CE MMPI-2 PATTERNS IN ELECTRICAL INJURY: A CONTROLLED INVESTIGATION

The Clinical Neuropsychologist, 22: 98 111, 2008 http://www.psypress.com/tcn ISSN: 1385-4046 print=1744-4144 online DOI: 10.1080/13825580601025924 CE MMPI-2 PATTERNS IN ELECTRICAL INJURY: A CONTROLLED INVESTIGATION A. H. Wicklund 1,2,5, A. Ammar 1, J. C. Weitlauf 3,4, R. L. Heilbronner 5, J. Fink 6, R. C. Lee 6, K. Kelley 6, and N. H. Pliskin 1 1 University of Illinois at Chicago, Department of Psychiatry, IL, 2 Northwestern Alzheimer s Disease Center, Feinberg School of Medicine, Northwestern University, IL, 3 Veteran Affairs Palo Alto Health Care System, CA, 4 Stanford University School of Medicine, CA, 5 Chicago Neuropsychology Group, IL, and 6 University of Chicago School of Medicine, IL, USA The psychological consequences of electrical injury (EI) are many. Depression, posttraumatic stress disorder, anxiety, and somatic preoccupation are often concomitant with this type of injury (Kelley, Pliskin, Meyer, & Lee, 1994). The present study utilized the MMPI-2 as a tool for characterizing profiles of psychological distress in EI. We examined MMPI-2 profiles in 79 EI patients and their relationship to both injury parameters (i.e., time since injury, LOC, voltage), and extra-diagnostic factors, such as litigation status. EI patient profiles were also compared to individuals with mild traumatic brain injury (TBI), and chronic pain sufferers (CP). Results indicated that in EI, clinical elevations (T 65) were found on the Hs and Hy scales, and approached clinical levels on the D scale. The injury parameter of time since injury was predictive of a distinctive profile, with individuals in the post acute phase experiencing more distress. Compared to other clinical groups, MMPI-2 scores on the Hs and Hy scales were significantly higher within the EI cohort as compared with their CP peers, with higher scores on the Pd scale for CP than EI. No statistically significant differences emerged between the EI and TBI groups. However, TBI patients showed significant elevations on Hy and D compared to CP, and EI patients endorsed more somatic symptoms than CP patients. Implications of these findings and future directions will be discussed. INTRODUCTION Electrical injury (EI) is an important though understudied condition in clinical psychology. Practitioners asked to treat this population are presented with a clinical quandary as individuals who have sustained EI often present with complex physical, cognitive, and emotional sequelae (Duff & McCaffrey, 2001; Heilbronner & Pliskin, 1999; Kelley et al., 1994; Pliskin, Capelli-Schellpfeffer, Law, Malina, Address correspondence to: Neil Pliskin, PhD, ABPP, University of Illinois at Chicago, Department of Psychiatry, 912 S. Wood St. (MC 913), Chicago, IL 60612 7327, USA. E-mail: NPliskin@uic.edu Accepted for publication: September 18, 2006. First published online: December 27, 2006. # 2006 Psychology Press, an imprint of the Taylor & Francis group, an Informa business

