Detection and diagnosis of malingering in electrical injury

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Archives of Clinical Neuropsychology 20 (2005) 365 373 Detection and diagnosis of malingering in electrical injury Kevin Bianchini a,b, Jeffrey M. Love a,1, Kevin W.

1 Archives of Clinical Neuropsychology 20 (2005) Detection and diagnosis of malingering in electrical injury Kevin Bianchini a,b, Jeffrey M. Love a,1, Kevin W. Greve a,b,, Donald Adams c Abstract a Department of Psychology, University of New Orleans-Lakefront, New Orleans, LA 70148, USA b Jefferson Neurobehavioral Group, USA c Jefferson Neurological Associates, USA Accepted 17 September 2004 This paper sought to demonstrate that diagnosable malingering does occur in Electrical Injury (EI) and examine the relationship of malingering to potential indicators of the presence and severity of neurological injury. Eleven consecutive EI patients seen for neuropsychological evaluation were presented. Over half the patients met the Slick et al. (1999) criteria for at least Probable MND. Most of the MND patients lacked evidence of a biologically meaningful exposure to electrical current. These findings highlight the importance of considering biological markers of neurological injury and of nonneurological factors, including effort/malingering, in the study of the neurocognitive consequences of EI Published by Elsevier Ltd on behalf of National Academy of Neuropsychology. Keywords: Electrical injury; Malingering; Effort testing; Neuropsychological assessment; Brain injury Electrical injury (EI) is a potential source of injury and death and most EI (excluding lightning strike) occur in the workplace (Duff & McCaffrey, 2001; Gourbiere, Corbut, & Bazin, 1994; Heilbronner & Pliskin, 1993). A number of studies have demonstrated cognitive performance deficits in EI patients and the observed patterns of cognitive symptoms and neurobehavioral deficits are very similar to those seen in traumatic brain injury (TBI; see Duff & McCaffrey, 2001, for an excellent review). However, in contrast to the recovery pattern in TBI, there has been speculation that EI may result in persistent, progressive, and/or delayed-onset neurocognitive and emotional effects (e.g., Farrell & Starr, Corresponding author. Tel.: ; fax: address: kgreve@uno.edu (K.W. Greve). 1 Jeffrey M. Love is now at Pennsylvania State University /$ see front matter 2004 Published by Elsevier Ltd on behalf of National Academy of Neuropsychology. doi: /j.acn

2 366 K. Bianchini et al. / Archives of Clinical Neuropsychology 20 (2005) ; Barrash, Kealey, & Janus, 1996; Pliskin et al., 1994, 1998, 1999). Many EI patients reporting neurocognitive impairment have suffered clearly demonstrable neurological injuries that one would expect to produce significant neurocognitive sequelae (e.g., coma, focal neurological signs; Hopewell, 1983). However, the neuropathology in other cases is more ambiguous. Therefore, when attempting to attribute cognitive deficits to the direct neurological effects of an electrical exposure, it would be helpful to have indicators that the body had actually absorbed a sufficient amount of electrical energy to produce injury. Entry and exit (EE) wounds are a certain indication that the body has conducted a significant amount of electrical current because they result from the conversion of the electrical energy into thermal energy due to the resistance of pathway tissues (e.g., skin, hair, bone; Solem, Fischer, & Strate, 1977). In the only study of the relationship of EE wounds to cognition, Grossman, Tempereau, Brones, Kulber, & Pembrook (1993) found a higher incidence of neurobehavioral problems in patients with EE wounds versus those without. While EE wounds are an indication that the body has absorbed sufficient electricity to cause injury, their presence does not necessarily indicate that the electrical exposure has caused nervous system injury. At the same time, the absence of EE wounds does not necessarily mean that EI has not occurred. Therefore, other indicators of acute central nervous system dysfunction such as those used to grade TBI severity (e.g., Glasgow Coma Scale score, length of coma and/or post-traumatic amnesia, structural damage to the nervous system) may also be helpful. Unfortunately, these have not been studied systematically in EI. The acute presence of burns, altered consciousness, focal neurological signs, and/or structural pathology would arguably indicate that exposure to electrical current has led to an internal dose sufficient to alter physiological function and damage neurological systems. However, like many mild TBI patients, EI patients reporting neurocognitive sequelae often have little or no objective evidence of acute injury (i.e., they have more ambiguous injuries). In the absence of such evidence, it is reasonable to be very cautious in attributing observed or reported cognitive deficits to neurological damage caused by electrical current, because, just like in TBI (Binder, 1997; Binder & Rohling, 1993), non-neurological factors including personality traits, stress, motivation, effort, and financial incentive likely influence the report of cognitive deficits in EI. In fact, a high proportion of electrical injuries do occur in a compensable context (Cherington, 1995; Duff & McCaffrey, 2001; Heilbronner & Pliskin, 1993). Mittenberg, Patton, Canyock, and Condit (2002) suggest that the baserate of malingering is as high as 40 percent in compensation seeking samples in general and 25 percent in EI in particular. However, published research on the cognitive and emotional effects of EI has not assessed, much less controlled for, exaggeration/malingering nor have the implications of potentially including malingerers in research samples been addressed. This paper presents a series of EI patients who have been carefully examined for malingering and in whom we have applied the criteria of Slick, Sherman, and Iverson (1999) for Malingering Neurocognitive Dysfunction (MND). The purpose of this paper is twofold: (1) demonstrate that malingering does occur in EI and can be diagnosed with the Slick et al. criteria; and, (2) examine the relationship of malingering to

