Markers of Auditory-Cognitive Aging: Evidence from Normal Hearing Listeners and Cochlear Implant Recipients

• Applicant: Professor Dr. Andrej Kral
• Subject Area: Otolaryngology, Phoniatrics and Audiology ; Clinical Neurology; Neurosurgery and Neuroradiology
• Term: from 2018 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 409496899

Approximately one in three people over 65 years and nearly half of those older than 75 have hearing loss that requires rehabilitation (NIDCD, 2017). With increasing age degenerative changes in the cochlea and central nervous system lead to gradual decrements in the ability to precisely detect, resolve, and represent the distinguishing physical properties of speech sounds. Together with the deterioration in cognitive abilities older adults show detriments in communication, especially in background noise that may drive the aging brain towards the use of compensatory auditory-cognitive strategies. Recent data indicate that hearing loss accelerates cognitive decline in older adults and increases the risk for developing dementia. While the causal relationship is not yet clear, hearing restoration by means of hearing aids and cochlear implants (CIs) may alleviate some of the deleterious effects of aging. The interaction between aging and hearing loss habilitated by a CI together with the corresponding listening strategies, however, are still unknown.In the present project we aim to investigate how age, hearing status, and increased perceptual and auditory-cognitive loads affect listening strategies and their neural underpinnings. For this purpose, behavioral measures and cortical neuronal responses will be acquired from young and older normal hearing and hearing-impaired listeners habilitated by cochlear implants during a vowel identification task and an auditory Stroop task presented in quiet and in background noise. This approach will uncover the separate and combined effects of perceptual (quiet vs. noise) and auditory-cognitive (vowel identification vs. Stroop) loads. EEG activity analyzed in the time and frequency domains as well as utilization of source localization algorithms may reveal the neural mechanisms and brain structures involved in auditory processing tasks that impose increasing perceptual and/or cognitive load. These data may explain some of the variability in performance of CI recipients by identifying EEG markers of auditory cognitive aging. To the best of our knowledge, the present proposal is unique in the use of a multi-measure-within-subject approach together with a between-group comparison approach in the domain of auditory aging.The proposed collaboration consists of a German research team with the largest clinical population of older adults with CIs and expertise in EEG recordings and analysis (Medical University Hannover) and an Israeli team with extensive experience in EEG recordings and in auditory-cognitive effects of aging (Tel Aviv University). The complementary expertise, available clinical population, and mutual research interest, set the grounds for substantial synergy. The developed research tools may be further valuable for early objective screening of auditory-cognitive decline before it becomes clinically overt.

• DFG Programme: Research Grants
• International Connection: Israel
• International Co-Applicant: Dr. Yael Henkin