Jordan P. Harp

Pb Neurotoxicity: Neuropsychological Effects of Lead Toxicity

Neurotoxicity is a term used to describe neurophysiological changes caused by exposure to toxic agents. Such exposure can result in neurocognitive symptoms and/or psychiatric disturbances. Common toxic agents include heavy metals, drugs, organophosphates, bacterial, and animal neurotoxins. Among heavy metal exposures, lead exposure is one of the most common exposures that can lead to significant neuropsychological and functional decline in humans. In this review, neurotoxic lead exposures pathophysiology, etiology, and epidemiology are explored. In addition, commonly associated neuropsychological difficulties in intelligence, memory, executive functioning, attention, processing speed, language, visuospatial skills, motor skills, and affect/mood are explored.

Using Symptom Validity Tests to Detect Malingered ADHD in College Students

Recently there has been growing concern that college students may feign symptoms of ADHD in order to obtain academic accommodations and stimulant medication. Unfortunately research has only begun to validate detection tools for malingered ADHD. The present study cross-validated the results of Sollman, Ranseen, and Berry (2010) on the efficacy of several symptom validity tests for detection of simulated ADHD among college students. Undergraduates with a history of diagnosed ADHD were randomly assigned either to respond honestly or exaggerate symptoms, and were compared to undergraduates with no history of ADHD or other psychiatric disorders who were also randomly assigned to respond honestly or feign symptoms of ADHD. Similar to Sollman et al. (2010) and other recent research on feigned ADHD, several symptom validity tests, including the Test of Memory Malingering (TOMM), Letter Memory Test (LMT), Digit Memory Test (DMT), Nonverbal Medical Symptom Validity Test (NV-MSVT), and the b Test were reasonably successful at discriminating feigned and genuine ADHD. When considered as a group, the criterion of failure of 2 or more of these SVTs had a sensitivity of. 475 and a specificity of 1.00.

The Effects of Mild Traumatic Brain Injury, Post-Traumatic Stress Disorder, and Combined Mild Traumatic Brain Injury/Post-Traumatic Stress Disorder on Returning Veterans.

United States veterans of the Iraqi (Operation Iraqi Freedom [OIF]) and Afghanistan (Operation Enduring Freedom [OEF]) conflicts have frequently returned from deployment after sustaining mild traumatic brain injury (mTBI) and enduring stressful events resulting in post-traumatic stress disorder (PTSD). A large number of returning service members have been diagnosed with both a history of mTBI and current PTSD. Substantial literature exists on the neuropsychological factors associated with mTBI and PTSD occurring separately; far less research has explored the combined effects of PTSD and mTBI. The current study employed neuropsychological and psychological measures in a sample of 251 OIF/OEF veterans to determine whether participants with a history of mTBI and current PTSD (mTBI+PTSD) have poorer cognitive and psychological outcomes than participants with mTBI only (mTBI-o), PTSD only (PTSD-o), or veteran controls (VC), when groups are comparable on intelligence quotient, education, and age. The mTBI+PTSD group performed more poorly than VC, mTBI-o, and PTSD-o groups on several neuropsychological measures. Effect size comparisons suggest small deleterious effects for mTBI-o on measures of processing speed and visual attention and small effects for PTSD-o on measures of verbal memory, with moderate effects for mTBI+PTSD on the same variables. Additionally, the mTBI+PTSD group was significantly more psychologically distressed than the PTSD-o group, and PTSD-o group was more distressed than VC and mTBI-o groups. These findings suggest that veterans with mTBI+PTSD perform significantly lower on neuropsychological and psychiatric measures than veterans with mTBI-o or PTSD-o. The results also raise the possibility of mild but persisting cognitive changes following mTBI sustained during deployment.