MMPI-2 PATTERNS IN ELECTRICAL INJURY 99 Kelley, & Lee, 1998; Pliskin et al., 1999; Pliskin, Meyer, Dolske, Heilbronner, Kelley, & Lee, 1994; Primeau, Engelstatter, & Bares, 1995), yet there are no clear guidelines or standards for the psychological assessment or treatment of such individuals. The neurologic and physical complaints in EI can be heterogeneous, depending on the mechanism and severity of injury. They can include, but are not limited to, burns, loss of consciousness, seizures, headaches, parasthesias, sensorimotor loss, chronic pain, and paralysis (Barrash, Kealey, & Janus, 1996; Grube & Heimbach, 1994; Hooshmand, Radfar, & Beckner, 1989; Janus & Barrash, 1996). Cognitive sequelae measured by neuropsychological testing include deficits in memory, attention, and concentration, and slowed mental processing speed (Ammar et al., 2003; Crews, Barth, Brelsford, Francis, & McArdle, 1997; Hopewell, 1983; Martin, Salvatore, & Johnstone, 2003; Miller, 1993; Pliskin et al., 2006, 1998; Ramati, Kelley, Wicklund, Lee, & Pliskin, 2006). Studies have also demonstrated significant psychiatric comorbidity in EI, including depression, posttraumatic stress disorder, anxiety, and somatic preoccupation (Daniel, Haban, Hutcherson, Bolter, & Long, 1985; Kelley et al., 1994; Kelley, Tkachenko, Pliskin, Fink, & Lee, 1999; Ramati et al., 2006). Over the course of the past 20 years, descriptive data on the psychological functioning of EI have been limited to case studies or small samples of EI patients primarily utilizing the Minnesota Multiphasic Personality Inventory (MMPI) (Daniel et al., 1985; Kelley et al., 1994; Mancusi-Ungaro, Tarbox, & Wainwright, 1986). In an examination of MMPI profiles in 11 EI patients with high-voltage injuries, Daniel and colleagues (1985) demonstrated elevations on scales Hs, D, Hy, Pt, and Sc. These results were replicated by Pliskin et al. (1993) who reported profiles suggestive of difficulty with emotional adjustment consisting of elevations on scales Hs, D, Pt, and Sc in a group of 12 EI patients. Some research suggests that these elevations may be related to the neurologic sequelae of the injury, as the same patterns of clinical scale elevations have also been demonstrated in populations of patients with primary neurologic dysfunction (Alfano, Finlayson, Stearns, & Neilson, 1990). Yet, electrical injury is a very unusual and distinctive injury experience. We posit that attributing all after-effects simply to the neurological sequelae of the injury is superficial. We are interested in also determining if a unique profile of psychological distress might also be associated with this type of injury. Further study is needed to determine if the MMPI-2 is sensitive enough to provide such a profile. The purpose of the present study was to investigate whether or not a unique cluster of psychological symptoms associated with EI can be detected with traditional instruments of emotional functioning, such as the Minnesota Multiphasic Personality Inventory 2nd edition (MMPI-2) (Butcher, Dahlstrom, Graham, Tellegan, & Kaemmer, 1989). Specifically, we examine: (a) whether individuals with EI demonstrate MMPI-2 profiles suggestive of psychological distress; (b) whether patterns of MMPI-2 profiles in EI are influenced by injury parameters such as acute (< 3 months post-injury) versus post-acute (> 3 months) injury status, loss of consciousness (LOC), low (< 1000 volts) versus high (> 1000 volts) voltage injuries, or extra diagnostic factors such as litigation status; and (c) whether the MMPI-2 profile demonstrated in EI is unique to this population or consistent with other forms of trauma such as mild traumatic brain injury or individuals experiencing chronic pain.

