentrates on interventions that are of direct benefit to patients and does not evaluate carer interventions unless they have been shown to benefit patients as well.

Benefits from complex interventions include delay in nursing home placement, 22,23 but at a practical level, primary care input through recognition of behavioural problems, education about dementia and attention to co-morbid physical and mental problems of patients and carers can help to reduce anxiety and depression in carers, improving their ability and motivation to continue managing the patient at home.

Conclusion

The number of people with dementia in the UK is growing rapidly. It remains an under-recognised and under-treated syndrome. Older people and healthcare professionals need to be aware of the potential significance of late onset memory impairment, especially if activities of daily living are affected.

Brief screening measures such as the MMSE can be helpful if these symptoms are present. More detailed intellectual and functional assessment can be undertaken by specialist services and neuropsychology can be particularly valuable for complex presentations.

The use of cholinesterase inhibitors in mild to moderate Alzheimer's disease is the most widely used specific therapy for dementia. These drugs are effective at improving cognition and stabilising function, and treating certain behaviours such as apathy, irritability and visual hallucinations.

They are not a direct alternative to antipsychotic medication which can be effective in reducing aggression and psychotic features, but which need to be used cautiously because of the risk of side-effects such as sedation, adverse cerebrovascular events and possible falls.

Although few cases of dementia are truly reversible, co-morbid physical and mental conditions such as hypothyroidism and depression are common and need identification and treatment in their own right.

Good communication and an interpersonal approach are essential to managing people with dementia successfully. However, the use of specific non-pharmacological interventions has very limited evidence and there is no clear guidance on which of these therapies is comparatively more effective at the different stages of dementia.

Further evaluation of their effectiveness is essential.

Most, although not all, people with dementia wish to know their diagnosis. Where possible people with dementia should continue to be involved in decision making about their own treatment.

Full copies of Management of patients with dementia can be downloaded from the SIGN website: www.sign.ac.uk.

 

  1. www.alzheimers.org.uk
  2. Scottish Intercollegiate Guidelines Network (SIGN 22). Interventions in the management of behavioural and psychological aspects of dementia. Edinburgh: SIGN, 1998
  3. Scottish Intercollegiate Guidelines Network (SIGN 86). Management of patients with dementia. Edinburgh: SIGN, 2006
  4. McKeith I, Mintzer J, Aarsland D et al. International Psychogeriatric Association Expert Meeting on DLB: Dementia with Lewy bodies. Lancet Neurol 2004; 3 (1):19-28.
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  12. Birks J, Grimley Evans J, Iakovidou V, Tsolaki M. Rivastigmine for Alzheimer's disease. Cochrane Database Syst Rev 2000; 4: CD001191.
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  17. www.mhra.gov.uk
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Guidelines in Practice, May 2006, Volume 9(5)
© 2006 MGP Ltd
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