3 K. Bianchini et al. / Archives of Clinical Neuropsychology 20 (2005) potential indicators of neurological injury so as to begin to understand their relevance in EI. 1. Method 1.1. Patients The cases are 11 consecutive EI referrals for neuropsychological evaluation to a single group practice in a Southeastern state between 1995 and Injury and demographic characteristics are presented in Table 1. Cases 1, 3, and 4 had repeat evaluations resulting in 14 sets of data. All patients (except case 10) had incentive in the form of a workers compensation claim. Case 10 was involved in personal injury litigation Malingering diagnosis Patients were categorized on the basis of the Slick et al. (1999) criteria for MND. Using this system, all diagnoses of malingering require the presence of external incentive (Criterion A) plus evidence of exaggeration from neuropsychological testing (Criterion B) and/or selfreport (Criterion C). A statistically below chance performance on a forced-choice symptom validity test alone is sufficient for a diagnosis of Definite MND. A Probable MND diagnosis requires: (1) two types of Criterion B evidence, or (2) one type of Criterion B evidence and one or more types of Criterion C evidence. Criterion C evidence is not sufficient for an MND diagnosis in the absence of Criterion B evidence. Criterion D requires that other factors not Table 1 Demographic data and evidence of injury Demographics Injury characteristics Case Age ED E/E LOC PTA TBI Scan Arrest Seizr 2nd Eval y y y y y y n y y y y n y n n n n n n n y y y y n n n y y n n n n n n n n y n n n n n y y y y n n n y y n n n n y y y n n y n n n n n n n n n n y n n n y n n Note. Age is age at exam; all patients were male; y: positive for the characteristic; n: negative for the characteristic; : no information on the characteristic or test not done; E/E: entry/exit wound; LOC: loss of consciousness; PTA: post-traumatic amnesia; TBI: traumatic brain injury; Imaging: diagnostic radiology; Arrest: cardio-pulmonary arrest; Seizr: seizure.

