Symptom Reporting Patterns of US Military Service Members with a History of Concussion According to Duty Status

Symptom Reporting Patterns of US Military Service Members with a History of Concussion According... Abstract Objective To compare symptom reporting patterns of service members with a history of concussion based on work status: full duty, limited duty, or in the Medical Evaluation Board (MEB)/disability process. Methods Retrospective analysis of 181 service members with a history of concussion (MEB n = 56; limited duty n = 62; full duty n = 63). Neurobehavioral Symptom Inventory (NSI) Validity-10 cutoff (>22) and Mild Brain Injury Atypical Symptoms Scale (mBIAS) cutoffs (≥10 and ≥8) were used to evaluate potential over-reporting of symptoms. Results The MEB group displayed significantly higher NSI scores and significantly higher proportion scored above the mBIAS ≥10 cutoff (MEB = 15%; limited duty = 3%; full duty = 5%). Validity-10 cutoff did not distinguish between groups. Conclusions MEB but not limited duty status was associated with increased risk of over-reporting symptoms in service members with a history of concussion. Results support the use of screening measures for over-reporting in the MEB/disability samples. Head injury, Traumatic brain injury, Malingering/symptom validity testing, Assessment From 2000 to 2016, the US military has documented 361,092 service members with traumatic brain injury (TBI), 82% of which are mild (DVBIC, 2017). Most mild TBI patients typically recover fully within 3 months of injury (Frencham, Fox, & Maybery, 2005; Iverson, 2005); however, 10–15% of patients do not follow this trajectory and continue to experience symptoms (Bazarian et al., 2005; Vanderploeg, Curtiss, Luis, & Salazar, 2007). Complicating the clinical presentation, mild TBI may also be accompanied by other physical injuries such as burn or orthopedic injuries associated with blast. Furthermore, symptoms of TBI are non-specific and also occur in individuals with depression or posttraumatic stress disorder. When medical conditions interfere with a service member’s ability to carry out duties, their commander can initiate a Medical Evaluation Board (MEB) process. This is the start of the Physical Disability Evaluation Process that could lead to medical separation from the military and disability determination in the Veterans Administration system. Because of the dependency on self-reported severity of symptoms in TBI evaluations and the potential for benefits compensation as a result of the MEB process, it has been necessary to consider validity of symptom reporting in active duty and veteran populations. The Neurobehavioral Symptom Inventory (NSI) is a self-report symptom measure endorsed by the Department of Defense (DoD) and Veterans Administration to track neurocognitive complaints after TBI. The Validity-10 scale of the NSI is composed of 10 items that are infrequently endorsed by those with mild TBI and may suggest negative impression management (Lange, Brickell, Lippa, & French, 2015; Vanderploeg et al., 2014). The Mild Brain Injury Atypical Symptoms Scale (mBIAS) is another symptom validity screening tool composed of five pseudo-neurological symptoms that are improbable after a mild TBI (Cooper, Nelson, Armistead-Jehle, & Bowles, 2011). These screening measures have been shown to predict validity of symptom profiles using more extensive measures such as the Personality Assessment Inventory and the Minnesota Multiphasic Personality Inventory – 2, Restructured Form (Dretsch et al., 2017; Lange, Brickell, & French, 2015; Lange, Brickell, Lippa, et al., 2015; Lippa, Axelrod, & Lange, 2016). Different cutoff scores for screening potential symptom over-reporting have been proposed for both the NSI Validity-10 and mBIAS (Armistead-Jehle et al., 2017; Cooper et al., 2011; Dretsch et al., 2017; Lange, Brickell, & French, 2015; Lange, Brickell, Lippa, et al., 2015; Lange, Edmed, Sullivan, French, & Cooper, 2013; Lippa, Axelrod, et al., 2016; Sullivan, Lange, & Edmed, 2016; Vanderploeg et al., 2014). The recommended cutoff scores for military samples tend to be higher than for civilian samples, which reflects the observation that deployment stress is associated with increased symptom reporting on the NSI, even in the absence of TBI (Soble et al., 2014). The MEB process has been associated with increased severity of reported symptoms, increased proportions of validity scores above cutoff suggesting symptom exaggeration (Lippa, Lange, et al., 2016), and increased proportions of response patterns on cognitive tests that suggest suboptimal performance (Armistead-Jehle & Buican, 2012). One study reported that service members on limited duty were also more likely to exceed symptom over-reporting cutoffs (Lippa, Lange, et al., 2016). Limited duty refers to a restriction of activities determined by a clinical provider to accommodate medical recovery. While some who are placed on limited duty status transition back to full duty, a proportion transition into the MEB process should recovery not progress. Little is known about symptom reporting patterns of this group of service members who may also be at high risk of pain, psychological distress, limitations in functional ability, and potential symptom exaggeration. The goal of this brief report is to compare symptom reporting patterns of service members with a history of concussion in MEB, limited duty, and full duty. Methods Data were analyzed from a repository database of service members who endorsed a history of TBI during a primary care visit screen in the Brooke Army Medical Center from August 2015 to August 2016 and completed a battery of questionnaires. The presence of TBI was confirmed for all cases, based on electronic medical record review and patient self-report elicited from a study-specific semi-structured interview with a trained research nurse. All research procedures were performed in compliance with DoD guidelines and approved by the local Institutional Review Board. Written informed consent was obtained from all participants. Of 211 cases, only those with mild TBI and complete scores on the NSI were included, yielding 181 cases. Mild TBI was defined using the DoD/Veterans Health Affairs criteria: Loss of consciousness no greater than 30 min and/or posttraumatic amnesia and/or alteration of consciousness no greater than 24 h. Of 181 cases, 62% had medical record documentation of the index mild TBI. We reported pain (McGill Pain Questionnaire), symptoms of depression and posttraumatic stress (Center for Epidemiological Studies – Depression [CES-D]; Posttraumatic Stress Disorder Checklist – Civilian [PCL-C]), and disability (Craig Handicap and Assessment Reporting Technique, Short Form [CHART-SF]) in post-hoc analyses to characterize our sample. Due to missing data, some analyses included less than 181 cases. Participants were divided into three groups: those who had started the MEB process (n = 56), those on limited duty (n = 62), and those on full duty (n = 63). Group differences for continuous demographic variables were evaluated with analysis of variance and followed up with Tukey Honest Significant Difference test. Demographic variables that differed between groups were entered as covariates when evaluating group differences on symptom variables. Group differences for categorical data were evaluated with contingency tables and Pearson’s χ2 analyses. Significant findings were followed up with Kruskal–Wallis tests. Validity cutoff scores were chosen for the active duty population. On the NSI Validity-10, the cutoff recommended by the developers (>22) was used (Vanderploeg et al., 2014). A higher diagnostic cutoff has been proposed for Validity-10 but was not used because no individual met this cutoff (≥33) in our sample (Armistead-Jehle et al., 2017). On the mBIAS, we examined both ≥8, the screening cutoff recommended by the developers (Cooper et al., 2011) and ≥10, the diagnostic cutoff later proposed in a follow-up multicenter study (Armistead-Jehle et al., 2017). Results All participants were adults aged 19–60. The sample was primarily male (89%, n = 161) with the following racial composition: 79% white (n = 143), 17% black (n = 30), 6% Native American/Alaska