Legal Update #24 Update on Post-Concussion: New Research Reflects Generic Nature of the Symptoms
NLBC LEGAL UPDATE: August, 2006 - Issue #24
Sam Goldstein, Ph.D., Editor
Complimentary Service of the Neurology, Learning and Behavior Center
Update On Post Concussion: New Research Reflects Generic Nature Of These Symptoms
In NLBC Legal Update (Issue 7), I reviewed the symptoms of post-concussion noting that these included problems of thinking, physical impairments involving fatigue, dizziness, headache and sensory sensitivity as well as mood changes. Fifty to 80% of individuals during an acute period following a mild head trauma were reported to exhibit some of these symptoms. Approximately 50% of affected individuals experienced symptoms for at least three months with 10% to 15% complaining of persistent post-concussive symptoms beyond that period. Yet less than 10% of individuals experiencing mild head injury have been found to demonstrate measurable neuropsychological deficits. In NLBC Legal Update, Issue 13, July, 2001 I addressed post-concussional symptoms and neurologic impairment. The subjective nature of post-concussive symptoms and the overlap with other physical and psychological conditions has made accurate assessment, interpretation and litigation difficult.
Although there is extensive literature addressing the cognitive and behavioral characteristics of mild traumatic brain injury patients, the majority of these studies have been conducted with patients who are typically months or even years post injury at which point their presentation likely differs greatly from those a number of days post-injury. The existing research on acute mild traumatic brain injury is limited relative to a larger body of work on mild traumatic brain injury in general. It also yields somewhat inconsistent findings. While many studies suggest a decline in cognitive functioning and/or an increase in post-concussive symptoms at various points post-injury, several studies find minimal or no evidence of such changes. This inconsistency may well reflect methodological variability in the research, particularly in older studies. Many older studies were conducted with small, potentially non-representative and poorly controlled samples. Outcome measures varied. Several studies lacked control groups.
In 2001, in one of the best controlled studies, Donald Trahan and colleagues evaluated the relationship between post-concussional type symptoms, depression and anxiety in neurologically normal adults and victims of mild traumatic brain injury. The sample included nearly 500 individuals with no history of neurologic problems. Fifty-six individuals with clinical depression and forty individuals with a history of mild head injury were also included. The results revealed moderate to high correlations between reports of post-concussion symptoms, depression and anxiety symptoms. Individuals with clinical depression scored significantly higher for self-report of post-concussive symptoms than either normal adults or, for that matter, mild head injury victims.
A recent issue of the Archives of Clinical Neuropsychology (Volume 21, #4), contains a number of important articles further advancing our understanding of post-concussional symptoms. In this legal update I will review these four articles and offer opinion concerning the state of science in understanding and interpreting symptoms that have traditionally been attributed to post-concussion.
Nancy Landre and colleagues (2006) address the issue of the potential contribution of non-neurological factors such as pain and emotional distress to the clinical picture of individuals suffering mild traumatic brain injury. The cognitive performance and subjective complaints of 37 hospitalized mild traumatic brain injury patients were compared to those of 39 hospitalized trauma subjects averaging four and a half days post-injury. Those with mild traumatic brain injury performed significantly worse on all cognitive measures but did not differ from trauma subjects in their report of post-concussive symptoms. Analyses of the data also revealed that cognitive performance was unrelated to pain severity or emotional distress. Post-concussive symptoms were similarly unrelated to pain severity but were consistently related to emotional distress.
Landre and colleagues' findings that pain ratings were related to neither cognitive performance nor post-concussive symptoms may reflect the fact that these patients were experiencing acute pain while the literature suggesting a relationship between pain and neuropsychological functioning which I have reviewed in previous legal updates is based primarily on studies conducted with chronic pain patients. It is important to note that these findings suggest that poor performance on cognitive measures in the early stages following a traumatic brain injury cannot simply be dismissed as a product of pain or emotional distress and should be managed accordingly. Further mild traumatic brain injury patients who acutely show normal cognitive performance but report high levels of post-concussive symptoms might benefit from an aggressive, psychologically based treatment approach combined possibly with psychiatric medication.
Wang and colleagues (2006) examined the relationship of post-concussion like symptoms in a group of university students and neuropsychological test performance. A sample of 124 students was recruited. They completed a post-concussion symptom questionnaire and a comprehensive set of neuropsychological tests. These subjects reported a relatively high base rate of post-concussion like symptoms. The most frequently endorsed symptoms were fatigue (76.9%), longer time to think (60.3%), poor concentration (58.7%), sleep disturbance (50.4%) and frustration (46.3%). There were no significant test differences between low symptom reporters and high symptom reporters except for self-reported dysexecutive problems. The comparison of the healthy symptom reporters and a convenient sample of traumatic brain injury patients revealed that the patients performed significantly worse on neuropsychological functions than the healthy symptom reporters despite non-significant differences between symptom endorsement. Wang and colleagues note their findings demonstrate that the base rate of post-concussion like symptoms in a group of healthy university students is relatively high and that post-concussion symptoms for the most part are not related to neuropsychological functioning in normal individuals. These findings lend even more data to the fact that post-concussive symptoms are in fact better described as life adversity or living life symptoms. Wang and colleagues' findings indicate that non-brain injury populations might also suffer a number of subjective complaints due to a variety of personal and psychological issues related to school, work and emotional state in every day life.
