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“I don’t remember things like I used to” - The role of neuropsychological assessment in determining post-trauma cognitive impairment.

Dr Kathryn Peace and Dr Diana Pidwell

Cognitive symptoms following traumatic brain injury (TBI) quite commonly occur. They may be due to a temporary disruption of brain function, to permanent brain injury, or may be secondary to emotional difficulties resulting from trauma. They can also be fully or partly a result of compensation-seeking. In a meta-analysis of 2353 cases of mild brain injury Binder and Rohling (1996) estimated that if financial compensation was removed as a factor, symptoms attributed to head injury would decrease by 23%.

The nature of reported cognitive difficulties following TBI are wide-ranging but commonly includes slowed thinking, poor concentration, forgetfulness, difficulty with planning and ability to organise as well as personality change with increased irritability and reduced tolerance of frustration. Many individuals also experience low mood and heightened anxiety as the changes in their mental abilities affect their everyday life and relationships.

Identifying the specific nature of the symptoms and likely cause is important for planning rehabilitation and therapy as well as for determining prognosis. For example, if a person’s poor concentration and memory are impaired as a direct result of brain injury the therapeutic strategies are quite different from those where the underlying cause of the poor concentration and memory is depression or elevated anxiety.

Neuropsychological assessment is the most effective method for evaluating and quantifying the psychological symptoms that have occurred following a TBI. There are five main goals of assessment:
  1. To determine the nature of the cognitive, emotional and behavioural difficulties following TBI (or any other form of brain injury).
  2. To assess the impact of those difficulties on the person’s everyday life and ability to function effectively.
  3. To assist in the development of a rehabilitation programme or course of therapy.
  4. To monitor change over time.
  5. To advise the courts in compensation cases about the effects of a particular accident/injury.
Clinical neuropsychologists use a number of sources of information in carrying out an assessment. These include:
  • Documentation about the person prior to the injury. This is crucial to provide baseline information against which one can measure post-injury capability, personality and emotional function. This information can be obtained from medical records, school or work records
  • Observation of the person during the assessment sessions. This provides information about their personality, emotional state, stress coping strategies, problem-solving ability, openness and spontaneity etc.
  • An interview with the injured person to provide data about their background, the injury, the person’s perception of their difficulties and their coping strategies for dealing with them.
  • An interview with a close relative or friend to gather further information about the injured person both prior to the accident and since. When the injured person lacks insight into his or her difficulties, as some do, the relative or friend can usually provide a more detailed account of the post-accident problems.
  • Administration of a battery of tests to quantify current cognitive ability and estimate pre-accident ability level. For most people, pre-accident general intelligence can be estimated with a reasonable degree of accuracy using a test of irregular word reading as in the healthy state this correlates highly with general intelligence and is usually very resistant to brain injury. Tests of current ability should include an assessment of general intelligence, attention, memory and capacity for new learning, visual-spatial ability, language skills and executive functioning (problem-solving, planning, ability to inhibit responses, divided attention etc). Emotional state can be determined using self-report questionnaires. Tests used in a neuropsychological assessment are required to meet certain standards of reliability and validity. Reliability refers to the extent to which a test will produce the same results if re-administered under the same conditions and validity refers to the extent to which a test measures what it is designed to measure. Because of the above requirements psychological tests take many years to develop and are available only to suitably qualified individuals.
As suggested earlier in this article an important issue for consideration in a neuropsychological assessment, especially when litigation is involved, is the extent to which the injured person is exaggerating or faking their symptoms by using non-optimal effort during testing. An experienced clinical neuropsychologist is usually able to give an opinion about this based on two main sources of information. The first of these is the use of particular tests designed to assess lack of effort during testing. These appear superficially to be quite challenging but are in fact very easy and have been developed in such a way that even an individual with a significant degree of brain injury can easily pass the test. Hence if an individual has a very poor score it can usually be inferred that they were deliberately trying to create an impression of significant impairment or just failing to put in adequate effort. The second source of information is qualitative scrutiny of the individual’s performance on certain routine cognitive tests. For example on word-list learning tests certain patterns of performance over repeated learning trials and recall/recognition can be indicative of lack of effort or active attempts to “fake bad”.

When seeking a neuropsychological opinion lawyers should check that the clinical neuropsychologist is a practitioner member of the Division of Neuropsychology of the British Psychological Society as well as a registered psychologist with the Health Professions Council in order to be sure that he/she has had adequate training and clinical experience. Significant time spent in a brain injury rehabilitation unit, neurology or neurosurgery service will also have provided the psychologist with the appropriate practical experience necessary to give sound opinions.

Binder LM and Rohling ML. Money Matters: A Meta-analytic review of the effects of financial incentives on recovery after closed-head injury. American Journal of Psychiatry. 1996. 153: 7-10.

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