Native (n = 11), 3% Asian or Pacific Islander (n = 5). One-third of the sample reported Hispanic/Latino heritage (n = 60). The sample consisted primarily of Army service members (92%, including Reserves and Guard, n = 166). Others included in this sample were Air Force (4%, n = 8), Navy (3%, n = 5) and Marine and Coast Guard (1%, n = 2) personnel. Table 1 shows that the limited duty group was younger than the full duty group, but the MEB group’s age did not differ from the others. The sample averaged 55 months post mild TBI. The average time since injury did not differ between groups, but χ2 test of proportion of cases in acute versus chronic phase since injury was significant. Of those in the MEB group, 41% were in the MEB process due to physical injuries, 21% due to mental health issues, and 27% due to both physical and mental health issues (remaining participants did not give permission for identifying information to be kept, which precluded subsequent review of medical records). The average time since the start of MEB process was 3 months (standard deviation [SD] = 4 months). Of those in the limited duty group, 50% had limited duty status due to physical issues, 11% due to mental health issues, and 13% due to both physical and mental health issues (remaining did not give permission for identifiers to be kept). The average time since the start of duty limitation was 7 months (SD = 14 months). In no case was anyone in the MEB or limited duty status for mild TBI alone; the primary issue was always another physical condition (e.g., amputation, back pain) or mental health condition (e.g., posttraumatic stress disorder, depression). Thus all cases had a remote history of mild TBI but the limited duty/MEB status was due to another problem with unknown relationship to the index TBI. Table 1 also shows that equivalent proportions of each duty status group received mild TBI while deployed for the Global War on Terrorism (including Operation Enduring Freedom, Operation Iraqi Freedom, and Operation New Dawn among others) versus other locations of injury. The majority of the sample was higher ranking enlisted personnel. χ2 test of proportion of cases across ranks was significant. Table 1. Means (and standard deviations) by duty status for demographic variables and proportion of participants by place of injury, time since injury, and military rank   No MEB  MEB (n = 56)  Inferential statistics  Full duty (n = 63)  Limited duty (n = 62)  Age  37.97 (6.72)a  33.77 (8.69)b  36.57 (7.93)  F(2,178) = 4.65, p = .01  Gender (M:F)  56:7  54:8  51:5  χ2(2,181) = 0.47, p = .79  Time since injury (in months)  63.37 (43.54)  44.08 (45.85)  56.46 (50.78)  F(2,178) = 2.73, p = .07  Time since injury   1–3 months  3 (5%)  11 (18%)  1 (2%)  Pearson’s χ2(4,181) = 20.78, p < .01   4–12 months  3 (5%)  13 (21%)  7 (12%)   >1 year  57 (90%)  38 (61%)  48 (86%)  Place of injury   GWOT  33 (52%)  28 (45%)  34 (61%)  Pearson’s χ2(2,181) = 2.85, p = .24   Non-GWOT  30 (48%)  34 (55%)  22 (39%)  Rank   Junior enlisted (E1–E4)  2 (3%)  13 (21%)  7 (13%)  Pearson’s χ2(4,181) = 12.68, p = .01   Noncommissioned officers (E5–E9)  43 (68%)  41 (66%)  40 (71%)   Officers (W1-O10)  18 (29%)  8 (13%)  9 (16%)    No MEB  MEB (n = 56)  Inferential statistics  Full duty (n = 63)  Limited duty (n = 62)  Age  37.97 (6.72)a  33.77 (8.69)b  36.57 (7.93)  F(2,178) = 4.65, p = .01  Gender (M:F)  56:7  54:8  51:5  χ2(2,181) = 0.47, p = .79  Time since injury (in months)  63.37 (43.54)  44.08 (45.85)  56.46 (50.78)  F(2,178) = 2.73, p = .07  Time since injury   1–3 months  3 (5%)  11 (18%)  1 (2%)  Pearson’s χ2(4,181) = 20.78, p < .01   4–12 months  3 (5%)  13 (21%)  7 (12%)   >1 year  57 (90%)  38 (61%)  48 (86%)  Place of injury   GWOT  33 (52%)  28 (45%)  34 (61%)  Pearson’s χ2(2,181) = 2.85, p = .24   Non-GWOT  30 (48%)  34 (55%)  22 (39%)  Rank   Junior enlisted (E1–E4)  2 (3%)  13 (21%)  7 (13%)  Pearson’s χ2(4,181) = 12.68, p = .01   Noncommissioned officers (E5–E9)  43 (68%)  41 (66%)  40 (71%)   Officers (W1-O10)  18 (29%)  8 (13%)  9 (16%)  Note: a,bStatistically different from each other. MEB = Medical Evaluation Board; GWOT = Global War on Terrorism; E = Enlisted; W = Warrant officer; O = Officer. Table 1. Means (and standard deviations) by duty status for demographic variables and proportion of participants by place of injury, time since injury, and military rank   No MEB  MEB (n = 56)  Inferential statistics  Full duty (n = 63)  Limited duty (n = 62)  Age  37.97 (6.72)a  33.77 (8.69)b  36.57 (7.93)  F(2,178) = 4.65, p = .01  Gender (M:F)  56:7  54:8  51:5  χ2(2,181) = 0.47, p = .79  Time since injury (in months)  63.37 (43.54)  44.08 (45.85)  56.46 (50.78)  F(2,178) = 2.73, p = .07  Time since injury   1–3 months  3 (5%)  11 (18%)  1 (2%)  Pearson’s χ2(4,181) = 20.78, p < .01   4–12 months  3 (5%)  13 (21%)  7 (12%)   >1 year  57 (90%)  38 (61%)  48 (86%)  Place of injury   GWOT  33 (52%)  28 (45%)  34 (61%)  Pearson’s χ2(2,181) = 2.85, p = .24   Non-GWOT  30 (48%)  34 (55%)  22 (39%)  Rank   Junior enlisted (E1–E4)  2 (3%)  13 (21%)  7 (13%)  Pearson’s χ2(4,181) = 12.68, p = .01   Noncommissioned officers (E5–E9)  43 (68%)  41 (66%)  40 (71%)   Officers (W1-O10)  18 (29%)  8 (13%)  9 (16%)    No MEB  MEB (n = 56)  Inferential statistics  Full duty (n = 63)  Limited duty (n = 62)  Age  37.97 (6.72)a  33.77 (8.69)b  36.57 (7.93)  F(2,178) = 4.65, p = .01  Gender (M:F)  56:7  54:8  51:5  χ2(2,181) = 0.47, p = .79  Time since injury (in months)  63.37 (43.54)  44.08 (45.85)  56.46 (50.78)  F(2,178) = 2.73, p = .07  Time since injury   1–3 months  3 (5%)  11 (18%)  1 (2%)  Pearson’s χ2(4,181) = 20.78, p < .01   4–12 months  3 (5%)  13 (21%)  7 (12%)   >1 year  57 (90%)  38 (61%)  48 (86%)  Place of injury   GWOT  33 (52%)  28 (45%)  34 (61%)  Pearson’s χ2(2,181) = 2.85, p = .24   Non-GWOT  30 (48%)  34 (55%)  22 (39%)  Rank   Junior enlisted (E1–E4)  2 (3%)  13 (21%)  7 (13%)  Pearson’s χ2(4,181) = 12.68, p = .01   Noncommissioned officers (E5–E9)  43 (68%)  41 (66%)  40 (71%)   Officers (W1-O10)  18 (29%)  8 (13%)  9 (16%)  Note: a,bStatistically different from each other. MEB = Medical Evaluation Board; GWOT = Global War on Terrorism; E = Enlisted; W = Warrant officer; O = Officer. Age and time since injury were entered as covariates in subsequent analyses of variance. Rank was not covaried because it correlated significantly with age (rs = 0.42, p < .01). Table 2 shows that on the NSI, the MEB group had higher score than limited and full duty groups. On the Validity-10, the MEB group scored significantly higher than the limited and full duty groups. However, when we categorized those who scored >22, the proportion of service members who scored above cutoff did not significantly differ between groups. On the mBIAS total score, a non-significant difference was found between the three groups. However, a higher proportion of individuals in the MEB group scored above the diagnostic cutoff of ≥10. When we applied a lower screening mBIAS cutoff of ≥8, there was no difference among groups in the proportion above this cutoff (Table 2). Table 2. Neurobehavioral Symptom Inventory (NSI) and Mild Brain Injury Atypical Symptoms Scale (mBIAS) scores by duty status   No MEB  MEB  Inferential statistics  Full duty  Limited duty  NSI  (n = 63)  (n = 62)  (n = 56)    Total mean (SD)  31.38 (18.23)a  36.18 (18.39)a  46.20 (16.56)b  F(2,176) = 11.04, p < .01†  Validity-10 mean (SD)  9.95 (7.74)a  11.94 (7.87)a  15.66 (7.17)b  F(2,176) = 9.21, p < .01†  Validity-10 number of cases (percent)   ≤22  57 (90%)  55 (89%)  47 (84%)  Pearson’s χ2(2,181) = 1.26, p = .53   >22  6 (10%)  7 (11%)  9 (16%)    mBIAS  (n = 62)  (n = 62)  (n = 56)    Total mean (SD)  5.94 (1.56)a  6.21 (2.12)  6.80 (2.41)b  F(2,174) = 2.64, p = .074†  mBIAS number of cases (percent)   <8  51 (82%)  53 (85%)  39 (71%)  Pearson’s χ2(2,179) = 4.19, p = .12   ≥8  11 (18%)  9 (15%)  16 (29%)   <10  59 (95%)  60 (97%)  47 (85%)  Pearson’s χ2(2,179) = 6.37, p = .04   ≥10  3 (5%)  2 (3%)  8 (15%)    No MEB  MEB  Inferential statistics  Full duty  Limited duty  NSI  (n = 63)  (n = 62)  (n = 56)    Total mean (SD)  31.38 (18.23)a  36.18 (18.39)a  46.20 (16.56)b  F(2,176) = 11.04, p < .01†  Validity-10 mean (SD)  