Brain oscillatory activity evoked by chirp modulated tones in healthy children.

Aim: To describe the features of cortical oscillatory activity and neuronal synchronization by monitoring responses evoked by chirp-modulated tone (CMT) and look for relationships with cognition in healthy children. Methods: We recruited 23 healthy children, 1-18 years old, assessed their cognitive abilities and recorded the cortical oscillatory activity evoked by CMTs. We obtained descriptive statistics and looked for correlations with cognitive abilities. Results: In the low gamma band, the neuronal synchronization evoked by CMTs increased with age, reaching adult features by 12 years of age (rho = 0.5; p = 0.042). In the high gamma band, neuronal recruitment was greater at younger ages (rho = -0.55; p = 0.029). In four of the six under-6-year-old participants, there was no CMT-evoked response. We found that the greater a child's receptive vocabulary skills, the lower the frequency at which maximal neuronal recruitment occurred (rho = -0.65; p = 0.003). Interpretation: CMT-evoked cortical oscillatory activity is affected by degree of brain maturation and could be a potential biomarker of language-related disability. Our description of the cortical responses evoked by CMTs in healthy children is a step towards recognition of abnormal patterns and the possible use of this approach as a biomarker of brain disorders in children.