Dementia and Memory

A Handbook for Students and Professionals

Simon B. N. Thompson

• Publisher: Routledge
• Year: 2017
• eBook ISBN: 9781351945400
• Edition: 1
• Topic: Medicine
• Subtopic: Physiology

Dementia and related diseases are likely to affect at least four in every hundred 75-79 year olds in the developed world over the coming years. Faced with an expanding older population, it is crucial that we develop our understanding of how to treat people suffering from such conditions. This accessible book provides extensive information on the different types of dementia and on memory problems more generally. It includes detailed coverage of how to alleviate memory problems and discussion on issues such as ageism. For the student reader, there are descriptions and discussions of key topics as well as practical step-by-step guidance. The book includes a memory test as well as a comprehensive list of useful addresses and suggestions for further reading. This book will be an invaluable resource for the trained healthcare and medical professional and for the student reader.

PART I
Defining Dementia and Memory

Chapter 1
Introduction to Dementia

Background

Increasing longevity, especially of people with learning disabilities (Jancar, 1984; Wolf & Wright, 1987; Eyman et al., 1987), has brought with it a seemingly ever-increasing demand on health and social services. In particular, clinical psychology services have seen an increasing number of referrals to assess older clients who have poor cognitive functioning and to provide advice for carers about clients who have declining memory ability (Thompson, 1994a). Supportive consultation with staff and clients alike is also important, and has increased the demands on all services as the size of the older population has grown.

Identifying signs of declining memory and general cognitive functioning early on clearly has many advantages (see Huppert & Tym, 1986), including the planning and provision of specialist care for these people. Researchers and clinicians have been interested in the effects of ageing on the normal population for some considerable time (for example, Holden, 1989), and have compared common impairments, such as short-term memory (McDade & Adler, 1980), age-related memory decline (Young & Kramer, 1991), and psychophysiological differences, such as auditory event-related potentials (Muir, Squire & Blackwood, 1988). The difficulties of a differential diagnosis between depression and dementia have also been examined (Warren, Holroyd & Folstein, 1989), but the stumbling block for researchers has often been the transferability of measures to different client groups (Rosen, Mohs & Davis, 1984). Often, standardised assessments are too difficult or are culturally dependent; testing some clients results in floor or ceiling effects, and other tests are simply too demanding on a subject’s attention or concentration.

Normal Ageing

In order to understand the complexities of dementia, it is worthwhile describing what happens in normal ageing, and understanding what can go wrong and gives rise to abnormal conditions such as dementia. Ageing can be distinguished in terms of biological, social and psychological factors, but there is often a great overlap and interaction between them. For example, a physical change, such as arthritis, can limit mobility, which in turn can reduce involvement in social activities or other previous sources of enjoyment (Alcott, 1993). The influence of one aspect of ageing on another should also be remembered; this is important when considering and comparing past and present cognitive functions within the same person.

Defining ‘normal’ is a difficult task, and it is surprising how ‘normal’ and ‘abnormal’ activities and attitudes often overlap. The blurring of boundaries occurs between different cultures, different environments or even between individuals. One misconception is to consider normality as distinct and opposite to abnormality, when in fact ‘normality’ refers to the ‘range around the middle of a dimension (for example, height) with two extremes at opposite ends (very tall and very short), rather than one extreme’ (Alcott, 1993, p. 9).

Different people have differing concepts of normality, and hence differing expectations about ageing. With the advance of medicines and technology, people generally live longer, so more people are exposed to older people and witness the variations in ageing of relatives and friends. In turn, people’s understanding of normal ageing is constantly being revised, as are their expectations of themselves and others.

Normal ageing brings with it changes, not just to an individual’s appearance, however subtle, but also to the higher mental functions or ‘cognitive’ functions. Memory can also be affected, sometimes because the individual has failed to receive information correctly, or sometimes because it can no longer be encoded or stored effectively. The effect of ageing on memory is very often one of the first of the cognitive changes to be noticed by others, and can cause considerable distress to the individual and to relatives, close friends and carers. Deterioration in memory functioning is characteristic of dementia, but it can also indicate other dysfunctions, which should always be considered in any assessment.

Generally, older people can learn as much as younger people, but more time is needed for them to achieve the same level of learning, as they cannot process and ‘absorb’ information as quickly as younger people. Sometimes this speed reduction becomes noticeable and marked, and leads to the onset of depression. If memory has noticeably changed, and continues to do so, it may indicate the onset of a dementing process.

Changes in language abilities can also be characteristic of dementia, but people’s voice characteristics tend to change with age as part of the normal ageing process with the pitch becoming higher during the fifties, the resonance thinner, and the volume lower (Alcott, 1993). Various factors, such as smoking, stooped posture, unclean environment (for example, dust) or prolonged abuse of the voice can contribute to these changes. Ill-fitting dentures, toothlessness or weakening of the muscles involved in speech production can all hinder speech, and it is worthwhile investigating all practical aspects of a person’s living environment and hygiene before drawing conclusions about a person’s abilities or cognitive status.