9.95 (7.74)a  11.94 (7.87)a  15.66 (7.17)b  F(2,176) = 9.21, p < .01†  Validity-10 number of cases (percent)   ≤22  57 (90%)  55 (89%)  47 (84%)  Pearson’s χ2(2,181) = 1.26, p = .53   >22  6 (10%)  7 (11%)  9 (16%)    mBIAS  (n = 62)  (n = 62)  (n = 56)    Total mean (SD)  5.94 (1.56)a  6.21 (2.12)  6.80 (2.41)b  F(2,174) = 2.64, p = .074†  mBIAS number of cases (percent)   <8  51 (82%)  53 (85%)  39 (71%)  Pearson’s χ2(2,179) = 4.19, p = .12   ≥8  11 (18%)  9 (15%)  16 (29%)   <10  59 (95%)  60 (97%)  47 (85%)  Pearson’s χ2(2,179) = 6.37, p = .04   ≥10  3 (5%)  2 (3%)  8 (15%)  Note: †Omnibus test of group differences with age and time since injury entered as covariates. When the omnibus F statistic is significant, follow-up group differences are indicated by superscripts. Within each row, superscripts (a,b,c) mark a significant difference between that cell and the cell(s) with a different superscript. Cells with no superscript do not differ from any group within the same row. MEB = Medical Evaluation Board. Table 2. Neurobehavioral Symptom Inventory (NSI) and Mild Brain Injury Atypical Symptoms Scale (mBIAS) scores by duty status   No MEB  MEB  Inferential statistics  Full duty  Limited duty  NSI  (n = 63)  (n = 62)  (n = 56)    Total mean (SD)  31.38 (18.23)a  36.18 (18.39)a  46.20 (16.56)b  F(2,176) = 11.04, p < .01†  Validity-10 mean (SD)  9.95 (7.74)a  11.94 (7.87)a  15.66 (7.17)b  F(2,176) = 9.21, p < .01†  Validity-10 number of cases (percent)   ≤22  57 (90%)  55 (89%)  47 (84%)  Pearson’s χ2(2,181) = 1.26, p = .53   >22  6 (10%)  7 (11%)  9 (16%)    mBIAS  (n = 62)  (n = 62)  (n = 56)    Total mean (SD)  5.94 (1.56)a  6.21 (2.12)  6.80 (2.41)b  F(2,174) = 2.64, p = .074†  mBIAS number of cases (percent)   <8  51 (82%)  53 (85%)  39 (71%)  Pearson’s χ2(2,179) = 4.19, p = .12   ≥8  11 (18%)  9 (15%)  16 (29%)   <10  59 (95%)  60 (97%)  47 (85%)  Pearson’s χ2(2,179) = 6.37, p = .04   ≥10  3 (5%)  2 (3%)  8 (15%)    No MEB  MEB  Inferential statistics  Full duty  Limited duty  NSI  (n = 63)  (n = 62)  (n = 56)    Total mean (SD)  31.38 (18.23)a  36.18 (18.39)a  46.20 (16.56)b  F(2,176) = 11.04, p < .01†  Validity-10 mean (SD)  9.95 (7.74)a  11.94 (7.87)a  15.66 (7.17)b  F(2,176) = 9.21, p < .01†  Validity-10 number of cases (percent)   ≤22  57 (90%)  55 (89%)  47 (84%)  Pearson’s χ2(2,181) = 1.26, p = .53   >22  6 (10%)  7 (11%)  9 (16%)    mBIAS  (n = 62)  (n = 62)  (n = 56)    Total mean (SD)  5.94 (1.56)a  6.21 (2.12)  6.80 (2.41)b  F(2,174) = 2.64, p = .074†  mBIAS number of cases (percent)   <8  51 (82%)  53 (85%)  39 (71%)  Pearson’s χ2(2,179) = 4.19, p = .12   ≥8  11 (18%)  9 (15%)  16 (29%)   <10  59 (95%)  60 (97%)  47 (85%)  Pearson’s χ2(2,179) = 6.37, p = .04   ≥10  3 (5%)  2 (3%)  8 (15%)  Note: †Omnibus test of group differences with age and time since injury entered as covariates. When the omnibus F statistic is significant, follow-up group differences are indicated by superscripts. Within each row, superscripts (a,b,c) mark a significant difference between that cell and the cell(s) with a different superscript. Cells with no superscript do not differ from any group within the same row. MEB = Medical Evaluation Board. Table 3 shows the concordance between the Validity-10 and mBIAS. Of the nine cases in the MEB group that scored above the Validity-10 cutoff, six scored ≥8 and four scored ≥10 on the mBIAS. This translated to a concordance rate, defined as the number of cases below Validity-10 and mBIAS cutoffs plus the number of cases above both cutoffs divided by the total number of cases, of 76% in the MEB group when using the mBIAS ≥8 cutoff, and 84% when using the mBIAS ≥10 cutoff. Across the entire sample (N = 179), concordance rate was 79% when using the mBIAS ≥8 cutoff, and 88% when using the mBIAS ≥10 cutoff. Table 3. Concordance between Validity-10 and mBIAS scores by duty status   No MEB  MEB  Full duty  Limited duty  (n = 62)  (n = 62)  (n = 56)  NSI ≤ 22  NSI > 22  NSI ≤ 22  NSI > 22  NSI ≤ 22  NSI > 22  mBIAS cutoff of ≥8   mBIAS <8  48  3  48  5  36  3   mBIAS ≥8  9  2  7  2  10  6  mBIAS cutoff of ≥10   mBIAS <10  55  4  54  6  42  5   mBIAS ≥10  2  1  1  1  4  4    No MEB  MEB  Full duty  Limited duty  (n = 62)  (n = 62)  (n = 56)  NSI ≤ 22  NSI > 22  NSI ≤ 22  NSI > 22  NSI ≤ 22  NSI > 22  mBIAS cutoff of ≥8   mBIAS <8  48  3  48  5  36  3   mBIAS ≥8  9  2  7  2  10  6  mBIAS cutoff of ≥10   mBIAS <10  55  4  54  6  42  5   mBIAS ≥10  2  1  1  1  4  4  Table 3. Concordance between Validity-10 and mBIAS scores by duty status   No MEB  MEB  Full duty  Limited duty  (n = 62)  (n = 62)  (n = 56)  NSI ≤ 22  NSI > 22  NSI ≤ 22  NSI > 22  NSI ≤ 22  NSI > 22  mBIAS cutoff of ≥8   mBIAS <8  48  3  48  5  36  3   mBIAS ≥8  9  2  7  2  10  6  mBIAS cutoff of ≥10   mBIAS <10  55  4  54  6  42  5   mBIAS ≥10  2  1  1  1  4  4    No MEB  MEB  Full duty  Limited duty  (n = 62)  (n = 62)  (n = 56)  NSI ≤ 22  NSI > 22  NSI ≤ 22  NSI > 22  NSI ≤ 22  NSI > 22  mBIAS cutoff of ≥8   mBIAS <8  48  3  48  5  36  3   mBIAS ≥8  9  2  7  2  10  6  mBIAS cutoff of ≥10   mBIAS <10  55  4  54  6  42  5   mBIAS ≥10  2  1  1  1  4  4  Medical record review revealed that 40% of those in the limited duty group entered into the MEB process subsequent to enrollment into this study (36% were not in the MEB process at the time of record review; 24% unknown because they did not give permission for identifiers to be kept). The proportion of cases that received a neuropsychological evaluation at the time of record review was small: 16% of the limited duty group (24% unknown) and 20% of the MEB group (9% unknown). We examined group differences on pain, psychological distress, and disability to characterize our sample. The MEB and limited duty groups reported similar pain scores (McGill Pain Questionnaire Total mean scores of 18.09 (SD = 9.49) and 15.32 (SD = 8.26), respectively), which were higher than the full duty group’s (mean = 11.92, SD = 9.10). The MEB group reported higher scores on measures of depressive and posttraumatic stress symptoms than the others, with no difference between limited and full duty groups (CES-D: MEB = 29.16 (SD = 13.69), limited duty = 21.34 (SD = 14.14), full duty = 17.02 (SD = 13.98); PCL-C: MEB = 57.61 (SD = 17.37), limited duty = 45.61 (SD = 18.47), full duty = 41.51 (SD = 16.64)). To put these scores in perspective, a cutoff of 16 on the CES-D has been recommended for screening depression in community samples (Radloff, 1977), and our sample means are higher than means of 12–15 reported in two military samples (Boisvert, McCreary, Wright, & Asmundson, 2003; Renshaw, Rodrigues, & Jones, 2009). With respect to the PCL-C, cutoff scores ranging from 28 to 60 have been proposed for screening posttraumatic stress disorder in veteran populations (Keen, Kutter, Niles, & Krinsley, 2008). On a measure of functional ability, the three groups did not differ from each other in domains of cognition, mobility, social integration, occupation, or physical independence (CHART-SF). Discussion In this active duty sample of service members who endorsed a history of concussion/mild TBI during a primary care visit screen, the limited duty and full duty groups showed very similar patterns across measures of psychological functioning and level of disability. The limited duty group reported a higher level of pain compared to the full duty group. With regard to postconcussive symptoms, the proportion of those exceeding symptom validity cutoffs was similar between the limited and full duty groups. These results suggest that limited duty status in our sample was not associated with symptom over-reporting, which may or may not be in contrast to Lippa and colleagues’ report of higher rates of over-reporting in the limited duty group compared to the full duty group (Lippa, Lange, et al., 2016). Differences in sample characteristics help explain these potentially incongruent findings. Medical record review revealed that reasons for limited duty and MEB included physical injuries, mental health issues, or both. In no case was any service member placed on limited duty or into the MEB process for mild TBI alone. Because our participants averaged 55 months post TBI but 7 months from the start of limited duty, we inferred that duty