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 electrophysi- ological 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. Keywords: Auditory brainstem response; speech acoustics; sleep; electroencephalography