Cortical activation during auditory working memory varies with hearing aid use status in age-related hearing loss

Abstract

Abstract Age-related hearing loss (ARHL) is associated with increased listening effort due to greater cognitive demands needed for supporting effective communication. Verbal working memory (WM) is an important mechanism supporting speech understanding in adults with ARHL. Using functional near-infrared spectroscopy and an auditory N-back task (0-, 1-, 2-back load), we examined whether hearing aid status was associated with cortical activation in adults with ARHL. Three groups were compared: typical-hearing adults, experienced hearing aid users, and newly fitted users. Linear mixed-effects models revealed significant Group × Load interactions across the left superior temporal gyrus (STG), left inferior parietal lobule (IPL), and left dorsolateral prefrontal cortex (DLPFC). Experienced users exhibited accuracy comparable to the typical-hearing adults and showed STG and IPL activation patterns more similar to the typical-hearing group, whereas newly fitted users showed reduced activation under higher WM load. These findings indicate that cortical activity during an auditory N-back task engaging verbal WM differs as a function of hearing aid status and is not explained by aided audibility alone. Overall, experienced users exhibited load-dependent cortical activation patterns that more closely resembled those of typical-hearing adults than newly fitted users during an auditory N-back task.