Detecting simulated amnesia for autobiographical and recently learned information using the P300 event-related potential.

To investigate whether the P300 (P3) event-related potential (ERP) can be used as an index of the intactness of recognition memory in subjects trying to simulate amnesia, two groups of subjects (n = 12 and n = 15) were instructed to simulate amnesia and one group of control subjects (n = 14) did not simulate amnesia while taking three recognition tests, during which ERPs were recorded. The three tests consisted of three different types of memory items: (1) the subject's birthday (birth), (2) the experimenter's name (name), (3) a word list of 14 nouns (words). The memory item was presented in a random series with other, similar in type, non-memory items. In group tests, memory items evoked larger amplitude P3s than non-memory items (p < 0.001). Within-subjects tests were used to determine whether the P3 amplitude in response to memory items was larger than the P3 amplitude in response to non-memory items for each individual. There was no difference between the sensitivity of the best within-subjects tests for amnesia simulators (birth = 0.9, name = 0.85, words = 0.53) versus non-simulators (birth = 1.0, name = 0.81, words = 0.5) averaged across the three test types. This suggests that P3 used as an index of the intactness of recognition memory may be useful in cases of suspected malingering.

Neuropsychological assessment and malingering: a critical review of past and present strategies.

In recent years, neuropsychologists and clinical psychologists have shown a greatly increased interest in methods of discriminating malingerers from legitimate psychiatric and neurological patients. In part, this increased interest has resulted from increased demand from the legal system (i.e., pertaining to disposition of personal injury, worker's compensation, medical malpractice, and criminal cases) for expert psychological testimony which can distinguish malingering from genuine neuropsychological deficits. Additional interest, and some controversy, has been generated by recent research studies that have reported no success in diagnosing malingering, although others have reported more positive evidence. The present literature review describes the historical and current methods of detecting malingerers, along with the empirical evidence supporting, or condemning, their use. The majority of empirical studies suggest that although malingering of brain dysfunction is not easy to detect, it is possible to detect, if looked for deliberately. Review and critique of the available strategies indicates that a multidimensional, multimethod approach is needed. Continued research effort is needed on this important clinical issue.

Neuropsychological functioning in migraine headache, nonheadache chronic pain, and mild traumatic brain injury patients.

There are conflicting reports in the literature concerning the neuropsychological functioning of migraine headache patients. The finding in some studies that migraineurs performed more poorly than healthy controls led to the hypothesis that chronic migraine may result in subtle but persistent cerebral dysfunction. Reports describing acute and between-headache neurophysiological disturbances in migraineurs lent support to this hypothesis. To elucidate the cognitive status of these patients, we administered a brief neuropsychological battery to 60 individuals with migraine headache (HA), nonheadache chronic pain (PAIN), or mild traumatic brain injury (MTBI). The PAIN group was included to test the hypothesis that cognitive difficulty in migraineurs might result from the discomfort, depression, medications, etc. often associated with chronic pain, rather than from brain dysfunction. The MTBI patients were considered a useful comparison for the migraineurs because their level of impairment was also expected to be mild, at worst. A MANOVA, with three cognitive index scores as the dependent variables, revealed that the three groups differed significantly. Follow-up contrasts demonstrated that the MTBI group was significantly more impaired on the memory index compared to the HA and PAIN groups, which did not differ from each other. The use of two different normative-based cutoffs to identify individuals who were impaired on the test battery revealed that the frequency of impairment within the two groups of pain patients, but not the MTBI patients, was within normal limits. Thus, the results did not support a link between migraine headache and cognitive impairment.

Utility of the Luria-Nebraska Neuropsychological Battery-Children's Revision in the evaluation of reading disabled children.

The Luria-Nebraska Neuropsychological Battery-Children's Revision (LNNBCR) was used to investigate differences between reading disabled (RD) and academically normal children. The groups of 32 subjects each were equivalent with regard to age, sex, race, IQ, and SES of primary wage earner in the family. RD subjects, all of whom had been identified as learning disabled by the school, were moderately to severely impaired in reading, but not in math. Performance of the groups was significantly different on the battery as a whole and on an abbreviated form of the battery which excluded scales composed of items measuring language, reading, and arithmetic. With the abbreviated battery, the largest group differences were found on the Rhythm scale. It is hypothesized that poor performance on the Rhythm scale may reflect impaired auditory processing, which has a negative impact on the development of basic skills required for reading. A stepwise discriminant function analysis using the abbreviated battery correctly identified 84% of subjects. Evidence supporting discriminative validity of two methods of identifying RD children was found. Performance on an Experimental scale composed of nonreading items presumed to assess the integrity of areas of the brain mediating basic reading skills was no worse than on an equivalent randomly selected pool of items. The LNNB-CR may be a potentially valuable instrument for investigating neuropsychological differences between RD and normal children in that it provides relevant information to educators who must formulate remediation programs for RD children.

