Auditory brainstem response elicited by synthetic consonant-vowel /da/ and three geometric pulse click stimuli.

Complex sounds elicit auditory brainstem response (ABR) that can reflect sustained phase-locking in the auditory system. Common stimuli include synthetic speech sounds like the consonant-vowel /da/ (CV-da). We introduce three geometric pulse click (GPC) stimuli: compound click-sawtooth wave (CSW), compound click-square wave (CQW), and compound click-triangular wave (CTW), to elicit ABR. These mathematically generated stimuli had a similar time-lock stimulation pattern to CV-da. ABRs were recorded from twenty-seven healthy adult volunteers, with all stimuli standardized to a peak-to-peak intensity of 40 dB SPL above the sensation level. The results revealed that ABR amplitudes were significantly greater for CSW and CV-da. CQW and CTW exhibited additional response peaks due to the presence of additional broadband energy within these stimuli. The correlations between the unfiltered stimulation wave and the response wave were also higher for GPC stimuli, with CSW reached a moderate level of correlation (r2 = 0.33). Response latencies strongly related to occurrence of energy spikes concentrated in ≥4 kHz. The three GPC stimuli evoked a strong and similar time-locking response compared to CV-da. Given the ease of modifying the energy and time-lock patterns of GPC stimuli, they hold potential for future basic and clinical applications.