Simulating a memory impairment: can amnesics implicitly outperform simulators?

Performance validity tests in nonlitigant patients with functional motor disorder

BACKGROUND AND PURPOSE

Performance validity tests (PVTs) are used in neuropsychological assessments to detect patterns of performance suggesting that the broader evaluation may be an invalid reflection of an individual's abilities. Data on functional motor disorder (FMD) are currently poor and conflicting. We aimed to examine the rate of failure on three different PVTs of nonlitigant, non-compensation-seeking FMD patients, and we compared their performance to that of healthy controls and controls asked to simulate malingering (healthy simulators).

METHODS

We enrolled 29 nonlitigant, non-compensation-seeking patients with a clinical diagnosis of FMD, 29 healthy controls, and 29 healthy simulators. Three PVTs, the Coin in the Hand Test (CIH), the Rey 15-Item Test (REY), and the Finger Tapping Test (FTT), were employed.

RESULTS

Functional motor disorder patients showed low rates of failure on the CIH and REY (7% and 10%, respectively) and slightly higher rates on the FTT (15%, n = 26), which implies a motor task. Their performance was statistically comparable to that of healthy controls but statistically different from that of healthy simulators (p < 0.001). Ninety-three percent of FMD patients, 7% of healthy simulators, and 100% of healthy controls passed at least two of the three tests.

CONCLUSIONS

Performance validity test performance of nonlitigant, non-compensation-seeking patients with FMD ranged from 7% to 15%. Patients' performance was comparable to that of controls and significantly differed from that of simulators. This simple battery of three PVTs could be of practical utility and routinely used in clinical practice.

The Coin in Hand-Extended Version: Development and Validation of a Multicultural Performance Validity Test

The number of computerized and reliable performance validity tests are scarce. This study aims to address this issue by validating a free and computerized performance validity test: the Coin in Hand-Extended Version (CIH-EV). The CIH-EV test was administered in four countries (Colombia, Spain, Portugal, and the United States) and performance was compared with other commonly used validated tests. Results showed that the CIH-EV has at least 95% specificity and 62% sensitivity, and performance was highly correlated with scores on the Test of Memory Malingering, Victoria Symptom Validity Test, and Digit Span of the Wechsler Adult Intelligence Scale. There were no significant differences in scores across countries, suggesting that the CIH-EV performs similarly in a variety of cultures. Our findings suggest that the CIH-EV has the potential to serve as a valid validity test either alone or as a supplement to other commonly used validity tests.

Psychologic treatment of patients with psychogenic nonepileptic seizures

Psychogenic nonepileptic seizures are relatively common, often disabling and costly to patients and society. Most authorities consider psychologic treatment as the therapeutic intervention of choice. This review is intended primarily for psychologists and therapists who treat patients with psychogenic nonepileptic seizures, and for neurologists who make the diagnosis and wish to find out more about psychologic treatment options. The first section describes the nature and etiology of psychogenic nonepileptic seizures. General questions regarding the psychologic treatment of patients with psychogenic nonepileptic seizures are addressed, before discussing specific therapeutic approaches. The final part summarizes the authors' views on optimal treatment and the direction of future research.

The detection of malingering in memory performance: The sensitivity and specificity of four measures in a UK population

OBJECTIVES

To investigate the validity of a clinical neuropsychological battery for the detection of malingering on tests of memory.

METHODS

A simulated scenario design was developed to investigate the effectiveness of a battery of four neuropsychological tests in the detection of malingering; the Coin in the Hand Test (CIH), Autobiographical Memory Index (AMI), Rey I 5-Item Test (RIT),and the Wechsler Mental Control Test (MCT). The performances of patients with an acquired brain injury (N = 40) were compared with two groups of controls instructed either to simulate a head injury performance (N = 40) or do their best (N = 40).

RESULTS

The CIH and MCT demonstrated good validity and displayed high sensitivity and specificity. The RIT and the AMI was relatively poor in distinguishing between simulators and patients.

