Functional Abnormalities in the Neural Circuitry of Reading in Men with Nonsyndromic Clefts of the Lip or Palate

Abstract

The current study was designed to evaluate the neurobiology of reading in a group of men with nonsyndromic clefts of the lip or palate (NSCLP) compared with healthy controls by positron emission tomography. SUBJECTS included eight men with NSCLP compared with six healthy control men. By using radioactively labeled water (O(15)), regional brain blood flow was obtained during the performance of three simple reading tasks: reading unrelated words, reading unrelated sentences, and reading a story. During each of the reading conditions, NSCLP subjects compared with healthy controls showed increased blood flow in areas previously reported to be involved in language processing and reading (inferior frontal lobe, cerebellum, and occipital lobe). The increased blood flow suggests a possible neural inefficiency. In contrast, when analyzing the brain regions involved in more complex language functioning (reading stories compared with reading only words), control subjects showed an increase in blood flow in a distributed neural circuit, whereas the NSCLP subjects showed a decrease in flow in these regions. Additionally, the NSCLP subjects had activation of several regions not activated in the healthy controls, suggesting a compensatory circuit used for this more complex reading task. These results indicate that subjects with NSCLP show abnormalities in the function of the distributed neural circuitry used for oral reading.