Events

Brainstem responses to clicks and tone bursts in infants have been well-documented; however, there is limited information regarding the brainstem response to speech in the first year of life. Although robust representation of the fundamental frequency in the frequency following response (FFR) has been recorded in infants, the development of other aspects of the FFR, such as timing and timbre, has not yet been examined. We evaluated brainstem responses to a speech syllable in 25 infants, ages three to nine months, who had normal peripheral function. We found that the amplitude of the fundamental frequency was variable, but was strongly represented in some infants as young as three months of age, replicating previous findings. The harmonics, however, showed a systemic increase in amplitude with age. In the timing domain, we found that the onset latency decreased with age, but peak latencies of the FFR did not change. These data are discussed in the context of subcortical changes across the lifespan and implications for early experience-dependent plasticity.