Accuracy of MMPI–2–RF Validity Scales for Identifying Feigned PTSD Symptoms, Random Responding, and Genuine PTSD

The Minnesota Multiphasic Personality Inventory–2–RF (MMPI–2–RF) validity scales were evaluated to determine accuracy when differentiating honest responding, random responding, genuine posttraumatic stress disorder (PTSD), and feigned PTSD. Undergraduate students (n = 109), screened for PTSD, were randomly assigned to 1 of 4 instructional groups: honest, feign PTSD, half random, and full random. Archival data provided clinical MMPI–2–RF profiles consisting of 31 veterans diagnosed with PTSD. Veterans were diagnosed with PTSD using a structured interview and had passed a structured interview for malingering. Validity scales working as a group had correct classification rates of honest (96.6%), full random (88.9%), genuine PTSD (80.7%), fake PTSD (73.1%), and half random (44.4%). Results were fairly supportive of the scales’ ability to discriminate feigning and full random responding from honest responding of normal students as well as veterans with PTSD. However, the RF validity scales do not appear to be as effective in detecting partially random responding.

Detection of Malingered Mental Retardation

In a cross-validation of results from L. O. Graue et al. (2007), standard psychological assessment instruments, as well as tests of neurocognitive and psychiatric feigning, were administered under standard instructions to 24 participants diagnosed with mild mental retardation (MR) and 10 demographically matched community volunteers (CVH). A 2nd group of 25 community volunteers was instructed to malinger MR (CVM) during testing. CVM participants obtained Wechsler Adult Intelligence Scale (3rd ed.; D. Wechsler, 1997) Full Scale Intelligence Quotient scores that were significantly lower than the demographically similar CVH group but comparable to the MR group, suggesting that CVM subjects feigned cognitive impairment. On the basis of standard cutting scores from test manuals or published articles, of the 11 feigning measures administered, only the Test of Memory Malingering (TOMM; T. N. Tombaugh, 1996) retention trial had a specificity rate >.90 in the MR group. However, the 2nd learning trial of the TOMM, as well as a short form of the Digit Memory Test (T. J. Guilmette, K. J. Hart, A. J. Guiliano, & B. E. Leininger, 1994), approached this level of specificity, with both at .88. These results raise concerns about the specificity rates at recommended cutting scores of commonly used feigning tests in defendants with MR.

Neuropsychological Effects of Self-Reported Deployment-Related Mild TBI and Current PTSD in OIF/OEF Veterans

Current combat veterans are exposed to many incidents that may result in mild traumatic brain injury (mTBI) and/or posttraumatic stress disorder (PTSD). While there is literature on the neuropsychological consequences of PTSD only (PTSD-o) and mTBI alone (mTBI-o), less has been done to explore their combined (mTBI+PTSD) effect. The goal of this study was to determine whether Operation Iraqi Freedom (OIF) and Operation Enduring Freedom (OEF) veterans with mTBI+PTSD have poorer cognitive and psychological outcomes than veterans with PTSD-o, mTBI-o, or combat exposure-only. The final sample included 20 OIF/OEF veterans with histories of self-reported deployment mTBI (mTBI-o), 19 with current PTSD (PTSD-o), 21 with PTSD and self-reported mTBI (mTBI+PTSD), and 21 combat controls (CC) (no PTSD and no reported mTBI). Groups were formed using structured interviews for mTBI and PTSD. All participants underwent comprehensive neuropsychological testing, including neurocognitive and psychiatric feigning tests. Results of cognitive tests revealed significant differences in performance in the mTBI+PTSD and PTSD-o groups relative to mTBI-o and CC. Consistent with previous PTSD literature, significant differences were found on executive (switching) tasks, verbal fluency, and verbal memory. Effect sizes tended to be large in both groups with PTSD. Thus, PTSD seems to be an important variable affecting neuropsychological profiles in the post-deployment time period. Consistent with literature on civilian mTBI, the current study did not find evidence that combat-related mTBI in and of itself contributes to objective cognitive impairment in the late stage of injury.