restrictions were not directly related to their TBI. Lippa and colleagues did not report reasons for limited duty, but given that time since TBI averaged 10 months in their sample, the possibility that duty restrictions related in some way to TBI seemed more plausible. The rate of exceeding the Validity-10 cutoff in the limited duty group was comparable between Lippa et al.’s and our samples (9% vs. 11%, respectively). The higher rate of over-reporting in their limited duty group arose out of comparison to their full duty group, only 4.5% of which scored >22 on the Validity-10. In our full duty group, 10% scored >22 on the Validity-10. The higher NSI score in our chronic sample was consistent with the observation that neurocognitive symptom endorsement after mild TBI increases with time (Lippa, Lange, et al., 2016). This study replicated previous findings that MEB status is associated with an increased risk of exceeding cutoffs on some symptom validity screens. Service members in the MEB process reported more pain and symptoms of depression and posttraumatic stress, which may reflect heightened psychological distress than those in full duty status. They reported more psychological distress than the limited duty group, but they did not differ significantly from the limited duty group in pain or functional ability (domains of mobility, social interaction, physical, cognitive, and occupational). A major limitation to interpretation of these findings is that causation cannot be inferred from these correlational relationships. We cannot determine if severe symptoms led to disability and subsequent MEB processing, or if the pursuit of disability compensation contributed to greater reporting of symptoms. Of the two screening instruments for symptom validity, only the mBIAS cutoff of ≥10 showed differential elevation by MEB status, with 15% above cutoff for those in the MEB group and 3–5% above cutoff in the full and limited duty groups, respectively (positive rate of 7% in the overall sample). This cutoff score was advocated by Armistead-Jehle and colleagues as a diagnostic indicator because of its associated high specificity and positive predictive power for symptom over-reporting as measured by the Minnesota Multiphasic Personality Inventory – 2, Restructured Form (Armistead-Jehle et al., 2017). The mBIAS cutoff of ≥8, as recommended by the original developers (Cooper et al., 2011), yielded a 20% positive rate from the overall sample and did not distinguish the MEB group from limited or full duty groups. These results suggest that mBIAS ≥8 can only serve as a screening cutoff that requires a more thorough clinical evaluation of validity. mBIAS ≥10 cutoff can be considered to “probably” indicate symptom exaggeration. However, even in these cases we advocate follow-up with a thorough clinical evaluation of validity. False positives are possible even with this cutoff, given that a small proportion (5%) of full duty service members who presumably do not have motivation for secondary gain scored above this cutoff. The NSI Validity-10 cutoff of >22 yielded a 12% positive rate in the overall sample and did not distinguish the MEB group from limited or full duty groups. For screening purposes, this NSI Validity-10 cutoff offered an overall positive rate that fell between the mBIAS cutoffs of ≥8 and 10. The concordance between Validity-10 and mBIAS with cutoff of ≥10 was 88% across our entire sample, which was higher than concordance of 79% with mBIAS with cutoff of ≥8. It would be informative to evaluate the concordance between these screening cutoffs and a psychometrically established criterion of symptom validity. Unfortunately these data were not available on our sample, imposing a significant limitation on our ability to address the relationship between symptom over-reporting and validity. Interestingly, no case scored ≥33 on the Validity-10, which was the cutoff recommended by Armistead-Jehle and colleagues from a multi-site study for “probable” symptom exaggeration (Armistead-Jehle et al., 2017). Our data suggested that Validity-10 ≥33 is rare even among service members who endorsed many problems on screening measures of psychological distress. An important limitation with studies of mild TBI is reliance on self-report of injury. In the present study, only 56% of the full duty group, 74% of the limited duty group, and 54% of the MEB group have documentation of TBI in their medical record. Many service members have an ingrained warrior ethos of self-sacrifice, mission-forwardness, and the desire to portray strength that gets in the way of help seeking behavior at the time of injury, and thus medical documentation of TBI may be lacking. In our study, reliance on self-report of TBI may have impacted the full duty and MEB groups more than the limited duty group. In conclusion, service members on limited duty status with a history of a mild TBI did not have an increased risk of symptom exaggeration. Those on MEB status, on the other hand, did show an increased risk of symptom over-reporting. We advocate that service members with a history of TBI who exceed cutoffs on the NSI Validity-10 or the mBIAS undergo a thorough clinical evaluation for symptom over-reporting using a clinical interview that relies on open-ended questions and instruments with established psychometric properties for symptom validity. Funding This work was supported by the United States Department of Defense/Department of Health Affairs’ Defense and Veterans Brain Injury Center, contract # W91YTZ-13-C-0015 20DEC18; General Dynamics Health Solutions. Conflict of Interest None declared. Acknowledgements We thank Lt Col Jeffrey C. McClean II and Richard A. Montgomery for administrative support. We thank John P. Bruno, RN, Maria M. Lara, MS, Cynthia L. Muncy, MA, and Joseph B. Warren, RN for data collection and database support. References Armistead-Jehle, P., & Buican, B. ( 2012). Evaluation context and Symptom Validity Test performances in a U.S. Military sample. Archives of Clinical Neuropsychology , 27, 828– 839. doi:10.1093/arclin/acs086. Google Scholar CrossRef Search ADS PubMed  Armistead-Jehle, P., Cooper, D. B., Grills, C. E., Cole, W. R., Lippa, S. M., Stegman, R. L., et al.  . ( 2017). 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Google Scholar CrossRef Search ADS   Soble, J. R., Silva, M. A., Vanderploeg, R. D., Curtiss, G., Belanger, H. G., Donnell, A. J., et al.  . ( 2014). Normative data for the Neurobehavioral Symptom Inventory (NSI) and post-concussion symptom profiles among TBI, PTSD, and nonclinical samples. The Clinical Neuropsychologist , 28, 614– 632. doi:10.1080/13854046.2014.894576. Google Scholar CrossRef Search ADS PubMed  Sullivan, K. A., Lange, R. T., & Edmed, S. L. ( 2016). Utility of the Neurobehavioral Symptom Inventory Validity-10 index to detect symptom exaggeration: An analogue simulation study. Applied Neuropsychology: Adult , 23, 353– 362. doi:10.1080/23279095.2015.1079714. Google Scholar CrossRef Search ADS PubMed  Vanderploeg, R. D., Cooper, D. B., Belanger, H. G., Donnell, A. J., Kennedy, J. E., Hopewell, C. A., et al.  . ( 2014). Screening for postdeployment conditions: Development and cross-validation of an embedded validity scale in the neurobehavioral symptom inventory. The Journal of Head Trauma Rehabilitation , 29 ( 1), 1– 10. doi:10.1097/HTR.0b013e318281966e. Google Scholar CrossRef Search ADS PubMed  Vanderploeg, R. D., Curtiss, G., Luis, C. A., & Salazar, A. M. ( 2007). Long-term morbidities following self-reported mild traumatic brain injury. Journal of Clinical and Experimental Neuropsychology , 29, 585– 598. doi:10.1080/13803390600826587. Google Scholar CrossRef Search ADS PubMed  Published by Oxford University Press 2018. This work is written by (a) US Government employee(s) and is in the public domain in the US. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Archives of Clinical Neuropsychology Oxford University Press

Symptom Reporting Patterns of US Military Service Members with a History of Concussion According to Duty Status

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Oxford University Press
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Published by Oxford University Press 2018.
