The persistent belief that VIQ-PIQ splits suggest lateralized brain damage.
There is a persistent belief in clinical psychology and neuropsychology that the Verbal IQ-Performance IQ (VIQ-PIQ) split can be used to reliably infer lateralized brain damage. We selected samples of patients with cleanly lateralized right (n = 23) or left (n = 26) hemisphere lesions and used Bayesian analyses to study the predictive validity of the Wechsler Adult Intelligence Scale-Revised VIQ-PIQ difference scores for identifying lateralized brain damage. The patients showed average VIQ-PIQ differences in the expected direction. However, on the basis of sensitivity, specificity, and positive predictive value statistics, we concluded that (a) the VIQ-PIQ split has no diagnostic predictive validity in persons with left hemisphere lesions (who are not aphasic) and (b) the VIQ-PIQ split has very limited diagnostic predictive validity in persons with right hemisphere lesions.
Department of Psychiatry, University of British Columbia, Vancouver, Canada.
Grant L
GL
Iverson
Adrianna
A
Mendrek
Russell L
RL
Adams
D000328:Adult; D001499:Bayes Theorem; D001925:Brain Damage, Chronic / Q000523:psychology*; D005260:Female; D007839:Functional Laterality / Q000502:physiology*; D006801:Humans; D007361:Intelligence Tests; D008297:Male; D009483:Neuropsychological Tests; D015588:Observer Variation; D011237:Predictive Value of Tests; D011597:Psychomotor Performance; D015203:Reproducibility of Results; D014888:Wechsler Scales