is it possible to use the speech-evoked auditory brainstem response test during sleep as it is used during wakefulness?

Background and aim: it is important to know how much are the auditory electrophysiological tests affected by sleep and wakefulness to be employed in different situations. this problem is more important for the speech-evoked auditory brainstem response (speech-abr) test that is affected by higher-level processing. this study aimed to compare the results of the speech-abr test between wakefulness and sleep states. methods: sixteen young male adults (aged 20–28 years) with normal hearing participated in this study. the speech-abr to the /da/ syllable was recorded during wakefulness and sleep. electroencephalography (eeg) and behavioral tests (eyes position, body movements, etc.) were monitored during the test time to confirm the sleep state. results: the speech-abr test parameters showed significant changes during sleep compared to wakefulness (latencies of waves v and a were longer and the amplitudes of waves v and a, the slope of v-a complex, and the spectral magnitude of f1 were lower). however, the spectral magnitude of higher frequencies was not significantly different. in addition, no significant statistical difference was observed in speech-abr parameters between right and left ears. conclusion: although the speech-abr originates from brainstem centers, unlike conventional click-evoked abr, it is affected by sleep as it is affected by the higher-level auditory processing functions. although, further studies are needed. however, our study opens the way for many applied auditory studies about the possibility to use speech-abr for auditory processing assessments in sleep state of different population groups, such as neonates.