J Head Trauma Rehabil Vol. 30, No. 6, pp. E30–E39 c 2015 Wolters Kluwer Health, Inc. All rights reserved. Copyright
Self- and Informant Ratings of Executive Functioning After Mild Traumatic Brain Injury Jacobus Donders, PhD, ABPP; Ye In Oh, BS; Jessica Gable, BA Objective: To determine correlates of self- and informant reports on a standardized rating of executive functioning in persons with mild traumatic brain injury. Setting: Outpatient clinic at a rehabilitation hospital. Participants: One hundred referred persons who met criteria for mild traumatic brain injury (ie, time to follow commands .05) between the participants with BRIEF-A informant protocols (n = 112) and those without such collateral information (n = 111) on the vast majority of the demographic, prior history, and injury variables, with 2 exceptions. Specifically, compared with persons who did have BRIEF-A informant data, those who did not have were more likely to be engaged in financial compensation seeking (χ 2 = 6.73; P < .001) and less likely to have positive intracranial findings on neuroimaging (χ 2 = 25.42; P < .0001). Premorbid histories were evaluated through a combination of semistructured clinical interview and review of available medical records. Persons with a premorbid history of attention -deficit/hyperactivity disorder (ADHD), learning disability, outpatient psychiatric treatment, personal abuse, or substance abuse were not excluded from this study because the impact of such histories on self- and informant BRIEF-A ratings was of particular interest for this study. In the final sample, 12 participants had a premorbid diagnosis of ADHD, 4 had received special education services for learning disability, 13 reported a remote history of personal trauma, 15 endorsed a prior history of substance abuse, and 49 described pre-TBI outpatient treatment of psychiatric reasons (most often adjustment disorder). It should be noted that several participants had more than 1 prior condition. A minority of the sample (n = 33) had no history of any premorbid complicating factors. Furthermore, in the complete sample, 18 persons were engaged in financial compensation seeking at the time of assessment, 7 of whom also had at least 1 premorbid condition. Only about a quarter (n = 26) of the participants in this study did not have any known premorbid or comorbid complicating factors. The final sample consisted of 52 men and 48 women, with a mean age of 39.66 years (SD = 16.80) who were evaluated with the BRIEF-A at a mean of 162.25 days
postinjury (SD = 93.95). The majority of the sample was Caucasian (n = 92), with other self-reported ethnicities including African American (n = 7) and Latino (n = 1). Participants had completed a mean of 13.56 years of education (SD = 2.67). About half of the sample (n = 51) was married or in a long-term cohabitating relationship. Informant data for the BRIEF-A were obtained from a spouse in 48 cases, from a parent in 34, and from another person who knew the patient at least moderately well in the remaining 18. Almost half of the participants (n = 46) had been injured in motor vehicle collisions, with the remaining most common causes including sports and other recreational activities (n = 27), falls (n = 18), and other (n = 9). A total of 23 participants had intracranial lesions on neuroimaging, most often involving focal hemorrhagic contusions.
Measures The BRIEF-A is a standardized rating of executive behaviors in the rated individual’s daily environment. It has a self-report version and an informant report version. Both versions include 75 items of behavioral descriptors that are answered according to a 3-point Likert scale (“never,” “sometimes,” and “often”) as pertaining to the last month. These items divide into 9 nonoverlapping clinical scales that combine to form 2 broadband indices, the Behavioral Regulation Index and the Metacognition Index, which, in turn, combine into an overall General Executive Composite. The Inhibit, Shift, Emotional Control, and Self-Monitor scales comprise the Behavioral Regulation Index, whereas the Initiate, Working Memory, Plan/Organize, Task Monitor, and Organization of Materials scales form the Metacognitive Index. All BRIEF-A variables are expressed as T scores (mean = 50, SD = 10), with higher scores reflecting more reported problems. The manual for the normative sample of the BRIEF-A6 demonstrates good reliability of the summary broadband indices, with internal consistency as well as test-retest values ranging from 0.93 to 0.96. The WCST is a laboratory test of executive functioning that requires the examinee to consider different possible solutions to a task and to learn from corrective feedback to modify his or her strategy, suppress perseverative tendencies, and adjust to changing task demands. Performance on the WCST is expressed in T scores (mean = 50, SD = 10), with higher scores reflecting better performance. Although many variables can be obtained from the WCST, we chose for this investigation the WCST Perseverative Responses score because it is the most robust and widely used variable.24 WCST data from 7 participants were excluded from the analyses because they reported being familiar with an online
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Informant Ratings of Executive Functioning After Mild TBI version of a game (“Blink”) that is very similar to the actual test and therefore invalidated the findings. Procedure BRIEF-A and WCST data were obtained during neuropsychological evaluations that were conducted in the context of outpatient differential diagnosis and treatment planning. Participants and informants always completed their respective versions of the BRIEF-A in a different room. Although the other tests that had been administered to the participants varied somewhat, they all completed a stand-alone performance validity task, the Test of Memory Malingering (TOMM).25 Although this sample had been selected on the basis of having no validity indices violated on the BRIEF-A, this instrument pertains to subjective symptom report whereas the TOMM pertains to validity of performance. A total of 24 participants failed validity criteria on the TOMM according to the criteria suggested by Greve and colleagues26 for application with persons with mild TBI. We also considered validity criteria that have been suggested for the WCST,27 but these data did not add meaningfully to the results from the TOMM. Specifically, of the 10 persons who failed the WCST validity criteria, 9 also failed the TOMM. The remaining participant had intracranial findings on neuroimaging and did not present with any significant premorbid (eg, psychiatric) or comorbid (eg, compensation seeking) complicating factors and appeared to be a false-positive. For these reasons, WCST validity criteria were not considered further in the analyses. Finally, 85 of the 93 participants for whom potentially interpretable WCST data were available had also completed an additional laboratory test of executive functioning, the Tower of London–Drexel University, Second Edition (TOL).28 This is a test that pertains to efficiency of planning abilities and its data were included as a secondary analysis. It requires the copying of a configuration of 3 colored beads on 3 sticks of various heights, in as few moves as possible. The Total Move Score of this instrument, expressed as a standard score (mean = 100, SD = 15; higher scores reflecting better performance), has been shown to correlate negatively with length to follow verbal commands, and persons with complicated mild TBI also performed worse on this measure than demographically matched controls.29 Data analyses BRIEF-A T scores were used for the statistical analyses. Pearson product-moment correlations were used both to compare the self- and informant BRIEF-A ratings and to compare BRIEF-A and WCST findings. The levels of agreement between self- and informant ratings