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0887-6177
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1873-5843
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10.1093/arclin/acy031
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Abstract

Abstract Objective To compare symptom reporting patterns of service members with a history of concussion based on work status: full duty, limited duty, or in the Medical Evaluation Board (MEB)/disability process. Methods Retrospective analysis of 181 service members with a history of concussion (MEB n = 56; limited duty n = 62; full duty n = 63). Neurobehavioral Symptom Inventory (NSI) Validity-10 cutoff (>22) and Mild Brain Injury Atypical Symptoms Scale (mBIAS) cutoffs (≥10 and ≥8) were used to evaluate potential over-reporting of symptoms. Results The MEB group displayed significantly higher NSI scores and significantly higher proportion scored above the mBIAS ≥10 cutoff (MEB = 15%; limited duty = 3%; full duty = 5%). Validity-10 cutoff did not distinguish between groups. Conclusions MEB but not limited duty status was associated with increased risk of over-reporting symptoms in service members with a history of concussion. Results support the use of screening measures for over-reporting in the MEB/disability samples. Head injury, Traumatic brain injury, Malingering/symptom validity testing, Assessment From 2000 to 2016, the US military has documented 361,092 service members with traumatic brain injury (TBI), 82% of which are mild (DVBIC, 2017). Most mild TBI patients typically recover fully within 3 months of injury (Frencham, Fox, & Maybery, 2005; Iverson, 2005); however, 10–15% of patients do not follow this trajectory and continue to experience symptoms (Bazarian et al., 2005; Vanderploeg, Curtiss, Luis, & Salazar, 2007). Complicating the clinical presentation, mild TBI may also be accompanied by other physical injuries such as burn or orthopedic injuries associated with blast. Furthermore, symptoms of TBI are non-specific and also occur in individuals with depression or posttraumatic stress disorder. When medical conditions interfere with a service member’s ability to carry out duties, their commander can initiate a Medical Evaluation Board (MEB) process. This is the start of the Physical Disability Evaluation Process that could lead to medical separation from the military and disability determination in the Veterans Administration system. Because of the dependency on self-reported severity of symptoms in TBI evaluations and the potential for benefits compensation as a result of the MEB process, it has been necessary to consider validity of symptom reporting in active duty and veteran populations. The Neurobehavioral Symptom Inventory (NSI) is a self-report symptom measure endorsed by the Department of Defense (DoD) and Veterans Administration to track neurocognitive complaints after TBI. The Validity-10 scale of the NSI is composed of 10 items that are infrequently endorsed by those with mild TBI and may suggest negative impression management (Lange, Brickell, Lippa, & French, 2015; Vanderploeg et al., 2014). The Mild Brain Injury Atypical Symptoms Scale (mBIAS) is another symptom validity screening tool composed of five pseudo-neurological symptoms that are improbable after a mild TBI (Cooper, Nelson, Armistead-Jehle, & Bowles, 2011). These screening measures have been shown to predict validity of symptom profiles using more extensive measures such as the Personality Assessment Inventory and the Minnesota Multiphasic Personality Inventory – 2, Restructured Form (Dretsch et al., 2017; Lange, Brickell, & French, 2015; Lange, Brickell, Lippa, et al., 2015; Lippa, Axelrod, & Lange, 2016). Different cutoff scores for screening potential symptom over-reporting have been proposed for both the NSI Validity-10 and mBIAS (Armistead-Jehle et al., 2017; Cooper et al., 2011; Dretsch et al., 2017; Lange, Brickell, & French, 2015; Lange, Brickell, Lippa, et al., 2015; Lange, Edmed, Sullivan, French, & Cooper, 2013; Lippa, Axelrod, et al., 2016; Sullivan, Lange, & Edmed, 2016; Vanderploeg et al., 2014). The recommended cutoff scores for military samples tend to be higher than for civilian samples, which reflects the observation that deployment stress is associated with increased symptom reporting on the NSI, even in the absence of TBI (Soble et al., 2014). The MEB process has been associated with increased severity of reported symptoms, increased proportions of validity scores above cutoff suggesting symptom exaggeration (Lippa, Lange, et al., 2016), and increased proportions of response patterns on cognitive tests that suggest suboptimal performance (Armistead-Jehle & Buican, 2012). One study reported that service members on limited duty were also more likely to exceed symptom over-reporting cutoffs (Lippa, Lange, et al., 2016). Limited duty refers to a restriction of activities determined by a clinical provider to accommodate medical recovery. While some who are placed on limited duty status transition back to full duty, a proportion transition into the MEB process should recovery not progress. Little is known about symptom reporting patterns of this group of service members who may also be at high risk of pain, psychological distress, limitations in functional ability, and potential symptom exaggeration. The goal of this brief report is to compare symptom reporting patterns of service members with a history of concussion in MEB, limited duty, and full duty. Methods Data were analyzed from a repository database of service members who endorsed a history of TBI during a primary care visit screen in the Brooke Army Medical Center from August 2015 to August 2016 and completed a battery of questionnaires. The presence of TBI was confirmed for all cases, based on electronic medical record review and patient self-report elicited from a study-specific semi-structured interview with a trained research nurse. All research procedures were performed in compliance with DoD guidelines and approved by the local Institutional Review Board. Written informed consent was obtained from all participants. Of 211 cases, only those with mild TBI and complete scores on the NSI were included, yielding 181 cases. Mild TBI was defined using the DoD/Veterans Health Affairs criteria: Loss of consciousness no greater than 30 min and/or posttraumatic amnesia and/or alteration of consciousness no greater than 24 h. Of 181 cases, 62% had medical record documentation of the index mild TBI. We reported pain (McGill Pain Questionnaire), symptoms of depression and posttraumatic stress (Center for Epidemiological Studies – Depression [CES-D]; Posttraumatic Stress Disorder Checklist – Civilian [PCL-C]), and disability (Craig Handicap and Assessment Reporting Technique, Short Form [CHART-SF]) in post-hoc analyses to characterize our sample. Due to missing data, some analyses included less than 181 cases. Participants were divided into three groups: those who had started the MEB process (n = 56), those on limited duty (n = 62), and those on full duty (n = 63). Group differences for continuous demographic variables were evaluated with analysis of variance and followed up with Tukey Honest Significant Difference test. Demographic variables that differed between groups were entered as covariates when evaluating group differences on symptom variables. Group differences for categorical data were evaluated with contingency tables and Pearson’s χ2 analyses. Significant findings were followed up with Kruskal–Wallis tests. Validity cutoff scores were chosen for the active duty population. On the NSI Validity-10, the cutoff recommended by the developers (>22) was used (Vanderploeg et al., 2014). A higher diagnostic cutoff has been proposed for Validity-10 but was not