It is reasonable to conclude that post-concussive symptoms are often observed in individuals with a variety of psychological, physical and life problems beyond mild traumatic brain injury. Past research has also suggested a significant relationship between mental health problems or psychopathology and cognitive impairment. Some studies have found that psychological disorders are associated with lower cognitive functioning. This research, however, has been limited, and also plagued by methodological problems and poor subject control. Recent studies have not consistently found a relationship between depressive symptoms and cognitive functioning even in individuals evaluated in medical legal contexts. These data would suggest that in forensic settings reasons other than psychopathology should be sought to explain deficits, particularly when evaluating individuals with mood or affective disorders. When such findings occur it is more likely that these factors are related to phenomena such as pre-existing history of learning disability or mild traumatic brain injury to a greater extent than to psychopathology.
Grant Iverson (2006) examined the prevalence of post-concussion like symptoms in individuals with depression. Sixty-four physician diagnosed individuals with depression who had independently confirmed diagnoses, completed a post-concussion symptom inventory. Specific endorsement rates of post-concussion-like symptoms ranged from 31.2% to 85.6% for symptoms, rated mild or greater and from 10.9% to 57.8% for symptoms rated moderate to severe. Approximately nine out of ten individuals with depression met liberal self-report criteria for a post-concussion syndrome and more than five out of ten met conservative criteria for this diagnosis. Iverson points out that his findings are consistent with previous studies reporting at least moderate correlations between post-concussion like symptoms and depression. Iverson notes the results also support a high endorsement rate of post-concussion like symptoms in normal populations, an issue addressed by Wang and colleagues as well.
Benjamin Morasco and colleagues (2006) attempted to assess the relationship between symptoms of psychopathology and cognitive functioning in individuals completing psychoeducational assessments at a university based outpatient mental health clinic. Though this study did not deal with post-concussive symptoms per se, the issue of pre-morbid personality style and possibly psychiatric impairments impacting an individual's psychological adjustment to a mild traumatic brain injury is an often complex issue in forensic settings. These authors find that typical neuropsychological tests do not correlate with psychiatric status. Measures of intelligence and memory for individuals with comorbid symptoms of depression and anxiety were comparable to scores for individuals without comorbid symptomatology. The authors suggest that psychopathology as measured by instruments such as the Minnesota Multiphasic Personality Inventory are likely minimally associated with intelligence and memory test performance.
In forensic settings differential diagnosis and etiology are critically important. Individuals with mild traumatic brain injuries, the research suggests, for the most part recover within weeks or months. Problems persisting beyond a year are often considered of low probability. In contrast, a depressed individual or someone experiencing chronic pain or both is likely to report the same symptoms reported by individuals with mild traumatic brain injury in the initial days and weeks following injury. Though some individuals may in fact experience persistent post-concussion syndrome, for many others continued post-concussive complaints may reflect a dual etiology with complaints initially resulting from a mild traumatic brain injury but then fueled by and persisting as the result of the development of depression or an affective condition over the coming months. In forensic settings, examiners diagnosing persistent post-concussive syndrome in individuals with co-morbid depression, chronic pain or other affective illness must possess considerable evidence to support this diagnosis in light of these data. Iverson further notes that it would be naive and biased to assume that because the vast majority of people who sustain uncomplicated mild traumatic brain injuries recover fully, that a person continuing to report symptoms two years post injury is exaggerating or malingering or in fact is disabled due to the effects of the mild traumatic brain injury. As Iverson points out, these are polarized and unscientific positions. He notes finally that "the extent to which these symptoms are due to biological effects of remote mild traumatic brain injuries is unknown" (pg. 308).
First, and most importantly, a forensic expert must speak to the science. The emerging science on post concussive symptoms demonstrates that although these symptoms were once thought of as solely a consequence of traumatic brain injury, it is now apparent that these are equal opportunity symptoms arising from a host of medical, psychological and even every day life phenomena. It would be inappropriate and pseudoscientific to suggest, however, that these data be used to impeach patient's complaints following concussion and TBI or to suggest that these symptoms when they present chronically are incompatible with mild TBI. Further, it is important to recognize that these studies focus on mildly traumatically brain injured individuals. Research with moderate to severely brain injured populations has yet to be comprehensively addressed. However, in these more significantly affected individuals, symptom complaints, psychiatric status and daily impairments may be more easily addressed and understood.
References
Iverson, G.L. (2006). Misdiagnosis of the persistent post-concussive syndrome in patients with depression. Archives of Clinical Neuropsychology, 21, 303-310.
Landre, N., Poppe, C.J., Davis, N., Schmaus, B., & Hobbs, S.E. (2006). Cognitive functioning and post-concussive symptoms in trauma patients with and without mild TBI. Archives of Clinical Neuropsychology, 21, 255-274.
Morasco, B.J., Getfeller, J.D., & Chibnall, J.T. (2006). The relationship between measures of psychopathology, intelligence and memory among adults seen for psychoeducational assessment. Archives of Clinical Neuropsychology, 21, 297-302.
Trahan, D.E., Ross, C.E., & Trahan, S.L. (2001). Relationships among post-concussional-type symptoms, depression and anxiety in neurologically normal young adults and victims of mild brain injury. Archives of Clinical Neuropsychology, 16, 435-445.
Wang, Y., Chen, R.C.K., & Deng, Y. (2006). Examination of post-concussion-like symptoms in health university students: Relationships to subjective and objective neuropsychological function performance. Archives of Clinical Neuropsychology, 21, 339-348.
The Neurology, Learning and Behavior Center provides clinical and forensic assessment, case management, trial consultation and treatment services for children and adults with brain injury and dysfunction, Attention-Deficit Hyperactivity Disorder, language disorders, learning disability, developmental delay, emotional disorders, Autism and adjustment problems. The Center is dedicated to the provision of treatment services.