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were also evaluated with t tests for paired observations. Several variables were selected on an a priori theoretical basis for inclusion in regression analyses to predict self- and informant scores on the BRIEF-A Behavioral Regulation Index, Metacognition Index, and General Executive Composite measures. These included level of education, interval between injury and psychometric assessment, presence or absence of prior outpatient psychiatric treatment, presence or absence of any other premorbid complicating factor (ie, ADHD, learning disability, personal abuse, or substance abuse), presence of absence of financial compensation seeking, presence or absence of an intracranial lesion on neuroimaging, and pass/fail of validity criteria on the TOMM. This allowed for an acceptable participant to variable ratio (>14:1). Consistent with recommendations in the literature,30 both statistically significant and nonsignificant variables were retained in the presented model to reflect their relative contributions. Variance inflation factors were inspected for collinearity, and these were less than 1.35 in all regression models, which was clearly acceptable.31 Effect sizes and proportions of variance accounted for were also considered, using previously specified criteria.32 The squared correlation coefficient (r2 ) was used to determine the amount of covariance accounted for by Pearson product-moment correlations, with values less than 0.10 considered weak, values 0.10 to 0.25 moderate, and values more than 0.25 strong. Cohen d was used to determine the magnitude of the differences between self- and informant BRIEF-A ratings, with values less than 0.50 considered small, values 0.50 to 0.80 medium, and values more than 0.80 large. The R2 statistic was used to determine the amount of variance accounted for by the regression models, with values less than 0.10 considered small, values 0.10 to 0.25 medium, and values more than 0.25 large. RESULTS Table 1 presents the BRIEF-A self- and informant scores for the main broadband variables. For illustrative purposes, the subscale scores are also presented in Figure 1. The self- and informant ratings on all 3 BRIEFA summary variables were strongly correlated (r2 = 0.40 for all). At the same time, the t tests revealed that on all BRIEF-A summary variables, participants rated themselves as functioning statistically significantly worse than did the informants. Effect sizes (d) for these discrepancies between the respective ratings were uniformly small. Because group means can obscure subgroups with or without impairment, we also calculated the proportion of participants who had BRIEF-A General Executive Composite scores of 65 or more, the criterion recommended in the test manual for clinical significance. In the complete sample, 52% of the participant ratings and www.headtraumarehab.com
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E34 TABLE 1
JOURNAL OF HEAD TRAUMA REHABILITATION/NOVEMBER–DECEMBER 2015
BRIEF-A index scores (N = 100)a
BRIEF-A Behavioral Regulation Index Metacognition Index General Executive Composite
Self
Informant
t
P
d
R
61.13 (14.51) 64.91 (14.64) 64.27 (15.20)
56.64 (10.88) 59.96 (11.40) 58.97 (10.98)
3.92 4.29 4.54
.0003 .0003 .0002
0.35 0.37 0.39
0.63b 0.64b 0.64b
Abbreviation: BRIEF-A, Behavior Rating Inventory of Executive Function–Adult Version. a P values corrected with the step-down Bonferroni method for multiple comparisons. b P < .0001.
Figure 1. BRIEF-A subtest profiles of 100 persons with mild traumatic brain injury. Vertical bars reflect standard error of the mean. BRIEF-A indicates Behavior Rating Inventory of Executive Function–Adult Version.
34% of the informant ratings met this criterion. This difference in proportions was statistically significant (z = 2.57; P < .02). Table 2 presents the regression models for the self- and informant ratings on the BRIEF-A Behavioral Regulation Index. The model for the self-ratings was statistically significant (F7,92 = 6.00; P < .0001) and explained a large
TABLE 2
amount of the variance. Higher levels of education and presence of intracranial findings on neuroimaging were both associated with better self-rated BRIEF-A Behavioral Regulation performance (ie, lower ratings), whereas the presence of a prior outpatient psychiatric treatment history was associated with worse self-rated performance on that same index (ie, higher ratings). The model for
Regression model for BRIEF-A Behavioral Regulation Index (N = 100)a Self
Variable Years of completed education Days since injury Prior psychiatric history Prior other complicating factors Financial compensation seeking Intracranial neuroimaging findings Failure on TOMM
Informant
SRC
t
P
− 0.24 0.15 0.37 0.04 0.03 − 0.21 0.12
− 2.57 1.60 3.73 0.42 0.28 − 2.29 1.31
.02 .12 .0003 .68 .78 .03 .20
R
2
0.26
SRC
t
P
R2
− 0.31 0.13 0.34 0.02 0.04 − 0.04 0.07
− 3.15 1.32 3.21 0.19 0.43 0.44 0.72
.003 .19 .002 .85 .67 .66 .47
0.17
Abbreviations: BRIEF-A, Behavior Rating Inventory of Executive Function–Adult Version; SRC, standardized regression coefficient; TOMM, Test of Memory Malingering. a R2 reflects the adjusted value for the composite model.
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Informant Ratings of Executive Functioning After Mild TBI the informant ratings was also statistically significant (F7,92 = 3.93; P < .0009) and explained a medium amount of the variance. Higher levels of education were associated with better informant-rated BRIEF-A Behavioral Regulation performance, whereas the presence of a prior outpatient psychiatric treatment history was associated with worse informant-rated performance on that same index. None of the other variables were statistically significant in either of the 2 models. The regression models for the self- and informant ratings on the BRIEF-A Metacognition Index are presented in Table 3. The model for the self-ratings was statistically significant (F7,92 = 5.80; P < .0001) and explained a large amount of the variance. The presence of intracranial findings on neuroimaging was associated with better self-rated BRIEF-A Metacognition performance (ie, lower ratings), whereas a longer time interval since injury and the presence of a prior outpatient psychiatric treatment history were both associated with worse self-rated performance on that same index (ie, higher ratings). The model for the informant ratings was also statistically significant (F7,92 = 4.64; P < .0002) and exTABLE 3
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plained a medium amount of the variance. Higher levels of education were associated with better informant-rated BRIEF-A Metacognition performance, whereas the presence of a prior outpatient psychiatric treatment history was associated with worse informant-rated performance on that same index. There was a statistically nonsignificant trend for a longer time interval since injury to also be associated with higher ratings on the Metacognition Index in the informant model, but none of the other variables approached such a trend level toward statistical significance in either of the 2 models. The regression models for the self- and informant ratings on the BRIEF-A General Executive Composite are presented in Table 4. The model for the self-ratings was statistically significant (F7,92 = 6.23; P < .0001) and explained a large amount of the variance. The presence of intracranial findings on neuroimaging was associated with better self-rated BRIEF-A General Executive performance (ie, lower ratings), whereas a longer time interval since injury and the presence of a prior outpatient psychiatric treatment history were both associated with worse self-rated performance on that same index (ie,
Regression model for BRIEF-A Metacognition Index (N = 100)a Self
Variable Years of completed education Days since injury Prior psychiatric history Prior other complicating factors Financial compensation seeking Intracranial neuroimaging findings Failure on TOMM
Informant
SRC
t
P
− 0.08 0.20 0.28 0.03 0.10 − 0.27 0.15
− 0.81 2.09 2.77 0.25 1.09 − 2.92 1.61
.42 .04 .007 .80 .28 .005 .0
R2
SRC
t
P
R2
0.25
− 0.26 0.18 0.32 0.07 0.06 − 0.14 0.10
− 2.77 1.84 3.06 0.66 0.64 − 1.46 1.02
.007 .07 .003 .51 .52 .15 .31
0.21
Abbreviations: BRIEF-A, Behavior Rating Inventory of Executive Function–Adult Version; SRC, standardized regression coefficient; TOMM, Test of Memory Malingering. a R2 reflects the adjusted value for the composite model.
