Tehran University of Medical Sciences Auditory and Vestibular Research 2423-480X 33 3 2024 01 31 219 226 EN Ahmad Khoshkhou Department of Audiology, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran Moslem Shaabani Department of Audiology, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran Enayatollah Bakhshi Department of Biostatistics and Epidemiology, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran Mohanna Javanbakht Department of Audiology, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran AND Pediatric Neurorehabilitation Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran 2023 09 17 2023 12 09 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. https://avr.tums.ac.ir/index.php/avr/article/view/1209 https://avr.tums.ac.ir/index.php/avr/article/download/1209/563