The three traditions

There are historically three traditions in clinical neuropsychology. The first, most eloquently expressed in the work of Luria (see Christensen, 1974), is based upon behavioural neurology, although it is a much more sophisticated extension of it. The approach is based upon the presentation of simple tasks, selected in a coherent way from a wide variety of tests available, which any normal individual can be expected successfully to complete without difficulty. Any failure on the task is a pathological sign and the pattern of these signs, in skilled hands, allows a psychological description to be built up.

The second tradition, associated with work in North America, is a psychometric battery-based approach, most notably expressed in the Halstead–Reitan and Luria Nebraska Neuropsychological Test Batteries (any apparent theoretical link with the approach of Luria is quite illusory). In this approach a standard, and often large, battery of tests is administered to all clients and the resulting descriptions arise out of a psychometric analysis of the pattern of test scores.

The third approach, the normative individual-centred approach, has been dominant in Europe, particularly in the UK, but is now the leading international methodology. It relies upon the use of specific tests, associated wherever possible with adequate normative standardization, which are selected to investigate hypotheses about the client’s deficits; testing these hypotheses permits the psychological description to be built up. Whilst requiring a high level of expertise, this neuropsychological detective work can be more efficient and provide a finer degree of analysis, when applied intelligently. In practice, many neuropsychologists employ a mixture of these approaches, although the normative individual-centred approach is generally becoming more dominant.

Cognitive functions

The greater part of neuropsychological assessment concentrates upon cognitive functions: perception, learning, memory, language, thinking and reasoning. This is a reflection of the principal interests of contemporary psychology. There is a bewildering variety of test procedures available to the clinical neuropsychologist, but most involve the presentation of standardized test materials in a controlled way; this can yield reliable scores which are then interpreted with respect to appropriate normative data. These norms may be more or less adequate for the clinical population under consideration, and there are certainly some excellent, some very good, and some rather inadequate tests.

Even a partial description of the most popular tests is outside the scope of this chapter, but a good introduction may be found in both Halligan et al. (2003) and Goldstein and McNeil (2004), and a more thorough account in Hobben and Milberg (2002), Lezak et al. (2004) and Spreen and Strauss (2006).

Behavioural assessment

Assessment of behaviour (as distinct from specifically cognitive performance), usually in relation to undesirable behaviours or defective interpersonal or social skills, relies more directly upon observational recording. Here the object is to identify the antecedents of the behaviour under investigation, and then to analyze the consequences of the behaviour for the individual. In this way an understanding can be gained of what ‘causes’ the behaviour, and what maintains the behaviour in the individual’s repertoire. This information can be used to construct a programme designed to modify behaviour (see below) or simply to provide feedback for the client allowing him or her to gain the insight to modify his or her own behaviour.

Behavioural sampling—the regular observation and recording of relevant aspects of behaviour for fixed samples of time—is frequently employed, and carers may also be requested to maintain records or diaries of specific events. Video recording, sometimes with detailed analysis, may also be employed.

Affective states

Clinical neuropsychologists are also commonly asked to evaluate other aspects of behaviour: affective states, motivation, insight, adjustment to disability, pain and, often most difficult of all, the possible psychological basis of apparently organic neurological states. It is for this reason, amongst others, that a thorough training in clinical psychology is considered essential for neuropsychological practice. A certain number of standard questionnaires and rating scales are available to assist in this assessment, but the neuropsychologist must commonly rely upon clinical experience and expertise in forming a judgement.

Outcome measures and the quality of life

The political climate of health service changes in the UK has forced health-care providers to consider the outcome of their interventions, and this can only be to the advantage of clients. Psychologists, because of their expertise in the measurement of behaviour, have been prominent in the development of outcome measures. Within neuropsychological rehabilitation there is a variety of measures, of which the Barthel Index (Wade, 1992) is widely used, and FIM–FAM (Functional Independence Measure–Functional Assessment Measure; Cook et al., 1994; Ditunno, 1992) is growing in popularity as it can be linked to problem-oriented and client-centred rehabilitation planning. However, none of the available scales is adequate to assess the status of severely disabled clients (Stokes, 2009), and there is also a lack of good measures of the specific outcome of psychological interventions. Research is actively being undertaken to fill these gaps, and a discussion is to be found in Fleminger and Powell (1999).

Allied to the need to assess outcomes has been a growing interest in ‘quality of life’ (QoL), recognizing that consideration should be given not only to functional and physical status, but also to the individual’s personal feelings and life experience. A central problem is that QoL is not a unitary concept and encompasses a range of ideas, from the spiritual and metaphysical to cognitions about health and happiness. What is clear is that QoL relates not in a direct, but in a very complex way to health status, physical disability and handicap, and that the precise nature of this relationship has yet to be clarified.