TABLE 4
Regression model for BRIEF-A General Executive Composite (N = 100)a Self
Variable Years of completed education Days since injury Prior psychiatric history Prior other complicating factors Financial compensation-seeking Intracranial neuroimaging findings Failure on TOMM
SRC − 0.15 0.19 0.33 0.04 0.07 − 0.25 0.14
t 1.62 1.99 3.34 0.35 0.76 − 2.81 1.50
Informant
P .11 .05 .002 .73 .45 .006 .14
R
2
0.27
SRC − 0.30 0.17 0.35 0.06 0.06 − 0.11 0.10
t − 3.24 1.74 3.48 0.57 0.62 − 1.15 1.03
P .002 .09 .0008 .57 .54 .25 .30
R2
0.23
Abbreviations: BRIEF-A, Behavior Rating Inventory of Executive Function–Adult Version; SRC, standardized regression coefficient; TOMM, Test of Memory Malingering. a R2 reflects the adjusted value for the composite model.
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JOURNAL OF HEAD TRAUMA REHABILITATION/NOVEMBER–DECEMBER 2015
higher ratings). The model for the informant ratings was also statistically significant (F7,92 = 5.21; P < .0001) and explained a medium amount of the variance. Higher levels of education were associated with better informantrated BRIEF-A General Executive performance, whereas the presence of a prior outpatient psychiatric treatment history was associated with worse informant-rated performance on that same index. There was a statistically nonsignificant trend for a longer time interval since injury to also be associated with higher ratings on the General Executive Composite in the informant model, but none of the other variables approached such a trend level toward statistical significance in either of the 2 models. We then considered the relationship between BRIEFA, WCST, and TOL findings in the groups of participants for whom potentially interpretable data on the latter 2 tests were available. In the complete subgroup for the WCST (n = 93), the mean level of performance on WCST Perseverative Responses was 47.30 (SD = 11.79) and 10 participants (11% of this subsample) had T scores on this variable that were 35 or less. In the complete subgroup for the TOL (n = 85), the mean level of performance on the TOL was 102.01 (SD = 17.20) and 7 participants (8% of this subsample) had standard scores on this variable that were 78 or less. In light of the fact that a considerable proportion of the sample violated performance validity criteria on the TOMM, we decided to evaluate correlations between BRIEF-A, on the one hand, and the WCST and TOL, on the other hand, separately in subsamples of those who did or did not put forth valid effort, according to the TOMM. In the former subgroup, mean WCST performance was 47.56 (SD = 11.69) whereas it was 46.45 (SD = 12.34) in the latter subgroup. Performance of the TOL in these 2 subgroups was 103.19 (SD = 14.24) and 97.01 (SD = 18.48), respectively. The correlations with either WCST Perseverative Responses or TOL Total Move Score did not approach even liberal criteria for potential statistical significance for any of the self- or informant BRIEF-A summary variables (P > .10 for all) in either subgroup. Finally, we evaluated whether the presence or absence on any of the variables that had been statistically significant predictors in the various regression models was related to performance on either the WCST or TOL. Performance on neither the WCST (r = 0.05; P > .66) nor the TOL (r = 0.11; P > .29) correlated significantly with time interval since injury. Performance on the TOL (r = 0.42; P < .0001) but not the WCST (r = 0.12; P > .26) correlated significantly with educational attainment (r = 0.12; P > .26), likely because the TOL norms do not take the level of education into account whereas the norms for the WCST do. The presence of intracranial findings on neuroimaging did not affect performance on either the WCST (F1,91 = 0.13; P > .71) or the
TOL (F1,83 = 1.14; P > .28), whereas the presence of a premorbid psychiatric history was associated with statistically significant differences on the TOL (F1,83 = 4.87; P < .03) but not the WCST (F1,91 = 1.43; P > .23). The group difference on the TOL Total Move Score actually favored the group with prior outpatient psychiatric treatment (mean = 105.71, SD = 15.64) as compared with those without such a premorbid history (mean = 98.59, SD = 14.09). The associated effect size (d = 0.48) was small. DISCUSSION The main purpose of this study was to determine which demographic, psychosocial, and medical variables predicted findings on the BRIEF-A after mild TBI. In addition, we aimed to determine the level of agreement between self- and informant ratings, as well as correlations with laboratory tests of executive functioning, the WCST and TOL. Consistent with hypothesis 1, the variable that was most consistently associated with worse ratings across all 3 BRIEF-A summary scales, in both patients and informants, was the presence of a prior psychiatric history. This finding is consistent with results from several comprehensive literature reviews that have identified psychosocial factors, and poor premorbid mental health in particular, as a significant risk factor for poor outcomes after mild TBI.14,15 In contrast, in all of the models pertaining to self-report, the presence of intracranial findings on neuroimaging was associated with better BRIEFA ratings. This was not expected and contrary to hypothesis 2. It could be argued that this effect might reflect limited deficit awareness in persons with complicated mild TBI, but this would not be consistent with the fact that intracranial findings did not factor in any of the models for the informant ratings. When considered in concert with the fact that, in several of the self- and informant models, longer duration of time since injury was associated with worse BRIEF-A ratings, these findings instead suggest that patients with mild TBI who have prolonged subjective symptoms may have a magnified perception of their deficits, as suggested in other research.33 In this context, the fact that failure on a stand-alone performance validity test (TOMM) did not figure significantly in any of the regression models may suggest that the BRIEF-A findings are not likely to reflect a deliberate component to this magnification. Instead, patients with a preexisting psychiatric history may simply be more inclined to re- or misattribute premorbid difficulties to a mild TBI, something that has been explained in the literature in terms such as the “good old days bias”34 and “cogniform condition.”35 Another, and not mutually exclusive, possible interpretation is that persons with mild TBI and a preexisting psychiatric history simply have a
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Informant Ratings of Executive Functioning After Mild TBI generally negative self-perception that extends to their view of subjective cognitive efficacy, as has previously been suggested in research with conditions ranging from depression36 to schizophrenia.37 The current findings suggest that, after accounting for premorbid outpatient psychiatric treatment, other potentially complicating psychosocial history variables, such as personal abuse or substance abuse, did not explain incremental variance in any of the regression models. Thus, screening for prior psychiatric health and resilience appears to be crucial when considering treatment planning after mild TBI.38 A higher number of years of completed education were associated with better BRIEF-A ratings in almost all of the regression models. In the pediatric literature on mild TBI, it has been suggested that cognitive reserve may moderate the impact of injury severity on subjective symptoms.39 Specifically, children with lower cognitive ability were noted to be relatively more prone to cognitive complaints for an extended period of time. However, in the current study, persons with complicated injuries actually reported relatively fewer problems. Cognitive reserve has also been suggested as a moderator of severe TBI,40,41 but all the participants in this sample had mild injuries. Rather, the influence of years of completed education in this study may reflect a correlate of limited vocational attainment, as it has been suggested that limited job independence and decision-making latitude are risk factors for poor outcomes after mild TBI.42 In this investigation, self- and informant BRIEF-A ratings were strongly correlated, as was predicted by hypothesis 3. These findings were also consistent with those reported