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1 This article was downloaded by:[wayne State University] On: 27 February 2008 Access Details: [subscription number ] Publisher: Psychology Press Informa Ltd Registered in England and Wales Registered Number: Registered office: Mortimer House, Mortimer Street, London W1T 3JH, UK The Clinical Neuropsychologist Publication details, including instructions for authors and subscription information: Brain injury severity, litigation status, and self-report of postconcussive symptoms John Tsanadis ab ; Eduardo Montoya a ; Robin A. Hanks ab ; Scott R. Millis b ; Norman L. Fichtenberg ab ; Bradley N. Axelrod c a Rehabilitation Institute of Michigan, Detroit, MI b Wayne State University School of Medicine, Detroit, MI c Department of Veteran Affairs John D. Dingell Medical Center, Detroit, MI, USA First Published on: 26 February 2008 To cite this Article: Tsanadis, John, Montoya, Eduardo, Hanks, Robin A., Millis, Scott R., Fichtenberg, Norman L. and Axelrod, Bradley N. (2008) 'Brain injury severity, litigation status, and self-report of postconcussive symptoms', The Clinical Neuropsychologist, 1-13 To link to this article: DOI: / URL: PLEASE SCROLL DOWN FOR ARTICLE Full terms and conditions of use: This article maybe used for research, teaching and private study purposes. Any substantial or systematic reproduction, re-distribution, re-selling, loan or sub-licensing, systematic supply or distribution in any form to anyone is expressly forbidden. The publisher does not give any warranty express or implied or make any representation that the contents will be complete or accurate or up to date. The accuracy of any instructions, formulae and drug doses should be independently verified with primary sources. The publisher shall not be liable for any loss, actions, claims, proceedings, demand or costs or damages whatsoever or howsoever caused arising directly or indirectly in connection with or arising out of the use of this material.

2 The Clinical Neuropsychologist, 2008, 1 13, ifirst ISSN: print/ online DOI: / BRAIN INJURY SEVERITY, LITIGATION STATUS, AND SELF-REPORT OF POSTCONCUSSIVE SYMPTOMS John Tsanadis 1,2, Eduardo Montoya 1, Robin A. Hanks 1,2, Scott R. Millis 2, Norman L. Fichtenberg 1,2, and Bradley N. Axelrod 3 1 Rehabilitation Institute of Michigan, Detroit, MI, 2 Wayne State University School of Medicine, Detroit, MI, and 3 Department of Veteran Affairs John D. Dingell Medical Center, Detroit, MI, USA The Postconcussive Symptom Questionnaire (PCSQ) was developed to assess the symptoms associated with the controversial diagnosis of postconcussion syndrome. We examined item endorsement on the PCSQ in two groups. The first group was made up of individuals diagnosed with moderate to severe traumatic brain injury. The second group was made up of individuals meeting criteria for mild traumatic brain injury who exhibited no evidence of neurological injury. In addition, they demonstrated poor effort during neuropsychological examination. Significant differences in item endorsement were found the majority of individual items as well as on the PCSQ indices. The poor effort mild traumatic brain injury group consistently reported more symptoms with greater severity. The results raise further questions about the validity of postconcussion symptoms. Keywords: Brain injury; Postconcussion; Litigation; Malingering; Effort INTRODUCTION The DSM-IV-TR includes Postconcussional Disorder in its criteria sets and axes provided for further study appendix. The research criteria provided (APA, 2002) include:a history of head trauma that causes significant cerebral concussion; Evidence from neuropsychological testing or quantified cognitive assessment of difficulty in attention or memory; and three or more of a variety of symptoms that have lasted for at least three months including becoming fatigued easily, disordered sleep, headache, vertigo or dizziness, irritability or aggression on little or no provocation, affective lability, changes in personality, and apathy or lack of spontaneity. A review of the empirical data on these diagnostic criteria reveals many questions regarding the utility and meaning of this diagnosis and the nature of the postconcussive symptoms. Address correspondence to: Rehabilitation Institute of Michigan, Department of Rehabilitation Psychology and Neuropsychology, 261 Mack Blvd, Detroit, MI jtsanadis@med.wayne.edu Accepted for publication: November 8, First published online: Month day, year. ß 2008 Psychology Press, an imprint of the Taylor & Francis group, an Informa business

