[Study on tinnitus masking--an evaluation of ipsilateral and contralateral masking for tinnitus]

In this study, the tinnitus masking curves measured by the ipsilateral and contralateral masking test were evaluated for the unilateral tinnitus cases of following 4 groups; 40 cases without hearing loss, 22 cases with symmetrical sensorineural hearing loss, 12 cases with unilateral deafness, and 70 cases with unilateral sensorineural hearing loss. Then the characteristics of tinnitus masking curves and central masking phenomenon for tinnitus masking were investigated. Consequently, tinnitus was masked by a masking tone given from nontinnitus ear when it reached at some definite loudness level, in spite of the presence of hearing loss or the degree of hearing loss in tinnitus ear. Then it was suggested to be a influence of central masking phenomenon in the contralateral tinnitus masking.