previously in a sample of persons with mild cognitive impairment.7 Patients in the current investigation did report statistically significantly more problems than their informants did. Although the associated effect size was somewhat small, about a third of a standard deviation, this stands in contrast to recent findings in a study that focused on persons with moderate-severe TBI, where no significant differences between self- and informant reports were found.13 The confluence of these findings is consistent with our interpretation of the effect of neuroimaging findings, that is, patients with mild TBI may have a somewhat (inadvertently) deflated perception of their executive abilities. A contributing factor in this regard may be the phenomenon of diagnosis threat, referring to the possibility that simply having too much attention paid to a history of mild TBI and its possible sequelae may result in negative self-expectations.43 In this context, the fact that our participants generally did well on several laboratory measures of executive functioning, despite rating themselves poorly on the BRIEF-A, is consistent with previous findings in the literature that suggested that diagnosis threat affects primarily perceived self-efficacy and not necessarily actual cognitive test performance.44
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Neither the self-ratings nor the informant ratings correlated with the results from the WCST or TOL. This was consistent with hypothesis 4. These findings are also consistent with previous studies that have found few and weak correlations between BRIEF-A ratings and traditional laboratory tests of executive functioning in general7,8,10 and between the BRIEF-A and the WCST in persons with moderate-severe TBI in particular.13 It is possible that this reflects, to some extent, differences in the nature of executive skills that are assessed by the respective instruments. However, given the fact that the average performance of this sample on WCST Perseverative Responses as well as the TOL Total Move Score was well within normal limits, the average relative elevation on BRIEF-A of almost 1.5 SDs again suggests that the participants likely had an unrealistically poor view of their own executive abilities. This interpretation was also bolstered by the fact that, despite the fact that persons with prior psychiatric histories rated themselves more poorly on the BRIEF-A, they actually did better on the TOL than did persons without such histories. Admittedly, the associated effect size was less than half a standard deviation and it may have been a spurious finding in light of multiple univariate comparisons, but the direction of the difference would argue against a true executive deficit in those who received outpatient psychiatric services before incurring their mild TBI. Potential limitations of this investigation must also be considered. This was a referred convenience sample, and there were about as many persons with mild TBI who did not have an informant accompany them to the evaluation as those who did. Since persons in the former group were more likely to be involved in financial compensation seeking, the potential influence of that particular variable cannot be ruled out on the basis of this investigation. At the same time, the fact that almost none of the potential participants without informant data had positive findings on neuroimaging strengthens our interpretation of the effect of that variable. Another limitation is the fact that this sample was largely Caucasian, and replication in an ethnically more diverse sample is needed. In addition, these findings are limited to persons with mild TBI and cannot be generalized to persons with moderate-severe TBI. Furthermore, it needs to be realized that the current sample was likely not representative of the entire population of individuals with mild TBI, many of whom have rapid resolution of symptoms and never present for neuropsychological evaluation more than 1 month later. A specific goal for future research is to evaluate the construct validity of the BRIEF-A across the entire range of injury severity after TBI in a representative sample, preferably along with consideration of the same phenomena in control participants with traumatic orthopedic injuries. This would likely also allow for exploration of the relationship www.headtraumarehab.com
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between the BRIEF-A and laboratory measures of executive functioning in a larger group of individuals with TBI who actually perform poorly on the latter measures whereas the vast majority of the participants in this investigation performed well on the WCST and the TOL. In such future studies, the degree to which findings from the BRIEF-A overlap with or supplement those from traditional measures of psychological adjustment or mood should also be explored. CONCLUSIONS Persons with mild TBI who are referred for neuropsychological evaluation because of persistent complaints tend to overestimate their degree of executive dysfunction in daily life, as assessed with the BRIEF-A. The presence of a premorbid psychiatric history and limited educational attainment in particular are risk factors for such overestimation, whereas the presence of intracranial complications does not lead to worse BRIEF-A ratings. It
is therefore important to not equate subjective symptom report with organic sequelae of mild TBI. Particularly, for those who present to a clinic more than 1 month after injury, careful screening for potential premorbid and comorbid complicating risk factors is important before commencing treatment of presumed “postconcussion” symptoms after mild TBI. This will be particularly important with increasing time since injury, when distorted or otherwise negative self-perceptions or expectations may have become more ingrained. Utilization of an instrument such as the BRIEF-A can be helpful in this context to explore discrepancies between self- and informant ratings of perceived executing functioning. Large discrepancies (eg, ≥1 SD) between the respective ratings should be particularly concerning in this context and indicative of a likely need for education of the patient, with correction of misperceptions or misattributions, as opposed to approaches that might inadvertently reinforce the sick role or otherwise contribute to iatrogenic effects.
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11. Donders J, DenBraber D, Vos L. Construct and criterion validity of the Behavior Rating Inventory of Executive Function (BRIEF) in children referred for neuropsychological assessment after traumatic brain injury. J Neuropsychol. 2010;4:197–209. 12. Sesma HW, Slomine BS, Ding R, McCarthy ML. Executive functioning in the first year after pediatric traumatic brain injury. Pediatrics. 2010;121:S1686–S1695. 13. Garc´ıa-Molina A, Tormos JM, Bernabeu M, Junqu´e C, Roig-Rovira T. Do traditional executive measures tell us anything about dailylife functioning after traumatic brain injury in Spanish-speaking individuals? Brain Inj. 2012;26:864–874. 14. Carroll LJ, Cassidy JD, Peloso PM, et al. Prognosis for mild traumatic brain injury: results of the WHO Collaborating Centre Task Force on Mild Traumatic Brain Injury. J Rehabil Med. 2004;43:84– 105. 15. Cassidy JD, Cancelliere C, Carroll LJ, et al. Systematic review of self-reported prognosis in adults after mild traumatic brain injury: results of the International Collaboration on Mild Traumatic Brain Injury Prognosis. Arch Phys Med Rehabil. 2014;95:S132–S151. 16. Larrabee GJ, Rohling ML. Neuropsychological differential diagnosis of mild traumatic brain injury. Behav Sci Law. 2013;6:686–701. 17. Smits M, Hunink MGM, van Rijssel DA, et al. Outcome after complicated minor head injury. Am J Neuroradiol. 2008;29:506– 513. 18. Deepika A, Munivenkatappa A, Devi BI, et al. Does isolated traumatic subarachnoid hemorrhage affect outcome in patients with mild traumatic brain injury? J Head Trauma Rehabil. 2014;28:442– 445. 19. Struchen MA, Clark AN, Sander AM, Mills MR, Evans G, Kurtz D. Relation of executive functioning and social communication measures to functional outcomes following traumatic brain injury. Neurorehabilitation. 2008;23:185–198. 20. Wilson KR, Donders J, Nguyen L. Self and parent ratings of executive functioning after adolescent traumatic brain injury. Rehabil Psychol. 2011;56:100–106.