Diagnostic efficiency and material specificity of the Warrington Recognition Memory Test: a collaborative multisite investigation.

Two studies examined the Warrington Recognition Memory Test (RMT) discrepancy index (Words-Faces) in a large sample of patients heterogeneous with respect to age, education, gender, and neurological diagnosis. In Study 1 (N = 504) we used cutoffs from the Words-Faces discrepancy scores derived from Warrington's original validation sample to attempt to accurately classify patients with left, right, or diffuse brain damage. Sensitivity for left hemisphere patients (Faces > Words) was 10% with a specificity of 88%, whereas sensitivity for right hemisphere patients (Words > Faces) was 48% with a specificity of 86%. For patients with diffuse brain damage (Words = Faces) sensitivity was 69% and specificity was 38%. In Study 2 (N = 263), we examined the relationship between the Words-Faces discrepancy score and Wechsler Memory Scale-Revised (WMS-R; Wechsler, 1981) Logical Memory and Visual Reproduction subtests. Contrary to predictions, patients with Words > Faces performed better on both WMS-R subtests; the Faces > Words discrepancy was not related to Visual Reproduction performance. Potential reasons for these negative findings are discussed, as well as cautions for future RMT discrepancy index use.

Further investigation of traumatic brain injury versus insufficient effort with the California Verbal Learning Test.

The present study replicates and attempts to extend previous research using the California Verbal Learning Test (CVLT) to identify malingerers. Documented moderate and severe traumatic brain injury patients (n = 42) were compared with clinical malingerers identified by criteria other than the CVLT (n = 21), malingering simulators instructed in realistic potential injury sequelae (n = 25), and normal controls (n = 21). Results of discriminant function analyses for high and low base rates are reported, showing similar results. Also, the four individual cutoff scores (Recognition Hits, Discriminability, Total Words Recalled, Long Delay Cued Recall) from Millis, Putnam, Adams, and Ricker (1995) were evaluated with these groups. Similar specificity rates were found with all four variables, while sensitivity rates were slightly lower than that of Millis. Adjusted cutoffs derived from the new samples resulted in slightly improved overall classification rates. Overall, present findings support those of Millis et al. (1995) with regard to the use of the CVLT in detection of malingering. Exploratory use of Total Intrusions and Recognition Hits Compared to Long Delay Free Recall was not promising. Simulators were found to be fairly comparable in performance to actual malingerers, affirming their use in malingering research.

Discrepancy between predicted and obtained WAIS-R IQ scores discriminates between traumatic brain injury and insufficient effort.

This study examines how well the discrepancy between predicted and obtained Wechsler Adult Intelligence Scale--Revised (WAIS-R) scores discriminate between insufficient effort (IE) and traumatic brain injury (TBI). The 27 IE patients performed significantly more poorly on the WAIS-R than the 48 moderate-severe TBI patients. Premorbid IQs were calculated with formulae that use demographics (Barona Index) or demographics and WAIS-R performance (Best-3 and the Oklahoma Premorbid Intelligence Estimation). Predictions were similar on the Barona, but IE patients' predicted IQs were lower than TBIs for measures with a performance component. IE patients demonstrated a greater discrepancy score (i.e., predicted IQ--obtained IQ) than TBIs; variable levels of sensitivity and specificity were obtained when discriminate functions were developed on these scores. The potential advantage of using discrepancy scores versus performance-based measures to detect insufficient effort is discussed.

Information/Orientation subtest of the Wechsler Memory Scale-Revised as an indicator of suspicion of insufficient effort.

The utility of the Information/Orientation (IO) subtest of the Wechsler Memory Scale-Revised in identifying insufficient effort was examined. Performances of 50 benefit-seeking patients were compared to previously generated norms based on a clinical sample. Of the 50 benefit-seeking patients, 6 (12%) had IO scores that were outside the performance ranges of the entire clinical sample. An additional 6 of 50 (24%) had performances that were comparable to less than 2% of the normative sample. These results are consistent with previously published estimates of insufficient effort base rates in benefit-seeking populations and demonstrate the utility of IO as an indicator of suspicion of insufficient effort.

