On "the lateralization of pain"

The hypothesis put forth by Merskey and Watson [16] that pain, when lateralized, occurs more often on the left was tested in a sample of 264 patients seen at the University of Washington Pain Service. Contrary to the hypothesis, pain occurred with equal frequency on the left and the right. No differences were observed between patients with left and right lateralized pain on the MMPI, IBQ or Zung depression scales. The discrepancy between these findings and those of Merskey and Watson probably reflects differences in the populations studied, differences in the conventions used to define pain laterality, and the fact that the multiple statistical tests on a single sample used by Merskey and his colleagues lead to a large probability of obtaining spuriously significant results.