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Informant Ratings of Executive Functioning After Mild TBI 21. Heaton RK, Chelune CJ, Talley JL, Kay GG, Curtiss G. Wisconsin Card Sorting Test Manual: Revised and Expanded. Odessa, FL: Psychological Assessment Resources; 1993. 22. Merrick EE, Donders J, Wiersum M. Validity of the WCST-64 after traumatic brain injury. Clin Neuropsychol. 2003;17:153–158. 23. Ord JS, Greve KW, Bianchini KJ, Aguerrevere LE. Executive dysfunction in traumatic brain injury: the effects of injury severity and effort on the Wisconsin Card Sorting Test. J Clin Exp Neuropsychol. 2010;32:132–140. 24. Alvarez JA, Emory E. Executive function and the frontal lobes: a meta-analytic review. Neuropsychol Rev. 2006;16:17–42. 25. Tombaugh TN. Test of Memory Malingering. Toronto, ON, Canada: Multi-Health Systems; 1996. 26. Greve KW, Bianchini KJ, Doane BM. Classification accuracy of the Test of Memory Malingering in traumatic brain injury: results of a known-groups analysis. J Clin Exp Neuropsychol. 2006;28:1176– 1190. 27. Suhr JA, Boyer D. Use of the Wisconsin Card Sorting Test in the detection of malingering in student simulator and patient samples. J Clin Exp Neuropsychol. 1999;21:701–708. 28. Culbertson W, Zillmer E. Tower of London–Drexel University, Second Edition. Chicago, IL: Multi-Health Systems; 2005. 29. Krishnan M, Smith N, Donders J. Use of the Tower of London– Drexel University, Second Edition (TOLD-X) in adults with traumatic brain injury. Clin Neuropsychol. 2012;26: 951–964. 30. Millis SR. Statistical practices: the seven deadly sins. Child Neuropsychol. 2003;9:221–233. 31. Fox J. Regression Diagnostics. Newbury Park, CA: Sage; 1991. 32. Murphy KR, Myors B. Statistical Power Analysis. 2nd ed. Mahwah, NJ: Lawrence Erlbaum; 2004. 33. Tsanadis J, Montoya E, Hanks RA, Millis SR, Fichtenberg NL, Axelrod BN. Bain injury severity, litigation status, and self-report of postconcussive symptoms. Clin Neuropsychol. 2008;22:1090–1092. 34. Iverson GL, Lange RT, Brooks BL, Rennison VLA. “Good old days” bias following traumatic brain injury. Clin Neuropsychol. 2010;24:17–37.
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35. Delis DC, Wetter SR. Cogniform disorder and cogniform condition: proposed diagnoses for excessive cognitive symptoms. Arch Clin Neuropsychol. 2007;22:589–604. 36. Lahr D, Beblo T, Hartje W. Cognitive performance and subjective complaints before and after remission of major depression. Cogn Neuropsychiatry. 2007;12:25–45. 37. Halari R, Mehrotra R, Sharma T, Kumari V. Does selfperceived mood predict more variance in cognitive performance that clinician-rated symptoms in schizophrenia? Schizophr Bull. 2006;32:751–757. 38. McCauley SR, Wilde EA, Miller EM, et al. Preinjury resilience and mood as predictors of early outcome following mild traumatic brain injury. J Neurotrauma. 2013;30:642–652. 39. Fay TB, Yeates KO, Taylor HG, et al. Cognitive reserve as a moderator of postconcussive symptoms in children with complicated and uncomplicated mild traumatic brain injury. J Int Neuropsychol Soc. 2010;16:94–105. 40. Kessler SR, Adams HF, Blassey CM, Bigler ED. Premorbid intellectual functioning, education and brain size in traumatic brain injury: an investigation of the cognitive reserve hypothesis. Appl Neuropsychol. 2003;10:153–162. 41. Levi Y, Rassovsky Y, Agranov E, Sela-Kaufman M, Vakil E. Cognitive reserve components as expressed in traumatic brain injury. J Int Neuropsychol Soc. 2013;19:664–671. 42. Cancelliere C, Kristman V, Cassidy JD, et al. Systematic review of return to work after mild traumatic brain injury: results of the International Collaboration on Mild Traumatic Brain Injury Prognosis. Arch Phys Med Rehabil. 2014;94:S201– S209. 43. Suhr JA, Gunstad J. Diagnosis threat: the effect of negative expectations on cognitive performance in head injury. J Clin Exp Neuropsychol. 2002;24:448–457. 44. Trontel HG, Hall S, Ashendorf L, O’Connor MK. Impact of diagnosis threat on academic self-efficacy in mild traumatic brain injury. J Clin Exp Neuropsychol. 2013;35:960– 970.
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Self- and Informant Ratings of Executive Functioning After Mild Traumatic Brain Injury Jacobus Donders, PhD, ABPP; Ye In Oh, BS; Jessica Gable, BA Objective: To determine correlates of self- and informant reports on a standardized rating of executive functioning in persons with mild traumatic brain injury. Setting: Outpatient clinic at a rehabilitation hospital. Participants: One hundred referred persons who met criteria for mild traumatic brain injury (ie, time to follow commands .05) between the participants with BRIEF-A informant protocols (n = 112) and those without such collateral information (n = 111) on the vast majority of the demographic, prior history, and injury variables, with 2 exceptions. Specifically, compared with persons who did have BRIEF-A informant data, those who did not have were more likely to be engaged in financial compensation seeking (χ 2 = 6.73; P < .001) and less likely to have positive intracranial findings on neuroimaging (χ 2 = 25.42; P < .0001). Premorbid histories were evaluated through a combination of semistructured clinical interview and review of available medical records. Persons with a premorbid history of attention -deficit/hyperactivity disorder (ADHD), learning disability, outpatient psychiatric treatment, personal abuse, or substance abuse were not excluded from this study because the impact of such histories on self- and informant BRIEF-A ratings was of particular interest for this study. In the final sample, 12 participants had a premorbid diagnosis of ADHD, 4 had received special education services for learning disability, 13 reported a remote history of personal trauma, 15 endorsed a prior history of substance abuse, and 49 described pre-TBI outpatient treatment of psychiatric reasons (most often adjustment disorder). It should be noted that several participants had more than 1 prior condition. A minority of the sample (n = 33) had no history of any premorbid complicating factors. Furthermore, in the complete sample, 18 persons were engaged in financial compensation seeking at the time of assessment, 7 of whom also had at least 1 premorbid condition. Only about a quarter (n = 26) of the participants in this study did not have any known premorbid or comorbid complicating factors. The final sample consisted of 52 men and 48 women, with a mean age of 39.66 years (SD = 16.80) who were evaluated with the BRIEF-A at a mean of 162.25 days
postinjury (SD = 93.95). The majority of the sample was Caucasian (n = 92), with other self-reported ethnicities including African American (n = 7) and Latino (n = 1). Participants had completed a mean of 13.56 years of education (SD = 2.67). About half of the sample (n = 51) was married or in a long-term cohabitating relationship. Informant data for the BRIEF-A were obtained from a spouse in 48 cases, from a parent in 34, and from another person who knew the patient at least moderately well in the remaining 18. Almost half of the participants (n = 46) had been injured in motor vehicle collisions, with the remaining most common causes including sports and other recreational activities (n = 27), falls (n = 18), and other (n = 9). A total of 23 participants had intracranial lesions on neuroimaging, most often involving focal hemorrhagic contusions.