Relationship between the Millon Behavioral Health Inventory and the minnesota multiphasic personality inventory (MMPI) in low-back pain patients.

The Millon Behavioral Health Inventory (MBHI) is being used with increasing frequency for the assessment of chronic pain, although there is a relative lack of evidence as to its utility, and prior studies have not examined low back pain. This investigation compared the MBHI to the MMPI in a sample of low-back pain patients and analyzed subgroups of pain patients based upon their MBHI responses. Subjects were 60 patients who had been admitted to outpatient multidisciplinary pain clinics of two Chicago-area hospitals. Patients completed both the MMPI and the MBHI and provided demographic information. Results of correlational analyses indicated strong relationships between the MBHI psychogenic attitude, psychosomatic correlate, and prognostic index scales and the validity scales of the MMPI. The MBHI Pain Treatment Responsivity scale (PP) correlated with 16 of the other 19 MBHI scales. PP did not demonstrate specificity with low back pain patients. The results of both the scale comparisons and the exploratory two-group cluster subgroup analysis support the notion that responses to the MBHI are largely affected by the respondent's tendency to deny psychopathology or to admit emotional distress.

Use of the California Verbal Learning Test to detect proactive interference in the traumatically brain injured.

Recent studies using the California Verbal Learning Test (CVLT) to investigate the learning and memory capacities of traumatically-brain injured (TBI) individuals have suggested that this population does not show the expected buildup of proactive interference (PI). The purpose of this study was to investigate whether PI could be detected on the CVLT, in a TBI sample, if PI were calculated using alternative methods. CVLT data from 25 TBI individuals with varying degrees of brain injury and 21 healthy controls were compared. Results from the various analyses suggested that TBI individuals show buildup and release from PI when learning and attempting to recall competing forms of information if appropriate methods of analysis are used. Although the CVLT differs considerably from traditional PI paradigms (e.g., Wickens, 1970), our results suggest it can be used to detect PI in TBI individuals.

Ten-year follow-up survey of clinical neuropsychologists: part I. Practices and beliefs.

A 21-item questionnaire previously used to survey practices and beliefs of clinical neuropsychologists (Sweet & Moberg, 1990; Sweet, Moberg, & Westergaard, 1996) was mailed in February 1999 to all ABPP Diplomates in clinical neuropsychology and a larger sample of randomly selected non-ABPP members of Division 40 (Clinical Neuropsychology) of the American Psychological Association. Results were compared with data previously collected in 1989 and 1994. Across 10 years there have been some persistent differences between neuropsychologists based on board certification status. These differences include degree of involvement in neuropsychological practice and forensic practice, involvement in research and teaching, frequency of subscribing to or regularly reading a variety of relevant journals, employment settings, use of assistants, and use of projective assessment. There are also a number of areas of shared belief and common practice. These important areas of agreement are unrelated to board certification status and are interpreted as signs of cohesiveness and maturity in the continuing evolution of the subspecialty. Shared beliefs and common practices include: appropriate field of training, type of degree, assessment philosophy, most types of information to be gathered in evaluations, and time spent per assessment. In general, the use of assistants is correlated significantly with the number of evaluations performed per month. Although sometimes viewed as exclusively providing assessment, the majority of neuropsychologists are also involved in treating patients with brain dysfunction. Survey data appear useful in characterizing and monitoring professional status and trends of clinical neuropsychology.

Ten-year follow-up survey of clinical neuropsychologists: part II. Private practice and economics.

Analyses of a 10-year follow-up survey of clinical neuropsychologists demonstrated significant changes in employment settings away from institutions, placing a clear majority of the field in private practice settings in 1999 (Sweet, Moberg, & Suchy, 2000). The present paper compares characteristics of practices and beliefs of clinical neuropsychologists who work in institutions versus private practice, using data from 1989, 1994, and 1999. Previous survey data had not been analyzed along the dimension of work setting. Among the significant findings are differences in age, referral sources, hours per week engaged in specific professional activities (clinical, neuropsychological, forensic, supervisory, research, teaching), ages of patients, type and frequency of data gathered in assessments, hours spent per evaluation, use of an assistant to gather data, and journal subscriptions. Economic changes within the last 5 years have had a differential impact for the two groups in terms of yearly income and hourly reimbursement. However, approximately half of the neuropsychologists in both groups have increased hours performing clinical work, hours performing administrative duties, and patient load to compensate for economic changes in the last 5 years. Decreases in clinical research and teaching activities are apparent in both groups, but in different amounts.