100 A. H. WICKLUND ET AL. METHOD Participants Electrical injury group. Participants in the cohort were 79 EI patients with archival MMPI-2 data selected from a larger sample of EI individuals treated by the Chicago Electrical Trauma Research Program (ETP). EI participants received emergency and acute care services at the University of Chicago Hospitals and the University of Illinois-Chicago Medical Center, or were referred to the program for post-acute evaluations and treatment. The source of electrical injury was primarily domestic and commercial power sources. Injury due to lightning strike (n ¼ 4) and cases in which head injury occurred secondary to EI (n ¼ 5) were excluded from the analyses. Any individual who did not pass symptom validity testing or who was diagnosed with malingering or conversion disorder was also excluded. Pending litigation status was not an exclusionary criterion. The EI patients were predominantly male (83.5%) and the group as a whole ranged in age from 20 to 59 years (M ¼ 38.4, SD ¼ 9.2), with an average of 12.8 years of education (range 7 18) (Table 1). The average length of time between injury and neuropsychological examination by the ETP was 21.0 months (range 0 163 months). A total of 30% were classified in the acute phase of injury (i.e. less than 3 months since injury) with 70.1% in the post-acute phase (i.e. greater than 3 months). Injuries resulting from low-voltage electrical current (< 1000 volts) occurred in 54.7% of the patients, the remaining 45.3% experienced high-voltage injuries ( >1000 volts). A total of 32% reported loss of consciousness (LOC), 64.6% indicated no LOC at the time of injury, and 3.8% had no documentation on whether they sustained LOC. Finally, 69.9% of the EI patients were involved in injury-related litigation at the time of their evaluation. The injury parameters are summarized in Table 2. Comparison group 1: Traumatic brain injury. Two additional patient populations were incorporated into the study as a comparison sample. The first group consisted of 19 individuals who had sustained a mild traumatic brain injury (TBI) (Table 1). Participants were included in the study if the mild nature of their injury could be confirmed by: (1) review of medical records; (2) patient report of the accident; (3) symptoms of post concussive syndrome; and, if available, (4) LOC determined by Glascow Coma Scale Score (Teasdale & Jennett, 1984). Injury Table 1 Patient demographics EI (n ¼ 79) TBI (n ¼ 19) CP (n ¼ 21) Age M 38.4 37.3 39.7 SD 9.2 13.0 13.8 Education M 12.8 14.3 16.0 SD 2.0 2.4 3.2 Gender (male) 83.5% 42.1% 47.6% Significant differences in education (p <.05), with EI < CP or TBI.

MMPI-2 PATTERNS IN ELECTRICAL INJURY 101 Table 2 EI and TBI injury variables EI TBI N % N % Loss of consciousness Yes 25 31.6 8 42.1 No 51 64.6 9 47.4 Time since injury Acute (<3 months) 23 29.9 4 21.1 Post-acute ( >3 months) 54 70.1 15 78.9 Voltage Low (<1000 volts) 41 54.7 High (>1000 volts) 34 45.3 Litigation Yes 51 69.9 18 94.7 No 22 27.8 1 5.3 variables for the TBI group are detailed in Table 2. Of the individuals with TBI, 95% were seeking or had sought litigation related to their injury. As such, all were screened for malingering and symptom validity. Only those TBI participants who passed symptom validity testing and had no diagnosis of conversion disorder or malingering were included in the study. Electrical injury was an exclusion criterion for this cohort; no TBI participants had sustained an electrical injury. Comparison group 2: Chronic pain patients. The second comparison group consisted of 21 individuals with chronic pain (CP) (Table 1) who met DSM-IV criteria for a diagnosis of pain disorder. Individuals were required to have a chronic pain rating, over the past 6 months, of at least 4 on a 10-point Likert-style pain scale (10 ¼ excruciating pain); however, pain related to central nervous system damage or disease was an exclusionary criterion. CP patients had no history of psychotic spectrum disorders, head injury, electrical injury, or substance abuse. CP patients were also screened for malingering. Only CP patients who passed symptom validity tests were included in the study. No CP patients were in pending litigation, and one had litigated in the past. Of the CP patients, 57% were working at the time of assessment, 13% were receiving disability or Social Security compensation and 7% workman s compensation, and there was no information on the work status of 7 of the patients. Measure Minnesota Multiphasic Personality Inventory 2nd Edition (MMPI-2; Bucher et al., 1989). Data on our primary measure, the MMPI-2, were drawn from archival sources. All participants had been individually administered the standard 567-item MMPI-2 as part of a comprehensive neuropsychological evaluation. The MMPI-2 is an empirically derived test of adult psychopathology. Items are rated true=false, and this test yields scales of clinical symptomatology that assess various aspects of psychopathology and emotional adjustment. These include: Scale 1:

102 A. H. WICKLUND ET AL. Hypochondriasis (Hs); Scale 2: Depression (D); Scale 3: Hysteria (Hy); Scale 4: Psychopathic Deviance (Pd); Scale 5: Masculinity Femininity, (Mf); Scale 6: Paranoia (Pa); Scale 7: Psychasthenia (Pt); Scale 8: Schizophrenia, (Sc); Scale 9: Mania (Ma); Scale 10: Social Introversion (Si). In addition, the MMPI-2 features primary validity scales that include the Lie (L) Scale, which is designed to measure deliberate or unsophisticated attempts to portray oneself in an unrealistically favorable manner, the Infrequency (F) Scale, an index of one s approach to test taking and a measure of deviant or atypical responding, and the Correction (K) scale, which measures defensiveness in response style (Graham, 2000). Additional measures of validity include the calculation of VRIN (Variable Response Inconsistency) and TRIN (True Response Inconsistency), which aid in the interpretation of the clinical scales as these validity measures detect response bias and random response patterns. Finally, the FBS, or Fake Bad Scale, is an additional measure of validity that helps to assess intentional exaggeration of negative or pathological symptoms. In our sample, all MMPI-2 raw scores were converted to T scores with K correction. The profiles were considered valid based on the following criteria (Graham, 1993): (a) Lie (L) scale T score < 65; (b) Infrequency (F) scale T score < 100; (c) Correction (K) scale T score < 65; (d) VRIN T score < 80; (e) TRIN T score < 80; and (f) a score on the Fake Bad Scale (FBS); (Lees-Haley, English, & Glenn, 1991) of < 30. Given the retrospective nature of the study, original protocols were not available for all participants. Supplemental information, including scales such as FBS, was ascertained for 76.5% of the participants. Using Graham s (1993) criteria for response validity, we excluded 35 EI cases, six cases from the pain control group, and three TBI cases. This resulted in the following final Ns for each group: Electrical Injury, n ¼ 79; Traumatic Brain Injury, n ¼ 19; Chronic Pain, n ¼ 21. Overview of Data Analysis We conducted a series of preliminary comparison and descriptive statistics prior to the commencement of formal analyses that explored group differences on the MMPI-2 clinical scales. Preliminary comparison of the groups revealed that there were no statistically significant differences in demographic variables or injury parameters (EI group only) between those included and excluded from the study. Next, descriptive statistics were calculated for the validity scales and 10 standard clinical scales for the EI group. On scales 1 10, T scores of greater than or equal to 65 were considered clinical elevations. To examine whether the MMPI-2 profiles differed in EI by specific injury variables, effect sizes (Cohen s d) were calculated for parameters of acute vs post-acute stage of injury, high vs low voltage, LOC, and litigation status, on scales with significant clinical scale elevations. Finally, additional analyses included a one-way analysis of variance (ANOVA) comparing litigating and non-litigating EI participants scores on the FBS scale. A series of one-way ANOVAs were conducted to examine potential group (EI, TBI, and CP) differences in demographics (i.e., age and education). Scheffe s posthoc tests were used in follow-up comparisons that examined group differences. Multivariate Analyses of Covariance (MANCOVAs) in which education was entered

