The Severity of Deformity in Metopic Craniosynostosis is Correlated with the Degree of Neurologic Dysfunction

Background: In recent years, metopic synostosis has represented up to 25 percent of all nonsyndromic craniosynostosis cases, manifesting with varying degrees of trigonocephaly. It is unknown whether the degree of severity of anterior dysmorphology is proportionate to neurologic dysfunction. This knowledge is essential to guide future surgical treatment recommendations. Given the reported correlation of abnormal auditory processing with future language dysfunction and poorer academic performance in craniosynostosis patients, the present study aims to evaluate auditory processing in preoperative patients with moderate and severe metopic synostosis, and in control infants, to discern the neurologic risk carried by different severities of trigonocephaly. Methods: Thirty-eight infants underwent evaluation of auditory processing: nine patients with severe metopic synostosis, seven with moderate metopic synostosis, and 22 controls. Brain activity was recorded by electroencephalography while the participants listened to language-based stimuli. Electroencephalographic data were analyzed to extract event-related potentials evoked by the speech sounds. Results: Severe metopic synostosis patients demonstrated significantly attenuated event-related potential responses in the left frontal scalp region overlying the left frontal lobe compared with controls (p < 0.05). The moderate metopic synostosis patients did not show significantly different language processing compared to the control infants or the severe metopic synostosis patients in the frontal scalp region. Conclusions: The results of this study suggest that untreated severe metopic synostosis is associated with reduced language response in the frontal cortex. Less severe (moderate) forms are indeterminate, and mild forms do not show calculable irregularity by the event-related potential method of analysis. CLINICAL QUESTION/LEVEL OF EVIDENCE: Risk, II.