Clinical Neuropsychology

A Practical Guide to Assessment and Management for Clinicians

Laura H. Goldstein, Jane E. McNeil, Laura H. Goldstein, Jane E. McNeil

• Publisher: Wiley
• Year: 2012
• ISBN:
  9781119966272
• Edition: 2
• Topic: Psychology
• Subtopic: Neuropsychology
• Index: Psychology

Featuring updates and revisions, the second edition of Clinical Neuropsychology provides trainee and practicing clinicians with practical, real-world advice on neuropsychological assessment and rehabilitation.

• Offers illustrated coverage of neuroimaging techniques and updates on key neuro-pathological findings underpinning neurodegenerative disorders
• Features increased coverage of specialist areas of work, including severe brain injury, frontotemporal lobar degeneration, assessing mental capacity, and cognitive impairment and driving
• Features updated literature and increased coverage of topics that are of direct clinical relevance to trainee and practicing clinical psychologists
• Includes chapters written by professionals with many years' experience in the training of clinical psychologists

Part 1

General Introduction

1

General Introduction: What Is the Relevance of Neuropsychology for Clinical Psychology Practice?

Laura H. Goldstein and Jane E. McNeil

Why Study Clinical Neuropsychology?

At this early stage in the 21st century, clinical neuropsychology is rightly finding its feet as a well-delineated and expanding clinical specialty within clinical psychology. It has moved away from the purely diagnostic role it acquired after the Second World War, to one in which the characterization of a person's functional strengths and weaknesses, and the explanation of their behaviour have become central in extending the range of meaningful questions that can be posed about an individual patient's presentation. The history of neuropsychology, and its development into a clinical specialty, has depended heavily on theoretical innovation and the constant need to develop a rigorous evidence base (Marshall and Gurd, 2010). Clinical neuropsychology is now very much valued as not simply involving the assessment of cognitive abilities in patients with cerebral pathology, but also as playing a major role in the rehabilitation of such people. It is also contributing to the understanding of the impact on cognitive functioning of disorders hitherto conceptualized as psychiatric or functional (rather than organic), for example depression or schizophrenia, and is being used to understand and hence possibly conceptualise in neuropsychological terms a variety of antisocial or maladaptive behaviours. Neuropsychology has expanded its area of enquiry beyond the testing room, and into the implications of cognitive impairment for everyday life, with a range of tests that are striving to be more ecologically valid (e.g., Wilson et al., 1996) as well as environmentally based (Shallice and Burgess, 1991; Alderman et al., 2003).

It is therefore important that all clinical psychologists, and not just those working in specialist neuropsychological settings, have a basic grounding in neuropsychology. Perhaps the simplest way of illustrating the widespread application of neuropsychological skills comes from the types of questions that clinical psychologists might need to answer about their patients. Thus, a clinical psychologist working in a primary-care setting, being the first person to undertake a formal assessment of a patient, might need to determine whether their patient's complaint of poor memory represents a condition that merits referral for further investigation by a neurologist or is likely to represent the consequences of anxiety or depression. In an adult mental-health setting, just as in a neuropsychiatry service, there may be the need to decide whether a newly developed memory disorder is psychogenically determined, perhaps even characteristic of factitious disorder or malingering. A clinical psychologist working with people with learning disabilities might need to be able to assess whether their patient's cognitive profile is indeed characteristic of a particular disorder (e.g., Down's Syndrome), or whether it represents the likely onset of the dementia that is often found in older adults with Down's Syndrome or points to the impact of some additional, acquired neuropathology (e.g., a recent head injury). In a forensic setting, the question for the clinical psychologist to address may well take the form of whether the person's offending behaviour could be accounted for by a previous head injury leading to impulsive behaviour characteristic of executive dysfunction. Working with older adults, the clinical psychologist may not only be trying to clarify whether the person's cognitive decline is representative of dementia rather than affective disorder but also may need to detail the precise nature of any dementia (e.g., Alzheimer's disease or fronto-temporal dementia). In an alcohol-abuse service, the evaluation of a person's memory and executive dysfunction may have implications for their future treatment or placement. In child-psychology settings, the need may well be to clarify the impact of developmental as well as acquired neuropathology on educational and social development.