Differential diagnosis of steroid-dependent nephrotic syndrome with psychosis: Practical and ethical issues.

The present case illustrates practical and ethical issues that can be encountered by clinical psychologists providing consultation services in medical settings. The neuropsychological consultation service was asked to evaluate a 22-year-old male with psychosis, steroid-dependent nephrotic syndrome, and a family history of schizophrenia. MRI revealedmarked cortical atrophy. Clinical findings were consistent with (1) steroid inducedapparent atrophy, which has been shown to be reversible with withdrawal of steroids; (2) uremia secondary to steroid withdrawal; (3) cortical atrophy, found in some schizophrenics; or (4) an atypical, diffuse degenerative disorder. Clinical interview and psychological testing revealed significant thought disorder, prominent delusions, somatic hallucinations, and mood disturbance. Deterioration in social and academic functioning was also present. Except for impaired attention and concentration, neuropsychological evaluation showed no clear evidence of brain-based dysfunction. Further, neuropsychological results effectively ruled out a degenerative process and were not consistent with a steroid effects profile. A conclusive differential diagnosis of steroid induced psychosis versus severe psychopathology would require withdrawal from steroids and antipsychotics. In addition to the practical and ethical issues of withholding antipsychotics, steroid withdrawal would require either dialysis or renal transplant surgery. Decision making regarding dialysis dependency and the possibility of postsurgical psychosis secondary to true psychopathology were salient issues to both the patient and the treatment team.

The diagnosis of brain-damage by the MMPI: a comprehensive evaluation.

A number of research studies have proposed various methods for using the MMPI to identify brain dysfunction. This previous research has taken one of three major approaches. The present study compared the major approaches in a population consisting of 30 schizophrenic, 30 brain-damaged and 30 hospitalized normal patients. The results indicated that the most effective diagnosis device was the use of the Sc scale alone or in conjunction with the remaining clinical scales and the F scale. None of the organic scales or keys were able to match the performance of the Sc scale alone. The poor results obtained bring into question the use of these scales in any other setting without an extensive research validation. An alternate method that might be used to employ the MMPI in the diagnosis of brain dysfunction was suggested.

Responses to perceived unethical practices in clinical neuropsychology: ethical and legal considerations.

Neuropsychologists often review the work of colleagues who have performed a neuropsychological evaluation. At times, these reviews may cause one to believe that a colleague acted in an unethical manner. However, it is often unclear whether the situation warrants contacting the colleague or filing a complaint. This article provides examples of potential unethical practices in neuropsychology, and then reviews the relevant ethical principles and legal precedents concerning the obligations and possible risks of reporting perceived unethical practices of a colleague. The paper concludes with a series of recommendations and options as to when and how one should proceed in such situations.

Normative clinical relationships between orientation and memory: age as an important moderator variable.

The present study examined the relationship between memory and orientation to time, place, and personal and general information, as moderated by age, education, and simple attentional ability. A heterogeneous sample of 312 clinical referrals was divided into four groups, according to delayed memory functioning. Patients with globally good, globally poor, poor visual, and poor auditory memory were at differential risk of being disoriented, with the globally poor memory patients having the greatest risk. Overall, poorly oriented patients were older and less educated, with worse recall of digits backward. Discriminant Function Analysis selected visual and auditory memory and age as predictors of orientation. Normative tables stratified by age and memory performance are presented.

P300 as an index of recognition in a standard and difficult match-to-sample test: a model of amnesia in normal adults.

Earlier research has supported the use of a P300 (P3)-based procedure to detect simulated amnesia. In the present experiment, an attempt was made to model the behavior and event-related potentials (ERPs) that amnestic patients might demonstrate with relatively easy recognition memory tests, by increasing the difficulty of a match-to-sample recognition memory test taken by 18 memory-unimpaired undergraduates. None of the participants in the modeled amnesic condition were classified as having intact recognition memory as the result of P3-based intra-individual tests (specificity = 100%). The results support the utility of a P3 procedure for the detection of malingering by demonstrating the procedure to be a valid measure of impaired recognition with this model of amnesia.