Cognitive neuropsychology

Cognitive neuropsychology should be understood as a distinct, and currently very fashionable, approach within neuropsychology. Of growing importance over the past decade, cognitive neuropsychology concentrates upon the single case and seeks to explain psychological deficits in terms of the components of cognitive information-processing models. Such models, which are now quite detailed in respect of functions, such as reading, spelling and face recognition, are based upon experimental data derived from normal individuals and from clinical investigations. These models are modular, and dysfunction can be understood in terms of the faulty performance of either the modules or the connections between them.

Cognitive neuropsychological analysis has been of enormous importance in developing our understanding of both normal and abnormal cognitive psychological functions within the brain but, partly because of the resources required to analyze a problem fully using this approach in the individual case, it has not made such a great impact upon the clinical practice of neuropsychologists.

Cognitive interventions

Cognitive interventions aim to reduce the impact of deficits in the areas of memory, learning, perception, language, and thinking and reasoning. How this is achieved depends in part upon the model of recovery that is adopted but, in general, requires either new learning or the development of strategies which bypass the abnormal components in the system. There are often a variety of routes by which an end result may be achieved. Perhaps trivially, consider how many ways 9 may be multiplied by 9 to achieve 81. There are in fact at least 9 ways. If you learnt the solution by rote learning, you may well find that your children have been taught a different method: 9 x 10 – 9, or the fact that the first digit of the solution is 9 – 1 and that the two digits of the answer sum to 9. These are different ‘strategies’ of finding the solution. If the previously available strategy has been lost, it may be more successful to teach a new strategy that relies upon different brain mechanisms.

Besides the explicit teaching of new strategies, appropriately structured training may be employed; this is often based upon ‘error-free learning’, which has been shown to be most effective following head injury. Aids to performance, which may be either external (such as diaries to aid memory) or internal (mnemonics), may also be successfully employed. These interventions are more fully developed in some areas than others, and have been used most extensively in the rehabilitation of memory (Baddeley et al., 2002; Wilson & Moffat, 1992), but the basic principles can be applied in any area of cognitive function (see also Ponsford, 1995; Prigatano, 1999; Riddoch & Humphreys, 1994; Sohlberg & Mateer, 2002).

Behavioural interventions

Behavioural interventions are less widely employed, but may be appropriate to address the remediation of undesirable behaviours and in situations where the residual cognitive function of the individual is severely limited. These interventions are based upon psychological learning theory that, put rather simply, states that behaviour is determined by its consequences. Behaviour that leads to a ‘good’ outcome for the individual will increase in frequency; that which has an undesirable outcome for the individual will decrease in frequency. Behaviours that are desirable (from the perspective of the rehabilitation goals) can therefore be increased by ensuring that they are positively reinforced (given a good outcome for the individual), whilst undesirable behaviours do not receive such reinforcement. In laboratory situations, negative reinforcement (punishment) might be used to reduce the frequency of a behaviour, but in a clinical situation its use would be extremely exceptional (perhaps only in relation to a significant life-threatening behaviour and then only with informed consent); in practice, the lack of positive reinforcement is sufficient for the undesired behaviour to reduce in frequency.

The range of behavioural techniques is both wider and more sophisticated than this brief account might suggest, and in certain selected contexts these approaches may be highly effective (Wood, 1990). However, the demands on resources and staff skills are high, given that a behavioural programme must be applied consistently, contingently and continuously, often over a very protracted period. For this reason, behavioural approaches are less commonly employed outside specialist facilities, although they are perhaps unreasonably neglected within other rehabilitation contexts.

Psychotherapy; staff, team and organizational support; research

Psychologists in neuropsychological practice are also involved in a variety of more general clinical psychological issues. Amongst these is the provision of psychotherapy or counselling, which may follow one of a large variety of models and is often eclectic in nature, addressing issues of personal loss, life changes, and adjustment to disability. The psychotherapeutic techniques appropriate to neuropsychological disability are relatively underdeveloped, and are associated with a number of specific problems, such as cognitive limitations and impairment of memory.

Because of their specialist knowledge of human and social relations, and of organizational processes, psychologists will advise and provide practical support to the construction and functioning of clinical teams, besides giving staff support at an individual level. Staff stress is often high in the neurological care setting and the health and welfare of staff is important, not only as an end in itself, but also because it has consequences for the care of patients.