Personality also plays a large part in normal ageing; some people adjust better than others to changes in circumstances, be it changes to their living environment, loss of occupational status, or physical changes such as decreased mobility, lack of independent transport, and so on. Some individuals become more restless or agitated at the frustration of their changed world, while others may be more placid or resigned and withdrawn. Others adapt to change, and are realistic about expectations and changes to their circumstances.

Social adaptation and sexual changes are very often major causes of people’s unhappiness, yet the general expectation that older people will not be sexually active is unfounded, since there is a great deal of variation in both sexual interest and activity among all groups of people, young or older. Availability of a capable partner and acceptance of the level of a close relationship seem to be important factors in determining sexual activity or fondness. Exceptions are often found in most groupings, and some older people never cease to amaze their younger relatives with energy and wisdom sometimes absent in their younger peers!

Structural changes to the brain give rise to cognitive changes that may be noticed by others observing the individual. In normal ageing, the brain undergoes several structural changes, including a decrease in size, flattening of the surface, and increasing amounts of intracranial space (Jernigan, Zatz & Feinberg, 1980). Other microscopic and biochemical changes occur, as well as changes to the electrical activity (electrophysiological changes) within the brain (Brizzee et al., 1980; Hansch, Syndulko & Pirozzolo, 1980; Zatz, Jernigan & Ahumada, 1982a, 1982b).

Verbal skills, particularly the well-learned skills of reading, writing, vocabulary and word usage, tend to be maintained (Botwinick, 1977), and the general intellectual status of healthy older people, as measured by neuropsychological tests, tends to remain within normal limits through the eighties (Benton, Eslinger & Damasio, 1981). Arithmetical ability is also generally stable among older people (Kramer & Jarvik, 1979; Williams, 1970). Arithmetic and memory tests that show decreased performance in older people - for example, Digits Backward of the Wechsler Adult Intelligence Scale - Revised (Wechsler, 1981a) - tend to reflect impaired concentration and mental tracking, rather than decreased cognitive functioning. However, a normal tendency for digit and letter memory span to be a little longer in the auditory than visual modality appears to increase with age (Craik, 1977; Kramer & Jarvik, 1979).

Contrary to conventional belief, normal ageing processes do not affect the immediate memory span in older people (Williams, 1970). Lezak (1983) points out that the normal intellectual decline associated with old age shows up most strikingly in four areas of intellectual activity; these can be summarised as follows:

1. The primary, or working, memory capacity of intact older people differs little from that of younger adults (Erickson, 1978), except when the amount of material to be remembered exceeds the normal primary storage capacity of six or seven items (Craik, 1977). Older people use less effective learning procedures (less elaborative encoding), and tend to show a greater differential between recall and recognition of learned material, particularly when the recognition tasks are easy (Botwinick & Storandt, 1974). Contrary to studies that indicate a progressive loss in recall of public events (Squire, 1974), Botwinick and Storandt (1980) reported that memory for remote events does not appear to change with the passage of time.
2. Diminished ability for abstract and complex conceptualisation typifies the intellectual functioning of older people (Botwinick, 1977; Denney, 1974; Reitan, 1967). The more meaningful and concrete the presentation of a reasoning problem, the greater the likelihood that people will succeed at it (Botwinick, 1978).
3. Mental inflexibility, manifesting as difficulty in adapting to new situations, solving novel problems or changing mental set, characterises intellectual performance failures of older age (Botwinick, 1978; Schaie, 1958).
4. General behavioural slowing is a predominant characteristic of ageing that affects perceptual (Kramer & Jarvik, 1979), cognitive (Botwinick, 1977; Thomas, Fozard & Waugh, 1977) and memory functions, as well as all psychomotor activity (Benton, 1977; Hicks & Birren, 1970; Welford, 1977). Accurate evaluation of older people’s poor performance on any timed test must depend on careful observation and analysis of the effect of time limits on the scores, for the score alone will tell little about the effects.

Physical and Psychological Problems of Ageing

Confusion is commonly misunderstood to be a part of the dementing process, when in fact an acute confusional state is ‘a consequence of change in the body’s metabolism which leads to high temperature, fever and delirium, which in turn can cause temporary disorientation, memory loss, a state of “muddled perplexity, poor concentration, hallucinations, clouding of consciousness and restlessness’ (Goudie, 1993, p. 29).

