ABSTRACT
BACKGROUND AND OBJECTIVES: When a disability is superimposed on a previous disability, the concept of aggravation of disability should be applied. In rating the disability for hearing loss, we focused on the aggravation of disability and the methods of assessment. SUBJECTS AND METHOD: For the past 12 years, we have provided legal advisory for 111 cases of hearing injury, for which disability had to be rated. In 11 of those 111 cases, disability was assessed in consideration of aggravation of disability. We assessed disability using three rating methods: they were based on 1) a change of hearing level from assumed normal, 2) apportionment of new hearing injury in final hearing, and 3) a change in disability rating. We evaluated for significant differences and correlations between the values obtained by each method. RESULTS: There was a significant difference between the results by the methods 1 and 2. The disability rating by the method 2 showed good correlations with those assessed by the methods 1 and 3. CONCLUSION: When considering aggravation of disability in hearing, the method 2 could be a good alternative when the standard method 3 is inappropriate.