Principal Investigator/Program Director (Last, first, middle): Zeng, Fan-Gang ABSTRACT The present administrative supplement proposes to examine the relationship between tinnitus and cognition and to treat tinnitus in patients with Alzheimer's disease and related dementia (ADRD). Tinnitus is a hearing disorder that produces auditory perception without auditory stimulation and affects 13-52% of the ARDR population. Using the same experimental protocols as in the active parent award and building upon the preliminary work from a previous supplement, the proposed work will achieve the following specific aims. Specific Aim 1 will investigate the relationship between tinnitus and cognition in ADRD patients. We predict that tinnitus severity will be positively correlated with cognitive decline. Specific Aim 2 will use electric brain stimulation to treat tinnitus in the same patients. The main hypothesis is that, compared with typical non-ADRD subjects, the ADRD patients would require different electric stimulation parameters for optimal tinnitus suppression. We predict that dynamic brain electric stimulation will be more effective than steady-state ear electric stimulation in suppressing tinnitus in ADRD subjects. Tinnitus characterization may serve as a biomarker for monitoring the onset and progression of ADRD, while tinnitus suppression may delay or reduce cognitive decline and development of ADRD. Research Strategy