목적: Hearing loss is the primary risk factor for demantia, and it may affect central auditory function and cognitive ability in the brains of older individuals. The speech-in-noise (SiN) test, involving sensory encoding and cognitive neural processing, assesses central auditory function. Electroencephalogram (EEG) has a history of quantifying neural responses to speech stimuli but has seen limited use in studying brain response changes in older adults concerning hearing and cognitive abilities. This study aims to measure brain oscillations during SiN listening and their relationship with cognitive abilities in older adults with hearing loss (HL) and/or mild cognitive impairment (MCI). 방법:A total of 20 participants were involved in this study, including 13 i ndividuals with mild cognitive impairment (MCI), 10 with hearing loss  (HL), and 7 with both MCI and HL (MCI+HL). Additionally, 10 individual s with normal hearing (NH) served as controls. All participants underw ent cognitive function assessment using the Montreal Cognitive Assessm ent (MOCA) test. EEG activity was recorded from 64 scalp electrodes while participants  actively performed the Korean digit-in- noise test. In a passive condition, participants listened to digit sti muli while watching silent, closed- captioned movies. We employed DICS beamforming to estimate the sources of neural activity for each frequency band. 결과:In behavioral data, both HL groups (HL only and MCI+HL) showed lower DiN thresholds compared to NH and MCI-only groups. The MCI+HL group had significantly reduced DiN accuracy during attentive listening. When comparing active versus passive listening, the HL group exhibited alpha event-related desynchrony (ERD) enhancements in broader areas of the brain compared to other groups. Moreover, a positive correlation between alpha power in the right frontal lobe and DiN performance was found in HL group. Conversely, MCI+HL group displayed increased frontal lobe activity in the theta rhythm. The theta power in MCI individuals is negatively associated with DiN performance and with MOCA scores. 결론:Our findings suggest that the alpha rhythm may serve as a neural correlate of auditory attention, while theta rhythm appears to be more sensitive to cognitive function. Neural activity during SiN listening is correlated not only with listening ability but with cognitive function.