MMPI-2 PATTERNS IN ELECTRICAL INJURY 103 Table 3 Mean MMPI-2 profile in electrical injury patients MMPI-2 scales Mean T-score SD L 54 8 F 53 12 K 50 10 VRIN 52 9 TRIN 56 6 Hs 71 14 D 64 15 Hy 70 17 Pd 55 11 Mf 46 9 Pa 55 14 Pt 61 13 Sc 61 16 Ma 52 11 Si 53 12 Italic values represent significant and nearly significant clinical scale elevations. as a covariate assessed potential group differences on the MMPI-2 validity scales (L, F, and K), and the MMPI-2 clinical scales. Follow-up univariate ANOVAs (including Scheffe s post hoc comparison tests) were conducted to examine significant interaction effects. Cohen s d was calculated for effect size comparisons between EI and TBI and EI and CP on the validity and clinical scales. RESULTS MMPI-2 Clinical Profile of EI Patients Table 3 and Figure 1 present the mean MMPI-2 profile for the EI group. Clinical scale elevations (scale value 65) were found on the Hs and Hy scales. Scores on the D scale nearly reached clinical elevation (T score for Scale D, M ¼ 64.3). Our results also indicated that time since injury predicted differences in the pattern of scale elevations (Table 4). Individuals in the post-acute injury phase showed greater scale elevations, demonstrated by large effect sizes, for the Hs (d ¼.95), and Hy (d ¼ 1.15) scales, and a medium effect size on the D (d ¼.67) scale. Only small effect sizes (d range ¼.0 to.4), indicating little to no difference in scale elevations, were apparent for parameters of voltage, LOC, and litigation status. There was no statistically significant difference in scores on FBS between litigating and nonlitigating EI subjects. Comparison of EI, TBI, and CP Groups No significant differences in age emerged between groups. However, there was a significant difference in educational level (p <.05), with EI patients having fewer

104 A. H. WICKLUND ET AL. Figure 1 Mean MMPI-2 profile in electrical injury. years of education than either the CP (p <.05) or TBI (p <.05) groups. As such, education was entered as a covariate in the multivariate analysis of variance examining the MMPI-2 profiles across the three patient groups. Table 5 and Figure 2 summarize the mean MMPI-2 profiles for the three patient groups. The results from the multivariate analysis for the validity scales revealed a significant interaction between education and the validity scales, F(2, 114) ¼ 1.0, p <.01, and an interaction for the validity scales and patient group, F(4, 230) ¼ 2.4, p <.05. Exploratory follow-up analyses on this trend demonstrated that this finding was due to a significant difference in the mean score on the L scale, with CP patients demonstrating a lower scale score than either the EI (p <.05) or TBI (p <.05) group. The EI and TBI groups did not differ from one another. It Table 4 MMPI-2 scales 1 (HS), 2 (D), and 3 (Hy): Mean scores by injury parameter in EI Parameter HS D HY No LOC M 70 64 69 SD 14 14 16 LOC M 72 63 71 SD 14 14 17 Acute (<3 months) M 62 58 58 SD 14 14 14 Post Acute (>3 months) M 75 67 75 SD 12 14 15 Low Voltage (<1000 v) M 72 64 74 SD 13 16 16 High Voltage (>1000 v)m 70 65 67 SD 14 13 16 Litigation Yes M 71 64 71 SD 13 13 16 Litigation No M 69 66 70 SD 16 19 19 Italic values represent significant and clinical scale elevations.

MMPI-2 PATTERNS IN ELECTRICAL INJURY 105 Table 5 MMPI-2 mean scale scores and effect sizes for EI, TBI, and CP groups MMPI-2 scale EI (n ¼ 79) TBI (n ¼ 19) CP (n ¼ 21) d EI vs. TBI dei vs. CP L M 54 56 47.33.81 SD 8 8 7 F M 53 62 61.72.54 SD 12 14 19 K M 50 52 48.15.22 SD 10 11 10 VRIN M 52 46 53.40.10 SD 9 7 11 TRIN M 56 57 58.10.37 SD 6 10 7 Hs M 71 70 61.08.74 SD 14 11 13 D M 64 72 60.49.32 SD 15 16 16 Hy M 70 72 59.10.66 SD 17 14 17 Pd M 55 60 64.41.71 SD 11 13 17 Mf M 46 48 48.18.22 SD 9 8 12 Pa M 55 63 56.56.10 SD 14 16 16 Pt M 61 66 62.43.07 SD 13 10 18 Sc M 61 71 63.66.15 SD 16 13 16 Ma M 52 57 56.43.42 SD 11 16 9 Si M 53 54 52.10.07 SD 12 11 13 Bold italic values represent significant and nearly significant clinical scale elevations. is important to note that the mean values on the L scale for all groups were within normal limits for what would be considered a valid MMPI-2 profile. There was no significant group difference in scores on the VRIN and TRIN scales. The MANCOVA of the 10 clinical scales demonstrated a main effect of the mean scale score, F(9, 107) ¼ 2.6, p <.05, a significant effect of education as a covariate, F(9, 107) ¼ 1.9, p <.05, and an interaction between the clinical scales and patient group, F(18, 216) ¼ 2.9, p <.05. Thus, when accounting for education, the relative relationship between the clinical scale scores was different across the groups. Follow-up analyses to further explore this interaction demonstrated that EI patients showed higher elevations when compared to CP on scales Hs (p ¼.01) and Hy (p ¼.03), and medium effect sizes were demonstrated for these differences (Hs d ¼.74; Hy d ¼.66). In addition, on scales Hy and D, TBI patients also showed a