In all of these settings, a good grounding in the principles of neuropsychological assessment and test interpretation (see Chapter 6) will contribute to the delivery of an effective and professional service. This grounding may also, given service constraints, permit the formulation of appropriate interventions designed to ameliorate the cognitive difficulties delineated by means of the assessment, as well as through observations of the patient's everyday behaviour. In all such instances, the clinical psychologist should be seeking to act as a scientist-practitioner, using the ever-growing neuropsychological literature on which to base hypotheses for their assessment and gathering information from as wide a range of sources as possible. As Walsh and Darby (1999) indicate, the clinical (neuro)psychologist may be setting out to confirm that certain features of the patient's presentation are consistent with a particular disorder or syndrome, to generate and then test their own hypotheses about the nature of the patient's deficits, or to decide between competing hypotheses about the person's deficits and their causes, often in a medicolegal setting of either a criminal or civil nature.

One of the main reasons why the clinical neuropsychologist's role has moved away from a strictly diagnostic one is the dramatic development in neuroimaging techniques that now offer markedly improved options for identifying structural and functional cerebral abnormalities (see Chapter 3). This has left clinical neuropsychologists free to develop a better understanding of the nature of different disorders and their neuropathological correlates. One example of this development is the careful study of different types of dementia, whereby distinctions have been made between Alzheimer's disease, vascular dementias and frontotemporal dementias (and their variants – see Chapter 15), based both on formal neuropsychological test batteries and on behavioural rating scales (e.g., Bathgate et al., 2001; Grace and Malloy, 2001; Kertesz et al., 2000; Snowden et al., 2001) as well as between dementias related to other neurodegenerative diseases (e.g., Snowden, 2010). There is now also a much better understanding of how to assess psychogenically determined as opposed to organic memory impairment (see, for example, Chapter 7), which has implications both for interventions and for medicolegal work, an area where clinical neuropsychologists can assume a very high profile (see Chapter 17).

It is inevitable that clinicians will develop differing approaches to the assessment and documentation of (and also interventions to deal with) their patients’ cognitive impairments. This will arise through differing training experiences and both pre- and postqualification clinical service constraints. Below, however, we will outline some of the principles we consider to be essential to the development of personal competence in the delivery of a service that is able to answer neuropsychological questions about patients. We will be focussing in large part on the assessment and interpretation of neuropsychological impairment.

Common Issues Across Different Assessments

Irrespective of the specific referral, there are certain types of information that must be collected prior to the assessment in order for the clinical psychologist to maximise their opportunity for collecting meaningful data. Here, we will expand on, and add to, some of the very helpful suggestions made by Powell and Wilson (1994), echoed also by Evans (2010). Thus, information should be collected on:

• the intended purpose of investigation; it is important to clarify with the referrer what information is being sought from an assessment, and it may well be necessary to reframe the referrer's question into one that is neuropsychologically meaningful and possible to answer, as neuropsychological assessments are time-intensive and should not be seen as ‘trawling’ exercises;
• the patient's demographic variables, for example, age, handedness, education/qualifications, current/previous profession and cultural background, in order to set the context for the interpretation of current test performance; understanding the difference between different types of educational attainments (e.g., grades attained for GCE O levels, CSEs, GCSEs, A levels, AS and A2 examinations within the English educational system) will also be informative when considering premorbid level of ability, and additional information concerning developmental stage reached will be particularly important in the case of children (see Chapter 13);
• the patient's previous as well as current medical history, as this may also be relevant to the development of cognitive impairment; history of alcohol and/or substance abuse;
• the results of previous investigations, for example, neurological investigations, EEGs, CT/MRI or functional brain scans, x-rays, biochemical tests, (see Chapter 3 for a description of neurological investigations) and previous (as well as current) psychiatric diagnoses, all of which can assist in the formulation of hypotheses about the patient's likely deficits, and so guide the assessment and its interpretation;
• the results of previous neuropsychological assessments; these can guide the choice of current tests and permit evaluation of change (see below);
• the history of the person's lesion/disorder, for example, site of trauma, age at and time since injury or onset of illness, history of epilepsy (either predating injury or post-traumatic) if relevant, whether or not anoxic episodes were associated with injury, length of post-traumatic amnesia (PTA) and retrograde amnesia, length of loss of consciousness, Glasgow Coma Scale scores, and operation reports, since again these will assist in the formulation of hypotheses about the aetiology, nature and severity of the deficits that may be revealed by the examination;
• factors that might affect testing, for example, drug types and levels (see Chapter 5), the timing of the assessment in relation to drug ingestion, which may have a direct effect on whether or not the person can be assessed (e.g., in the case of drugs used to treat Parkinson's disease, where ‘off’ periods at the end of the drug's effectiveness may make assessment extremely difficult or impossible), recent epileptic seizure activity (if relevant), mood and motivation (see Chapter 4), motor/speech/visual problems (which may determine which tests are feasible to administer), and the patient's likely distractibility;
• informants’ views of the person, their deficits and if/how they have changed; many patients with acquired brain injury will have little insight into the reason for their referral for assessment/treatment, and the nature and/or extent of their own cognitive deficits. Thus, informants may provide important information about the areas to be explored in the neuropsychological assessment (see Chapter 9);
• the context in which the assessment takes place, that is, whether there are relevant compensation or other medicolegal factors that might affect the person's motivation during the assessment.

