GABA and Glutamate/Glutamine Concentration in Auditory Cortex Correlate with Hearing Loss in Older Participants

Poster Session E - Monday, April 15, 2024, 2:30 – 4:30 pm EDT, Sheraton Hall ABC

Ms. Violet Zhou¹ (violetz@umich.edu), Esther Kim, Noah Reardon, Kayla Wyatt, Zoe Li, Shruthi Chakravarthy; ¹University of Michigan

Age-related hearing loss is characterized by reduced speech intelligibility in complex acoustic environments. Previous studies have reported that individual differences in levels of the inhibitory neurotransmitter gamma-aminobutyric acid (GABA) in the auditory cortex are associated with individual differences in auditory function. However, the impact of the excitatory neurotransmitter glutamate, as well as the ratio of glutamate to GABA (E/I balance), on auditory function is still unclear. In the present work, we analyzed MEGA-PRESS magnetic resonance spectroscopy (MRS) data collected as part of the Michigan Neural Distinctiveness (MiND) Study to estimate GABA and Glutamate/Glutamine (Glx) concentration in both the left and right auditory cortices of 60 young and 144 older adults. GABA and Glx were estimated in the MEGA-PRESS difference spectrum using the Gannet toolbox in MATLAB, correcting for tissue composition. Additionally, auditory performance was measured during Speech-in-Noise, Words-in-Noise, Digits-in-Noise, and Pure-Tone Threshold tasks. Linear regression analysis was applied to examine the association between GABA/Glx levels and auditory performance. We replicated previous findings that lower GABA in the right auditory cortex was associated with worse speech-in-noise performance in older adults. Further, we found that lower Glx levels in the right auditory cortex were also associated with poorer performance in all three hearing in noise measures in the older cohort, while EI balance was not correlated with auditory performance.

Topic Area: PERCEPTION & ACTION: Audition