3 2 JOHN TSANADIS ET AL. Several criticisms have been offered against postconcussional disorder/ postconcussion syndrome as a diagnostic category. One criticism is that the constellation of symptoms occurs at a fairly high base rate in the normal population (Iverson & Lang, 2003; Wang, Chan, & Deng, 2006). For example, more than half of a control group of 50 patients from an outpatient family practice reported symptoms of anxiety or nervousness, sleep problems, headaches, and fatigue. At least one quarter reported depression, concentration problems, irritability, feeling disorganized, loss of interest, dizziness, and health worries; and 20% reported memory problems (Lees-Haley & Brown, 1993). Other studies have found similar rates of such symptoms in healthy controls (Iverson & Lang, 2003; Trahan, Ross, & Trahan, 2001). Along similar lines, the symptoms thought to constitute PCS are not unique to PCS thus, there is a lack of specificity in this symptom constellation (Larrabee, 2005). For example, the symptoms occur at a fairly high rate in the normal population, but they are also common in individuals with minor medical problems (Lees-Haley & Brown, 1993), orthopedic injuries (Mickeviciene, Schrader, & Nestvold, 2002), and individuals with chronic pain (Iverson & McCracken, 1997). In addition, postconcussive symptoms are shared by several other disorders that generally contain medically unexplained symptoms (Binder, 2005). Illnesses such as fibromyalgia, chronic fatigue syndrome, multiple chemical sensitivities, and sick building syndrome share most of the symptoms of postconcussion syndrome, are usually of unknown origin, and have been referred to as functional somatic syndromes (Barsky & Borus, 1999). Some of the strongest criticisms against postconcussion syndrome come from the expanding scientific knowledge base about the natural course of recovery from mild traumatic brain injuries. The consensus emerging from reviews of the extant literature is that the expected outcome following an uncomplicated mild traumatic brain injury for the majority of patients is full recovery (Belanger & Vanderploeg, 2005; Carroll et al., 2004). This is further supported by the sports concussion literature. For example, a prospective study found that concussed college football players showed mild impairments in cognitive processing and verbal memory 2 days after concussion compared to baseline; however, they returned to baseline within 5 to 7 days (McCrea et al., 2003). While problems persist for a neurobiological explanation for postconcussion symptoms, significant evidence exists for a psychological basis. For example, postconcussion-like symptoms are common in outpatients seen for psychological treatment (Fox, Lees-Haley, Ernest, & Dolezal-Wood, 1995) and patients with post-traumatic stress disorder (Foa, Cashman, Jaycox, & Perry, 1997). Some studies have shown that depression and not head injury status account for postconcussion symptoms including cognitive symptoms (Suhr & Gunstad, 2002). A recent study explored the relationship between depression and postconcussion syndrome in 64 inpatients and outpatients diagnosed with depression (Iverson, 2006). Diagnosis was independently confirmed using the Structured Clinical Interview for DSM-IV (SCID-I). Results showed that approximately 5 out of 10 patients with depression met conservative criteria for diagnosis, based on the DSM-IV criteria, of postconcussion syndrome (Iverson, 2006). When a more liberal criterion for diagnosis of postconcussion syndrome was used, approximately 9 out of 10 depressed patients met the criteria. These findings indicate both a

4 BRAIN INJURY SEVERITY & POSTCONCUSSIVE SYMPTOMS 3 psychological basis for the symptoms and problems with differential diagnosis between the two disorders. Furthermore, it points to a more affective basis for these symptoms rather than symptoms emanating from neurological insult. Perhaps the most contentious area of discussion regarding postconcussion syndrome has to do with litigation. It is well known that studies exploring the issue of litigation and postconcussion syndrome symptoms have found a higher rate of complaint base rates occurring in personal injury claimants (Lees-Haley & Brown, 1993). A meta-analytic review by Binder and Rohling (1996) found a moderate overall effect size for the effects of financial incentives on recovery following brain injury, particularly in those with mild brain trauma. It has been suggested that the process of litigation influences patient behavior to such a great degree that the validity of psychological assessment procedures are likely to be undermined (Lees-Haley, 1988). A more recent review of 120 studies by Carroll et al. (2004) found that, where symptoms persist following mtbi, compensation/ litigation was the only consistent predictor found across studies. A 2006 study by Greiffenstein and Baker found an inverse dose response relationship, with minor compensable injuries resulting in more pseudo-abnormalities with memory and motor abnormalities being more common than psychotic ones. They also explored subjective postconcussive complaints and found that half of their sample reported 0 6 symptoms, with only 2% showing invalid signs in three functional domains (memory, motor, psychiatric) under the probable definition (performance at or below 1 SD of a more seriously injured