Invalid performance validity test but normal cognitive test performances, What does it mean?

Abstract

While use of performance validity tests (PVTs) has become a standard of practice in neuropsychology, there are varying opinions regarding how to interpret cognitive test data, especially 'average' range data, if PVTs are failed. This study examined whether 'average' scores underrepresent functioning when PVTs are failed. Participants, randomly assigned to either a simulated malingering group (n=50) instructed to mildly suppress test performances or a best-effort/control group (n=50), completed the California Verbal Learning Test-II (CVLT-II) and Test of Memory Malingering (TOMM). Groups were not significantly different in age, education, or predicted IQ, but simulators performed significantly worse than controls on both the TOMM and CVLT-II short delay free recall (p<.05). Of simulators who failed the TOMM, 36% scored no worse than average (>25th percentile) and 73% scored no worse than low average (>10th percentile) on the CVLT-II. Given that simulators were instructed to suppress their cognitive performances and they scored worse than controls on the TOMM and CVLT-II, it is apparent their CVLT-II test performances were indeed suppressed despite generally being no worse than low average. These results indicate 'normal' cognitive test scores cannot be interpreted as accurately reflecting an individual's cognitive capabilities when obtained in the presence of failed PVTs.