Psychologists, who have been trained in methods of research design and analysis, are also commonly active in research relating to neurodisability and in supporting the research of others, and regard it as an important aspect of their role.

Focal versus diffuse

Focal, relatively localized, lesions result in quite different effects from lesions which diffusely affect the cerebral cortex. Most specific neuropsychological deficits of cognitive function are associated with relatively focal lesions (following trauma, tumours, or surgical intervention), and these have generally been the area of study of neuropsychologists. By contrast, diffuse lesions (following infections, generalized degeneration or widespread closed head injury) tend to affect level of consciousness, attention, motivation and initiation and affect, rather than specific psychological functions.

Acute versus chronic

Acute lesions have greater effects than chronic lesions. In the acute period following the acquisition of a lesion there may be widespread disruption of psychological functions, together with changes in the level of consciousness, confusion and loss of orientation. Amnesia is common in the acute period, and the duration of post-traumatic amnesia, before continuous memory and full orientation return, is the best indicator of the severity of the lesion (see Ch. 3). Neuropsychological consequences diminish over time, most of the recovery occurring within the first 6–12 months, but with further improvements occurring over the next year or a little longer.

Progressive versus static; speed of development

Lesions that continue to develop, such as tumours and degenerative conditions, have a greater impact than lesions that are essentially static after the initial acute period, such as trauma, cerebrovascular accidents and surgical interventions. The assumption is that the brain accommodates more readily the presence of a static lesion, but must continue to adapt to a developing lesion.

Within progressive lesions, those that develop more rapidly will cause greater psychological disruption than those which develop more slowly. This effect is seen most clearly in the case of tumours, where slow-growing tumours such as meningiomas have much less effect than more rapidly growing tumours such as gliomas. Indeed, meningiomas may grow to a very considerable size before they cause sufficient interference with psychological function to come to medical attention; this is most unlikely to happen in the case of the more aggressive tumours, where a much smaller lesion will have dramatic behavioural consequences.

Site and lateralization

The site is obviously of relevance in the case of a focal lesion, and will determine the neuropsychological consequences within the principle of relative localization (see above). Lateralization, whether the lesion is primarily located in the left or right hemisphere of the cerebral cortex, is also of relevance as the psychological functions assumed by the two hemispheres are known to differ. There is an enormous literature on cerebral lateralization, which was the most prominent research topic of neuropsychology for the two decades from about 1960, and most functions show some degree of differential lateralization. The clearest case is speech, which is exclusively located in the left hemisphere of about 95% of right-handed individuals (Beaumont et al., 1996; Kolb & Whishaw, 2003).

Age of acquisition

The age at which a lesion is acquired may also be of relevance, as the effects are less in the younger patient and throughout the childhood years (the Kennard principle). This was previously attributed to an increased ‘plasticity’ of the developing brain, in that alternative regions could subsume the functions previously destined to be located in the area containing the lesion. However, there is now some doubt over this hypothesis, partly due to accumulating evidence for the continuing neural adaptability of the brain in adult life (DeFlna et al., 2009; Hoffman & Harrison, 2009; Stein & Hoffman, 2003). The explanation may lie at least as much in the cognitive flexibility of the developing psychological systems and the greater opportunities for alternative forms of learning in the pre-adult period.

Head injury

Head injury is the most common cause of neurodisability for which rehabilitation is undertaken (see Ch. 3). It affects young males more than any other group and effective intervention can result in a very favourable outcome. Head injuries range from very mild to very severe and profound, with dramatic differences in the behavioural consequences up to and including prolonged coma and vegetative states. The lesions associated with head injury are generally focal or multifocal, and static, although acceleration–deceleration closed head injuries may result in widespread and diffuse lesions across the cortex. An important consideration is that even apparently very mild head injuries associated with a brief period of concussion may sometimes have significant behavioural consequences in terms of anxiety, depression, changes in personality and subtle disorders of memory, with consequent effects upon occupational performance, social activity and personal relationships.

Stroke

Stroke, perhaps because it tends to occur in the more elderly, has received less attention than head injury. The effects of strokes and other cerebrovascular accidents will depend upon the area and proportion of the arterial distribution which is lost, ranging from the whole territory of one of the main cerebral arteries, which is a substantial proportion of the cortex, down to relatively discrete focal lesions associated with a distal portion of one of these arteries (see Ch. 2). Although the neuropsychological consequences depend primarily on the area of cortex affected, the picture is often complicated by the occurrence of further, perhaps minor, strokes that prevent the psychological condition being stable, and by associated arterial disease, which may result in more general and perhaps fluctuating insufficiency of the blood supply to the entire cortex.

