You searched for: “hypoacusis
hypoacusis (s) (noun), hypoacuses (pl)
Reduced or slightly impaired hearing which often involves neurosensory organs: In the early 1930s, when Bill realized that he was experiencing hypoacusis, he could not afford a hearing aid, so he put a small button on a string, put the button in his ear and the string in his pocket and, as a result, Bill noticed that people automatically spoke louder and so he had no trouble understanding them."