Amsterdam Short-Term Memory Research Articles

Detecting malingered neurocognitive dysfunction: Comparative analysis of freestanding and embedded performance validity tests

Detecting malingered neurocognitive dysfunction is a major issue in forensic context, particularly in legal proceeding/insurance assessment after a traumatic brain injury (TBI), condition frequently associated with persistent cognitive impairments that may potentially be related to malingering. Consequently, research has devoted considerable efforts on developing tools to verify symptoms authenticity. This study compared two freestanding performance validity tests (PVTs) (Amsterdam Short-Term Memory Test—ASTM; Word Completion Memory Test—WCMT) and five embedded PVTs (Rey Complex Figure Test—RCFT—Copy and Recall trials; Reliable Digit Span—RDS; Rey Auditory Verbal Learning Test—RAVLT—Recognition and Total Learning trials) in a sample of 120 participants, including 15 patients with TBI (Mage = 44.40), 52 experimental simulators (Mage = 29.52) and 53 control (Mage = 29.77). Group performance was analyzed to assess tests’ discriminatory power, and Receiver Operating Characteristic (ROC) curves were used to examine tools’ sensitivity and specificity. Results indicated that experimental simulators performance on the ASTM, WCMT, and RAVLT differed significantly from TBI patients and controls. The RDS and RCFT did not discriminate experimental simulators from TBI group. ROC curves analysis reveals that the most accurate tests in this battery for detecting malingering were the ASTM and the RAVLT-Total Learning score. This study offers implications for identifying malingering in medico-legal settings, underscoring the importance of incorporating PVTs into clinical practice.

Validity of the Groningen Effort Test in patients with suspected chronic solvent-induced encephalopathy.

The use of performance validity tests (PVTs) in a neuropsychological assessment to determine indications of invalid performance has been a common practice for over a decade. Most PVTs are memory-based; therefore, the Groningen Effort Test (GET), a non-memory-based PVT, has been developed. This study aimed to validate the GET in patients with suspected chronic solvent-induced encephalopathy (CSE) using the criterion standard of 2PVTs. A second goal was to determine diagnostic accuracy for GET. Sixty patients with suspected CSE referred for NPA were included. The GET was compared to the criterion standard of 2PVTs based on the Test of Memory Malingering and the Amsterdam Short Term Memory Test. The frequency of invalid performance using the GET was significantly higher compared to the criterion of 2PVTs (51.7% vs. 20.0% respectively; p < 0.001). For the GET index, the sensitivity was 75% and the specificity was 54%, with a Youden's Index of 27. The GET showed significantly more invalid performance compared to the 2PVTs criterion suggesting a high number of false positives. The general accepted minimum norm of specificity for PVTs of >90% was not met. Therefore, the GET is of limited use in clinical practice with suspected CSE patients.

The impact of fabrication on recognition memory: An experimental study

We examined whether fabrication affects memory using a new paradigm combining the Deese/Roediger-McDermott paradigm (DRM) and the Amsterdam Short Term Memory task (ASTM). Participants were assigned to either a forced fabrication or honest condition, and encoded emotionally-negative and neutral wordlists by reading words out loud. The wordlists contained words that were associatively related to each other (e.g., symphony, sound, piano, radio, sing, orchestra), and converged to a non-presented critical word (e.g., music). Next, all participants had to indicate two words that were previously read out loud. However, participants in the forced fabrication condition had to fabricate that they read two additional words out loud, which were associated to the same DRM list. Participants in the forced fabrication condition formed false memories for their self-generated fabrications. Although fabrication did not increase spontaneous false memory rates for non-presented critical words, our results did highlight the perils of forcing people to fabricate.

Performance Validity and Outcome of Cognitive Behavior Therapy in Patients with Chronic Fatigue Syndrome

There is limited research examining the impact of the validity of cognitive test performance on treatment outcome. All known studies to date have operationalized performance validity dichotomously, leading to the loss of predictive information. Using the range of scores on a performance validity test (PVT), we hypothesized that lower performance at baseline was related to a worse treatment outcome following cognitive behavioral therapy (CBT) in patients with Chronic Fatigue Syndrome (CFS) and to lower adherence to treatment. Archival data of 1081 outpatients treated with CBT for CFS were used in this study. At baseline, all patients were assessed with a PVT, the Amsterdam Short-Term Memory test (ASTM). Questionnaires assessing fatigue, physical disabilities, psychological distress, and level of functional impairment were administered before and after CBT. Our main hypothesis was not confirmed: the total ASTM score was not significantly associated with outcomes at follow-up. However, patients with a missing follow-up assessment had a lower ASTM performance at baseline, reported higher levels of physical limitations, and completed fewer therapy sessions. CFS patients who scored low on the ASTM during baseline assessment are more likely to complete fewer therapy sessions and not to complete follow-up assessment, indicative of limited adherence to treatment. However, if these patients were retained in the intervention, their response to CBT for CFS was comparable with subjects who score high on the ASTM. This finding calls for more research to better understand the impact of performance validity on engagement with treatment and outcomes.

