title: Use of psychometric measures and nonorganic signs testing in detecting nomogenic disorders in low back pain patients.
abstract: The effect of financial compensation on responses to psychometric testing was studied in 231 chronic back pain patients. Item by item comparison of responses to two tests, readministered within 4 hours, yielded inconsistency scores. These inconsistency scores, along with scores on other psychometric measures and on Waddell's nonorganic signs test, of a group of 97 patients anticipating or receiving financial compensation (AFC), and a group of 134 patients not receiving or anticipating financial compensation (non-AFC) were compared. The AFC group had significantly higher mean scores than did the non-AFC group on the inconsistency measures, on almost all psychometric tests and on nonorganic signs. Almost all non-AFC subjects scored "0" on nonorganics, whereas 83% of AFC subjects scored "2" or higher. Prediction analysis revealed that the nonorganics score alone can predict AFC/non-AFC status; 90% of subjects were correctly classified. The inconsistency scores correctly classified 78%. Together, they correctly classified 93%. It was concluded that nonorganic scores and inconsistency scores (as defined by the investigators) distinguish between, and can predict membership in AFC and non-AFC groups. The significantly higher inconsistency scores obtained by the AFC group suggest that these psychometric test results are unreliable and hence invalid for this group.
authors.affiliation: Department of Psychology, University Hospital Back Pain Clinic, University of British Columbia, Vancouver.
authors.forename: B
authors.initials: B
authors.lastname: Hayes
authors.forename: C A
authors.initials: CA
authors.lastname: Solyom
authors.forename: P C
authors.initials: PC
authors.lastname: Wing
authors.forename: J
authors.initials: J
authors.lastname: Berkowitz
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D017116:Low Back Pain / Q000191:economics / Q000523:psychology*; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011594:Psychometrics; D015203:Reproducibility of Results; D012737:Sex Factors; D014942:Workers' Compensation