4 368 K. Bianchini et al. / Archives of Clinical Neuropsychology 20 (2005) fully account for the positive B and C criteria and was met in our cases. The reader is referred to Slick et al. (1999) or Millis (2004) for details of these diagnostic criteria. 2. Results Table 2 presents the raw data from the various psychometric indicators of malingering obtained during these evaluations and the MND findings for these cases. Given the 14 sets of evaluation data, five cases did not meet Slick et al. (1999) criteria MND, eight were diagnosed as Probable MND, and one met criteria for Definite MND. Only Case 3 had a different MND diagnosis on the two evaluations (Possible and Probable, respectively). The relationship between injury markers and malingering diagnosis was examined using Fisher s Exact Test (Agresti, 1992), a chi-square test for small samples. Cohen s d was used as the index of effect size (Cohen, 1988). The results are presented in Table 3. Statistically significant associations and large effect sizes were observed for EE and TBI, meaning that the absence of either of EE or TBI was associated with a higher probability of malingering. Though not statistically significant, PTA and the composite marker (positive on any two of EE, TBI, or scan) showed a large effect size. These large effect sizes raise the possibility of a meaningful association that is worthy of further investigation. Overall, most of the patients who were negative for a given marker met criteria for MND. At the same time, some patients who were positive on one or more of the markers were diagnosed as malingering. An MND diagnosis in some patients with positive markers is consistent with the idea that some persons with objectively documented neuropathology can and do malinger (Bianchini, Greve, & Love, 2003). 3. Discussion This study demonstrates that malingering is a factor that must be considered when attempting to understand the cognitive and emotional effects of EI. It also indicates that while persons with demonstrable neurologic insult following EI do malinger, persons meeting criteria for malingering are more likely to have suffered a more ambiguous neurological injury. It is important to note that our findings related to objective severity of EI are based on a limited sample which should be replicated in larger samples. However, it is known that evidence of malingering is more common among TBI patients with more ambiguous injuries (i.e., mild TBI; see, for example, Binder & Willis, 1991). Our findings do not provide any evidence that EI is different than TBI in this regard. The study of markers associated with acute neurological injury in EI may be valuable independent of their relationship to malingering. Their use in neuropsychological studies of EI may help insure that such studies include patients who have suffered a neurologic injury. This does not mean that patients without such markers have not suffered a meaningful neurological injury, but studying those with ambiguous injuries separately would help address potential confounding factors. The demonstration of malingering in this sample has important implications for the study of EI. Most electrical injuries occur in a potentially compensable context. Therefore, the failure to address issues related to motivation and effort (as well as other non-neurological factors

5 Table 2 Psychometric indicators of negative response bias Specialized tests Derived indicators MMPI-2 Number of MND criteria met Case PDRT TOMM RDS DFA Millis F Fp FBS B criteria C criteria MND Dx 1a 7.95 n/a 1 0 None 1b 22/19/ None 2 34/29/63 50/ b,c 0 1 None 3a 18 c /18 c /36 c 5 c 2.81 c 1.32 c b,c 2 1 Probable 3b 28 c /21 c 6 c 1.45 c 3.00 c Probable 4a 32/23/ b,c 0 1 None 4b 17 c /19/36 46/ c 1 1 Probable 5 12 c /11 a /23 a 20 c /18 c 4 c.61 c 1.31 c 82 c b,c 4 a 2 Definite 6 29/28/57 49/ None 7 24/28/52 5 c.21 c 2.08 c 89 c 84 c Probable 8 19/17 c /36 c 6 c 1.83 c n/a 98 c b,c 1 1 Probable 9 23/18/41 37 c /35 c 7.68 c c Probable 10 25/25/ Probable 11 21/21/42 46/ c Probable Note. DFA: Mittenberg formula for Wechsler Adult Intelligence Scale (Mittenberg et al., 2002); F: MMPI- 2Infrequency scale T-score; FBS: Fake Bad Scale raw score (Lees-Haley, English, & Glenn, 1991); Millis: Millis formula for California Verbal Learning Test (Millis, Putnam, Adams, & Ricker, 1995); PDRT: Portland Digit Recognition Test (Easy/Hard/Total; Binder, 1997); RDS: reliable digit span (Greiffenstein, Baker, & Gola, 1994); TOMM: Test of Memory Malingering (Trial 2/Retention; Tombaugh, 1996). a Force-choice symptom validity test score is significantly below chance. b Indicates that MMPI-2 Hypochondriasis and Hysteria were 80 T (FBS complex positive; Larrabee, 1998). c Score is in the range consistent with negative response bias. K. Bianchini et al. / Archives of Clinical Neuropsychology 20 (2005) Downloaded from at Pennsylvania State University on March 5, 2016

