Hearing loss has been identified as a major modifiable risk factor for cognitive decline. The Early Age-Related Hearing Loss Investigation (EARHLI) study will assess the mechanisms linking early age-related hearing loss (ARHL) and cognitive impairment. Randomized, controlled, single-site, early phase II, superiority trial. Tertiary academic medical center. One hundred fifty participants aged 55 to 75 years with early ARHL (severity defined as borderline to moderate) and amnestic mild cognitive impairment will be included. Participants will be randomized 1:1 to a best practice hearing intervention or a health education control. The primary study outcome is cognition measured by the Alzheimer Disease Cooperative Study-Preclinical Alzheimer Cognitive Composite. Secondary outcomes include additional measures of cognition, social engagement, and brain organization/connectivity. Trial enrollment will begin in early 2024. After its completion in 2028, the EARHLI trial should offer evidence on the effect of hearing treatment versus a health education control on cognitive performance, social engagement, and brain organization/connectivity in 55- to 75-year-old community-dwelling adults with early ARHL and amnestic mild cognitive impairment.