Direct Brain Recordings in Craniosynostosis Can Predict Future Language Development

Purpose: Non-syndromic craniosynostosis is associated with a multitude of language deficits. Early detection and prevention is essential for language remediation in these cohorts. The current standard assessment, the Bayley Scales of Infant Development (BSID), provides little predictive value for long-term development. Auditory event-related potentials (ERPs), in particular the mismatch negativity (MMN), measure passive neurological responses to speech sounds and suggest a promising avenue for analyzing infant speech development, particularly in craniosynostosis. We now provide long-term follow up neurocognitive assessment of patients with midline synostosis (sagittal and metopic) in comparison to BSID and ERP testing in infancy.

 

Methods: Non-syndromic craniosynostosis infants who received surgical correction for craniosynostosis were recruited one month post-operatively from the institutional Craniofacial Clinic. Participants were given the BSID by a licensed child psychologist. Immediately following, participants were presented with a non-native phoneme discrimination paradigm involving the Hindi retroflex phoneme /da/ and the dental phoneme /da/ in random order. Auditory stimuli were set at 80 dB, and EEG was recorded at 250 Hz with a 128-channel HydroCel Geodesic Sensor Net. Analysis focused on four electrode clusters: left and right frontal electrodes and left and right central electrodes. The MMN component was calculated as the largest negative amplitude in the difference wave between 80-300ms after stimulus presentation. Once patients reached >6 years of age, they completed a battery of neurodevelopmental tests (Wechsler Abbreviated Scale of Intelligence and Wechsler Fundamentals) with 6 sub-assessments that measure language-related functional domains. Statistical comparisons were performed with univariate regressions.

 

Results: Of twenty non-syndromic sagittal and metopic craniosynostosis patients who received BSID/ERP testing post-operatively and are currently eligible for long-term neurocognitive follow-up, data is currently available for nine (average age 8.1 years; 22% female; 55% sagittal, 33% metopic, 11% metopic and sagittal; all patients received whole vault cranioplasties). Univariate regression analyses showed that left frontal cluster MMN positively predicted word reading scores (β 3.00, R² 0.48), reading comprehension scores (β 3.57, R² 0.54), and reading composite scores (β 3.33, R² 0.57). Right frontal and bilateral central clusters did not significantly predict scores. In comparison, BSID receptive language scores negatively predicted word reading (β -27.48, R² 0.67) and reading comprehension (β -17.41, R² 0.86), while BSID cognitive, expressive language, and language composite scores had no predictive value for future neurocognitive language scores. 

 

 Conclusion: Our prospective longitudinal assessment shows that ERP assessment in patients with sagittal and metopic synostosis has significantly better predictive value for future neurocognitive assessment than the current gold standard BSID test. Left frontal measurements approximate the location of language associated brain centers. This suggests that high fidelity ERP testing should be performed following surgical correction of craniosynostosis. This may help tailor treatment for possible language deficits in future development.