CONCLUSIONS

The sensitivity and specificity of all four tests to the detection of malingering has been assessed. Two of the tests the CIH and MCT would be useful as a quick and accurate screening tool for detecting malingering.

An investigation into the validity of effort tests in a working age dementia population

OBJECTIVES

Performance on neuropsychological tests can be influenced by non-cognitive factors, including deliberate underperformance, stress, the need to fulfil a sick role, depression, un-cooperativeness, fatigue and unhappiness with the evaluative situation. Tests to detect suboptimal effort are becoming widely used in clinical practice and are based on their reported insensitivity to cognitive dysfunction. A diagnosis of dementia has life-changing implications for an individual of working age. It is therefore crucial that clinicians can be confident they have obtained a valid estimate of current cognitive functioning. This study aimed to establish whether mood or cognitive functioning adversely influenced performance on symptom validity tests (SVTs) in individuals with working age dementia, who were judged to be using full effort.

METHOD

Forty-two participants with dementia diagnosed before the age of 65 completed measures of emotional and cognitive functioning and six SVTs.

RESULTS

There were no significant correlations between emotional functioning and measures of effort. However, cognitive functioning, in particular new learning, was significantly related to SVT performance. Participants with mild dementia performed significantly better on all six SVTs than those with moderate/severe dementia. The results also suggest that the SVTs are not equally sensitive to cognitive dysfunction. Rey's Dot Counting Test (DCT) (times criterion) achieved 100% specificity, and was the only test passed by every participant.

CONCLUSION

Rey's DCT is the only SVT that can be recommended for use in those under 65 years with possible dementia at this time until further validation studies are undertaken.

The base rate of effort test failure in patients with medically unexplained symptoms

BACKGROUND

"Effort tests" (i.e., tests that indicate whether appropriate effort is being made) are increasingly used in neuropsychological assessments. However, not all failures on effort tests are necessarily attributable to lack of effort. Understanding the factors that contribute to failure on effort tests has important clinical implications.

OBJECTIVES

This study aimed (a) to establish the extent to which patients with medically unexplained symptoms (MUS) presenting to neurology fail effort tests, (b) examine the performance of "mild" and "strong" simulators on effort tests, and (c) compare the performance of simulators and MUS patients.

METHODS

Forty-three MUS patients, 35 mild simulators, and 39 strong simulators undertook a battery of effort tests. The groups were matched for age, estimated IQ, and gender. The MUS patients were not involved in litigation.

RESULTS

The failure rate (defined as failing two or more effort tests) was 11% in the MUS group, 94% in the mild simulation groups, and 100% in the strong simulation group.

CONCLUSIONS

A minority of nonlitigant MUS patients who present to neurology fail effort tests. Possible reasons for this are discussed. In that they do not produce below-chance performance (in contrast with many of the simulators), there is no clear indication of deliberate failure, though this cannot be ruled out. The very high failure rate in the mild simulation group (who were instructed not to overact) indicates the sensitivity of effort tests to lack of effort and the value of including such tests in neuropsychological assessments.

Alters in dissociative identity disorder. Metaphors or genuine entities?

How should the different identities (i.e., alters) that are thought to be typical for dissociative identity disorder (DID) be interpreted? Are they just metaphors for different emotional states or are they truly autonomous entities that are capable of willful action? This issue is important because it has implications for the way in which courts may handle cases that involve DID patients. Referring to studies demonstrating that alters of DID patients differ in their memory performance or physiological profile, some authors have concluded that alters are more than just metaphors. We argue that such line of reasoning is highly problematic. There is little consensus among authors about the degree to which various types of memory information (implicit, explicit, procedural) may leak from one to the other alter. Without such theoretical accord, any given outcome of memory studies on DID may be taken as support for the assumption that alters are in some sense "real." As physiological studies on alter activity often lack proper control conditions, most of them are inconclusive as to the status of alters. To date, neither memory studies nor psychobiological studies have delivered compelling evidence that alters of DID patients exist in a factual sense. As a matter of fact, results of these studies are open to multiple interpretations and in no way refute an interpretation of alters in terms of metaphors for different emotional states.