In this study of 46 elderly patients with age-related hearing loss, using alpha lipoic acid (60 mg/d) and vitamin C (600 mg/d), in combination with rebamipide (an antioxidant medication being researched for gastritis, ulcerative colitis, etc.), for a period of 8 weeks, was found to significantly improve hearing levels at all frequencies. The authors conclude, "The results of this study suggest that therapy with radical scavengers has the potential to become an effective new therapy for age-related hearing loss."
Though rebamipide is not yet available (and may not be needed given the availability of natural antioxidants) I would recommend a good multivitamin powder plus lipoic acid 200-300 mg a day to optimize hearing.
Radical scavengers for elderly patients with age-related hearing loss," Takumida M, Anniko M, et al, Acta Otolaryngol, 2008 June 11; 1-9