WAIS digit span-based indicators of malingered neurocognitive dysfunction: classification accuracy in traumatic brain injury

The present study determined specificity and sensitivity to malingered neurocognitive dysfunction (MND) in traumatic brain injury (TBI) for several Wechsler Adult Intelligence Scale (WAIS) Digit Span scores. TBI patients (n = 344) were categorized into one of five groups: no incentive, incentive only, suspect, probable MND, and definite MND. Performance of 1,063 nonincentive patients (e.g., cerebrovascular accident, memory disorder) was also examined. Digit Span scores included reliable digit span, maximum span forward both trials correct, maximum span forward, combined maximum forward and backward span, Digit Span scaled score, maximum span backward both trials correct, and maximum span backward. In TBI, sensitivity to MND ranged from 15% to greater than 30% at specificities of 92% to 98%. Patient groups with documented brain pathology had higher false-positive error rates. These results replicate previous known-groups malingering studies and provide valuable data supporting the WAIS Digit Span scores in detection and diagnosis of malingering.     

Utility of the trauma symptom inventory's atypical response scale in detecting malingered post-traumatic stress disorder

The authors examined the Trauma Symptom Inventory's (TSI) ability to discriminate 88 student post-traumatic stress disorder (PTSD) simulators screened for genuine PTSD from 48 clinical PTSD-diagnosed outpatients. Results demonstrated between-group differences on several TSI clinical scales and the Atypical Response (ATR) validity scale. Discriminant function analysis using ATR revealed 75% correct patient classification but only 48% correct simulator classification, with an overall correct classification rate of 59% (positive predictive power [PPP] = .71; negative predictive power [NPP] = .51). Individual ATR cutoff scores did not yield impressive classification results, with the optimal cutoff (T score = 61) correctly classifying only 61% of simulators and patients (PPP = .66, NPP = .54). Although ATR was not developed as a malingered PTSD screen, instead serving as a general validity screen, caution is recommended in its current clinical use for detecting malingered PTSD.     

Sensitivity and specificity of reliable digit span in malingered pain-related disability

The reliable digit span (RDS) performance of chronic pain patients with unambiguous spinal injuries and no evidence of exaggeration or response bias (n = 53) was compared to that of chronic pain patients meeting criteria for definite malingered neurocognitive dysfunction (n = 35), and a group of nonmalingering moderate-severe traumatic brain injury (TBI) patients (n = 69). The results demonstrated that scores of 7 or lower were associated with high specificity (> .90) and sensitivity (up to .60) even when moderate to severe TBI are included. Multiple studies have demonstrated that RDS scores of 7 or lower rarely occur in TBI and pain patients who are not intentionally performing poorly on cognitive testing. This study supports the use of the RDS in detecting response bias in neuropsychological patients complaining of pain as well as in the assessment of pain-related cognitive impairment in patients whose primary complaint is pain.     

Deletion of the mu opioid receptor results in impaired acquisition of Pavlovian context fear

The mu opioid receptor may constitute a critical component of a negative feedback system that regulates Pavlovian fear conditioning. We investigated context fear conditioning acquisition and expression in mu opioid receptor knockout mice (on an inbred, C57 genetic background). We discovered that the mu receptor knockout results in an unexpected and significant deficit in context fear acquisition. Mice lacking the mu receptor showed normal fear acquisition when subjected to a 1-day fear conditioning protocol but evinced deficient fear learning when acquisition was conducted across 5 days. The knockout mice showed normal reactivity to footshock in both fear conditioning protocols. Finally, we confirmed the effectiveness of the receptor deletion in the C57 strain by subjecting the mice to a test of morphine analgesia in the hot-plate assay. As has been seen with mixed genetic background, the receptor deletion resulted in a complete lack of analgesic response to 10 mg/kg morphine. Surprisingly, mice with a single copy of the mu receptor gene (heterozygous knockouts) showed intact sensitivity to morphine but a significant deficit in Pavlovian fear conditioning. The results indicate that deletion of the mu receptor gene impairs fear conditioning and that the conditioning and analgesia effects of heterozygous deletion are dissociable. The conditioning deficit seen in this line of mice may be related to impairment in hippocampus function.     

The relationship of body image dissatisfaction to cigarette smoking in college students

This study examined the association of cigarette smoking status and body image dissatisfaction as measured by the Multidimensional Body-Self Relations Questionnaire (MBSRQ), in 1575 young adult college students, 18–24 years of age. Respondents were current cigarette smokers (N = 482) or never tobacco users (N = 1093). Smoking status was found to be significantly associated with 5 of the 10 MBSRQ subscales, with current smokers having lower scores on Fitness Orientation, Health Evaluation and Health Orientation (all p < 0.001) and higher scores on Appearance Orientation (p = 0.01) and Overweight Preoccupation (p = 0.03) compared with never tobacco users. Furthermore, among current smokers, a higher number of days smoked in the last 30 days were associated with lower scores on all MBSRQ subscales, except Self-Classified Weight. In terms of clinical implications, interventions for smoking cessation among college students might benefit from inclusion of components for addressing body image dissatisfaction and improving health beliefs.     

In sight but out of mind: do competing views test the limits of perception without awareness?

Over a century's worth of research suggests that "perception" without awareness is a genuine phenomenon. However, relatively little research has explored the question of whether all visually presented information activates representations in long term memory without awareness. Two experiments explored the use of a figure-ground display consisting of competing views in which one view dominates the other such that subjects are (initially) unaware of the non-dominant view. Neither experiment provided evidence that the non-dominant view (an embedded word) activated its representation in long term memory when the subject failed to report being aware of the embedded word in that priming was not seen on a subsequent stem completion task. In contrast, priming was seen when subjects reported being aware of the embedded word. It is suggested that two competing figure-ground relations are not concurrently computed unconsciously.     

The broth in my brother’s brothel: Morpho-orthographic segmentation in visual word recognition

Much research suggests that words comprising more than one morpheme are represented in a “decomposed” manner in the visual word recognition system. In the research presented here, we investigate what information is used to segment a word into its morphemic constituents and, in particular, whether semantic information plays a role in that segmentation. Participants made visual lexical decisions to stem targets preceded by masked primes sharing (1) a semantically transparent morphological relationship with the target (e.g.,cleaner-CLEAN), (2) an apparent morphological relationship but no semantic relationship with the target (e.g.,corner-CORN), and (3) a nonmorphological form relationship with the target (e.g.,brothel-BROTH). Results showed significant and equivalent masked priming effects in cases in which primes and targets appeared to be morphologically related, and priming in these conditions could be distinguished from nonmorphological form priming. We argue that these findings suggest a level of representation at which apparently complex words are decomposed on the basis of their morpho-orthographic properties. Implications of these findings for computational models of reading are discussed.