Normalization of Speech Processing After Whole-Vault Cranioplasty in Sagittal Synostosis

Neurocognitive studies have found impairments in language-related abilities in nonsyndromic craniosynostosis, highlighting clinical importance of early language processing. In this study, neural response to speech sounds in infants with nonsyndromic sagittal craniosynostosis (NSC) is compared, preoperatively and postoperatively, using event-related potentials (ERPs) to objectively characterize development in language processing.

Electroencephalogram was recorded while 39 infants (12 NSC and 27 controls; ages 73-283 days) listened to the Hindi dental /(Equation is included in full-text article.)a/ and retroflex /da/ phonemes (non-native phonemic discrimination task). The mismatch negativity (MMN) ERP was extracted as the peak amplitude of the largest negative deflection in the difference wave over 80 to 300 milliseconds poststimulus. Differences in MMN were analyzed using repeated measures analysis of variance.

The MMN amplitude was attenuated in the infants with NSC preoperatively compared with controls (P = 0.047). A significant region by group interaction (P = 0.045) was observed, and infants with NSC displayed attenuated MMN in the frontal electrodes compared with controls (P = 0.010). Comparing the preoperative and postoperative MMN, a time by group interaction trend (P = 0.070) was observed. Pair-wise comparisons showed a trend for increase in MMN amplitude from preoperatively to postoperatively in the infants with NSC (P = 0.059). At the postoperative time point, infants with NSC showed no significant difference in MMN from controls (P = 0.344).

Infants with NSC demonstrated atypical neural response to language preoperatively. After undergoing surgery, infants with NSC showed increased MMN amplitude which was not significantly different from controls. These findings support the idea that whole vault cranioplasty may improve neurocognitive outcomes in sagittal craniosynostosis.