Malingering in toxic exposure: classification accuracy of reliable digit span and WAIS-III Digit Span scaled scores.

This study examined the sensitivity and false-positive error rate of reliable digit span (RDS) and the WAIS-III Digit Span (DS) scaled score in persons alleging toxic exposure and determined whether error rates differed from published rates in traumatic brain injury (TBI) and chronic pain (CP). Data were obtained from the files of 123 persons referred for neuropsychological evaluation related to alleged exposure to environmental and industrial substances. Malingering status was determined using the criteria of Slick, Sherman, and Iverson (1999). The sensitivity and specificity of RDS and DS in toxic exposure are consistent with those observed in TBI and CP. These findings support the use of these malingering indicators in cases of alleged toxic exposure and suggest that the classification accuracy data of indicators derived from studies of TBI patients may also be validly applied to cases of alleged toxic exposure.

Pain, malingering and the WAIS-III Working Memory Index.

BACKGROUND CONTEXT: Pain patients often report cognitive symptoms, and many will include them in their claims of disability. There is empirical evidence that patients with pain do experience problems on attention-demanding cognitive tasks, but the results are mixed and the potential impact of exaggeration in the context of pain-related litigation has not been addressed. PURPOSE: 1) Examine the impact of pain and malingering on attention; 2) determine if the Working Memory Index (WMI) of the Wechsler Adult Intelligence Scale-3 (WAIS-III) can reliably detect malingering. STUDY DESIGN/SETTING: Study 1: simulator design; Study 2: clinical known-groups design. PATIENT SAMPLE: Study 1 used healthy college students; Study 2 used chronic pain patients and neurological patients. OUTCOME MEASURES: The WMI and its constituent subtests. METHODS: Study 1: College students were administered the WMI under three conditions: standard administration, with cold-pressor induced pain, or with instructions to simulate impairment due to pain. Study 2: Known-groups design in which the WMI was examined in non-malingering and definite malingering chronic pain patients, non-malingering moderate-severe traumatic brain injury, and memory disorder patients seen for routine psychological evaluation. Malingering was operationalized using published criteria. RESULTS: There were no group differences in WMI or its subtests among non-malingering groups, but some individual clinical patients with pain did score at a level suggestive of attentional impairment. The lowest scores were found in the simulated malingering college students and definite malingering clinical pain groups, in which about half scored worse than 95% of the non-malingering clinical patients. CONCLUSIONS: This study demonstrated that even when controlling for exaggeration some pain patients do exhibit problems with attentional function. However, significant impairment in WMI performance (eg, index score

Test of Memory Malingering Performance is unaffected by laboratory-induced pain: implications for clinical use.

The Test of Memory Malingering (TOMM) is a well-validated and widely used forced-choice symptom validity test. However, little is known about how TOMM performance is affected by pain. The present study evaluated the sensitivity of the TOMM to pain induced in healthy participants via the cold-presser test. Participants (n=20 per group) were administered the TOMM under one of three conditions: (1) standard instructions; (2) instructions to simulate pain-related memory deficit in pursuit of personal injury litigation; (3) while experiencing cold-induced pain. Results indicate that TOMM performance was unaffected by laboratory-induced moderate to severe pain and support the TOMM's use in evaluating clinical patients with pain.

Reliable digit span is unaffected by laboratory-induced pain: implications for clinical use.

Reliable Digit Span (RDS) is an indicator used to assess the validity of cognitive test performance. Scores of 7 or lower suggest poor effort or negative response bias. The possibility that RDS scores are also affected by pain has not been addressed thus potentially threatening RDS specificity. The current study used cold pressor-induced pain to investigate the effect of pain on RDS scores. Sixty undergraduate volunteers randomly assigned to one of three conditions (control, simulator, pain) completed the Digit Span subtest from the Wechsler Adult Intelligence Scale-III from which the RDS is derived. No differences in RDS scores were found between the control and pain groups, and neither group scored below 8. Sixty-five percent of the simulator group scored 7 or below. These results suggest that RDS is not affected by pain, and scores of 7 or less in persons with pain can be more confidently attributed to negative response bias.