106 A. H. WICKLUND ET AL. Figure 2 Mean profile for MMPI-2 validity scales in EI, TBI, and CP groups. Note: EI > CP; #TBI > CP. significantly different mean scale score when compared to CP (p <.05). Chronic pain patients showed a significant elevation on Pd when compared to EI (p ¼.01; d ¼.71). However scores for both groups were below the clinically significant range. By contrast, EI and TBI mean scale scores did not differ significantly on any of the clinical scales. A medium effect size was demonstrated between the difference in scores on the Sc scale (d ¼.66) between the EI and TBI group. Differences in scores on the Pa scale were also moderate (d ¼.56), however, scores for both groups were below the clinically significant threshold. DISCUSSION We assessed personality and emotional functioning (MMPI-2) in a large group of well-characterized patients belonging to one of three diagnostic categories: electrical injury (EI), traumatic brain injury (TBI), and chronic pain (CP). We explored whether a distinctive clinical profile emerged for EI and whether common injury parameters (LOC, time since injury, and voltage) and extra diagnostic factors (litigation status) offered additional predictive value regarding the type or intensity of psychological symptoms reported. Our results suggest that EI patients most common MMPI-2 profile consisted of clinical elevations on the Hs and Hy scales, while elevations on Scale D were nearly in the clinical range. This cluster of scale elevation typically signifies preoccupation of somatic symptoms, depression, and anxiety (Graham, 1993). Despite the heterogeneous pattern of experiences that can occur with electrical injury, our findings robustly document a general picture of significant clinical distress. In addition, our findings also suggest that salient injury parameters can impact patients profile of emotional distress (reflected in MMPI-2 clinical scale elevations). While elevations on Hs and Hy were typically in the clinical range for all EI participants, amplification of these scale elevations as well as the D scale was revealed in EI patients in the post-acute phase of injury. By contrast, intensity of electrical exposure (high vs low voltage) and loss of consciousness, did not predict significant amplification of clinical symptoms, nor did litigation status.

MMPI-2 PATTERNS IN ELECTRICAL INJURY 107 Previous research has described increased emotional difficulties and symptom endorsement in EI patients in the post-acute phase of injury. This has been hypothesized to reflect delayed onset of central nervous system dysfunction or progressive emotional and functional maladjustment following electrical injury associated with limitations in activities of daily living or learning to live with changes in functional ability (cf. Pliskin et al., 1998). The MMPI-2 profile was not distinguishable between groups on the basis of other injury parameters, and clinical elevations were apparent for individuals with both high- and low-voltage injuries and with and without loss of consciousness. However, the literature suggests that there may be differences in the emotional response based on these parameters. For example, lower-voltage injuries tend to be associated with less obvious physical sequelae i.e., invisible injuries (Kelley et al., 1999). It is also possible that emotional distress is actually heightened relative to those EI patients with higher-voltage injuries producing more visible injuries. The impact of litigation may also play a role in the level of emotional distress however, our ability to detect the impact of litigation status on patients clinical profiles is limited because we screened out patients who were determined to be malingering, had a diagnosis of conversion disorder, or those who failed symptom validity tests. In general, the emotional difficulties and somatic concerns reflected in the overall MMPI-2 profile in EI are consistent with findings from the literature reporting these same difficulties on other self-report questionnaires of physical and emotional sequelae following EI (Pliskin et al., 1998). The present investigation is consistent with the findings of other studies that have examined psychological functioning using the MMPI-2 in small groups of EI patients. Daniel and colleagues (1985) reported elevations on