The etiology of postconcussive symptoms is not clearly understood. Development of etiological models of those symptoms will be helpful for accurate diagnosis and for planning effective treatment. Such a model should characterize the role of subject characteristics (education, premorbid intelligence), social psychological factors and symptom validity. Toward that end, the present study examined the association of postconcussive complaints and cognitive performance with symptom attribution and level of effort on testing. In a sample of 155 veterans, attribution to concussion was associated with endorsement of more severe postconcussive complaints, after controlling for the effects of other factors such as subject characteristics. Similarly, effort was associated with cognitive performance after controlling for the effects of these other factors. The present findings are consistent with previous reports that illness perception and effort on testing are associated with postconcussive complaints. This supports previous recommendations to routinely educate all concussion patients immediately after injury to reduce distorted perceptions and related persistent complaints. Finally, these findings highlight a need for routine assessment of patients’ perception of their injury to identify cases that may require psychotherapy to address any misattributions that develop. (JINS, 2013, 19, 1–8)

Patients with a history of mild (n = 134) or moderate-to-severe (n = 91) TBI were asked to complete the Neurobehavioral Symptom Inventory (NSI) and the Posttraumatic Stress Disorder Checklist. Consistent with prior research, significantly more postconcussion symptoms were endorsed by the mild group. After controlling for age, time since injury, and mechanism of injury, TBI severity continued to be significantly related to postconcussion complaints on the NSI. However, after controlling for these same variables, along with posttraumatic stress disorder symptom severity, there no longer were differences between the TBI severity groups. That is, patients with mild TBI did not endorse significantly more complaints (adjusted mean = 22.4) than the moderate-to-severe group (adjusted mean = 21.8). These findings suggest that much of the symptom complaints in mildly injured patients may be due to emotional distress. (JINS, 2010, 16, 194–199.)

Motor measures are sensitive to central lesions, but they are also affected by peripheral injury and motivation. The motor skills profiles of proven brain injury clients were compared with the profiles of healthy postconcussion patients. The chief result was a double dissociation: The traumatic brain injury (TBI) group produced a motor dysfunction gradient consistent with upper motor neuron disease, while the compensation-seeking postconcussion group produced a nonphysiologic pattern. Objective measures of behavioral pain and emotional distress did not correlate with the findings. Motor skill deficiencies in postconcussion syndrome (PCS) are probably functional in nature. (JINS, 1996, 2, 477–485.)

The dimensions of postconcussive symptoms (PCS) were examined in a prospective, longitudinal study of 186 8 to 15 year old children with mild traumatic brain injuries (TBI). Parents and children completed a 50-item questionnaire within 2 weeks of injury and again at 3 months after injury, rating the frequency of PCS on a 4-point scale. Common factor analysis with target rotation was used to rotate the ratings to four hypothesized dimensions, representing cognitive, somatic, emotional, and behavioral symptoms. The rotated factor matrix for baseline parent ratings was consistent with the target matrix. The rotated matrix for baseline child ratings was consistent with the target matrix for cognitive and somatic symptoms but not for emotional and behavioral symptoms. The rotated matrices for ratings obtained 3 months after injury were largely consistent with the target matrix derived from analyses of baseline ratings, except that parent ratings of behavioral symptoms did not cluster as before. Parent and child ratings of PCS following mild TBI yield consistent factors reflecting cognitive and somatic symptom dimensions, but dimensions of emotional and behavioral symptoms are less robust across time and raters. (JINS, 2009, 15, 19–30.)

Speed of information processing in persons with postconcussion syndrome (PCS) was examined using word fluency tasks. Twenty patients with PCS and twenty controls matched for age, gender, and occupation were given two word fluency tasks, and the speed of word generation was measured. Response latencies were analyzed to determine whether slowed retrieval or degradation of words in semantic memory was responsible for problems with word retrieval after traumatic brain injury. The PCS group recalled fewer words, had significantly longer interresponse times, and took significantly longer to generate their first word than the controls. There was no evidence that either structure loss or slowness in word retrieval from semantic memory could account for the word fluency deficits. Rather, the findings suggest that the primary cause of word retrieval difficulties in patients with PCS is a generalized slowness of cognitive processing (JINS, 2007, 13, 178–182.)The study described was part of Maria Crawford's doctoral thesis. This research was supported by a University of Otago Research Grant awarded to Robert G. Knight and a Ph.D. scholarship awarded to Maria Crawford.

A growing number of studies show postconcussion syndrome (PCS) symptom report is influenced by factors other than head injury, suggesting symptoms typically associated with PCS may not be specific to head injury. Given the role that symptom expectation has been hypothesized to play in PCS symptom etiology, a comparison of symptoms expected for various disorders seems overdue. The present study asked 82 undergraduates to report the symptoms they currently experience, and then to report the symptoms they would expect to experience if they had had suffered either a head injury, an orthopedic injury, posttraumatic stress, or depression. No current differences in overall symptoms or in symptom subscales emerged. Results showed individuals portraying head injury, posttraumatic stress, and depression expected an increase in total symptoms, though individuals portraying an orthopedic injury did not expect such an increase. Results also showed simulators of head injury, posttraumatic stress, and depression expected equivalent rates of overall symptoms, memory/cognitive complaints, somatic concerns, and distracter symptoms, though head-injured individuals reported fewer affective symptoms than those portraying psychological disorders. In all, these findings suggest that individuals have a relative lack of specificity in symptom expectation for various disorders, with the implication that symptom checklists for “PCS” may not be useful for diagnosis. (JINS, 2002, 8, 37–47.)

The present study explored the explanatory power of Mittenberg's “expectation as etiology” theory for the persistence of postconcussion syndrome (PCS) complaints. One hundred forty-one participants completed a PCS symptom checklist under 2 conditions. Normal controls, healthy athletes and depressed individuals reported current symptoms and symptoms expected following a hypothetical mild head injury. Head-injured athletes, chronic headache sufferers, and a 2nd sample of normal controls reported current symptoms and retrospective symptoms (prior to their injury/illness or from some point in the past). Depressed individuals reported more current symptoms than normal controls and healthy athletes, demonstrating that “PCS” symptoms are not specific to PCS. All groups expected more symptoms following mild head injury than currently experienced, supporting the idea that individuals expect negative consequences following head injury. However, healthy athletes expected fewer symptoms than normals or depressed individuals, possibly due to preexisting expectations for speedy recovery. Both head-injured athletes and headache sufferers reported more current symptoms than the past, but not at a rate lower than baseline of normal controls. Results suggest that the “expectation as etiology” hypothesis may be too specific, and that, following any negative event, people may attribute all symptoms to that negative event (the “good old days” hypothesis). (JINS, 2001, 7, 323–333.)