used because no individual met this cutoff (≥33) in our sample (Armistead-Jehle et al., 2017). On the mBIAS, we examined both ≥8, the screening cutoff recommended by the developers (Cooper et al., 2011) and ≥10, the diagnostic cutoff later proposed in a follow-up multicenter study (Armistead-Jehle et al., 2017). Results All participants were adults aged 19–60. The sample was primarily male (89%, n = 161) with the following racial composition: 79% white (n = 143), 17% black (n = 30), 6% Native American/Alaska Native (n = 11), 3% Asian or Pacific Islander (n = 5). One-third of the sample reported Hispanic/Latino heritage (n = 60). The sample consisted primarily of Army service members (92%, including Reserves and Guard, n = 166). Others included in this sample were Air Force (4%, n = 8), Navy (3%, n = 5) and Marine and Coast Guard (1%, n = 2) personnel. Table 1 shows that the limited duty group was younger than the full duty group, but the MEB group’s age did not differ from the others. The sample averaged 55 months post mild TBI. The average time since injury did not differ between groups, but χ2 test of proportion of cases in acute versus chronic phase since injury was significant. Of those in the MEB group, 41% were in the MEB process due to physical injuries, 21% due to mental health issues, and 27% due to both physical and mental health issues (remaining participants did not give permission for identifying information to be kept, which precluded subsequent review of medical records). The average time since the start of MEB process was 3 months (standard deviation [SD] = 4 months). Of those in the limited duty group, 50% had limited duty status due to physical issues, 11% due to mental health issues, and 13% due to both physical and mental health issues (remaining did not give permission for identifiers to be kept). The average time since the start of duty limitation was 7 months (SD = 14 months). In no case was anyone in the MEB or limited duty status for mild TBI alone; the primary issue was always another physical condition (e.g., amputation, back pain) or mental health condition (e.g., posttraumatic stress disorder, depression). Thus all cases had a remote history of mild TBI but the limited duty/MEB status was due to another problem with unknown relationship to the index TBI. Table 1 also shows that equivalent proportions of each duty status group received mild TBI while deployed for the Global War on Terrorism (including Operation Enduring Freedom, Operation Iraqi Freedom, and Operation New Dawn among others) versus other locations of injury. The majority of the sample was higher ranking enlisted personnel. χ2 test of proportion of cases across ranks was significant. Table 1. Means (and standard deviations) by duty status for demographic variables and proportion of participants by place of injury, time since injury, and military rank   No MEB  MEB (n = 56)  Inferential statistics  Full duty (n = 63)  Limited duty (n = 62)  Age  37.97 (6.72)a  33.77 (8.69)b  36.57 (7.93)  F(2,178) = 4.65, p = .01  Gender (M:F)  56:7  54:8  51:5  χ2(2,181) = 0.47, p = .79  Time since injury (in months)  63.37 (43.54)  44.08 (45.85)  56.46 (50.78)  F(2,178) = 2.73, p = .07  Time since injury   1–3 months  3 (5%)  11 (18%)  1 (2%)  Pearson’s χ2(4,181) = 20.78, p < .01   4–12 months  3 (5%)  13 (21%)  7 (12%)   >1 year  57 (90%)  38 (61%)  48 (86%)  Place of injury   GWOT  33 (52%)  28 (45%)  34 (61%)  Pearson’s χ2(2,181) = 2.85, p = .24   Non-GWOT  30 (48%)  34 (55%)  22 (39%)  Rank   Junior enlisted (E1–E4)  2 (3%)  13 (21%)  7 (13%)  Pearson’s χ2(4,181) = 12.68, p = .01   Noncommissioned officers (E5–E9)  43 (68%)  41 (66%)  40 (71%)   Officers (W1-O10)  18 (29%)  8 (13%)  9 (16%)    No MEB  MEB (n = 56)  Inferential statistics  Full duty (n = 63)  Limited duty (n = 62)  Age  37.97 (6.72)a  33.77 (8.69)b  36.57 (7.93)  F(2,178) = 4.65, p = .01  Gender (M:F)  56:7  54:8  51:5  χ2(2,181) = 0.47, p = .79  Time since injury (in months)  63.37 (43.54)  44.08 (45.85)  56.46 (50.78)  F(2,178) = 2.73, p = .07  Time since injury   1–3 months  3 (5%)  11 (18%)  1 (2%)  Pearson’s χ2(4,181) = 20.78, p < .01   4–12 months  3 (5%)  13 (21%)  7 (12%)   >1 year  57 (90%)  38 (61%)  48 (86%)  Place of injury   GWOT  33 (52%)  28 (45%)  34 (61%)  Pearson’s χ2(2,181) = 2.85, p = .24   Non-GWOT  30 (48%)  34 (55%)  22 (39%)  Rank   Junior enlisted (E1–E4)  2 (3%)  13 (21%)  7 (13%)  Pearson’s χ2(4,181) = 12.68, p = .01   Noncommissioned officers (E5–E9)  43 (68%)  41 (66%)  40 (71%)   Officers (W1-O10)  18 (29%)  8 (13%)  9 (16%)  Note: a,bStatistically different from each other. MEB = Medical Evaluation Board; GWOT = Global War on Terrorism; E = Enlisted; W = Warrant officer; O = Officer. Table 1. Means (and standard deviations) by duty status for demographic variables and proportion of participants by place of injury, time since injury, and military rank   No MEB  MEB (n = 56)  Inferential statistics  Full duty (n = 63)  Limited duty (n = 62)  Age  37.97 (6.72)a  33.77 (8.69)b  36.57 (7.93)  F(2,178) = 4.65, p = .01  Gender (M:F)  56:7  54:8  51:5  χ2(2,181) = 0.47, p = .79  Time since injury (in months)  63.37 (43.54)  44.08 (45.85)  56.46 (50.78)  F(2,178) = 2.73, p = .07  Time since injury   1–3 months  3 (5%)  11 (18%)  1 (2%)  Pearson’s χ2(4,181) = 20.78, p < .01   4–12 months  3 (5%)  13 (21%)  7 (12%)   >1 year  57 (90%)  38 (61%)  48 (86%)  Place of injury   GWOT  33 (52%)  28 (45%)  34 (61%)  Pearson’s χ2(2,181) = 2.85, p = .24   Non-GWOT  30 (48%)  34 (55%)  22 (39%)  Rank   Junior enlisted (E1–E4)  2 (3%)  13 (21%)  7 (13%)  Pearson’s χ2(4,181) = 12.68, p = .01   Noncommissioned officers (E5–E9)  43 (68%)  41 (66%)  40 (71%)   Officers (W1-O10)  18 (29%)  8 (13%)  9 (16%)    No MEB  MEB (n = 56)  Inferential statistics  Full duty (n = 63)  Limited duty (n = 62)  Age  37.97 (6.72)a  33.77 (8.69)b  36.57 (7.93)  F(2,178) = 4.65, p = .01  Gender (M:F)  56:7  54:8  51:5  χ2(2,181) = 0.47, p = .79  Time since injury (in months)  63.37 (43.54)  44.08 (45.85)  56.46 (50.78)  F(2,178) = 2.73, p = .07  Time since injury   1–3 months  3 (5%)  11 (18%)  1 (2%)  Pearson’s χ2(4,181) = 20.78, p < .01   4–12 months  3 (5%)  13 (21%)  7 (12%)   >1 year  57 (90%)  38 (61%)  48 (86%)  Place of injury   GWOT  33 (52%)  28 (45%)  34 (61%)  Pearson’s χ2(2,181) = 2.85, p = .24   Non-GWOT  30 (48%)  34 (55%)  22 (39%)  Rank   Junior enlisted (E1–E4)  2 (3%)  13 (21%)  7 (13%)  Pearson’s χ2(4,181) = 12.68, p = .01   Noncommissioned officers (E5–E9)  43 (68%)  41 (66%)  40 (71%)   Officers (W1-O10)  18 (29%)  8 (13%)  9 (16%)  Note: a,bStatistically different from each other. MEB = Medical Evaluation Board; GWOT = Global War on Terrorism; E = Enlisted; W = Warrant officer; O = Officer. Age and time since injury were entered as covariates in subsequent analyses of variance. Rank was not covaried because it correlated significantly with age (rs = 0.42, p < .01). Table 2 shows that on the NSI, the MEB group had higher score than limited and full duty groups. On the Validity-10, the MEB group scored significantly higher than the limited and full duty groups. However, when we categorized those who scored >22, the proportion of service members who scored above cutoff did not significantly differ between groups. On the mBIAS total score, a non-significant difference was found between the three groups. However, a higher proportion of individuals in the MEB group scored above the diagnostic cutoff of ≥10. When we applied a lower screening mBIAS cutoff of ≥8, there was no difference among groups in the proportion above this cutoff (Table 2). Table 2. Neurobehavioral Symptom Inventory (NSI) and Mild Brain Injury Atypical Symptoms Scale (mBIAS) scores by duty status   No MEB  MEB  Inferential statistics  Full duty  Limited