Memory deficits in patients with major depression: yes, they are trying hard enough!

ABSTRACTBackground: Cognitive impairment is a common symptom of patients with Major Depression (MDD) with negative clinical and social effects. With this study we investigated the question of whether MDD patients’ effort to memorize items is reduced and whether this reduction is related to patients’ memory impairment.Research design and methods: Twenty-two patients with MDD and 28 healthy control participants took part in the study. Both groups did not differ with respect to age, gender, and basic education. MDD was confirmed by the Mini Diagnostic Interview for Mental Disorders (Mini-DIPS). Willingness to make an effort was assessed by the Amsterdam Short-Term Memory Test (ASTM). Logical Memory (LM) from the Wechsler Memory Scale (WMS IV) was used to assess verbal memory.Results: With respect to the willingness to make an effort, all MDD-patients performed above the cutoff and did not perform worse than healthy control participants. Depression appears to have a negative impact on recall and recognition of verbal information, but the effect on recall was larger.Conclusions: These findings support studies indicating no motivational deficits in patients with depression during standardized neuropsychological testing. Reduced motivation is not a plausible explanation for depressive patients’ cognitive deficits assessed with neuropsychological tests.

Feedback on underperformance in patients with Chronic Fatigue Syndrome: The impact on subsequent neuropsychological test performance

Performance Validity Tests (PVTs) are used to measure the credibility of neuropsychological test results. Until now, however, a minimal amount is known about the effects of feedback upon noncredible results (i.e., underperformance) on subsequent neuropsychological test performance. The purpose of this study was to investigate the effects of feedback on underperformance in Chronic Fatigue Syndrome (CFS) patients. A subset of these patients received feedback on Amsterdam Short-Term Memory (ASTM) failure (i.e., feedback [FB] group). After matching, the final sample consisted of two comparable groups (i.e., FB and No FB; both n = 33). At baseline and follow-up assessment, the patients completed the ASTM and two measurements of information processing speed (Complex Reaction Time [CRT] and Symbol Digit Test [SDT]). Results indicated that the patients in the FB group improved significantly on the CRT, compared to the No FB group. Although not significant, a comparable trend-like effect was observed for the SDT. Independent of the feedback intervention there was a substantial improvement on ASTM performance at re-administration. A limited feedback intervention upon underperformance in CFS patients may result in improvement on information processing speed performance. This implies that such an intervention might be clinically relevant, since it maximizes the potential of examining the patients’ actual level of cognitive abilities.

Symptom validity testing (SVT) and social security disability claims

Background and aimsOver 50% of adult disability claimants fail some form of SVT. While some over report psychological, affective symptoms, others may report incredible cognitive symptoms. We examined effects of different types of response bias on free recall and self-reported depression.Participants and methods This is a single site cross-sectional study using a convenience sample (n = 224) of disability claimants in the Netherlands. The Green Word Memory Test (GWMT) was administered to all subjects. The Amsterdam Short Term Memory Test (AKTG), the Structured Inventory of Malingered. Symptomatology (SIMS), and the beck depression inventory (BDI-II) were administered in subsamples. Participant classification according to GWMT and SIMS outcomes resulted in four groups, G+/S+, G+/S−, G−/S+ and G−/S−.ResultsAverage age of the participants was 46.3 years (SD 9.9), 41.5% were female, and 43% were higher educated. GWMT was positive in 48.2% of all subjects, and 27.6% scored positive on both GWMT and SIMS. Analysis of variance of GWMT Free recall and Beck depression scores showed significant group differences [F(3, 123) = 33.21, P = .000] and [F(3, 106) = 25.17, P = .000] respectively.ConclusionsNon credible test performance was prevalent in this Dutch study of disability claimants. Insufficient effort and over reporting of psychological symptoms are associated with different score profiles on regular tests and self-rating scales.Disclosure of interestThe author receives funding for his work as a neuropsychologist in an expertise setting.

