Effect of auditory memory load on speech-evoked P300 in healthy adolescents

Background: The P300 is a late cortical neurophysiological response that can be elicited with auditory and visual stimulation, by presenting the stimuli in an odd-ball paradigm. When deviant stimuli are elicited using auditory stimuli, the P300 is recorded as a large positive peak approximately 300 ms after the stimulus onset in the waveform. Adolescent brain development is heavily influenced by hormonal and physical transitions. Most of the investigations have been done in children and adults, with a limited focus on adolescents. Hence, there is a need to understand the characteristics of P300 in this group. Objective: The current research was planned to measure the effect of auditory memory load on speech-evoked P300 in healthy adolescents. Methods: A total of 14 late adolescents aged between 18.1 and 24 years participated in the study. The P300 was used to record speech stimuli in N-back (zero-back, one-back, and two-back) tasks using 64 channels. Results: There was a significant difference in the latency and amplitude of P300 across the N-back tasks. The mean amplitude of P300 was the highest in a zero-back task and the lowest in a one-back task, and the mean latency of P300 was the lowest in a zero-back task and the highest in a one-back task. Conclusion: Prolonged latency and smaller amplitude of the P300 as the N-back difficulty level increased from zero-back to one-back and then two-back tasks in healthy adolescents.