duty  NSI  (n = 63)  (n = 62)  (n = 56)    Total mean (SD)  31.38 (18.23)a  36.18 (18.39)a  46.20 (16.56)b  F(2,176) = 11.04, p < .01†  Validity-10 mean (SD)  9.95 (7.74)a  11.94 (7.87)a  15.66 (7.17)b  F(2,176) = 9.21, p < .01†  Validity-10 number of cases (percent)   ≤22  57 (90%)  55 (89%)  47 (84%)  Pearson’s χ2(2,181) = 1.26, p = .53   >22  6 (10%)  7 (11%)  9 (16%)    mBIAS  (n = 62)  (n = 62)  (n = 56)    Total mean (SD)  5.94 (1.56)a  6.21 (2.12)  6.80 (2.41)b  F(2,174) = 2.64, p = .074†  mBIAS number of cases (percent)   <8  51 (82%)  53 (85%)  39 (71%)  Pearson’s χ2(2,179) = 4.19, p = .12   ≥8  11 (18%)  9 (15%)  16 (29%)   <10  59 (95%)  60 (97%)  47 (85%)  Pearson’s χ2(2,179) = 6.37, p = .04   ≥10  3 (5%)  2 (3%)  8 (15%)    No MEB  MEB  Inferential statistics  Full duty  Limited duty  NSI  (n = 63)  (n = 62)  (n = 56)    Total mean (SD)  31.38 (18.23)a  36.18 (18.39)a  46.20 (16.56)b  F(2,176) = 11.04, p < .01†  Validity-10 mean (SD)  9.95 (7.74)a  11.94 (7.87)a  15.66 (7.17)b  F(2,176) = 9.21, p < .01†  Validity-10 number of cases (percent)   ≤22  57 (90%)  55 (89%)  47 (84%)  Pearson’s χ2(2,181) = 1.26, p = .53   >22  6 (10%)  7 (11%)  9 (16%)    mBIAS  (n = 62)  (n = 62)  (n = 56)    Total mean (SD)  5.94 (1.56)a  6.21 (2.12)  6.80 (2.41)b  F(2,174) = 2.64, p = .074†  mBIAS number of cases (percent)   <8  51 (82%)  53 (85%)  39 (71%)  Pearson’s χ2(2,179) = 4.19, p = .12   ≥8  11 (18%)  9 (15%)  16 (29%)   <10  59 (95%)  60 (97%)  47 (85%)  Pearson’s χ2(2,179) = 6.37, p = .04   ≥10  3 (5%)  2 (3%)  8 (15%)  Note: †Omnibus test of group differences with age and time since injury entered as covariates. When the omnibus F statistic is significant, follow-up group differences are indicated by superscripts. Within each row, superscripts (a,b,c) mark a significant difference between that cell and the cell(s) with a different superscript. Cells with no superscript do not differ from any group within the same row. MEB = Medical Evaluation Board. Table 2. Neurobehavioral Symptom Inventory (NSI) and Mild Brain Injury Atypical Symptoms Scale (mBIAS) scores by duty status   No MEB  MEB  Inferential statistics  Full duty  Limited duty  NSI  (n = 63)  (n = 62)  (n = 56)    Total mean (SD)  31.38 (18.23)a  36.18 (18.39)a  46.20 (16.56)b  F(2,176) = 11.04, p < .01†  Validity-10 mean (SD)  9.95 (7.74)a  11.94 (7.87)a  15.66 (7.17)b  F(2,176) = 9.21, p < .01†  Validity-10 number of cases (percent)   ≤22  57 (90%)  55 (89%)  47 (84%)  Pearson’s χ2(2,181) = 1.26, p = .53   >22  6 (10%)  7 (11%)  9 (16%)    mBIAS  (n = 62)  (n = 62)  (n = 56)    Total mean (SD)  5.94 (1.56)a  6.21 (2.12)  6.80 (2.41)b  F(2,174) = 2.64, p = .074†  mBIAS number of cases (percent)   <8  51 (82%)  53 (85%)  39 (71%)  Pearson’s χ2(2,179) = 4.19, p = .12   ≥8  11 (18%)  9 (15%)  16 (29%)   <10  59 (95%)  60 (97%)  47 (85%)  Pearson’s χ2(2,179) = 6.37, p = .04   ≥10  3 (5%)  2 (3%)  8 (15%)    No MEB  MEB  Inferential statistics  Full duty  Limited duty  NSI  (n = 63)  (n = 62)  (n = 56)    Total mean (SD)  31.38 (18.23)a  36.18 (18.39)a  46.20 (16.56)b  F(2,176) = 11.04, p < .01†  Validity-10 mean (SD)  9.95 (7.74)a  11.94 (7.87)a  15.66 (7.17)b  F(2,176) = 9.21, p < .01†  Validity-10 number of cases (percent)   ≤22  57 (90%)  55 (89%)  47 (84%)  Pearson’s χ2(2,181) = 1.26, p = .53   >22  6 (10%)  7 (11%)  9 (16%)    mBIAS  (n = 62)  (n = 62)  (n = 56)    Total mean (SD)  5.94 (1.56)a  6.21 (2.12)  6.80 (2.41)b  F(2,174) = 2.64, p = .074†  mBIAS number of cases (percent)   <8  51 (82%)  53 (85%)  39 (71%)  Pearson’s χ2(2,179) = 4.19, p = .12   ≥8  11 (18%)  9 (15%)  16 (29%)   <10  59 (95%)  60 (97%)  47 (85%)  Pearson’s χ2(2,179) = 6.37, p = .04   ≥10  3 (5%)  2 (3%)  8 (15%)  Note: †Omnibus test of group differences with age and time since injury entered as covariates. When the omnibus F statistic is significant, follow-up group differences are indicated by superscripts. Within each row, superscripts (a,b,c) mark a significant difference between that cell and the cell(s) with a different superscript. Cells with no superscript do not differ from any group within the same row. MEB = Medical Evaluation Board. Table 3 shows the concordance between the Validity-10 and mBIAS. Of the nine cases in the MEB group that scored above the Validity-10 cutoff, six scored ≥8 and four scored ≥10 on the mBIAS. This translated to a concordance rate, defined as the number of cases below Validity-10 and mBIAS cutoffs plus the number of cases above both cutoffs divided by the total number of cases, of 76% in the MEB group when using the mBIAS ≥8 cutoff, and 84% when using the mBIAS ≥10 cutoff. Across the entire sample (N = 179), concordance rate was 79% when using the mBIAS ≥8 cutoff, and 88% when using the mBIAS ≥10 cutoff. Table 3. Concordance between Validity-10 and mBIAS scores by duty status   No MEB  MEB  Full duty  Limited duty  (n = 62)  (n = 62)  (n = 56)  NSI ≤ 22  NSI > 22  NSI ≤ 22  NSI > 22  NSI ≤ 22  NSI > 22  mBIAS cutoff of ≥8   mBIAS <8  48  3  48  5  36  3   mBIAS ≥8  9  2  7  2  10  6  mBIAS cutoff of ≥10   mBIAS <10  55  4  54  6  42  5   mBIAS ≥10  2  1  1  1  4  4    No MEB  MEB  Full duty  Limited duty  (n = 62)  (n = 62)  (n = 56)  NSI ≤ 22  NSI > 22  NSI ≤ 22  NSI > 22  NSI ≤ 22  NSI > 22  mBIAS cutoff of ≥8   mBIAS <8  48  3  48  5  36  3   mBIAS ≥8  9  2  7  2  10  6  mBIAS cutoff of ≥10   mBIAS <10  55  4  54  6  42  5   mBIAS ≥10  2  1  1  1  4  4  Table 3. Concordance between Validity-10 and mBIAS scores by duty status   No MEB  MEB  Full duty  Limited duty  (n = 62)  (n = 62)  (n = 56)  NSI ≤ 22  NSI > 22  NSI ≤ 22  NSI > 22  NSI ≤ 22  NSI > 22  mBIAS cutoff of ≥8   mBIAS <8  48  3  48  5  36  3   mBIAS ≥8  9  2  7  2  10  6  mBIAS cutoff of ≥10   mBIAS <10  55  4  54  6  42  5   mBIAS ≥10  2  1  1  1  4  4    No MEB  MEB  Full duty  Limited duty  (n = 62)  (n = 62)  (n = 56)  NSI ≤ 22  NSI > 22  NSI ≤ 22  NSI > 22  NSI ≤ 22  NSI > 22  mBIAS cutoff of ≥8   mBIAS <8  48  3  48  5  36  3   mBIAS ≥8  9  2  7  2  10  6  mBIAS cutoff of ≥10   mBIAS <10  55  4  54  6  42  5   mBIAS ≥10  2  1  1  1  4  4  Medical record review revealed that 40% of those in the limited duty group entered into the MEB process subsequent to enrollment into this study (36% were not in the MEB process at the time of record review; 24% unknown because they did not give permission for identifiers to be kept). The proportion of cases that received a neuropsychological evaluation at the time of record review was small: 16% of the limited duty group (24% unknown) and 20% of the MEB group (9% unknown). We examined group differences on pain, psychological distress, and disability to characterize our sample. The MEB and limited duty groups reported similar pain scores (McGill Pain Questionnaire Total mean scores of 18.09 (SD = 9.49) and 15.32 (SD = 8.26), respectively), which were higher than the full duty group’s (mean = 11.92, SD = 9.10). The MEB group reported higher scores on measures of depressive and posttraumatic stress symptoms than the others, with no difference between limited and full duty groups (CES-D: MEB = 29.16 (SD = 13.69), limited duty = 21.34 (SD = 14.14), full duty = 17.02 (SD = 13.98); PCL-C: MEB = 57.61 (SD = 17.37), limited duty = 45.61 (SD = 18.47), full duty = 41.51 (SD = 16.64)). To put these scores in perspective, a cutoff of 16 on the CES-D has been recommended for screening depression in community samples (Radloff, 1977), and our sample means are higher than means of 12–15 reported in two military samples (Boisvert, McCreary, Wright, & Asmundson, 2003; Renshaw, Rodrigues, & Jones, 2009). With respect to the PCL-C, cutoff scores ranging from 28 to 60 have been proposed for screening posttraumatic stress disorder in veteran populations (Keen, Kutter, Niles, & Krinsley, 2008). On a measure of functional