Measures The BRIEF-A is a standardized rating of executive behaviors in the rated individual’s daily environment. It has a self-report version and an informant report version. Both versions include 75 items of behavioral descriptors that are answered according to a 3-point Likert scale (“never,” “sometimes,” and “often”) as pertaining to the last month. These items divide into 9 nonoverlapping clinical scales that combine to form 2 broadband indices, the Behavioral Regulation Index and the Metacognition Index, which, in turn, combine into an overall General Executive Composite. The Inhibit, Shift, Emotional Control, and Self-Monitor scales comprise the Behavioral Regulation Index, whereas the Initiate, Working Memory, Plan/Organize, Task Monitor, and Organization of Materials scales form the Metacognitive Index. All BRIEF-A variables are expressed as T scores (mean = 50, SD = 10), with higher scores reflecting more reported problems. The manual for the normative sample of the BRIEF-A6 demonstrates good reliability of the summary broadband indices, with internal consistency as well as test-retest values ranging from 0.93 to 0.96. The WCST is a laboratory test of executive functioning that requires the examinee to consider different possible solutions to a task and to learn from corrective feedback to modify his or her strategy, suppress perseverative tendencies, and adjust to changing task demands. Performance on the WCST is expressed in T scores (mean = 50, SD = 10), with higher scores reflecting better performance. Although many variables can be obtained from the WCST, we chose for this investigation the WCST Perseverative Responses score because it is the most robust and widely used variable.24 WCST data from 7 participants were excluded from the analyses because they reported being familiar with an online
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Informant Ratings of Executive Functioning After Mild TBI version of a game (“Blink”) that is very similar to the actual test and therefore invalidated the findings. Procedure BRIEF-A and WCST data were obtained during neuropsychological evaluations that were conducted in the context of outpatient differential diagnosis and treatment planning. Participants and informants always completed their respective versions of the BRIEF-A in a different room. Although the other tests that had been administered to the participants varied somewhat, they all completed a stand-alone performance validity task, the Test of Memory Malingering (TOMM).25 Although this sample had been selected on the basis of having no validity indices violated on the BRIEF-A, this instrument pertains to subjective symptom report whereas the TOMM pertains to validity of performance. A total of 24 participants failed validity criteria on the TOMM according to the criteria suggested by Greve and colleagues26 for application with persons with mild TBI. We also considered validity criteria that have been suggested for the WCST,27 but these data did not add meaningfully to the results from the TOMM. Specifically, of the 10 persons who failed the WCST validity criteria, 9 also failed the TOMM. The remaining participant had intracranial findings on neuroimaging and did not present with any significant premorbid (eg, psychiatric) or comorbid (eg, compensation seeking) complicating factors and appeared to be a false-positive. For these reasons, WCST validity criteria were not considered further in the analyses. Finally, 85 of the 93 participants for whom potentially interpretable WCST data were available had also completed an additional laboratory test of executive functioning, the Tower of London–Drexel University, Second Edition (TOL).28 This is a test that pertains to efficiency of planning abilities and its data were included as a secondary analysis. It requires the copying of a configuration of 3 colored beads on 3 sticks of various heights, in as few moves as possible. The Total Move Score of this instrument, expressed as a standard score (mean = 100, SD = 15; higher scores reflecting better performance), has been shown to correlate negatively with length to follow verbal commands, and persons with complicated mild TBI also performed worse on this measure than demographically matched controls.29 Data analyses BRIEF-A T scores were used for the statistical analyses. Pearson product-moment correlations were used both to compare the self- and informant BRIEF-A ratings and to compare BRIEF-A and WCST findings. The levels of agreement between self- and informant ratings
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were also evaluated with t tests for paired observations. Several variables were selected on an a priori theoretical basis for inclusion in regression analyses to predict self- and informant scores on the BRIEF-A Behavioral Regulation Index, Metacognition Index, and General Executive Composite measures. These included level of education, interval between injury and psychometric assessment, presence or absence of prior outpatient psychiatric treatment, presence or absence of any other premorbid complicating factor (ie, ADHD, learning disability, personal abuse, or substance abuse), presence of absence of financial compensation seeking, presence or absence of an intracranial lesion on neuroimaging, and pass/fail of validity criteria on the TOMM. This allowed for an acceptable participant to variable ratio (>14:1). Consistent with recommendations in the literature,30 both statistically significant and nonsignificant variables were retained in the presented model to reflect their relative contributions. Variance inflation factors were inspected for collinearity, and these were less than 1.35 in all regression models, which was clearly acceptable.31 Effect sizes and proportions of variance accounted for were also considered, using previously specified criteria.32 The squared correlation coefficient (r2 ) was used to determine the amount of covariance accounted for by Pearson product-moment correlations, with values less than 0.10 considered weak, values 0.10 to 0.25 moderate, and values more than 0.25 strong. Cohen d was used to determine the magnitude of the differences between self- and informant BRIEF-A ratings, with values less than 0.50 considered small, values 0.50 to 0.80 medium, and values more than 0.80 large. The R2 statistic was used to determine the amount of variance accounted for by the regression models, with values less than 0.10 considered small, values 0.10 to 0.25 medium, and values more than 0.25 large. RESULTS Table 1 presents the BRIEF-A self- and informant scores for the main broadband variables. For illustrative purposes, the subscale scores are also presented in Figure 1. The self- and informant ratings on all 3 BRIEFA summary variables were strongly correlated (r2 = 0.40 for all). At the same time, the t tests revealed that on all BRIEF-A summary variables, participants rated themselves as functioning statistically significantly worse than did the informants. Effect sizes (d) for these discrepancies between the respective ratings were uniformly small. Because group means can obscure subgroups with or without impairment, we also calculated the proportion of participants who had BRIEF-A General Executive Composite scores of 65 or more, the criterion recommended in the test manual for clinical significance. In the complete sample, 52% of the participant ratings and www.headtraumarehab.com
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E34 TABLE 1
JOURNAL OF HEAD TRAUMA REHABILITATION/NOVEMBER–DECEMBER 2015
BRIEF-A index scores (N = 100)a
BRIEF-A Behavioral Regulation Index Metacognition Index General Executive Composite
Self
Informant
t
P
d
R
61.13 (14.51) 64.91 (14.64) 64.27 (15.20)
56.64 (10.88) 59.96 (11.40) 58.97 (10.98)
3.92 4.29 4.54
.0003 .0003 .0002
0.35 0.37 0.39
0.63b 0.64b 0.64b
Abbreviation: BRIEF-A, Behavior Rating Inventory of Executive Function–Adult Version. a P values corrected with the step-down Bonferroni method for multiple comparisons. b P < .0001.
Figure 1. BRIEF-A subtest profiles of 100 persons with mild traumatic brain injury. Vertical bars reflect standard error of the mean. BRIEF-A indicates Behavior Rating Inventory of Executive Function–Adult Version.
34% of the informant ratings met this criterion. This difference in proportions was statistically significant (z = 2.57; P < .02). Table 2 presents the regression models for the self- and informant ratings on the BRIEF-A Behavioral Regulation Index. The model for the self-ratings was statistically significant (F7,92 = 6.00; P < .0001) and explained a large
TABLE 2
amount of the variance. Higher levels of education and presence of intracranial findings on neuroimaging were both associated with better self-rated BRIEF-A Behavioral Regulation performance (ie, lower ratings), whereas the presence of a prior outpatient psychiatric treatment history was associated with worse self-rated performance on that same index (ie, higher ratings). The model for
Regression model for BRIEF-A Behavioral Regulation Index (N = 100)a Self
Variable Years of completed education Days since injury Prior psychiatric history Prior other complicating factors Financial compensation seeking Intracranial neuroimaging findings Failure on TOMM
Informant
SRC
t
P
− 0.24 0.15 0.37 0.04 0.03 − 0.21 0.12
− 2.57 1.60 3.73 0.42 0.28 − 2.29 1.31
.02 .12 .0003 .68 .78 .03 .20
R
2
0.26
SRC
t
P
R2
− 0.31 0.13 0.34 0.02 0.04 − 0.04 0.07
− 3.15 1.32 3.21 0.19 0.43 0.44 0.72
.003 .19 .002 .85 .67 .66 .47
0.17
Abbreviations: BRIEF-A, Behavior Rating Inventory of Executive Function–Adult Version; SRC, standardized regression coefficient; TOMM, Test of Memory Malingering. a R2 reflects the adjusted value for the composite model.
