Nine-hundred and four consecutive patients, including 80 neurological patients and 470 with head injuries, were given neuropsychological tests. All 43 test scores were converted to normative Z ...-scores and averaged, giving an Overall Test Battery Mean (OTBM). A variable measuring effort correlated 0.73 with the OTBM. The OTBM mean score was 1.20 SD lower in those who failed the Word Memory Test (WMT) than in those who passed the WMT. Sub-optimal effort suppressed the OTBM 4.5 times more than did moderate-severe brain injury. When only those making a good effort were included, patients with severe brain injuries and neurological diseases scored significantly lower than groups presumed to have no neurological impairment, but these group differences were not seen when all cases were analysed together. These data illustrate the importance of measuring and controlling for sub-optimal effort in individual neuropsychological evaluations, as well as in empirical research with similar groups of patients.
To examine whether symptom exaggeration is a factor in complaints of cognitive dysfunction using 2 new validated instruments in patients with fibromyalgia (FM).
Ninety-six patients with FM and 16 ...patients with rheumatoid arthritis (RA) were administered 2 effort or symptom validity tests designed to detect exaggerated memory complaints as part of a battery of psychological tests and self-report questionnaires.
A large percentage of patients with FM who were on or seeking disability benefits failed the effort tests. Only 2 patients with FM who were working and/or not claiming disability benefits and no patient with RA scored below the cutoffs for exaggeration of memory difficulties.
This study illustrates the importance of assessing for exaggeration of cognitive symptoms and biased responding in patients with FM presenting for disability related evaluations.
