Detection of simulated malingering using forced choice recognition enhanced with event-related potential recording

A modified forced-choice procedure (HFCP) based on that of Hiscock and Hiscock (1989) for use with suspected malingerers is described. The major modification involves recording of the P300 event-related brain potential in response to the screen to which the subject responds. This 'probe' screen is, in turn, modified to contain either a match or a mismatch to the initial sample number, as opposed to having the subject choose the match from a pair of stimuli (match and mismatch) which are simultaneously presented in the standard HFCP. The P300 recording procedure necessitated this change, which also forces the subject to say 'yes' or 'no' (to match and mismatch, respectively), rather than choosing the match. We found that behavioral performance on the standard HFCP correlated highly and significantly with performance on the P300-enhanced HFCP. Three variants of the modified HFCP were explored. In all variants, P300 amplitude was significantly larger to the match than to the mismatch in standard group statistical tests. In the best variant, more than 70% of the simulators' match P300s were significantly greater (on tests within each individual) than the mismatch P300s.