Dementia assessment, diagnosis and giving the news

CHAPTER 13 Dementia assessment, diagnosis and giving the news

Michael Murray, David Ames, Lynette Moore

FRAMEWORK

The authors present a significant argument for the early diagnosis of dementia but do not suggest that wide screening programs are beneficial. Opportunistic age-related screening may be appropriate to provide a future baseline for subsequent assessment when and if the person presents with cognitive changes later. The authors suggest that mandatory cognitive assessment should be done on admission to hospital or residential aged care and where there are major transition points that affect the person’s ability to cope. The importance of a comprehensive history of the person’s lifestyle, abilities, reactions to change and the use of suitable assessment tools cannot be underestimated. A full medical examination of physical functioning, including the neurological system and comorbid treatable illnesses, should be undertaken. The use of diagnostic tests (e.g., X-ray, scans, blood tests) to exclude other health problems, and perhaps liver biopsy if alcoholism is suspected, may be useful. Diagnosis should be made by specialists and the outcomes fully disclosed and relayed to the person and their family in a sensitive manner with referral to support services as needed. [RN, SG]

Introduction

Australia, like the rest of the world, is an ageing society. In 2007, 13% of Australia’s population was aged over 65; by 2056 this will rise to between 23 to 25% (ABS 2008). Whilst it is likely that the trend to better health at a given older age may well continue for at least the younger cohort of older people, it is less clear that this will be the case for the old-old. Thus a substantial challenge to our society will be the management of ageing-associated chronic diseases and the minimisation of any resultant disability in older people. Whilst age alone is clearly not the only factor in the aetiology of dementia, the incidence of the predominant form (i.e. Alzheimer’s disease) is strongly age-associated, nearly doubling each five years from the age of 60 (Australian Institute of Health and Welfare [AIHW] 2007), so that for people older than 85 years the prevalence of dementia is estimated at 22.4% (AIHW 2007). Access Economics has estimated that there are in the order of 50 000 new cases of dementia each year in Australia (Access Economics 2005).

The incidence of the predominant form of dementia (i.e., Alzheimer’s disease) is strongly age-related.

Dementia assessment

Is it worth doing and if so for whom?

In the past there has been some debate as to the utility and appropriateness of assessing for and making the diagnosis of any condition where the treatment options are limited and, as in the case of carcinoma of the prostate, survival benefits from diagnosis and treatment are modest at best, or limited to small subgroups. Similar arguments could be extended to dementia, particularly Alzheimer’s disease (AD). In part this may have been driven by the belief that few effective therapeutic options exist and that the utility of making the diagnosis is lacking. Further there is the belief or mistaken observation that people with dementia and their carers neither wish to know the diagnosis nor do they seek assessment or diagnosis. Finally, there is a belief by many general practitioners (GPs) that they lack the skills and diagnostic acumen to diagnose dementia accurately, and/or once having made the diagnosis, to manage it appropriately.

On occasion individuals will present or be presented to their GP on the basis of perceived cognitive symptoms, however there is little doubt that many will not, and thus a combination of approaches to detection will be required if it is concluded that early detection and management of dementia is desirable, offering benefits to both the individual and family. Such approaches could include limited screening and case finding.

In general, screening (detection in asymptomatic individuals) is not recommended in consensus guidelines (New South Wales Department of Health 2003; Scottish Intercollegiate Guidelines Network [SIGN] 2006). Dementia remains a clinical diagnosis and both in less experienced hands and early on in the disease process the false positive rate in any screening program is likely to be significant. Screening asymptomatic 65–74-year-olds is likely to yield a false positive rate in the order of 93% (New South Wales Department of Health 2003). A substantial false positive rate is likely to be associated with significant distress and would divert already insufficient early diagnostic resources away from areas where they could be better used.

Dementia remains a clinical diagnosis and both in less experienced hands and early on in the disease process the false positive rate in any screening program is likely to be significant.

However, limited screening could be undertaken in high risk individuals in some circumstances such as those with known risk factors and particularly when appropriate functional and clinical history is deficient by virtue of diminished ability to self-report, or lack of a competent or reliable informant. Candidates include: people with Down’s syndrome; older individuals with multiple probable risk factors such as vascular risk factors (including diabetes, hypertension and hyperlipidaemia); people with established central or peripheral vascular disease; smokers; and in those with known or suspected previous significant cognitive insults, including chronic or persistent episodic alcohol abuse and cerebral injuries. Whilst one may argue this pushes the boundary between screening and case finding, in practice such boundaries are indistinct.