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Informant Ratings of Executive Functioning After Mild TBI the informant ratings was also statistically significant (F7,92 = 3.93; P < .0009) and explained a medium amount of the variance. Higher levels of education were associated with better informant-rated BRIEF-A Behavioral Regulation performance, whereas the presence of a prior outpatient psychiatric treatment history was associated with worse informant-rated performance on that same index. None of the other variables were statistically significant in either of the 2 models. The regression models for the self- and informant ratings on the BRIEF-A Metacognition Index are presented in Table 3. The model for the self-ratings was statistically significant (F7,92 = 5.80; P < .0001) and explained a large amount of the variance. The presence of intracranial findings on neuroimaging was associated with better self-rated BRIEF-A Metacognition performance (ie, lower ratings), whereas a longer time interval since injury and the presence of a prior outpatient psychiatric treatment history were both associated with worse self-rated performance on that same index (ie, higher ratings). The model for the informant ratings was also statistically significant (F7,92 = 4.64; P < .0002) and exTABLE 3
E35
plained a medium amount of the variance. Higher levels of education were associated with better informant-rated BRIEF-A Metacognition performance, whereas the presence of a prior outpatient psychiatric treatment history was associated with worse informant-rated performance on that same index. There was a statistically nonsignificant trend for a longer time interval since injury to also be associated with higher ratings on the Metacognition Index in the informant model, but none of the other variables approached such a trend level toward statistical significance in either of the 2 models. The regression models for the self- and informant ratings on the BRIEF-A General Executive Composite are presented in Table 4. The model for the self-ratings was statistically significant (F7,92 = 6.23; P < .0001) and explained a large amount of the variance. The presence of intracranial findings on neuroimaging was associated with better self-rated BRIEF-A General Executive performance (ie, lower ratings), whereas a longer time interval since injury and the presence of a prior outpatient psychiatric treatment history were both associated with worse self-rated performance on that same index (ie,
Regression model for BRIEF-A Metacognition Index (N = 100)a Self
Variable Years of completed education Days since injury Prior psychiatric history Prior other complicating factors Financial compensation seeking Intracranial neuroimaging findings Failure on TOMM
Informant
SRC
t
P
− 0.08 0.20 0.28 0.03 0.10 − 0.27 0.15
− 0.81 2.09 2.77 0.25 1.09 − 2.92 1.61
.42 .04 .007 .80 .28 .005 .0
R2
SRC
t
P
R2
0.25
− 0.26 0.18 0.32 0.07 0.06 − 0.14 0.10
− 2.77 1.84 3.06 0.66 0.64 − 1.46 1.02
.007 .07 .003 .51 .52 .15 .31
0.21
Abbreviations: BRIEF-A, Behavior Rating Inventory of Executive Function–Adult Version; SRC, standardized regression coefficient; TOMM, Test of Memory Malingering. a R2 reflects the adjusted value for the composite model.
TABLE 4
Regression model for BRIEF-A General Executive Composite (N = 100)a Self
Variable Years of completed education Days since injury Prior psychiatric history Prior other complicating factors Financial compensation-seeking Intracranial neuroimaging findings Failure on TOMM
SRC − 0.15 0.19 0.33 0.04 0.07 − 0.25 0.14
t 1.62 1.99 3.34 0.35 0.76 − 2.81 1.50
Informant
P .11 .05 .002 .73 .45 .006 .14
R
2
0.27
SRC − 0.30 0.17 0.35 0.06 0.06 − 0.11 0.10
t − 3.24 1.74 3.48 0.57 0.62 − 1.15 1.03
P .002 .09 .0008 .57 .54 .25 .30
R2
0.23
Abbreviations: BRIEF-A, Behavior Rating Inventory of Executive Function–Adult Version; SRC, standardized regression coefficient; TOMM, Test of Memory Malingering. a R2 reflects the adjusted value for the composite model.
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JOURNAL OF HEAD TRAUMA REHABILITATION/NOVEMBER–DECEMBER 2015
higher ratings). The model for the informant ratings was also statistically significant (F7,92 = 5.21; P < .0001) and explained a medium amount of the variance. Higher levels of education were associated with better informantrated BRIEF-A General Executive performance, whereas the presence of a prior outpatient psychiatric treatment history was associated with worse informant-rated performance on that same index. There was a statistically nonsignificant trend for a longer time interval since injury to also be associated with higher ratings on the General Executive Composite in the informant model, but none of the other variables approached such a trend level toward statistical significance in either of the 2 models. We then considered the relationship between BRIEFA, WCST, and TOL findings in the groups of participants for whom potentially interpretable data on the latter 2 tests were available. In the complete subgroup for the WCST (n = 93), the mean level of performance on WCST Perseverative Responses was 47.30 (SD = 11.79) and 10 participants (11% of this subsample) had T scores on this variable that were 35 or less. In the complete subgroup for the TOL (n = 85), the mean level of performance on the TOL was 102.01 (SD = 17.20) and 7 participants (8% of this subsample) had standard scores on this variable that were 78 or less. In light of the fact that a considerable proportion of the sample violated performance validity criteria on the TOMM, we decided to evaluate correlations between BRIEF-A, on the one hand, and the WCST and TOL, on the other hand, separately in subsamples of those who did or did not put forth valid effort, according to the TOMM. In the former subgroup, mean WCST performance was 47.56 (SD = 11.69) whereas it was 46.45 (SD = 12.34) in the latter subgroup. Performance of the TOL in these 2 subgroups was 103.19 (SD = 14.24) and 97.01 (SD = 18.48), respectively. The correlations with either WCST Perseverative Responses or TOL Total Move Score did not approach even liberal criteria for potential statistical significance for any of the self- or informant BRIEF-A summary variables (P > .10 for all) in either subgroup. Finally, we evaluated whether the presence or absence on any of the variables that had been statistically significant predictors in the various regression models was related to performance on either the WCST or TOL. Performance on neither the WCST (r = 0.05; P > .66) nor the TOL (r = 0.11; P > .29) correlated significantly with time interval since injury. Performance on the TOL (r = 0.42; P < .0001) but not the WCST (r = 0.12; P > .26) correlated significantly with educational attainment (r = 0.12; P > .26), likely because the TOL norms do not take the level of education into account whereas the norms for the WCST do. The presence of intracranial findings on neuroimaging did not affect performance on either the WCST (F1,91 = 0.13; P > .71) or the
TOL (F1,83 = 1.14; P > .28), whereas the presence of a premorbid psychiatric history was associated with statistically significant differences on the TOL (F1,83 = 4.87; P < .03) but not the WCST (F1,91 = 1.43; P > .23). The group difference on the TOL Total Move Score actually favored the group with prior outpatient psychiatric treatment (mean = 105.71, SD = 15.64) as compared with those without such a premorbid history (mean = 98.59, SD = 14.09). The associated effect size (d = 0.48) was small. DISCUSSION The main purpose of this study was to determine which demographic, psychosocial, and medical variables predicted findings on the BRIEF-A after mild TBI. In addition, we aimed to determine the level of agreement between self- and informant ratings, as well as correlations with laboratory tests of executive functioning, the WCST and TOL. Consistent with hypothesis 1, the variable that was most consistently associated with worse ratings across all 3 BRIEF-A summary scales, in both patients and informants, was the presence of a prior psychiatric history. This finding is consistent with results from several comprehensive literature reviews that have identified psychosocial factors, and poor premorbid mental health in particular, as a significant risk factor for poor outcomes after mild TBI.14,15 In contrast, in all of the models pertaining to self-report, the presence of intracranial findings on neuroimaging was associated with better BRIEFA ratings. This was not expected and contrary to hypothesis 2. It could be argued that this effect might reflect limited deficit awareness in persons with complicated mild TBI, but this would not be consistent with the fact that intracranial findings did not factor in any of the models for the informant ratings. When considered in concert with the fact that, in several of the self- and informant models, longer duration of time since injury was associated with worse BRIEF-A ratings, these findings instead suggest that patients with mild TBI who have prolonged subjective symptoms may have a magnified perception of their deficits, as suggested in other research.33 In this context, the fact that failure on a stand-alone performance validity test (TOMM) did not figure significantly in any of the regression models may suggest that the BRIEF-A findings are not likely to reflect a deliberate component to this magnification. Instead, patients with a preexisting psychiatric history may simply be more inclined to re- or misattribute premorbid difficulties to a mild TBI, something that has been explained in the literature in terms such as the “good old days bias”34 and “cogniform condition.”35 Another, and not mutually exclusive, possible interpretation is that persons with mild TBI and a preexisting psychiatric history simply have a