Unlike the situation where the person is suffering from dementia, the disorientation and confusion will improve if the underlying cause is treated. Regular check-ups are therefore important in ensuring that health problems and reactions to medication are dealt with before they lead to serious consequences. Misdiagnosis can often occur in people who are over 65 years old, mainly because certain reactions seem to indicate dementia at first glance. For example, acute confusional state can be caused by: poor diet, chest and urinary infections, heart disease, faecal impaction, sensory deprivation (for example, poor eyesight, poor hearing, social isolation), grief reaction to bereavement, and so on.

Signs such as changes in muscle tone, persistent language problems, perceptual problems and personality changes may indicate other conditions such as transient ischaemic attack (TIA) or a cerebrovascular accident (‘stroke’). Haemorrhage in the blood vessels leading to the brain or in the vessels of the brain itself can result in a stroke. The cognitive changes associated with a stroke can be confused with a dementing process if the physical effects of the stroke are disguised or are subtle. Indeed, some small strokes do not cause devastating or obvious outward changes, but many small strokes that cause death to specific brain sites (multi-infarcts) often lead to dementia (Thompson & Morgan, 1996).

In Murphy’s 1982 survey, about 30 per cent of people were found to be depressed. Indeed, it is the most common emotional problem affecting older adults (Goudie, 1993). Even when the condition has been properly identified, many individuals do not receive treatment with antidepressants (McDonald, 1986), or are referred for specialist therapy, such as cognitive therapy (Blackburn & Davidson, 1990). Some believe that depression in older age is ‘normal’, and that older people are rigid thinkers and are uncooperative. In fact, many older people adapt well to the times (for example, changes in currency, government policies, and so on) and are able to reflect on the past in order to apply their experienced skills to the present day.

Identifying the signs of dementia and depression are crucial to treatment. While it is generally not too difficult to list the signs of depression - for example, Hanley & Baikie (1984) list low mood, loss of interest, sleep disturbance, weight loss, hopelessness, helplessness, thoughts of death or suicide, preoccupation with somatic complaints, agitation, loss of energy, feelings of worthlessness and guilt, thinking and concentration disturbances and forgetfulness - it is sometimes harder to distinguish between an older person suffering from depression alone, versus depression and dementia. Some key diagnostic points for depression are also important in diagnosing dementia: forgetfulness, thinking and concentration disturbances, inability to maintain a task, and lack of concentration. Typical symptoms of depression may be compared with those of Alzheimer’s-type dementia (Figure 1.1).

Normal Memory

Memory failure is a common and significant problem in dementia, hence it is important to first assess the extent to which it is a problem and for whom the problem is an obstacle.

A distinction is commonly drawn between a short-term memory system with limited capacity (a few items at most) and a storage time of seconds, and a long-term system with perhaps limitless capacity and indefinite storage time (Atkinson & Shiffrin, 1968). Short-term memory, now elaborated into the concept of ‘working memory’ (Baddeley, Wilson & Watts, 1995), is the system which enables a new telephone number to be remembered while dialling it - as long as there is no distraction. Long-term memory allows one to remember a familiar telephone number from day to day and year to year (Collerton, 1993). This terminology differs from commonplace use, where short-term memory is taken to be the memory for the preceding hours, days or months, and long-term memory for many years in the past.

It is now believed that there are four stages involved in memory:

1. registration;
2. encoding;
3. storage;
4. retrieval.

For information to be stored in memory, it must first be attended to, or registered. Encoding is the process whereby this information may be semantically or phonologically encoded (encoded in terms of meaning or sound, respectively) (Baddeley, 1978). Storage is the process by which information is maintained in memory. It is widely accepted that different types of knowledge appear to be stored differently, so that, for example, knowing what a person ate for lunch (episodic memory) would be stored differently from knowing the word lunch’ means a mid-day meal (semantic memory). Cohen and Squire (1981) have subsumed these terms under ‘declarative memory’, and reserve a further definition, termed ‘procedural memory’, for skills and routines including some types of sensory memory (for example, knowing how to ride a motorbike is a procedural memory, knowing how the engine works is declarative). These functional definitions of memory have practical applications for therapists and are also more simplistic than earlier definitions. Retrieval is the process by which information is made available from memory, and is thought to be dependent upon a number of factors, such as the closeness of match between conditions at encoding and retrieval (Tulving, 1979), and the strategy used for retrieving memorised information (Roediger & Blaxton, 1987).

It is important for clinicians and therapists to understand the mechanisms i...

Table of contents

• Cover Page
• Dementia and Memory: A Handbook for Students and Professionals
• Copyright Page
• Contents
• Preface
• Acknowledgements
• Introduction
• PART 1 Defining Dementia and Memory
• PART 2 Coping with Memory Problems
• PART 3 Coping with Dementia
• Glossary of Terms
• Useful Journals and Magazines
• Bibliography
• Index