The link between cranial deformity and "functional" disability is not obvious in single-suture sagittal craniosynostosis. Physicians have anecdotally reported that children with simple craniosynostosis often seem to have a higher proportion of learning disabilities and cognitive problems than their nonafflicted peers. These problems have not been systematically studied, however. This study examined the long-term neuropsychological effects of single-suture sagittal craniosynostosis on selected aspects of neurological development. It did so by going beyond global measures of mental function (intelligence quotient) in an attempt to assess the incidence of subtle neuropsychological sequelae. Retrospective inspection of the Yale Department of Neurosurgery records between 1980 and 1990 was used to identify study subjects born with nonsyndromic sagittal suture craniosynostosis who were between 6 and 16 years of age at the time of the study. Of the 16 study subjects born with sagittal synostosis, which is thought to be among the most benign of the single-suture craniosynostoses, this study found that 50% had a reading and/or spelling learning disability. Although children with single-suture sagittal craniosynostosis fall within the normal range for intelligence, there is a significantly higher incidence of learning disabilities in this group than in the general population.