Discriminating Among ADHD Alone, ADHD With a Comorbid Psychological Disorder, and Feigned ADHD in a College Sample

Since the early 2000s concern has increased that college students might feign ADHD in pursuit of academic accommodations and stimulant medication. In response, several studies have validated tests for use in differentiating feigned from genuine ADHD. Although results have generally been positive, relatively few publications have addressed the possible impact of the presence of psychological disorders comorbid with ADHD. Because ADHD is thought to have accompanying conditions at rates of 50% and higher, it is important to determine if the additional psychological disorders might compromise the accuracy of feigning detection measures. The present study extended the findings of Jasinski et al. (2011) to examine the efficacy of various measures in the context of feigned versus genuine ADHD with comorbid psychological disorders in undergraduate students. Two clinical groups (ADHD only and ADHD + comorbid psychological disorder) were contrasted with two non-clinical groups (normal controls answering honestly and normal participants feigning ADHD). Extending previous research to individuals with ADHD and either an anxiety or learning disorder, performance validity tests such as the Test of Memory Malingering (TOMM), the Letter Memory Test (LMT), and the Nonverbal Medical Symptom Validity Test (NV-MSVT) were effective in differentiating both ADHD groups from normal participants feigning ADHD. However, the Digit Memory Test (DMT) underperformed in this study, as did embedded validity indices from the Wechsler Adult Intelligence Scale-IV (WAIS-IV) and Woodcock Johnson Tests of Achievement-III (WJ-III).

Exploring the Relationship Between Mild Traumatic Brain Injury Exposure and the Presence and Severity of Postconcussive Symptoms Among Veterans Deployed to Iraq and Afghanistan

The aim of this study was to describe the association between mild traumatic brain injury (mTBI) and persisting postconcussive symptoms according to symptom category, number, and severity.

Algorithm for symptom attribution and classification following possible mild traumatic brain injury

Objective:To present a heuristic model of a symptom attribution and classification algorithm (SACA) for mild traumatic brain injury (mTBI). Setting: VA Polytrauma sites. Participants: 422 Veterans. Design: Cross-sectional. Main Measures: SACA, Comprehensive TBI Evaluation (CTBIE), Structured TBI Diagnostic Interview, Minnesota Multiphasic Personality Inventory (MMPI-2-RF), Letter Memory Test, Validity-10. Results: SACA and CTBIE diagnoses differ significantly (P < .01). The CTBIE, compared with SACA, attributes 16% to 500% more symptoms to mTBI, behavioral health (BH), mTBI + BH and symptom resolution. Altering SACA criteria indicate that (1) CTBIE determination of cognitive impairment yields 27% to 110% more mTBI, mTBI + BH and symptom resolution diagnoses, (2) ignoring timing of symptom onset yields 32% to 76% more mTBI, mTBI + BH and Other Condition diagnoses, (3) Proportion of sample having questionably valid profiles using structured TBI diagnostic interview and MMPI-2-RF and Letter Memory Test is 26% whereas with CTBIE item number 23 and Validity-10 is 6% to 26%, (4) MMPI-2-RF F-scale is the only measure identifying Veterans with posttraumatic amnesia for more than 24 hours as having questionably valid profiles. Conclusions: Symptom attribution–based diagnoses differ when using status quo versus the SACA. The MMPI-2-RF F-scale, compared with the Validity-10 and Letter Memory Test, may be more precise in identifying questionably valid profiles for mTBI + BH. The SACA provides a framework to inform clinical practice, resource allocation, and future research.

The effects of symptom information coaching on the feigning of adult ADHD.

College students without ADHD may feign symptoms of ADHD to gain access to stimulant medications and academic accommodations. Unfortunately, research has shown that it can be difficult to discriminate malingered from genuine ADHD symptomatology, especially when evaluations are based only on self-report questionnaires. The present study investigated whether nonclinical college students given no additional information could feign ADHD as successfully as those who were coached on symptoms of the disorder. Similar to Jasinski et al. (2011) and other research on feigned ADHD, a battery of neuropsychological, performance validity, and self-report tests was administered. Undergraduates with no history of ADHD or other psychiatric disorders were randomly assigned to 1 of 2 simulator groups: a coached group that was given information about ADHD symptoms, or a noncoached group that was given no such information. Both simulator groups were asked to feign ADHD. Their performance was compared to a genuine ADHD group and a nonclinical group asked to respond honestly. Self-report, neuropsychological, and performance validity test data are discussed in the context of the effect of coaching and its implications for ADHD evaluations. Symptom coaching did not have a significant effect on feigning success. Performance validity tests were moderately effective at detecting feigned ADHD.