Detecting malingerers by means of response-sequence analysis.
The feigning of sensory loss (malingering) poses a challenge for psychophysicists. To uncover malingerers by means of psychophysical testing, we combined measures of response-sequence randomness with the maximum-likelihood adaptive-staircase procedure used to measure sensory detection thresholds. The two-alternative, forced-choice maximum-likelihood adaptive-staircase procedure calculates an estimate of the threshold after each trial and also recommends the stimulus concentration for the next trial. Olfactory detection thresholds for butyl alcohol were measured in 7 normals, 6 anosmics, and 6 malingerers. Each participant was tested for 20 trials. A discriminant analysis, using threshold concentration and probability of being correct over the 20 trials, could correctly classify only 68% of the malingerers and anosmics. Correct classification of anosmics and malingerers rose to 100% when statistical measures of randomness in the response sequences were included in the discriminant analysis. We conclude that the maximum-likelihood adaptive-staircase procedure, combined with response-sequence analysis, is a powerful addition to the arsenal of techniques for detecting malingerers in the evaluation of sensory ability.
Linschoten
Miriam R
MR
University of Colorado Health Sciences Center, Denver, Colorado 80262, USA. miriam.linschoten@uchsc.edu
Harvey
Lewis O
LO
D000328:Adult; D000440:Butanols; D003627:Data Interpretation, Statistical; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D016013:Likelihood Functions; D008297:Male; D008306:Malingering / Q000175:diagnosis* / Q000523:psychology; D000857:Olfaction Disorders / Q000175:diagnosis* / Q000523:psychology; D011601:Psychophysics; D011930:Reaction Time; D012684:Sensory Thresholds
D000440:Butanols