reference group) and 25.6% showing invalid signs in the three domains under the possible definition (performance at or below the reference group mean). For individuals reporting 9 10 postconcussive symptoms, 26.7% showed invalid signs in the three domains under the probable definition and 53.3% under the less restrictive possible definition. However, there is some evidence to indicate that this litigation effect may not generalize to individuals with more severe injuries (Wood & Rutterford, 2006), where equivalent outcomes are likely for both litigating and non-litigating individuals. For the most part, accidents that result in moderate to severe brain injuries are not contested and therefore do not result in litigation as often, but many equivocal injuries or mild injuries with protracted symptoms result in litigation, given the lack of recovery demonstrated in such cases. To date, the cluster of postconcussion symptoms has been found to be common in a variety of patient populations; however, there is a paucity of information about the presence of these symptoms in individuals with more objective evidence of traumatic brain injury than is usually available in the typical individual meeting criteria for postconcussion syndrome. At this time it is relatively well established that postconcussive symptoms are not specific to mild head injury, as they have been shown to be common in a number of clinical conditions. Currently there is a lack of information regarding the presence of these symptoms in individuals with well-established histories of moderate or severe traumatic brain injury. The purpose of the present study is to explore the frequency and type of postconcussive symptoms reported by individuals with moderate to severe traumatic brain injuries, and to compare these findings to individuals with mild uncomplicated brain injuries who demonstrate poor effort during neuropsychological evaluation. It was hypothesized that postconcussion symptoms would be

5 4 JOHN TSANADIS ET AL. endorsed to a greater degree in the mild traumatic brain injury group compared to the moderate to severe brain injury group, since previous research indicates that non-neurological factors contribute to these symptoms. METHOD Participants This was an archival study that included 158 participants who received consecutive evaluations at an outpatient neuropsychology program at a major rehabilitation hospital in the Midwestern United States. For purposes of comparison, two groups were created. The first group was comprised of 133 participants (55 females and 78 males) who met criteria for moderate to severe brain injury (M-S TBI). All patients (a) had medically documented brain injuries from an external cause, (b) were determined by a team of rehabilitation clinicians to have sustained functional losses and be in need of treatment for cognitive deficits, and (c) had GCS ratings below 13 upon admission to the emergency room. Neuroimaging was positive in all but seven cases and not available for two individuals. Ages of this group ranged from 15 to 80 years (M ¼ 39.59, SD ¼ 13.88). The group mean for time from injury to assessment was months, with a range from 2 weeks to 139 months. Of the M-S TBI participants, 44 were known to be involved in litigation; however, statistical analysis did not find any significant difference between the litigating and non-litigating patient vis-a` -vis performance level on the neuropsychological testing and in most cases the group means were almost identical. Additionally, three participants were receiving worker s compensation. The second group was a poor effort group (PE), which consisted of 25 participants (11 female and 14 male). For this group, the ages ranged from 24 to 61 (M ¼ 43.12, SD ¼ 11.65). The mean for time from injury to assessment was months, with a range from 1 month to 78 months. All participants in this study were raised and educated in North America and spoke English fluently. Probability of major brain dysfunction was minimized by restricting participants to those with a history of mild head trauma. Specifically, participants were excluded from this group with: (a) an admission GCS of less than 15, (b) histories of loss of consciousness greater than 30 minutes or PTC greater than 1 hour, (c) positive neuroimaging, or (d) any history of neurologic disorder. This group included 14 individuals in litigation, 1 individual receiving worker s compensation, and 10 individuals who were neither in litigation nor receiving workers compensation. Inclusion in the PE group required failure on two symptom validity tests, defined as scores below empirically derived cut-offs for the Recognition Memory Test (RMT; Millis, 1992; Millis & Putnam, 1994; Warrington, 1984), the Test of Memory malingering (TOMM; Tombaugh, 1997), and the Word Memory Test (Green, 1999). All participants in the PE group met the Slick, Sherman, and Iverson (1999) criteria for probable or definite malingering neurocognitive dysfunction.