6 370 K. Bianchini et al. / Archives of Clinical Neuropsychology 20 (2005) Table 3 Relationship between injury characteristics and malingering status MND status Pos Neg X 2 p d Entry/exit wounds Pos Neg 6 0 Post-traumatic amnesia Pos ns 1.15 Neg 3 0 Loss of consciousness Pos ns Neg 2 0 Traumatic brain injury Pos Neg 9 2 Brain scan Pos ns Neg 8 3 Cardio-pulmonary arrest Pos ns Neg 4 2 Acute seizure Pos ns Neg 8 4 Composite marker a Pos ns 1.21 Neg 8 2 a A positive finding on any two of entry/exit wound, traumatic brain injury, and imaging, is a positive on the composite marker. such as depression, anxiety, and somatization) in the empirical study of EI may result in the inaccurate characterization of the nature, severity, and course of any neurocognitive and other (e.g., emotional) deficits attributed to the injury. Because these empirical studies may be used to guide clinical decision-making and inform legal proceedings and decisions about civil damage settlements, their accuracy is practically important. In short, competent clinical practice and good science demand that potential malingering as well as other non-neurological sources of impaired test performance be addressed in a sophisticated and scientifically supportable manner. The consequences of inadequately addressing these issues is particularly notable in discussions of course and prognosis following EI. Unlike TBI, very little is known about the course of recovery from EI. Jafari, Couratier, and Camu (2001) recently reported cases of progressive peripheral neuropathology associated with EI. Pliskin et al. (1999) suggested that EI may produce a progressive neurocognitive and/or emotional syndrome. However, his suggestion

7 K. Bianchini et al. / Archives of Clinical Neuropsychology 20 (2005) was based on data from a cross-sectional symptom survey of predominantly litigating (57% of the acute group, 90% of the chronic group) EI patients with ambiguous injuries in whom no malingering tests or other symptom validity checks were used. Duff and McCaffrey (2001) expressed concern about the validity of delayed and progressive sequelae. Such sequelae secondary to acute neurological injury are a relatively rare phenomenon (e.g., the delayed neurological sequelae of carbon monoxide poisoning; e.g., Duenas-Laita et al., 2001). Thus, given the methodological limitations of existing psychological studies, reports of persistent, progressive, and/or delayed-onset higher order cognitive deficits are not convincing and it is premature to argue that such a rare neurological phenomenon is attributable to the direct neurological effects of EI. More parsimonious and plausible explanations should be considered and addressed; in the context of litigation, malingering should be among those potential explanations. The current state of research in EI argues for caution in the clinical diagnosis of malingering in EI precisely because the pathological mechanisms, neurobehavioral and neurocognitive effects, and manifestations of malingering are not as well understood as in other forms of neuropathology (e.g. TBI). It must also be remembered that malingering detection techniques are not perfect and should not be used in isolation for the clinical diagnosis of malingering. The Slick et al. criteria represent a comprehensive system for integrating diverse clinical information including data from psychometric detection procedures. Application of the Slick et al. criteria depends, in part, on reliable empirical information about the true neurocognitive effects of a given disease or injury in order to establish inconsistencies. Since the literature on the neurocognitive effects of EI is often inconsistent and can be equivocal, some of the Slick et al. criteria cannot be used. However, as more reliable data on the cognitive effects of electrical injuries are obtained, more of the individual Slick et al. criteria can be applied. Nonetheless, even in the absence of such knowledge, some Slick et al. criteria can still be utilized and MND can therefore be diagnosed in EI. However, because fewer criteria are applicable in less wellstudied forms of neuropathology, diagnoses based on the Slick system are inherently more conservative and cautious. 4. Conclusions This paper demonstrated that malingering of neurocognitive deficits does occur in electrical injury and supports the application of the application of the Slick et al. criteria for the diagnosis of Malingered Neurocognitive Dysfunction. The Slick et al. criteria represent a systematic, comprehensive, integrated, research-based approach to the diagnosis of malingering. Moreover, these criteria provide a method of classifying electrical injury patients so as to facilitate the empirical study of malingering in this population. While the present paper provides important information on detecting and diagnosing malingering in electrical injury, many issues require further study. In particular, further research is required to provide a clearer understanding of the role of biological markers in EI in relation to both outcome and malingering. Secondly, examination of the course and outcome regarding the neurocognitive consequences of electrical injury using longitudinal designs with appropriate consideration of non-neurological factors including malingering is also something worthy of investigation.

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