ability, the three groups did not differ from each other in domains of cognition, mobility, social integration, occupation, or physical independence (CHART-SF). Discussion In this active duty sample of service members who endorsed a history of concussion/mild TBI during a primary care visit screen, the limited duty and full duty groups showed very similar patterns across measures of psychological functioning and level of disability. The limited duty group reported a higher level of pain compared to the full duty group. With regard to postconcussive symptoms, the proportion of those exceeding symptom validity cutoffs was similar between the limited and full duty groups. These results suggest that limited duty status in our sample was not associated with symptom over-reporting, which may or may not be in contrast to Lippa and colleagues’ report of higher rates of over-reporting in the limited duty group compared to the full duty group (Lippa, Lange, et al., 2016). Differences in sample characteristics help explain these potentially incongruent findings. Medical record review revealed that reasons for limited duty and MEB included physical injuries, mental health issues, or both. In no case was any service member placed on limited duty or into the MEB process for mild TBI alone. Because our participants averaged 55 months post TBI but 7 months from the start of limited duty, we inferred that duty restrictions were not directly related to their TBI. Lippa and colleagues did not report reasons for limited duty, but given that time since TBI averaged 10 months in their sample, the possibility that duty restrictions related in some way to TBI seemed more plausible. The rate of exceeding the Validity-10 cutoff in the limited duty group was comparable between Lippa et al.’s and our samples (9% vs. 11%, respectively). The higher rate of over-reporting in their limited duty group arose out of comparison to their full duty group, only 4.5% of which scored >22 on the Validity-10. In our full duty group, 10% scored >22 on the Validity-10. The higher NSI score in our chronic sample was consistent with the observation that neurocognitive symptom endorsement after mild TBI increases with time (Lippa, Lange, et al., 2016). This study replicated previous findings that MEB status is associated with an increased risk of exceeding cutoffs on some symptom validity screens. Service members in the MEB process reported more pain and symptoms of depression and posttraumatic stress, which may reflect heightened psychological distress than those in full duty status. They reported more psychological distress than the limited duty group, but they did not differ significantly from the limited duty group in pain or functional ability (domains of mobility, social interaction, physical, cognitive, and occupational). A major limitation to interpretation of these findings is that causation cannot be inferred from these correlational relationships. We cannot determine if severe symptoms led to disability and subsequent MEB processing, or if the pursuit of disability compensation contributed to greater reporting of symptoms. Of the two screening instruments for symptom validity, only the mBIAS cutoff of ≥10 showed differential elevation by MEB status, with 15% above cutoff for those in the MEB group and 3–5% above cutoff in the full and limited duty groups, respectively (positive rate of 7% in the overall sample). This cutoff score was advocated by Armistead-Jehle and colleagues as a diagnostic indicator because of its associated high specificity and positive predictive power for symptom over-reporting as measured by the Minnesota Multiphasic Personality Inventory – 2, Restructured Form (Armistead-Jehle et al., 2017). The mBIAS cutoff of ≥8, as recommended by the original developers (Cooper et al., 2011), yielded a 20% positive rate from the overall sample and did not distinguish the MEB group from limited or full duty groups. These results suggest that mBIAS ≥8 can only serve as a screening cutoff that requires a more thorough clinical evaluation of validity. mBIAS ≥10 cutoff can be considered to “probably” indicate symptom exaggeration. However, even in these cases we advocate follow-up with a thorough clinical evaluation of validity. False positives are possible even with this cutoff, given that a small proportion (5%) of full duty service members who presumably do not have motivation for secondary gain scored above this cutoff. The NSI Validity-10 cutoff of >22 yielded a 12% positive rate in the overall sample and did not distinguish the MEB group from limited or full duty groups. For screening purposes, this NSI Validity-10 cutoff offered an overall positive rate that fell between the mBIAS cutoffs of ≥8 and 10. The concordance between Validity-10 and mBIAS with cutoff of ≥10 was 88% across our entire sample, which was higher than concordance of 79% with mBIAS with cutoff of ≥8. It would be informative to evaluate the concordance between these screening cutoffs and a psychometrically established criterion of symptom validity. Unfortunately these data were not available on our sample, imposing a significant limitation on our ability to address the relationship between symptom over-reporting and validity. Interestingly, no case scored ≥33 on the Validity-10, which was the cutoff recommended by Armistead-Jehle and colleagues from a multi-site study for “probable” symptom exaggeration (Armistead-Jehle et al., 2017). Our data suggested that Validity-10 ≥33 is rare even among service members who endorsed many problems on screening measures of psychological distress. An important limitation with studies of mild TBI is reliance on self-report of injury. In the present study, only 56% of the full duty group, 74% of the limited duty group, and 54% of the MEB group have documentation of TBI in their medical record. Many service members have an ingrained warrior ethos of self-sacrifice, mission-forwardness, and the desire to portray strength that gets in the way of help seeking behavior at the time of injury, and thus medical documentation of TBI may be lacking. In our study, reliance on self-report of TBI may have impacted the full duty and MEB groups more than the limited duty group. In conclusion, service members on limited duty status with a history of a mild TBI did not have an increased risk of symptom exaggeration. Those on MEB status, on the other hand, did show an increased risk of symptom over-reporting. We advocate that service members with a history of TBI who exceed cutoffs on the NSI Validity-10 or the mBIAS undergo a thorough clinical evaluation for symptom over-reporting using a clinical interview that relies on open-ended questions and instruments with established psychometric properties for symptom validity. Funding This work was supported by the United States Department of Defense/Department of Health Affairs’ Defense and Veterans Brain Injury Center, contract # W91YTZ-13-C-0015 20DEC18; General Dynamics Health Solutions. Conflict of Interest None declared. Acknowledgements We thank Lt Col Jeffrey C. McClean II and Richard A. Montgomery for administrative support. We thank John P. Bruno, RN, Maria M. Lara, MS, Cynthia L. Muncy, MA, and Joseph B. Warren, RN for data collection and database support. References Armistead-Jehle, P., & Buican, B. ( 2012). Evaluation context and Symptom Validity Test performances in a U.S. Military sample. Archives of Clinical Neuropsychology , 27, 828– 839. doi:10.1093/arclin/acs086. Google Scholar CrossRef Search ADS PubMed  Armistead-Jehle, P., Cooper, D. B., Grills, C. E., Cole, W. R., Lippa, S. M., Stegman, R. L., et al.  . ( 2017). 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Published: Mar 28, 2018

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