6 BRAIN INJURY SEVERITY & POSTCONCUSSIVE SYMPTOMS 5 Measure The Postconcussive Symptom Questionnaire (PCSQ) contains 45 items that describe symptoms which participants may have experienced (Lees-Haley, 1992). Items reflect a variety of psychological (i.e., anxiety, depression, irritability), cognitive (i.e., concentration, memory), and somatic (i.e., nausea, headaches, fatigue) symptoms. It was designed to measure a four-factor model of symptoms reported by an individual who has experienced a mild head injury. This four-factor model has been confirmed in other studies (Cicerone & Kalmar, 1995). The PCSQ contains four indices: (A) Psychological, (B) Cognitive, (C) Somatic, and (D) Infrequency (e.g., items intended to reflect negative impression management). Overall composite reliability of this four-factor model for the PCSQ was.89 (Axelrod, Fox, Lees-Haley, Earnest, & Dolezal-Wood, 1996). Construct validity of the PCSQ was established by a comparing it to the MMPI-2 in a heterogeneous patient sample referred for neuropsychological evaluation (Axelrod & Lees-Haley, 2002). Higher global scores on the PCSQ were associated with an overall heightened distress on the MMPI-2. Relationships were found between the Psychological Index of the PCSQ and MMPI-2 scales 6 and 2; the Somatic Index and scales 1, 4, and F; The Cognitive Index and scale 8; and the Infrequency Index and scales 8 and 9. Procedure Approval was obtained from the institution s review board to conduct this archival study. All participants completed the PCSQ as part of their outpatient neuropsychological evaluations. They rated each item on a 5-point Likert-like scale with 1 indicating not at all and 5 representing a great deal. In addition, participants rated each item in terms of symptom status as either getting better, staying about the same, or getting worse. For statistical analysis, participants responses on the Likert scale were transformed into a dichotomous variable with a response greater than 2 indicating the presence of a symptom. Also, the four indices were computed in order to compare groups. Responses on the symptom status scale were coded as 0 for getting better, 1 for staying about the same, and 2 for getting worse. RESULTS Due to the ethnic diversity of the sample, a chi-square analysis was conducted to explore for proportional differences of ethnicities between the two groups. There was a significant association between group and ethnicity, 2 (4) ¼ 15.79, p For the MS-TBI group the sample was 38% African American, 56% Caucasian American, 1.5% Hispanic/Latin American, 0.8% Asian/Pacific Islander, and 3% other. For the PE group the sample was 52% African American, 24% Caucasian American, 8% Hispanic, and 16% other. African Americans were compared with Caucasian Americans were compared across PCSQ Indices in both the PE and M-S TBI groups. No significant differences were found, with the exception of the

7 6 JOHN TSANADIS ET AL. Table 1 Comparisons of moderate to severe traumatic brain injury and poor effort groups on the Postconcussive Symptom Questionnaire indices Index M-S TBI (n ¼ 133) PE (n ¼ 25) p d Psychological (13.23) (13.95) Cognitive (4.84) (5.39) Somatic (10.22) (15.06) Infrequency (4.04) (6.47) M-S TBI ¼ Moderate to severe traumatic brain injury; PE ¼ Poor effort. Infrequency Index in the M-S TBI group with African Americans having a higher group mean (p ¼.05). Means for the M-S TBI group and the PE group on the four PCSQ indices are presented in Table 1. An independent samples t-test was conducted to compare group differences on each of the four PCSQ indices. Significant differences were found between the groups on all four indices, with the PE group having a higher group mean on each. Thus, the PE group reported a higher rate of psychological symptoms (p 5.001), cognitive symptoms (p 5.001), somatic