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The following four articles address a number of the most pressing issues in the neuropsychological/legal arena. These studies represent but a few of the increasing number of questions being asked and addressed in research settings concerning the validity of neuropsychological tests, accuracy of patient reports, impact of other life factors upon symptom complaints and the issue of emotional change independent of cognitive differences secondary to brain injury.
Busch, C.R. & Alpern, H.P. (1998). Depression after mild traumatic brain injury: A review of current research. Neuropsychology Review, 8, 95-108.
Changes in personality, mood and behavior are often much more difficult to evaluate and correlate with brain injury than cognitive impairments. However, personality change including symptoms of depression have been reported to occur following brain injury. Most studies have involved more severely brain injured individuals. These authors critically review a dozen research papers from 1984 through 1996 in an effort to correlate severity of traumatic brain injury with depression. Despite acknowledging that many of the studies suffered from a lack of universally accepted definition of mild traumatic brain injury, the findings were consistent with the prevalence of depression found in somewhere between 35% and 87% of individuals depending upon the particular study reviewed. The studies also consistently demonstrated that symptoms of post-concussive syndrome overlap symptoms of depression and appear to be reported more in mild traumatic brain injury with depression than without depression. Depression was found to occur for many years after injury and it may be different in those patients where depression has an acute onset and is resolved within three months.
Although it has been suggested that depression seen after mild traumatic brain injury is related to disability, loss of work, guilt, anger, pain or reaction to the experience of loss and life style change, the research reviewed led these authors to conclude that mild traumatic brain injury can be a triggering event for a set of pathophysiological changes and a concomitant depressive episode in a vulnerable subset of the population. They also conclude that it cannot be definitely determined that the underlying substraits of depression seen after mild traumatic brain injury and non-traumatic clinical depression are one in the same. Although these studies provide strong support that at least a significant minority of mild head injured individuals develop what appears to be neurologically based depression, significantly more research is needed to understand premorbid risks, precipitating factors and long term prognosis.
Kibby, M.Y., Schmitter-Edgecomb, M. & Long, C.J. (1998). Ecological validity of neuropsychological tests: Focus on the California Verbal Learning Tests and the Wisconsin Card Sorting Test. Archives of Clinical Neuropsychology, 13, 523-534.
To date, few studies have evaluated the ecological validity of current measures of memory and executive function. Ecological validity refers to the appropriateness of drawing conclusions about an individual’s capacity to function in the real world based upon laboratory administered neuropsychological tests. Frequently attorneys are told by neuropsychologists that an individual is unfit for work based solely upon neuropsychological tests. Questions have been raised as to whether or not this is a valid procedure. These authors examined an auditory memory task and a test of concept formation evaluating an individual’s ability to shift set and avoid perseverative responding in a group of severely head injured adults one year or more post injury. Both instruments were about equally predictive of the type of work an individual was doing at the time of assessment. The verbal memory task was best at predicting performance on the job.
This study which likely is the first in a long series of studies to evaluate how well neuropsychological tests predict a person’s competency on the job, suggest that at least for the time being the use of these laboratory measures as key ingredients in the decision making process is justified. Very clearly, further research is needed with larger samples and multiple tests. For the time being it appears that neuropsychologists applying a reasoned and reasonable interpretation of their test data stand on firm ground when using these data as an integral part of a decision making process concerning predictions about readiness to return to work and potential success on the job.
Nelson, L.D., et. al. (1998). Personality change in head trauma: A validity study of the neuropsychology behavior and affect profile. Archives of Clinical Neuropsychology, 13, 549-560.
These authors evaluated two groups of closed head injury patients in an effort to validate a self-report measure designed to assess emotional functioning before and following brain injury. The measure, the Neuropsychological Behavior and Affect Profile, was completed by relatives or close friends of study participants. Although the results suggest that this instrument is valid, the study is of interest to attorneys for a second, unexpected reason. The authors report that significantly lower levels of premorbid emotional problems were reported in the clinical but not research population. The authors suggest that this may result in interpretations regarding emotional change that are inadvertently altered by yet unknown factors.
These findings suggest that friends and family members may place selectively greater weight on current condition while simultaneously making premorbid levels of functioning less severe than they really were thus leading to a report of greater change for the worse.
Machulda, M.M., et. al. (1998). Relationships between stress, coping and post-concussion symptoms in a healthy adult population. Archives of Clinical Neuropsychology, 13, 415-424.
These authors examined the association and stability of post-concussive symptoms, daily stress and the level of perceived stress over a month’s period in a group of young adults. A significant relationship between intensity of post-concussive symptoms and impact of daily stress as well as level of perceived stress independent of the frequency of stressful events experienced was found. The authors suggest that persistent symptoms in some individuals with post-concussive syndrome may be due at least in part to individual differences in the perceived stress of incurring a mild traumatic brain injury.
The existence of post-concussion syndrome following mild traumatic brain injury will likely continue to be an area of controversy. Outcome studies which have primarily focused on cognitive deficits and physical sequelae may have neglected important factors related to psychosocial variables. Very clearly additional research is needed to better understand the relationship between actual symptoms and perception of illness. At this time it is reasonable to conclude that pre-existing characterological features that may be subclinical and not differentiate individuals under stable, non-stressful conditions may come to the forefront under stressful situations and differentiate an individual’s reaction to a stressful event. In other words, normal variance in an individual’s response to stress in most environmental conditions is exaggerated when they are faced with more challenging and often confusing environmental conditions such as a mild traumatic brain injury.
I trust this information will be of assistance in working with your brain injured clients. Should you have additional questions or concerns, please feel free to contact me. As always, I am available for consultation, case management, expert opinion and court room testimony.