Proactive, or failing this, opportunistic, age-related screening may be appropriate to provide a future baseline for subsequent assessment and in the older old population where the incidence of the screened-for condition (in this case dementia) is very high and the diagnostic utility exceeds the diagnostic and management challenges of mild cognitive impairment (MCI). Cognitive screening should, however, be considered mandatory in high risk populations, and at key transition points such as entry to hospital and entry to residential care. Non-elective admission to hospital is commonly associated with delirium and cognitive impairment is associated with poorer outcomes, impaired capacity to consent to necessary medical procedures, and safety considerations in an at-risk environment. Assessment should also be undertaken at other transition points where significant cognitive change is likely or known to have occurred, and when the information gathered is likely to inform care, with safety and capacity issues raised. Such transition points include admission to a step-down facility, subacute or transition care unit, and discharge from hospital post-delirium, as a high percentage of those who experience delirium in hospital will have incomplete resolution of their symptoms upon discharge.

Cognitive screening should, however, be considered mandatory in high risk populations.

Opportunistic assessment should be undertaken for those cases or individuals presenting with symptom clusters or behaviours that may relate to, or be exacerbated by, cognitive impairment, including people with poor self-management. Initially this should include a search for an underlying aetiology, with exclusion of an active medical illness, together with some form of cognitive assessment. Assessment should be undertaken when amnestic symptoms are reported or suspected; for example, when it is evident that there is significant medication non-compliance, confusion about a long-standing medication regimen, or difficulties in adapting to changes such as those that may occur with an individual’s medication regime or upon entering a new residential environment. Similarly, even reports of multiple failures to attend social engagements or missed scheduled appointments would support the need for an assessment that would include cognitive review. Though there are other important causes of a loss of social engagement, including depression and a contraction of social support networks through death and illness, an apparent voluntary social withdrawal should alert a health professional to the need for a comprehensive assessment, which would include assessment of cognition. In many circumstances it may be difficult to determine the presence of what is most typically a slow change. Chronic illnesses are common in the older population; thus, even in the absence of reported decline, and given that for the most part interactions within a standard GP consultation are brief, regular opportunity for cognitive review needs to be ensured. If this is not done by the GP themselves, then it can be accomplished by a trained member of the practice staff, such as practice nurse or associated nurse practitioner.

Opportunistic assessment should be undertaken for those cases or individuals presenting with symptom clusters or behaviours that may relate to, or be exacerbated by, cognitive impairment.

Evidence of a decline in activities of daily living (ADL), recent worsening of a previously stable chronic illness such as diabetes, or even an increase in falls, should alert the clinician to the need for a more comprehensive assessment, which should always include cognition.

In situations where there is no established cognitive diagnosis and the deficits may be thought to be more than simply amnestic, or where executive functioning may be compromised, one may choose to screen more comprehensively. Presentations suggesting frontal lobe or executive dysfunction which warrant assessment include: where a person presents following a number of (even minor) motor vehicle accidents; circumstances where a person’s judgment reasonably may be called into question; an individual’s behaviour or risk-taking profile becomes notably different (such as new onset or high-stakes gambling); or there is increasing difficulty managing instrumental ADLs. It should be mandatory for a more thorough assessment using a more comprehensive assessment tool, in the case of suspected frontal lobe dysfunction, or where the results of simple screening are inconsistent with the apparent symptoms, as is often the case using simple screening tools. If local competency in undertaking a more comprehensive assessment is lacking, a referral should occur.

Whilst progressive impairment in memory and higher cortical functioning are characteristic of dementia, there exist a number of other medical conditions that feature similar symptoms of varying degree and duration.

Acute medical illness associated with cognitive changes, particularly impaired and unusually fluctuating attention, as in the case of delirium, need to be excluded, with the precipitating factor or factors identified and promptly treated. In the community setting this may represent a medical emergency with prompt recognition, management and emergency department referral required. In a palliative environment, or within high level residential care at a time when the expected end of life approaches, delirium is extremely common, and indeed may be considered the norm, so a more conservative approach may be appropriate, with the priority being symptom control, preservation of comfort and dignity and the provision of support for grieving friends and loved ones.

Acute medical illness associated with cognitive changes, particularly impaired and unusually fluctuating attention, as in the case of delirium, need to be excluded.