Hs, D, Hy, Pt, and Sc in 11 EI participants, all victims of high-voltage injuries. Mancusi-Ungaro et al. (1986) described elevations on scales D, Pd, and Sc in a small group of EI burn patients. A study of subjective psychological functioning in electrical workers demonstrated that electricians tend to avoid articulating their concerns of electrical injury, suggesting that elevations seen on the MMPI-2 may be representative of individuals who are internalizing their feelings or have poor coping mechanisms to deal with the psychological distress associated with the experience of an electrical injury (Tkachenko, Kelley, Pliskin, & Fink, 1999). Although traditional interpretation of elevations on these (Hy, Hs, D) scales suggests somatization as a primary coping mechanism, in the EI and TBI population, this may also be reflective of overt, concomitant neurological symptoms. For example, Alfano and colleagues (1990) showed consistent elevations on Hs, D, Hy, Pt, Sc, and Ma in individuals with primary neurologic disease. After applying a neurocorrection factor (Gass, 1991) to their patient profiles, which took into consideration items reflecting valid neurologic dysfunction, they demonstrated a reduction in the prominence of these clinical scale elevations. Subtle differences in scores on the Sc scale between the EI and TBI groups may also reflect the endorsement of sensory and cognitive changes, which has been shown to result in aboveaverage scores on this scale in individuals with closed head injuries (cf. Graham, 2000). Other studies have demonstrated elevations in Sc in the EI population as well (Daniel et al., 1985; Pliskin et al., 1993). In the present study, scores on the Sc scale approached, but did not reach, clinical significance.

108 A. H. WICKLUND ET AL. However, the somatic aspects of an electrical injury differ in many ways from mild traumatic brain injury. For example, in EI the mechanism of injury can be quite diverse and patients may sustain very painful burns, peripheral nervous system damage, neuropathy, and parasthesias. These symptoms are not typically part of the constellation of symptoms that occur in mild traumatic brain injury. In addition, in the present sample, the EI participants sustained no head injury secondary to the electrical injury. Thus, while the MMPI-2 profiles may be similar, the pathways to these profiles may be quite different. In electrical injury, patients report significant somatic symptomatology (Pliskin et al., 1998) as opposed to somatic amplification, which has been purported to be the basis behind MMPI-2 elevations in mild TBI (Youngjohn, Burrows, & Erdal, 1995). Therefore, the similarity between the profiles may reflect the insensitivity of the MMPI-2 to differentially recognize the uniqueness of the electrical injury and its physical and emotional consequences. The MMPI-2 profiles for EI and CP patients also had considerable overlap. However, EI patients endorsed significantly more somatic complaints. Individuals with EI have reported experiencing physical pain following injury (e.g., parasthesias, muscle spasms, headaches), which raises the question of whether or not preoccupation with pain might mediate more general levels of psychological distress (Pliskin et al., 1998). Historically, research has documented many similarities in the MMPI (and MMPI-2) profiles of acute chronic pain patients (cf. Keller & Butcher, 1991) and the present EI sample. Some studies have shown that elevations of scales Hs, Hy, and D are the most useful at discriminating between chronic pain and control populations, while others have described this as the neurotic triad which only accounts for one type of a multitude of profiles on the MMPI-2 (Riley & Robinson, 1998; Slesinger, Archer, & Duane, 2002). However, in our study, EI patients demonstrated significantly greater elevations on Hy and Hs when compared to the pain group. This may reflect, in part, some anomalies inherent within our CP sample. For instance, individuals in our CP group were considerably more functional than the more homogeneous and acute samples described elsewhere (e.g., Keller & Butcher, 1991). Further, our pain sample may have been quite different than other samples (see Butcher & Keller, 1991) because our participants were solicited for research participation based on a pain criterion and were not actively seeking treatment for pain. Moreover, compensation issues were low in this sample, as