Introduction

Dementia represents a decline in cognitive function not because of impaired level of consciousness. In other words, it reflects a lower level of mental capacity and function than had been the case for a given individual. It demonstrates a process in which intellectual level has deteriorated despite retaining consciousness, thus excluding the confounding variable of delirium. The DSM IV-R diagnosis of dementia includes memory impairment and abnormalities in at least one of the following domains: language; judgment; abstract thinking; performance of tasks; constructional capabilities; or visual recognition.¹

What this dictates is a need to document impairment and decline of cognition, namely mental functioning, while concurrently excluding delirium. Delirium may occur consequent to a confusional state associated with interrupted vigilance, incapacity for maintenance of retained thought process, and impaired goal-directed activities.² Thus delirium may co-exist as a confounding factor and needs to be excluded when diagnosing dementia. Delirium may accompany a host of medical diagnoses as produced by metabolic derangement, exposure to toxins, drug effects (either licit or illicit), infections (either systemic with septicaemia or affecting the central nervous system (CNS) directly), head trauma or peri-ictal epileptic states. It follows that diagnosis of dementia should not be confounded by these concomitant illnesses, although the presence of these conditions, in the absence of any associated delirium, would not exclude dementia.³ Cerebral pathology, resulting in dysphasia or psychiatric disorders, such as depression, also needs to be excluded. This may evoke a picture similar to dementia, resulting in pseudo-dementia.

For a diagnosis of dementia to be considered, the deficit must be of sufficient magnitude to interfere with activities of daily living, work function or other social activities. The diagnosis of dementia does not of itself necessarily imply a specific underlying pathology. Nor does it universally suggest a progressive cause or irreversibility. The diagnosis cannot be applied unless there has been adequate assessment of mental status in the absence of confounding variables, as already defined.

As the population ages and the normal degenerative process continues to affect the population, so too the impact of dementia increases within the community. The incidence or prevalence of dementia, particularly Alzheimer’s disease, increases exponentially with age—effectively doubling with each half decade⁴ after the age of 60 years. It is said that Alzheimer’s disease, the most common form of dementia, has an incidence of 1% per annum for those over 65 years of age with a prevalence of approximately 50% in those 85 years and older. It follows that general practitioners will be confronted with dementia in growing proportions and will need to appreciate how to best manage affected patients.⁵

This chapter will serve to assist in this process by providing a broad overview of dementia. It recognises that dementia is a final common pathway of a number of neurological conditions, which results in declining cognition without necessarily influencing level of consciousness. The general practitioner is usually the first to be consulted about evolving dementia and may be ‘too close’ to the patient to recognise the telltale signs.

History

The general practitioner is ideally placed to identify those individuals in whom dementia should be sought (see Box 15.1). They are the best positioned to identify changes in a patient, such as: the well dressed patient who no longer takes pride in their appearance; the patient who no longer attends to personal hygiene; the patient failing to keep routine appointments; or not requesting repeat routine prescriptions for previously stable treatment regimes. These factors should alert the general practitioner, as should repeated minor driving accidents, loss of employment or difficulty coping without an alternative cause.

Despite suggestion that general practitioners are perfectly placed to provide the initial diagnosis based on warning signs, less than 40% regularly screen for dementia.⁶ Often the diagnosis is not initiated by either the doctor or patient but by a concerned family member or close friend who has observed the change in the patient. The patient may present complaining of symptoms of dementia and yet still function so well on official higher centre function tests (see Ch 2), that their complaint is dismissed. Personal experience has taught that ignoring such complaints may be at the patient’s peril. An intelligent patient may be acutely aware of impaired functioning and identify this to the doctor. The doctor may not be able to confirm damage because the patient was well above the norm before noting the decline. The patient may still be above the norm, even allowing for the real decline that has occurred. Personal experience has taught that such a patient deserves a trial of therapy if reporting impaired cognition, in the absence of confounding factors discussed in this chapter. If they report improvement sufficient to justify the patient paying for medication at their own expense, then that is a reasonable option. ‘Willingness to pay’ is an accepted health economic measure, which has relevance within this context. The patient, at this level of functioning, retains the wherewithal to take responsibility for their wellbeing. This type of patient is also able to assess if performance has improved. This approach imposes no cost on society and may allow a patient to remain at an acceptable level of independence for longer.

What is important, especially for the general practitioner who is the family physician, is to explore questions of estate planning, organisation of personal affairs, both with respect to the patient as well as possibly other family members, and to discuss issues such as: advanced directives; enduring power of attorney; expression of wishes if in a vegetative state; and disposal of assets. This will ensure that the patient can make personal decisions while still competent to do so. While treatment of dementia is designed to delay progression of disease, it does not arrest it, so it is imperative that suspicion of dementia be accompanied by discussion of personal planning for the future. This is a necessary part of history taking and no doctor is better positioned to understand both the patient’s needs and the family dynamics than the general practitioner.

Where there is doubt about the diagnosis of dementia, it is appropriate to seek the patient’s permission to also interview family and possibly close friends. Such people may be able to report on domestic circumstances, such as neglected cleanliness at home, failure to shop alone or incapacity in activities of daily living—all of which suggest advanced disease. They may also offer more subtle clues, like the attentive spouse who forgot a birthday or wedding anniversary for the first time; the loving grandparent who simply forgot the grandchild’s birthday; or the bridge partner who could no longer be relied upon to make the right bid or play properly.

As already stated, it is dangerous to ignore such clues because there comes a time, especially in rapidly advancing disease, when the patient passes the point of competence sufficient to be allowed to make personal decisions into the future. After this point, all future decisions may require the involvement of a guardianship board or similar protective authority. Once this point has arrived the dysfunctional family may use the patient to settle family scores, protect personal wealth at a cost to the patient, and deny the patient the right to personally direct any wishes or wants.

Examination

The critical examination of the patient with suspected dementia is the testing of higher centre function (see Ch 2). To be able to prescribe pharmacological treatments in Australia requires testing with the Mini Mental State Examination (MMSE), a tool that has been available for many years.⁷

Unlike the approach set out in Chapter 2, the MMSE is not used to assess the site of lesion but rather to give an overview of the degree of impairment. The maximal score is 30 and hence a score of 20+ is deemed ‘minimal’ or ‘mild impairment’, a score of 15–19 is classed as ‘moderate’, and less than 14 is considered ‘severe’. The problem with this approach is that the MMSE includes asking the patient to repeat the phrase ‘no ifs, ands or buts’. Even native English-speaking patients may have trouble with this and non-English-speaking patients find it impossible. Some speaking poor English have difficulty differentiating between ‘country’ and ‘state’. Serial 7s are only conducted to 65, which fails to detect subtle change as personal normative data suggests 44 is the cut off (see Ch 2).

The team at Liverpool Hospital in Sydney, Australia, have developed an alternative tool, the Rowland Universal Dementia Assessment Scale (RUDAS),⁸ which includes six items that assess multiple cognitive domains including memory, praxis, language, judgment, drawing and body orientation.⁸