Maryam Aghamolaei1, Zahra Jafari2, Sabine Grimm3, Katarzyna Zarnowiec4, Mojtaba Najafi-Koopaie5, Carles Escera6. 1. Department of Audiology, School of Rehabilitation, Shahid Beheshti University of Medical Sciences, Tehran, Iran; Audiology Department, Mofid Children's Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran. Electronic address: m.aghamollaie@gmail.com. 2. Department of Basic Sciences in Rehabilitation, School of Rehabilitation Sciences, Iran University of Medical Sciences (IUMS), Tehran, Iran; Department of Neuroscience, Canadian Center for Behavioural Neuroscience (CCBN), University of Lethbridge, Lethbridge, AB, Canada. 3. Cognitive and Biological Psychology, Institute of Psychology, Leipzig University, Neumarkt 9-19, 04109 Leipzig, Germany. 4. Institute of Neurosciences, University of Barcelona, Passeig de la vall d'Hebron 171, 08035 Barcelona, Catalonia, Spain; Brainlab-Cognitive Neuroscience Research Group, Department of Clinical Psychology and Psychobiology, University of Barcelona, Passeig de la vall d'Hebron 171, 08035 Barcelona, Catalonia, Spain. 5. Electronics Group, Faculty of Engineering, Shahed University, Tehran, Iran. 6. Institute of Neurosciences, University of Barcelona, Passeig de la vall d'Hebron 171, 08035 Barcelona, Catalonia, Spain; Brainlab-Cognitive Neuroscience Research Group, Department of Clinical Psychology and Psychobiology, University of Barcelona, Passeig de la vall d'Hebron 171, 08035 Barcelona, Catalonia, Spain; Institut de Recerca Sant Joan de Déu, Santa Rosa 39-57, 08950 Esplugues de Llobregat, Catalonia, Spain.
Abstract
OBJECTIVE: The aging effects on auditory change detection have been studied using the Mismatch Negativity (MMN) potential. However, recent studies have found earlier correlates of deviance detection at the level of the middle-latency response (MLR) and the effects of aging on this deviant-related response have not yet been clarified. The purpose of this study was to examine the effects of aging on both levels of the auditory deviance detection system. METHODS: MMN and MLR responses were recorded in 33 young and 29 older adults from 32 scalp electrodes during frequency oddball and swapped-oddball conditions. RESULTS: In the young group, modulation of MLR and a clear MMN response were observed, whereas in the aged group, no evidence of deviance detection was found at the level of MLR and the MMN amplitude was significantly diminished. CONCLUSIONS: Based on the obtained results, aging affects both levels of the auditory deviance detection system which seems to be a result of deficits in regularity encoding along the auditory hierarchy. SIGNIFICANCE: The current findings suggest that age-related physiological changes result in deficits in regularity encoding, starting from early stages of processing. This might eventually affect stream segregation and induce difficulties in understanding speech in complex environments.
OBJECTIVE: The aging effects on auditory change detection have been studied using the Mismatch Negativity (MMN) potential. However, recent studies have found earlier correlates of deviance detection at the level of the middle-latency response (MLR) and the effects of aging on this deviant-related response have not yet been clarified. The purpose of this study was to examine the effects of aging on both levels of the auditory deviance detection system. METHODS: MMN and MLR responses were recorded in 33 young and 29 older adults from 32 scalp electrodes during frequency oddball and swapped-oddball conditions. RESULTS: In the young group, modulation of MLR and a clear MMN response were observed, whereas in the aged group, no evidence of deviance detection was found at the level of MLR and the MMN amplitude was significantly diminished. CONCLUSIONS: Based on the obtained results, aging affects both levels of the auditory deviance detection system which seems to be a result of deficits in regularity encoding along the auditory hierarchy. SIGNIFICANCE: The current findings suggest that age-related physiological changes result in deficits in regularity encoding, starting from early stages of processing. This might eventually affect stream segregation and induce difficulties in understanding speech in complex environments.