Poor symptom and performance validity in regularly referred Hospital outpatients: Link with standard clinical measures, and role of incentives

We investigated the frequency of symptom validity test (SVT) failure and its clinical correlates in a large, heterogeneous sample of hospital outpatients referred for psychological assessment for clinical purposes. We studied patients (N=469), who were regularly referred for assessment to the psychology departments of five hospitals. Background characteristics, including information about incentives, were obtained with a checklist completed by the clinician. As a measure of over-reporting, the Structured Inventory of Malingered Symptomatology (SIMS) was administered to all patients. The Amsterdam Short-Term Memory test (ASTM), a cognitive underperformance measure, was only administered to patients who were referred for a neuropsychological assessment. Symptom over-reporting occurred in a minority of patients, ranging from 12% to 19% in the main diagnostic patient groups. Patients with morbid obesity had a low rate of over-reporting (1%). The SIMS was positively associated with levels of self-reported psychological symptoms. Cognitive underperformance occurred in 29.3% of the neuropsychological assessments. The ASTM was negatively associated with memory test performance. We found no association between SVT failure and financial incentives. Our results support the recommendation to routinely evaluate symptom validity in clinical assessments of hospital patients. The dynamics behind invalid symptom reporting need to be further elucidated.

Faking ADHD? Symptom Validity Testing and Its Relation to Self-Reported, Observer-Reported Symptoms, and Neuropsychological Measures of Attention in Adults With ADHD

Objective: To compare ADHD patients who failed a symptom validity test with those who passed the test to explore whether there are signs of negative response bias on group level. Method: In our outpatient department, 196 adults were diagnosed with ADHD using a comprehensive diagnostic strategy featuring a detailed clinical history, clinical interview, observer rating, several self-rating scales, and neuropsychological attention tests. The Amsterdam Short Term Memory Test (AKGT) was applied as a symptom validity measure. Results: Sixty-three patients (32.1%) scored below the AKGT cutoff level. The two groups did not significantly differ regarding self-report and observer ratings. Those who failed the AKGT had higher reaction time variabilities in selective, auditory and visual divided attention, and higher omission errors in sustained attention. Conclusion: We found no strong indicators for negative response bias in ADHD patients who failed a symptom validity test. New measures and approaches to detect feigned ADHD should be developed.

Swiss population-based reference data for six symptom validity tests

Symptom validity test (SVT) results should be resistant against sociodemographic variables. Healthy, cooperative respondents should be able to pass these tests. The purpose of the study was to collect reference data for a selection of SVTs (Medical Symptom Validity Test, Structured Inventory of Malingered Symptomatology, Amsterdam Short-Term Memory Test, Emotional Numbing Test, Reliable Digit Span, Maximum Span Forward). A representative population-based sample of 100 German speaking Swiss citizens from 18 to 60 years of age was investigated. Multiple regression analyses revealed that age and verbal intelligence had an effect on various SVTs, whereas sex and education did not. The rate of positive test scores ranged from 1% (Emotional Numbing Test, Structured Inventory of Malingered Symptomatology) to 4% (Maximum Span Forward). One of the pertinent questions is if such positive results in reference or normative samples represent false positives or true positives and how to deal with the problem.

Does neuropsychological test performance predict outcome of cognitive behavior therapy for Chronic Fatigue Syndrome and what is the role of underperformance?

ObjectiveA subgroup of patients with Chronic Fatigue Syndrome (CFS) has cognitive impairments, reflected by deviant neuropsychological test performance. However, abnormal test scores can also be caused by suboptimal effort. We hypothesized that worse neuropsychological test performance and underperformance were related to each other and to a smaller reduction in fatigue, functional impairments, physical limitations and higher dropout rates following cognitive behavior therapy (CBT) for CFS. MethodsData were drawn from a previous trial, in which CFS patients were randomized to two conditions; 1) guided self-instruction and additional CBT (n=84) or 2) waiting period followed by regular CBT for CFS (n=85). Underperformance was assessed using the Amsterdam Short Term Memory Test (<84). To test neuropsychological test performance, the Symbol Digit Modalities Task, a simple reaction time task and a choice reaction time task were used. Interaction effects were determined between underperformance and neuropsychological test performance on therapy outcomes. ResultsUnderperformance was associated to worse neuropsychological test performance, but there were no significant interaction effects of these two factors by therapy on fatigue severity, functional impairments and physical limitations, but there was a significant main effect of underperformance on functional impairments, physical limitations and dropout rates. ConclusionUnderperformance or neuropsychological test performance was not related to the change in fatigue, functional impairments, and physical limitations following CBT for CFS. However, underperforming patients did drop out more often. Therapists should pay attention to beliefs and behavioral or environmental factors that might maintain underperformance and increase the risk of dropout.

