Cognitive functioning in children and adults with nonsyndromal cleft lip and/or palate: a meta-analysis.

OBJECTIVE To provide a meta-analysis of research that has examined the cognitive functioning of children and adults with cleft lip (CL), cleft palate (CP), and cleft lip and palate (CLP). METHODS Data from 29 studies, which compared persons with a cleft to a control group on tests of cognitive functioning, were analyzed. The data were obtained from 1,546 persons with cleft and 279,805 controls. RESULTS Participants with a cleft performed significantly worse on 7 cognitive domains. However, the only moderate and significant deficit, which was based on nonheterogeneous study findings and not subject to publication bias, was in the language domain. CL, CP, and CLP were all associated with cognitive impairments, although the profiles for the groups differed. CONCLUSIONS Cross-sectional studies suggest that persons with clefts experience poorer cognitive functioning across a range of domains, although large-scale longitudinal studies are needed to more definitively differentiate outcomes by cleft type.