Sharif University of Technology Scientia Iranica 1026-3098 Articles in Press 2024 04 28 Investigating the attentional effect and stimulus selectivity at the brainstem during auditory selective attention to dichotically presented /ba/ and /da/ stimuli 23579 10.24200/sci.2024.63390.8370 EN Azadeh Ghalyanchi-Langeroudi Department of Medical Physics and Biomedical Engineering, Tehran University of Medical Sciences (TUMS), Tehran, Iran. -Research Center for Biomedical Technologies and Robotics (RCBTR), Tehran, Iran Zahra Shirzhiyan -Department of Medical Physics and Biomedical Engineering, Tehran University of Medical Sciences (TUMS), Tehran, Iran. -Computational Neuroscience, Institute of Medical Technology, Brandenburg University of Technology Cottbus-Senftenberg, Elham Shamsi Department of Medical Physics and Biomedical Engineering, Tehran University of Medical Sciences (TUMS), Tehran, Iran. - Research Center for Biomedical Technologies and Robotics (RCBTR), Tehran, Iran. Ahmadreza Keihani Department of Medical Physics and Biomedical Engineering, Tehran University of Medical Sciences (TUMS), Tehran, Iran. - Research Center for Biomedical Technologies and Robotics (RCBTR), Tehran, Iran. Morteza Farahi Department of Medical Physics and Biomedical Engineering, Tehran University of Medical Sciences (TUMS), Tehran, Iran. - Research Center for Biomedical Technologies and Robotics (RCBTR), Tehran, Iran. Amin Asgharzadeh-Alvar Department of Medical Physics and Biomedical Engineering, Tehran University of Medical Sciences (TUMS), Tehran, Iran. - Research Center for Biomedical Technologies and Robotics (RCBTR), Tehran, Iran. Amir Homayoon Jafari Department of Medical Physics and Biomedical Engineering, Tehran University of Medical Sciences (TUMS), Tehran, Iran. Research Center for Biomedical Technologies and Robotics (RCBTR), Tehran, Iran Akram Pourbakht Department of Audiology, School of Rehabilitation Sciences, Iran University of Medical Sciences (IUMS), Tehran, Iran. Journal Article 2023 11 04 While selective attention is known to modulate speech encoding in cortical responses, it is unclear whether such modulation also occurs in brainstem responses. The present study investigates the impact of selective attention on brainstem responses to consonant-vowel stimuli. The study examined auditory brainstem responses to dichotically delivered /ba/ and /da/ in 15 normal hearing subjects (8 males). Subjects were asked to selectively attend to a stimulus, and their responses were evaluated using the short-time Fourier transform (STFT) and phase difference comparison. Our findings reveal significant changes in the mean phase values for brainstem responses during selective attention. The mean phase values in brainstem responses to da were consistently positive, whereas those in brainstem responses to ba were consistently negative compared to responses without attention. In the steady-state region, the mean difference of the brainstem responses varied in the high frequency (-0.022±0.008, 0.021±0.007) and middle frequency (-0.026±0.008, 0.024±0.007) ranges. Furthermore, the high frequency of the transitional part of the response changed (-0.024±0.01, 0.033±0.009) when attention was directed to /ba/ and /da/, respectively. Our findings suggest that selective attention can significantly alter brainstem responses during auditory processing, resulting in significant phase changes in both the middle and high-frequency ranges. https://scientiairanica.sharif.edu/article_23579_5e718b39318922768e80c7f55e2bd521.pdf