most of the CP sample was comprised of police officers who were highly motivated to remain working on the job. Restoration of health and mental health complaints via return to work may have blunted our participants profiles on the MMPI-2, making them appear more atypical than other pain samples. Despite this, given that chronic pain patients in the current sample also have consistently elevated levels of pain and somatic preoccupation, but relatively lower levels of psychological distress, we conclude that pain alone likely does not account for the psychiatric symptoms in EI patients following their injury. Another limitation to our methods involves the use of small comparison groups, which may result in a lack of statistical power and hence a risk of under-detection of actual between-group differences. Future studies designed to replicate the present findings would benefit from larger patient samples. Other future directions include examining the data by applying a neurocorrection factor (Gass, 1991), as has been

MMPI-2 PATTERNS IN ELECTRICAL INJURY 109 done in other medical populations, to help discern the contribution of legitimate somatic symptoms to the profile of psychological stress in EI. Examining profiles in EI patients with and without complaints of chronic pain may also help elucidate the contribution of physical pain to the profile of emotional distress. A primary conclusion of our study is the limited sensitivity of tools like the MMPI-2 to distinguish subtle but important distinctions in psychological adjustment and functioning in individuals with different types of traumatic injury. The current study indicates that the MMPI-2 is useful in delineating the degree of psychological distress and somatic concerns manifested following electrical injury, but not sensitive enough to yield a fully distinctive profile unique to the experience of electrical injury. Moreover, injury parameters such as time since injury may influence the degree of psychological distress, and should be considered in interpretation of the MMPI-2. Thus, in a clinical setting, the MMPI-2 may be useful as part of a comprehensive evaluation of the EI patient, but it should be used cautiously or in conjunction with other clinically relevant information to determine if psychological treatment is warranted. Further, beyond the concern about the utility of the MMPI-2, broad clinical questions about the nature of EI and its psychological sequelae remain open for future research to explore. One major area concerns the etiology and phenomenology of psychological symptoms that follow EI. For example, psychiatric comorbidity following electrical injury is extremely common. In a large group of EI patients studied through an electrical trauma program, 76.0% had been diagnosed with a psychiatric condition, while only 10.0% of EI victims had any history of mental health problems prior to their injury (Ramati et al., 2006). It remains to be determined to what extent this psychiatric comorbidity is a direct neurophysiological effect of the electrical exposure itself or if it reflects post-traumatic psychological adjustment and pain issues. REFERENCES Alfano, D. P., Finlayson, M. A. J., Stearns, G. M., & Neilson, P. M. (1990). The MMPI and neurologic dysfunction: Profile configuration and analysis. The Clinical Neuropsychologist, 4(1), 69 79. Ammar, A. M., Pliskin, N., Fink, J., Peterson, K., Kelley, K. M., Lee, R. et al. (2003). Subjective and objective evidence of impaired learning following electrical injury. Journal of the International Neuropsychological Society, 9(2), 308. Barrash, J., Kealey, G., & Janus, T. (1996). Neurobehavioral sequelae of high voltage electrical injuries: Comparison with traumatic brain injury. Applied Neuropsychology, 3(2), 75 81. Butcher, J. N., Dahlstrom, W. G., Graham, J. R., Tellegan, A., & Kaemmer, B. (1989). Manual for administration and scoring of the MMPI-2. Minneapolis, MN: University of Minnesota Press. Crews, W., Barth, J., Brelsford, T., Francis, J., & McArdle, P. (1997). Neuropsychological dysfunction in severe accidental electrical shock: Two case reports. Applied Neuropsychology, 4, 208 219. Daniel, M., Haban, G. F., Hutcherson, W. L., Bolter, J., & Long, C. (1985). Neuropsychological and emotional consequences of accidental high-voltage electrical shock. International Journal of Clinical Neuropsychiatry, 7(2), 102 106.

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