Auditory Sensitive Period Timing and Language Development in Infants
with Prior GABA-ergic Drug Exposure
Yearly, 1-2 million infants undergo general anesthesia (GA) during medical procedures in the United States, with some procedures necessitating sedation for days at a time. Research in animal models suggests that a critical way GA exposure in early life impacts development is by accelerating sensitive periods in the brain. How and when GA exposure influences human sensitive periods remains a critical open question to inform risk for maladaptive development in this population. To address this question, we focused on a language phoneme sensitive period in the first year after which infants cease discriminating non-native phoneme sounds. We tested whether prolonged GA in the first two months of life accelerates this sensitive period’s timing over temporal cortex using a native-non-native phoneme EEG/ERP paradigm at 10 months in two groups of infants with (n = 33) and without (n = 30) prior GA exposure. We hypothesize that the GA group will significantly differ from the non-GA group in discriminating non-native phonemes, indexed by the auditory ERP
amplitude difference between non-native and native standard phonemes. The GA group will differentiate less between phoneme conditions at 10 months, indicating worse discrimination of nonnative sounds (early closure of phoneme sensitive period). We hypothesize that across infants, this amplitude difference between phoneme conditions will correlate with receptive language skills measured by the Bayley scales, with early closure of the phoneme sensitive period correlating with lower receptive language scores at 10 months. These results can inform how human sensitive period developmental timing affects subsequent learning and behavior.