Swiss population-based reference data for six symptom validity tests

Symptom validity test (SVT) results should be resistant against sociodemographic variables. Healthy, cooperative respondents should be able to pass these tests. The purpose of the study was to collect reference data for a selection of SVTs (Medical Symptom Validity Test, Structured Inventory of Malingered Symptomatology, Amsterdam Short-Term Memory Test, Emotional Numbing Test, Reliable Digit Span, Maximum Span Forward). A representative population-based sample of 100 German speaking Swiss citizens from 18 to 60 years of age was investigated. Multiple regression analyses revealed that age and verbal intelligence had an effect on various SVTs, whereas sex and education did not. The rate of positive test scores ranged from 1% (Emotional Numbing Test, Structured Inventory of Malingered Symptomatology) to 4% (Maximum Span Forward). One of the pertinent questions is if such positive results in reference or normative samples represent false positives or true positives and how to deal with the problem.

Cognitive Underperformance and Symptom Over-Reporting in a Mixed Psychiatric Sample

The current study examined the prevalence of cognitive underperformance and symptom over-reporting in a mixed sample of psychiatric patients (N = 183). We employed the Amsterdam Short-Term Memory Test (ASTM) to measure cognitive underperformance and the Structured Inventory of Malingered Symptomatology (SIMS) to measure the tendency to over-report symptoms. We also administered neuropsychological tests (e.g., Concept Shifting Task; Rey's Verbal Learning Test) and the Symptom Checklist-90 (SCL-90) to the patients. A total of 34% of them failed the ASTM, the SIMS or both tests. ASTM and SIMS scores were significantly, albeit modestly, correlated with each other (r = −.22). As to the links between underperformance, over-reporting, neuropsychological tasks, and the SCL-90, the association between over-reporting on the SIMS and SCL-90 scores was the most robust one. The subsample that only failed on the ASTM performed significantly worse on a compound index of memory performance. Our findings indicate that underperformance and over-reporting are loosely coupled dimensions and that particularly over-reporting is intimately linked to heightened SCL-90 scores.

Detection of Feigned Crime-Related Amnesia: A Multi-Method Approach

Claims of crime-related amnesia appear to be common. Using a mock crime approach, the diagnostic power of seven symptom validity instruments was investigated. Sixty participants were assigned to three conditions: responding honestly; feigning crime-related amnesia; feigning amnesia with a warning not to exaggerate. High sensitivity and specificity were obtained for the Structured Inventory of Malingered Symptomatology, the Amsterdam Short-Term Memory Test, and the Morel Emotional Numbing Test. Only three warned malingerers went undetected. The results demonstrate that validated instruments exist to support forensic decision making about crime-related amnesia. Yet, warning may undermine their effectiveness, even when using a multi-method approach.

Validation of Symptom Validity Tests Using a "Child-model" of Adult Cognitive Impairments

Validation studies of symptom validity tests (SVTs) in children are uncommon. However, since children's cognitive abilities are not yet fully developed, their performance may provide additional support for the validity of these measures in adult populations. Four SVTs, the Test of Memory Malingering (TOMM), the Word Memory Test (WMT), the Amsterdam Short-Term Memory (ASTM) test, and the Word Completion Memory Test (WCMT), along with several neuropsychological instruments were administered to 48 Dutch school children aged 7-12. All children scored above the established adult cut-offs on the TOMM and the WMT. They could pass the ASTM test if their reading skills were at a level equivalent to that of 9 year olds. All children passed our criterion of a negative WCMT score. However, the WCMT does seem sensitive to the level of verbal fluency. Implications for the applicability of these SVTs in adult populations are discussed.

Identifying deliberate attempts to fake memory impairment through the combined use of reaction time and event-related potential measures

The central aim of this study was to evaluate the value of reaction time (RT) measures and event-related potentials (ERPs) for the assessment of simulated memory impairment. In two identical experiments (N=24), healthy volunteers carried out an adapted version of the Amsterdam Short-Term Memory (ASTM) test. In half of the cases participants were instructed to perform to their best of abilities (control condition) while in the other half participants were asked to feign a believable memory deficit (simulation condition). Compared to controls, simulating participants were found to produce longer and more variable RTs. In addition, they took longer to respond to new words than to old words, while control participants showed the opposite pattern. Both early (300–500 ms) and late (500–800 ms) ERP old/new effects were similar in magnitude and scalp distribution for both groups of participants, regardless of the fact that simulating participants had significantly lower recognition accuracy than controls. The ERP old/new effect was assumed to reflect unaffected retrieval mechanisms and thus the discrepancy between this measure and recognition performance was interpreted as evidence for intentional underperformance. Results are discussed in relation to clinical observations and deception detection studies. It was concluded that the combined use of RT and ERP measures could be useful to detect and evaluate simulation of memory impairment but that future studies should include patient groups to test some of our assumptions.