symptoms (p 5.001), as well as unusual symptoms (p 5.05) compared to the M-S TBI group. A receiver operating characteristic (ROC) curve analysis was conducted to assess the ability of the Infrequency index to differentiate between the PE and M-S TBI groups (Figure 1). Results indicate an area under the curve of.58 with a standard error of.06. The 95% confidence interval was 0.46 to Overall, this scale was not effective at discriminating between the two groups. Additional analyses were performed to determine the relationship between litigation and symptom report. Litigants in the M-S TBI group were compared to litigants in the PE group. Results are presented in Table 2. Significant differences were found on all indices except for the Infrequency index. Thus PE group litigants reported a higher degree of psychological symptoms (p 5.008), cognitive symptoms (p 5.028), and somatic symptoms (p 5.009). A final index analysis was conducted by comparing litigants and non-litigants in the M-S TBI group. Results are presented in Table 3. Litigants reported a higher degree of psychological (p 5.001), cognitive (p 5.001), and unusual symptoms (p 5.001) compared to non-litigants. A one-way analysis of covariance was conducted on each PCSQ index in order to control for GCS. No significant differences were found on the four PCSQ indices; however, the covariate (GCS) was significant for the Psychological index (p 5.001), Cognitive index (p 5.05), and Somatic index (p 5.001), with a higher GCS being associated with a greater score on each index. An item by item analysis was conducted using Fisher s exact test to examine proportional differences in item endorsement between the groups. Significance levels for each item are presented in Table 4. Results showed a significant difference (p 5.05) on 30 of the 45 PCSQ items. On each significant item, the PE group had a higher proportion of item endorsement then the M-S TBI group. Thus, individuals with mild head injury who are involved in litigation and demonstrate poor effort on neuropsychological assessment report a higher frequency of

8 BRAIN INJURY SEVERITY & POSTCONCUSSIVE SYMPTOMS 7 Sensitivity Specificity Figure 1 ROC Curve analysis of the poor effort and moderate to severe traumatic brain injury groups on the Postconcussive Symptom Questionnaire Infrequency scale. postconcussive symptoms across cognitive, psychological, and somatic domains than do individuals with moderate to severe brain injuries. The PE group had an endorsement rate of 70% or higher on 15 of the PCSQ items. In comparison, the M-S TBI group only had two items with an endorsement rate higher than 50% ( memory problems ¼ 55%; concentration problems ¼ 53%, compared to 92% and 88% for the PE group respectively). An examination of the individual items reveals statistically significant group discrimination on 12 out of the 13 items that make up the Psychological index, all five items that make up the Cognitive index, and 10 out of the 13 items comprising the Somatic index. The Infrequency index had the least number of items that differed between groups, with only 3 out of the 11 items. An analysis was conducted on the symptom status scale by creating a total score for each participant. A independent t-test reached significance with the PE group achieving a higher score, t(156) ¼ 2.12, p Individuals in the PE group had a higher score reflecting more endorsement of items reflecting symptom status as unchanged or worsened.

