Proteasome Activity in the Plasma as a Novel Biomarker in Mild Cognitive Impairment with Chronic Tinnitus Manuscript Number: 20-0728R2 Author(s): Won Hoon Choi, Young Ho Kim, Yun Kyung Kim, Dong Han Lee, Jun-Young Lee, Jung Hoon Lee, Min Jae Lee, Sang-Yeon Lee, Jong-Chan Park, Yejin Yun