Degenerative conditions

Interest in the degenerative conditions from a neuropsychological perspective has grown in recent years. Other than the dementias of later life, principally dementia of the Alzheimer type, which are clearly associated with deficits of cognitive function of a progressive nature, there are a number of other degenerative conditions which occur in adult life, but of which the neuropsychological consequences are only beginning to be understood. Multiple sclerosis, the most common neurological disease of the population, Parkinson’s disease, Huntington’s disease and motor neurone disease, sometimes referred to collectively as the subcortical dementias, are all associated with cognitive, affective and behavioural deficits in a significant proportion of those with the disease, and almost all those whose disease progresses to an advanced stage suffer psychological sequelae (see Chs 5–8). Disorders of memory, attention and affect are common as primary consequences of the disease in this group, and there are naturally significant psychological disturbances associated with being a sufferer of one of these diseases.

Spinal injuries

Spinal cord injury clearly differs from other neurological conditions in that the patient has suffered a disabling condition, but all neural systems supporting psychological functions are intact (see Ch. 4). The main issue is therefore one of adjustment to the disability, both in terms of the primary impairment dependent upon the spinal cord lesion, and the secondary consequences of handicap that follow from the disability. Amongst the primary disabilities are loss of mobility and other functional capacities (especially if the upper limbs are affected), together with loss of bladder and bowel control, and, most importantly for psychological health, sexual function may also be affected. Depression is very common following spinal injury, and the facilitation of insight and adjustment to the disability is a primary task for the neuropsychologist.

Apraxia

Apraxia refers to disorders of voluntary movement in the absence of sensory loss, paresis or motor weakness. It is normally demonstrated when the patient is asked to respond to a command, or to produce an action outside its normal context. It is therefore probably the intentional aspects of the task that are the root of the problem. A distinction is often drawn between ideomotor and ideational apraxia. Ideomotor apraxia is a disorder affecting the ability to produce simple gestures either on command or by imitation, while the ability to perform more complex tasks may be largely intact; that ‘the patient knows what to do but not how to do it’ is a helpful dictum. By contrast, ideational apraxia refers to the inability to perform actions requiring a well-ordered sequence of elements. However, while this is an important distinction in the literature there is still considerable debate about the dissociability of these two conditions. Both conditions are associated with lesions in the posterior cortical regions, especially the parietal lobe, and in the dominant hemisphere. An interesting feature of both conditions is that the relevant behaviours may be performed without difficulty in everyday life; the problem only appears when conscious attention is directed to the task. Dressing apraxia has been regarded as an independent form of apraxia, but there is some reason to believe that it is only the difficulty of this particular task which involves the integration of body elements with external space, and complex personal movements in relation to highly plastic objects that makes it appear a distinct entity. Constructional apraxia is, however, a distinct type of apraxia and involves a defect in the spatial aspects of a task in relationship to individual motor movements. The problem appears to lie in the integration of visuospatial information and voluntary motor acts, and may be apparent in drawing, or in the construction of 3D models. The disorder is also associated with lesions of parietal cortex and some believe that it may take a different form when the right hemisphere is involved affecting visuospatial perception, or the left hemisphere affecting motor execution.

Neglect

Unilateral neglect, or unilateral hemi-inattention, has attracted considerable research interest in recent years. Patients with this disorder act as if one side of space, more commonly the left side of space following right parietal lesion, did not exist. This is in the absence of any visual field defect. In extreme cases the patient may only eat food on the right half of their plate, dress the right side of their body and attend to visual events to their right. It can occur in relation to imagined scenes as to real stimuli. There is still considerable debate about whether the problem is one of disordered internal representations, or one of attentional deficit. It seems clear, however, that patients have some semantic access to the information appearing in the neglected space, but this information does not enter consciousness, or direct behaviour. Voluntary limb activation, out of sight and on the neglected side, has proved the most effective treatment approach to date.

Motor memory

Memory for motor acts, and in particular motor skills, has been shown to be distinct from memory for semantic or episodic information. It is noteworthy that even patients with a dense global amnesia, as in the amnesic syndrome, may retain the ability to perform previously learned motor skills. Their ability to acquire new motor skills may be less impaired than their ability to learn new semantic information or recall recent events. While disorders of motor memory are much less well researched than other aspects of memory, it is worth noting that even a serious impairment of memory will not necessarily prevent the learning of new motor tasks. We can conversely assume that there are specific disorders of motor memory in the absence of other memory problems, but these are little studied.