On the limits of effort testing: Symptom validity tests and severity of neurocognitive symptoms in nonlitigant patients

Modern symptom validity tests (SVTs) use empirical cutoffs for decision making. However, limits to the applicability of these cutoffs may arise when severe cognitive symptoms are present. The purpose of the studies presented here was to explore these limits of applicability. In Experiment 1, a group of 24 bona fide neurological patients without clinically obvious cognitive symptoms was compared to a group of 24 patients with rather severe symptoms. A comprehensive test battery was employed, which included four SVTs (the Test of Memory Malingering, TOMM, the Word Memory Test, WMT, the Bremer Symptomvalidierung, BSV, and the Amsterdam Short-Term Memory Test, ASTM). In Experiment 2, a group of 20 patients with mild Alzheimer's disease was compared to 14 healthy controls. Results of both studies showed that cognitive impairment may significantly interfere with SVT performance. Correlation analyses revealed dissimilar relationships between SVTs and neuropsychological test measures. Whereas TOMM and WMT correlated mainly with tests of declarative memory, the BSV correlated with tests of attention, and ASTM correlated with tests of working memory. Intercorrelations between symptom validity measures were relatively low. The published cutoffs of the TOMM would be suitable for estimating effort in patients with Mini-Mental State Examination scores of 24 or above. More research will be necessary to investigate how performance in SVTs is related to cognitive functioning in populations of severely impaired patients.

DETECTION OF FEIGNED COGNITIVE DYSFUNCTION USING SPECIAL MALINGER TESTS: A SIMULATION STUDY IN NAÏVE AND COACHED MALINGERERS

The aim of the present study was to compare the accuracy of the Amsterdam Short Term Memory (ASTM) test with that of the Structured Inventory of the Malingered Symptomatology (SIMS) in detecting feigning of cognitive dysfunction in naïve and coached participants. Ninety undergraduate students were administered the ASTM and the SIMS and asked to respond honestly (controls; n = 30), or instructed to malinger cognitive dysfunction due to head injury. Before the both instruments were administered, naïve malingerers received no further information (n = 30), whereas coached malingerers were given some information about brain injury and a warning not to exaggerate symptoms (n = 30). Both tests correctly classified 90% of the naïve malingerers. The ASTM detected 70% of the coached malingerers, whereas the SIMS continued to detect 90% of them. The findings suggest that coaching undermines the diagnostic accuracy of the ASTM, but does not seem to influence the accuracy of the SIMS.

Cognitive performance after Mild Traumatic Brain Injury: The impact of poor effort on test results and its relation to distress, personality and litigation

Primary objective: To compare consecutive Mild Traumatic Brain Injury (MTBI) patients with and without adequate effort on cognitive performance, litigation status, fatigue, distress and personality.Research design: (Neuro)psychological assessment was done 6 months post-injury in 110 patients from a cohort of 618 consecutive MTBI patients aged 18–60, who attended the emergency department of our level I trauma centre. Effort was tested with the Amsterdam Short Term Memory test.Main outcome and results: Thirty patients (27%) failed the effort test. Poor effort was associated with significantly poorer scores on seven out of eleven measures, covering all tested domains. Poor effort was associated with lower educational level and changes in work status, but not litigation. Furthermore, poor effort was related to high levels of distress, Type-D personality and fatigue.Conclusions: Even in a sample of non-referred MTBI patients, poor effort was common and was strongly associated with inferior test performance. These findings imply that effort testing should be part of all cognitive assessments, also outside mediolegal settings. Behavioural factors like distress and personality should be considered as potential threats to the validity of neuropsychological testing after MTBI.

Symptom Information—Warning—Coaching

Abstract Coaching is a topic of utmost importance for forensic neuropsychological assessment, and symptom validity tests (SVTs) should be resistant against it. Four groups of experimental malingerers (n = 15, each) were given scenarios to feign cognitive symptoms after traumatic brain injury. Group A obtained a basic scenario. For Group B, symptom information was added. Group C received an explicit warning against exaggerating symptom presentation. Group D obtained a specific coaching which contained an introduction into principles of effort measurement. All groups were given a short neuropsychological battery including three SVTs: the Amsterdam Short-Term Memory Test (ASTM), the Medical Symptom Validity Test (MSVT), and the Word Completion Memory Test (WCMT). While a general trend for gradually better results in SVTs from Group A to Group D was observed, only in Group D were pass rates elevated for the MSVT and the WCMT. Not a single participant passed the ASTM test. Coaching appears to be more effective...