Acyclovir--therapeutic use Adolescent Adult Aged Aged, 80 and over Ambulatory Care Anti-Inflammatory Agents--therapeutic use Audiometry, Pure-Tone Dexamethasone--therapeutic use Dextrans--therapeutic use Female Follow-Up Studies Hearing Loss, Sudden--drug therapy Humans Male Middle Aged Niacin--therapeutic use Papaverine--therapeutic use Retrospective Studies Young Adult