While not all of the information will be available in every case, it is important to gather as much information as possible prior to seeing the patient since, as indicated with respect to medicolegal work in Chapter 17; this also permits the clarification with the patient of inconsistencies in the history and allows what may be a limited time in which to undertake an assessment to be used to cover the most important areas of that person's cognitive function.

The selection of the tests to be administered then needs to be based on

• predictions of the likely range of deficits to be found, given what is known about the person's history, neurological investigations, presenting complaints and the neuropsychological profile of that particular disorder and other relevant disorders that may form part of a ‘differential diagnosis’;
• the time available in which to undertake the assessment (e.g., it may be practical to assess an inpatient on more than one occasion but only one session may be possible, albeit less than desirable, for someone living at a great distance from the clinical setting) and the patient's likely tolerance of testing;
• the suitability of the test in terms of its standardization when compared with the patient, that is, whether or not the patient is similar to the standardization sample in terms of IQ, age and so on;
• the potential adaptability of the test to overcome problems posed by the patient's motor/speech/sensory deficits and how this might affect interpretation of the results that are obtained;
• the need for an interpreter where the patient's first language is not the same as that of the psychologist or that in which the test is published/standardized;
• the tests that have previously been administered, that is, one may need to use parallel forms of tests if they are available and consider the possibility that practice effects may be present on other measures, serving to mask deterioration;
• whether the patient is part of a research cohort (e.g., evaluating a neurosurgical intervention for epilepsy; deciding upon the suitability of the patient for pharmacological treatment of dementia – see Chapter 23), in which case a fixed protocol may be required for the assessment;
• whether it will be particularly important to use tests that are statistically interrelated (e.g., the Wechsler Test of Adult Reading, the Wechsler Adult Intelligence Scale (WAIS) – 3rd Edition and the Wechsler Memory Scale – 3rd Edition, or, as will become increasingly used, the Test of Premorbid Functioning (TOPF), the Wechsler Adult Intelligence Scale – 4th Edition (WAIS-IV) and the Wechsler Memory Scale – 4th Edition) or whether this would pose too taxing an assessment load for the patient to yield interpretable data, in which case other tests might be more suitable;
• what is then found during the assessment, that is, one may wish to follow up on specific findings with further standardized tests or the development of more idiosyncratic measures using a single case design.

It will not be uncommon for a clinician to develop greater familiarity with some tests than with others (see also Chapter 9), but the clinician should remain open to the need to be flexible in their choice of tests when this enables them better to answer the clinical question being posed in an individual case. It is also important to remain up to date with the development of new neuropsychological tests and to be aware of the psychometric implications of changing between older and newer versions of similar tests for the interpretation of between-assessment results. An important example of this is the difference in IQ scores yielded by different versions of the Wechsler Adult Intelligence Scale.

There is also a clear balance to be drawn between undertaking an adequate assessment and overassessing a patient. It is a frequent mistake for inexperienced clinical neuropsychologists to suppose that the more tests given, the better. It is also not uncommon to see reports where patients have been subjected to hours and hours of testing. This is rarely necessary. If, after several hours of testing, one is still unsure of what to conclude, it will normal...