Biomedical subjects

Thomas Merten

Publications and source records attributed to Thomas Merten.

5 recordsLinked to original sources

PubMed2006

Objective tests of symptom exaggeration in independent medical examinations.

OBJECTIVE: This study used the Medical Symptom Validity Test (MSVT) to examine exaggeration of memory impairment in disability claimants. METHODS: The MSVT was administered to patients with soft tissue injuries undergoing an independent medical examination (IME). Their results were compared with those from groups of volunteers who were either trying their best on the test or simulating memory impairment. RESULTS: Non-French-speaking volunteers, who were tested in French, showed near perfect performance on the effort subtests, but 42% of IME patients failed the effort tests in English. Their overall results were very similar to those of simulators. CONCLUSION: This study suggests that exaggeration of cognitive symptoms is widespread in disability-related evaluations. It would be unwise to accept self-reported memory complaints at face value. Criteria-normed symptom validity testing should be done to rule out symptom exaggeration.

Adolescent↗

PubMed2005

Factor structure of the Hooper Visual Organization Test: a cross-cultural replication and extension.

To investigate construct validity of the Hooper Visual Organization Test (VOT), a principal-axis analysis was performed on the neuropsychological test results of 200 German-speaking neurological patients who received a comprehensive battery, encompassing tests of visuospatial functions, memory, attention, executive functions, naming ability, and vocabulary. A four-factor solution was obtained with substantial loadings of the VOT only on the first factor, interpreted as a global dimension of non-verbal cognitive functions. This factor loaded significantly on numerous measures of visuospatial processing and attention (with particularly high loadings on WAIS-R Block Design, Trails A and B, and Raven's Standard Progressive Matrices). The remaining three factors were interpreted as memory, verbal abilities (vocabulary), and a separate factor of naming abilities.

Adolescent↗

PubMed2005

Analog validation of German-language symptom validity tests and the influence of coaching.

Although symptom validity testing is an integral part of the repertory of neuropsychologists in a number of countries, this is not yet true for Germany. The German adaptations of two effort tests, the Medical Symptom Validity Test (MSVT) by Green and the Amsterdam Short-Term Memory Test (ASTM) by Schmand et al., were investigated with a German-language sample. An analog study was performed with 18 healthy experimental malingerers and 18 controls with a mean age of 25.4 years. The scenario contained detailed information about mild post-traumatic cognitive impairment, as well as an explicit warning against symptom exaggeration. In addition to MSVT and ASTM, the Trail Making Test (TMT), the Complex Figure Test (CFT), and Digit Span were performed. Half of the sample were also given Rey's 15-Item-Test (FIT). Both groups were significantly different in all effort and performance measures, with the exception of the ratio TMT-B:TMT-A. With MSVT and ASTM, correct classification of group membership was between 97 and 100%. For the ratio TMT-B:TMT-A, there was a considerable overlap in the test scores for the two groups and the sensitivity of the FIT was too low. Although the ASTM and the MSVT were identified by a number of subjects as possible effort measures, both tests obtained very good results within this analog design.

Adult↗

PubMed2004

A short version of the Hooper Visual Organization Test: reliability and validity.

Based on a detailed item analysis, Merten (2002) developed a 15-item short version of the Hooper Visual Organization Test (VOT) intended to resolve a number of shortcomings of the original scale. Problematic test items were eliminated, scoring rules were clarified, and new instructions and a graphic illustration of the task were introduced. This revision was aimed at reducing testing time by maintaining or even improving the scale's potential as a screener for visuospatial dysfunction. In this study, the short version was given for the first time "in its own right" to a sample of 153 neurological patients with a mean age of 60.0 years. Estimates of internal consistency for the resulting short form yielded acceptable results (.82 and .84). A retest analysis for a subsample of n = 72 at an interval of 2 to 3 days showed a mean increase in test scores of .6 points and a test-retest correlation of .93. Correlations with other test data are presented. The results indicate that the short version is comparable with the full scale in important psychometric aspects. With the elimination of a number of weak points, it may constitute a good substitute for the full VOT.

Adult↗

PubMed2002

A short version of the Hooper Visual Organization Test: development and validation.

Based on a previous analysis of the test protocols of 320 German-speaking neurological patients (Merten & Beal, 1999), a short form of the Hooper Visual Organization Test (VOT) was developed and examined using an independent sample composed of another 320 patients with a mean age of 55.7 years. Of the original 30 VOT items, 15 were maintained. Estimates of internal consistency for the resulting short form yielded acceptable results (0.82 and 0.84). Particularly high correlations of the short form (0.71) and the original VOT (0.75) were found with WAIS Block Design. Scoring rules for the proposed short version were thoroughly revised, and expanded test instructions presented, which includes a graphic demonstration of the task. Based on a regression analysis with the total sample of N = 640, preliminary cutoff points for the short version can be computed from traditionally employed VOT cutoffs.

Adolescent↗