Miller was (mostly) right: Head injury severity inversely related to simulation

Abstract

Purpose. British neurologist Henry Miller (1961; Miller & Cartlidge, 1972) provoked controversy by asserting late post-concussion syndrome (LPCS) is explained by simulation. The present study examines Miller's inverse dose-response assertion; the more minor the compensable injury, the greater the likelihood of deficit simulation. Method. We examined the prevalence of three types of simulation (memory, motor, and psychiatric) in two archival cohorts of compensation seekers (N = 391 and 368) representing a broad range of cranio-cervical injury severity. A moderate-severe brain injured group provided two sets of performance floors to establish 'possible' or 'probable' pseudoabnormalities. Instruments included the Key word recognition list, the Smedley dynamometer, the Test of Memory Malingering, and the MMPI-2 infrequency scale. Results. Chronic whiplash and minor head-injury litigants produced more invalid signs than severely injured persons on measures of simulated memory and motor deficits irrespective of definitional stringency. ANOVA revealed striking inverse linear trends as a function of severity. Under a 'possible' rule, at least one pseudoabnormality was present in 80% of LPCS claimants. Memory and motor pseudoabnormalities were more common than psychotic ones. Conclusions. These findings support Miller and Cartlidge's (1972) observations that embellishment rises as injury severity decreases in a compensable context. Simulating litigants may 'tailor' performance to fit aetiological expectations, as we found a low prevalence of psychosis simulation. © 2006 The British Psychological Society.