9 8 JOHN TSANADIS ET AL. Table 2 Comparisons of moderate to severe traumatic brain injury and poor effort litigants on the Postconcussive Symptom Questionnaire indices Index M-S TBI (n ¼ 44) PE (n ¼ 14) p d Psychological (12.97) (10.44) Cognitive (4.96) (4.78) Somatic (10.94) (14.14) Infrequency (4.49) (6.78) M-S TBI ¼ Moderate to severe traumatic brain injury; PE ¼ Poor effort. Table 3 Comparison of moderate to severe traumatic brain injury litigants and non-litigants on the Postconcussive Symptom Questionnaire indices Index M-S TBI (n ¼ 89) M-S TBI Litigants (n ¼ 44) p d Psychological (12.78) (12.97) Cognitive (4.60) (4.96) Somatic (9.80) (10.94) Infrequency (3.68) (4.49) M-S TBI ¼ Moderate to severe traumatic brain injury. DISCUSSION Previous research has questioned the neurological basis of postconcussive symptoms due to the lack of specificity of the constellation of symptoms (Larrabee, 2005; Lees-Haley & Brown, 1993), the relationship between depression and symptoms (Suhr & Gunstad, 2002), and the higher base rate of symptoms occurring in individuals in litigation (Lees-Haley & Brown, 1993). Using the Postconcussive Syndrome Questionnaire (PCSQ), the current study found group differences across the PCSQ indices, with the mild brain injury group reporting a higher degree of psychological, cognitive, and somatic symptoms. A significant difference was not found on the Infrequency index, which is made up of the least commonly reported complaints related to a brain injury. Further analysis of the scale indicated that it is not able to differentiate between the two groups examined in this study. This raises questions regarding the usefulness of this scale, and based on the results of this study it is considered an unnecessary addition to the PCSQ. Additional analyses found that individuals with mild TBI who were in litigation and failed effort tests reported more postconcussion symptoms compared to individuals with known moderate to severe TBI who were also in litigation. However, individuals with known moderate to severe TBI who were in litigation reported more symptoms that non-litigating moderate to severe TBI patients. These findings are generally consistent with the idea of a litigation effect as reported by previous authors (Lees-Haley, 1988), but are inconsistent with other findings suggesting equivalent outcome in moderate to severe traumatic brain injury (Wood & Rutterford, 2006). Significant differences were also found on 30 out of the 45 PCSQ items in terms of proportion of in-group endorsement of dichotomously scored

10 BRAIN INJURY SEVERITY & POSTCONCUSSIVE SYMPTOMS 9 Table 4 Comparison of the moderate to severe traumatic brain injury and poor effort groups on individual Postconcussive Symptom Questionnaire items PCSQ Item p value % of endorsement by M-S TBI group (n ¼ 133) % of endorsement by PE group (n ¼ 25) d 1 Anxiety or feeling nervous % 76% Back pain % 60% Bleeding % 0% Broken bones % 4% Bumping into things % 64% Bumped head % 24% Change in head size.410 1% 4% Concentration problems % 88% Confusion % 84% Constipation % 24% Depression % 71% Diarrhea.021 3% 17% Dizziness % 50% Elbow pain % 28% Fatigue (mental or physical) % 84% For feeling disorganized % 80% Foot pain % 32% Hair pain.688 7% 8% Headaches % 80% Impatience % 88% Impotence % 29% Involved in a lawsuit % 29% Irritability (getting angry more easily than you used to) % 80% Knocked unconscious.378 6% 12% Loss of interest % 60% Memory problems % 92% Nausea % 40% Neck pain % 68% Numbness % 56% Restlessness % 76% Ringing or buzzing in ears % 32% Seizures.251 3% 8% Sexual problems % 33% Shoulder pain % 76% Sleeping problems (too much, too little, and waking up, etc.) % 84% Speech problems % 44% Teeth itching.013 1% 12% Too sensitive to noise % 52% Tremors or shaking % 40% Trouble doing everyday tasks % 72% Trouble finding the right word or using the wrong word % 72% Trouble reading (can t understand what you read) % 64% Visual problems % 42% Worry about health % 68% Triple vision.408 7% 12% 0.19 PCSQ ¼ Postconcussive Syndrome Questionnaire; M-S TBI ¼ Moderate to severe traumatic brain injury; PE ¼ Poor effort. Item endorsement is identified as endorsing a 3 or higher on the 5-point scale.

