Functional neuroanatomy of lexical processing in children with cleft lip and palate

Abstract

Background: Patients with palatal clefts are predisposed to developing speech and language abnormalities. Emerging evidence indicates that children with cleft lip and/or cleft palate have higher rates of learning disabilities than the general population and differences in brain morphology.

Methods: Magnetic resonance imaging of 12 individuals with isolated unilateral complete clefts of the lip and palate produced functional images during three lexical processing tasks: generation of verbs, opposites, and rhymes. Direct statistical comparisons were made between subjects with cleft lip and palate and controls (matched for age and performance) from an extant data set, both as a group and individually.

Results: Two types of differences were found. Compared with unaffected controls, subjects with clefts showed a delayed and elongated blood oxygen level-dependent response in regions found throughout the cerebrum, including in the prefrontal cortex, cingulate gyrus, right precuneus, and right temporal gyrus. A right middle frontal gyrus region was activated by these tasks in controls but not in subjects with clefts. Developmental analysis showed that subjects 14.5 years and older (n = 5) had a larger number of age-related regions differing in blood oxygen level-dependent response from controls than did younger subjects (n = 7). Single-patient analysis demonstrated substantial individual variability.

Conclusions: Children with cleft lip and palate, performing lexical processing tasks at a comparable level of proficiency, use a similar but nonidentical functional neuroanatomy than peers without clefts. Differing neural circuitry for language tasks and differing developmental trajectories could help explain the predisposition to velopharyngeal dysfunction and learning disabilities in this population.