Tehran University of Medical Sciences Auditory and Vestibular Research 2423-480X 0 0 2025 12 08 1470 1470 Majid Bershan School of Rehabilitation, Shahid Beheshti University of Medical Sciences, Tehran, Iran. or Hamid Jalilvand - Sara Sardari - Maryam Yazdi - 2025 07 14 2025 11 01 Background and Aims: Aging leads to noticeable functional changes in central auditory processing and dichotic function. The aim of this study was comparison of dichotic function between young and elderly people, as a factor of Stimulus Onset Asynchrony (SOA). Methods: Persian syllables were presented dichotically to the participants. The onset time of the concurrent stimuli differed from 0 to 150 ms between the right and left ear. The effects of SOA changes (from 0 to 150 ms) were investigated in 20 normal- hearing young adults (aged 18 to 29 years) and 20 elderly individuals (aged 60 to 75 years) The Binaural (Both) Ear Correct (BEC%) score, as an indicative of dichotic performance, was measured. Results: The BEC% scores decreased as SOA was reduced in both groups. However, this decline was more pronounced and significant in the elderly group. In contrast, young adults achieved higher BEC% scores across all SOA levels compared with the elderly individuals. Conclusion: The reduction in BEC% scores in elderly individuals (particularly at lower SOA levels), indicates a decline in central auditory processing function in this group. This study highlights the impact of aging on central auditory processing and dichotic function, which could be implemented in designing and updating rehabilitative programs. https://avr.tums.ac.ir/index.php/avr/article/view/1470