11 10 JOHN TSANADIS ET AL. (i.e., presence or absence) symptoms. On the whole, individuals who may have had an equivocal or very mild brain injury, and who may also be involved in litigation, reported more symptoms, and to a higher degree, than a group of individuals with known moderate to severe brain injury. These results support the idea that subjective symptom complaints after a mild head injury may be more related to non-neurological factors rather than neurologically based changes (Iverson, 2006; Suhr & Gunstad, 2002). The strength of the current study is that it allowed for comparison of subjective complaints in a group of individuals with known moderate to severe traumatic brain injury to those in a group of individuals meeting criteria for mild traumatic brain injury who clearly demonstrated poor effort on neuropsychological assessment. Previous research has shown that neuropsychological complaint base rates are high in personal injury claimants with no history of brain injury or documented neuropsychological impairment, and that they differ significantly from controls made up of general outpatient medical patients (Lees-Haley & Brown, 1993). The current study found similar differences with a group of individuals who may have had equivocal or mild traumatic brain injuries, most of whom are in litigation, and demonstrate poor effort during neuropsychological assessment (PE group) in comparison to a group of moderate to severely brain-injured participants (M-S TBI group). This provides further evidence that subjective postconcussive symptom reports are not indicative of brain injury or neuropsychological impairment in cases of mild traumatic brain injury where poor effort on neuropsychological assessment is documented. An interesting finding of the current study was the differences in PCSQ indices of litigating versus non-litigating individuals in the M-S TBI group. This finding is consistent with the notion of a litigation effect. It does raise the question of why the PE group reported such greater symptomatology compared to even the M-S TBI individuals who were in litigation. However, the overall results are consistent with an inverse dose response relationship between severity of brain injury and postconcussive symptom report (Greiffenstein & Baker, 2006). This raises the question as to the reason for this higher complaint rate in some individuals with mild traumatic brain injury. Also, previous research points to the nonspecificity of postconcussion symptoms (Larrabee, 1997). Several studies have shown a clear relationship between litigation status and complaint base rates (Lees-Haley & Brown, 1993; Mittenberg, DiGiulio, Perrin, & Bass, 1992). The findings of the current study are consistent in that the litigation group had a higher complaint base rate than the moderate to severe brain injury group. It can be inferred from these consistent findings that litigation plays a significant role and the ensuing subjective postconcussive complaints may be viewed as a form of negative impression management. Regarding the motivation for negative impression management, malingering seems to be the most likely explanation in the current study. Although not all of the PE participants were self-identified as being in litigation, it would not be surprising if those who were not had the intention of pursuing litigation in the future. Other forms of secondary gain can also play an important role. For example, relationship and family demands may decrease in the context of a brain injury. In individuals prone to somatization, a mild injury may create an expectation of impaired function and increase subjective

12 BRAIN INJURY SEVERITY & POSTCONCUSSIVE SYMPTOMS 11 somatic symptoms. In addition, certain vulnerable personality styles may influence symptom presentation subsequent to a mild traumatic brain injury (Ruff, Camenzuli, & Mueller, 1996). Some studies have shown that emotional factors are more closely related to postconcussive symptoms than is head injury status (Suhr & Gunstad, 2002), and postconcussive symptoms have been shown to increase in relation to stress independent of history of mild traumatic brain injury (Gouvier, Cubic, Jones, Brantley, & Cutlip, 1992). One of the weaknesses of this particular study is the absence of information regarding the self-awareness of symptoms in the moderate to severely brain-injured group. An argument could be made that because symptom reporting is based on self-awareness and self-report, the PCSQ could be impacted by the lack of awareness in the more impaired group. Although this was not measured directly, there is literature to indicate that those with more severe brain injury, and therefore greater cognitive impairment, may not be accurate at estimating cognitive or emotional impairment, but are better at awareness of physical deficit and somatic symptoms (Hart et al., 2003; Mahmood, Rapport, Hanks, & Fichtenberg, 2004). Future research should include comparison groups of individuals with mild traumatic brain injury, both in litigation and not in litigation, and explore a variety of psychological, emotional, and psychosocial variables such as family support. Future research should also explore the other factors involved in the welldocumented pattern of increased symptom reports in a minority of mild traumatic brain-injured individuals in order to explore other factors besides outright malingering that may play a role in this phenomenon. As a result, it will be easier to delineate the effects of litigation and other variables on subjective postconcussive symptoms. Additionally, studies in this area should include a variety of performance-based and self-report symptom validity indicators in order to control for negative impression management. The empirical evidence supporting a postconcussion syndrome continues to be problematic. If future research continues to indicate an absence of sufficient data for this construct, it should follow that clinical use of this term should cease. If the formal diagnostic criteria are to be evaluated, the examiner needs to consider the lack of specificity of the criteria that subsequently undermines the construct validity of this diagnostic entity. ACKNOWLEDGMENTS This research was supported by the National Institute on Disability and Rehabilitation Research (Grant # H133A020515). REFERENCES American Psychiatric Association. (2000). Diagnostic and Statistical Manual of Mental Disorder (4th ed., Text Revision). Washington, DC: American Psychiatric Association. Axelrod, B. N., Fox, D. D., Lees-Haley, P. R., Earnest, K., & Dolezal-Wood, S. (1996). Application of the Postconcussive Syndrome Questionnaire with medical and psychiatric outpatients. Archives of Clinical Neuropsychology, 13(6),

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