The process of assessment

Assessment of cognitive functioning requires the gathering of a history from both the individual being assessed and, whenever possible, from an informant who knows the person well. Indeed, research has shown that an informant history of cognitive decline and a decrease in social or occupational function is the most important factor in allowing the determination of a diagnosis of dementia; it is more important even than the results of cognitive assessment in this regard.

An informant history of cognitive decline and a decrease in social or occupational function is the most important factor in allowing the determination of a diagnosis of dementia.

If the informant history suggests the presence of cognitive impairment, one should search for evidence of more generalised cognitive changes. The presence of a baseline established earlier can give an invaluable reference point for detecting any subsequent change, so routine assessment of cognition for individuals above a certain age (75 is recommended in the UK) may have future utility even when normal results are found. Use of a screening tool appropriate to the educational, cultural and linguistic attributes of the person to be assessed is preferable, particularly if formal or informal education is at a relatively lower level than the population’s aged-matched median, making comparisons between the case at hand and the ‘normal’ population more difficult.

All of the shorter portable screening tools have limitations, as one would expect, where to some extent brevity and convenience are emphasised at the expense of breadth and detail. In a screening environment such as general practice, hospital admission or at a transition point within the health system, this is acceptable, as experience suggests that the number of screens completed is to some extent inversely proportional to the time taken and to the complexity of its administration. Further, the competency of administration of any test is such that a shorter, simpler test may be administered by a more diverse group of health practitioners with a higher probability of accurate completion.

All of the shorter portable cognitive screening tools share, to varying degrees, limitations at both upper and lower ends of their ranges with a ceiling effect evident at the upper end and non-linearity particularly at the lower end of the range. Again, for a screening test as part of a more comprehensive assessment, where limitations of simple screening tests were understood, and informant history was sought, this would be acceptable. Whilst earlier studies suggested screening tests to be somewhat interchangeable (Stuss et al 1996) more recent reviews suggest accuracy is sacrificed for brevity (Cullen et al 2007).

Assessment practices will vary according to the setting (general practice, specialist rooms, memory clinic, hospital admission); however the basic steps that need to be followed are the same wherever the assessment is conducted.

Assessment practices will vary according to the setting (general practice, specialist rooms, memory clinic, hospital admission); however the basic steps that need to be followed are the same wherever the assessment is conducted.

The person who may have dementia should be assessed alone, an informant or informants interviewed separately (in parallel by another health practitioner if resources permit, or after the person if only one practitioner is available), and all interested parties seen for feedback at the end of the process. The assessment process may take more than one visit. A history of the presenting complaint should be sought, with particular emphasis upon previous skills that may no longer be exercised competently (driving, shopping, bill paying, housework, hobbies, etc). Does the person being assessed mislay objects, forget names, get lost in familiar areas, have word-finding difficulty or experience problems in the manipulation of objects? Is there a history of depression or other illness that could complicate the picture? What medications are taken and have these changed recently? Is alcohol consumed and if so how often, how much and has the pattern of consumption changed? Are behavioural and psychological symptoms of dementia appearing, such as mood changes, misidentifications, delusions, hallucinations, motor disorders, sleep problems, apathy, altered sexual behaviour, noisiness, resistiveness to help, irritability or aggression? How is the carer coping? Many have symptoms of anxiety and depression themselves.

A full mental state examination must look for symptoms of depression, anxiety and perceptual abnormalities such as hallucinations and delusions.

Cognitive assessment may not take very long when dementia is clear-cut. A Mini-Mental State Examination (MMSE) may be all that is required when the score is 12, for example. However, when the presence of dementia is equivocal, the symptoms atypical, or there are challenges in the assessment (for example, a lack of formal education or language other than that of the examiner spoken), more detailed instruments such as the Cambridge Cognitive Examination, ADAS-Cog or, more usefully when available, full neuropsychological assessment by an expert neuropsychologist, will be required.

Physical examination is mandatory and must be thorough. As well as looking for causes of cognitive impairment (e.g., signs of hypothyroidism, focal neurological signs, carotid bruits) the assessing practitioner must ensure that comorbid treatable illnesses (which are common in people with dementia) are not missed. Common problems include arthritis, chest and heart disease, auditory and visual impairments and diseases of the dentition and feet.

Physical examination is mandatory and must be thorough.

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Tags: Nursing Older People

Dec 10, 2016 | Posted by admin in NURSING | Comments Off

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