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Informant Ratings of Executive Functioning After Mild TBI generally negative self-perception that extends to their view of subjective cognitive efficacy, as has previously been suggested in research with conditions ranging from depression36 to schizophrenia.37 The current findings suggest that, after accounting for premorbid outpatient psychiatric treatment, other potentially complicating psychosocial history variables, such as personal abuse or substance abuse, did not explain incremental variance in any of the regression models. Thus, screening for prior psychiatric health and resilience appears to be crucial when considering treatment planning after mild TBI.38 A higher number of years of completed education were associated with better BRIEF-A ratings in almost all of the regression models. In the pediatric literature on mild TBI, it has been suggested that cognitive reserve may moderate the impact of injury severity on subjective symptoms.39 Specifically, children with lower cognitive ability were noted to be relatively more prone to cognitive complaints for an extended period of time. However, in the current study, persons with complicated injuries actually reported relatively fewer problems. Cognitive reserve has also been suggested as a moderator of severe TBI,40,41 but all the participants in this sample had mild injuries. Rather, the influence of years of completed education in this study may reflect a correlate of limited vocational attainment, as it has been suggested that limited job independence and decision-making latitude are risk factors for poor outcomes after mild TBI.42 In this investigation, self- and informant BRIEF-A ratings were strongly correlated, as was predicted by hypothesis 3. These findings were also consistent with those reported previously in a sample of persons with mild cognitive impairment.7 Patients in the current investigation did report statistically significantly more problems than their informants did. Although the associated effect size was somewhat small, about a third of a standard deviation, this stands in contrast to recent findings in a study that focused on persons with moderate-severe TBI, where no significant differences between self- and informant reports were found.13 The confluence of these findings is consistent with our interpretation of the effect of neuroimaging findings, that is, patients with mild TBI may have a somewhat (inadvertently) deflated perception of their executive abilities. A contributing factor in this regard may be the phenomenon of diagnosis threat, referring to the possibility that simply having too much attention paid to a history of mild TBI and its possible sequelae may result in negative self-expectations.43 In this context, the fact that our participants generally did well on several laboratory measures of executive functioning, despite rating themselves poorly on the BRIEF-A, is consistent with previous findings in the literature that suggested that diagnosis threat affects primarily perceived self-efficacy and not necessarily actual cognitive test performance.44
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Neither the self-ratings nor the informant ratings correlated with the results from the WCST or TOL. This was consistent with hypothesis 4. These findings are also consistent with previous studies that have found few and weak correlations between BRIEF-A ratings and traditional laboratory tests of executive functioning in general7,8,10 and between the BRIEF-A and the WCST in persons with moderate-severe TBI in particular.13 It is possible that this reflects, to some extent, differences in the nature of executive skills that are assessed by the respective instruments. However, given the fact that the average performance of this sample on WCST Perseverative Responses as well as the TOL Total Move Score was well within normal limits, the average relative elevation on BRIEF-A of almost 1.5 SDs again suggests that the participants likely had an unrealistically poor view of their own executive abilities. This interpretation was also bolstered by the fact that, despite the fact that persons with prior psychiatric histories rated themselves more poorly on the BRIEF-A, they actually did better on the TOL than did persons without such histories. Admittedly, the associated effect size was less than half a standard deviation and it may have been a spurious finding in light of multiple univariate comparisons, but the direction of the difference would argue against a true executive deficit in those who received outpatient psychiatric services before incurring their mild TBI. Potential limitations of this investigation must also be considered. This was a referred convenience sample, and there were about as many persons with mild TBI who did not have an informant accompany them to the evaluation as those who did. Since persons in the former group were more likely to be involved in financial compensation seeking, the potential influence of that particular variable cannot be ruled out on the basis of this investigation. At the same time, the fact that almost none of the potential participants without informant data had positive findings on neuroimaging strengthens our interpretation of the effect of that variable. Another limitation is the fact that this sample was largely Caucasian, and replication in an ethnically more diverse sample is needed. In addition, these findings are limited to persons with mild TBI and cannot be generalized to persons with moderate-severe TBI. Furthermore, it needs to be realized that the current sample was likely not representative of the entire population of individuals with mild TBI, many of whom have rapid resolution of symptoms and never present for neuropsychological evaluation more than 1 month later. A specific goal for future research is to evaluate the construct validity of the BRIEF-A across the entire range of injury severity after TBI in a representative sample, preferably along with consideration of the same phenomena in control participants with traumatic orthopedic injuries. This would likely also allow for exploration of the relationship www.headtraumarehab.com
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between the BRIEF-A and laboratory measures of executive functioning in a larger group of individuals with TBI who actually perform poorly on the latter measures whereas the vast majority of the participants in this investigation performed well on the WCST and the TOL. In such future studies, the degree to which findings from the BRIEF-A overlap with or supplement those from traditional measures of psychological adjustment or mood should also be explored. CONCLUSIONS Persons with mild TBI who are referred for neuropsychological evaluation because of persistent complaints tend to overestimate their degree of executive dysfunction in daily life, as assessed with the BRIEF-A. The presence of a premorbid psychiatric history and limited educational attainment in particular are risk factors for such overestimation, whereas the presence of intracranial complications does not lead to worse BRIEF-A ratings. It
is therefore important to not equate subjective symptom report with organic sequelae of mild TBI. Particularly, for those who present to a clinic more than 1 month after injury, careful screening for potential premorbid and comorbid complicating risk factors is important before commencing treatment of presumed “postconcussion” symptoms after mild TBI. This will be particularly important with increasing time since injury, when distorted or otherwise negative self-perceptions or expectations may have become more ingrained. Utilization of an instrument such as the BRIEF-A can be helpful in this context to explore discrepancies between self- and informant ratings of perceived executing functioning. Large discrepancies (eg, ≥1 SD) between the respective ratings should be particularly concerning in this context and indicative of a likely need for education of the patient, with correction of misperceptions or misattributions, as opposed to approaches that might inadvertently reinforce the sick role or otherwise contribute to iatrogenic effects.
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