The Evaluation Test And Masking Therapy Of Subject Tinnitus

Objective: To undergo tinnitus evaluation test and masking therapy of subject tinntus associated with sensorineural hearing loss as a reference for diagnosis and guiding masking therapy.Materials and methods: All the 66 patients with subject tinnitus are come from outpatients of Xiang Ya Hospital Of Central South University and diagnosed as sensorineural hearing loss by detail examinations. The results of pure tone audiometry(PTA) show that there are three types of audiometric curve: steep drop type,slow drop type and flat type. 66 patients divide into three groups acoording to the results of PTA : steep drop type: 28 patients; slow drop type: 20 patients; flat type: 18 patients; All the patients underwent tinnitus evaluation tests(pitch matching,intensity matching, tinnitus masking curves, residual inhibition) and masking therapy. We take the tinnitus handicap inventory (THI) to evaluate the efficacy of masking therapy. We compared the results of the tinnitus tests and efficacy of masking therapy among the three groups.Results: (1)The average tinnitus pitch of the three groups is respectively 4559Hz (steep drop type),4016 Hz(slow drop type), 1644 Hz(flat type). The percentage of the tinnitus picth which is in 4KHz and above is respectively 57.1%(steep drop type), 55%(slow drop type), 16.7%(flat type). The comparison of the average tinnitus pitch among the three groups was statistically significant(P<0.01). The significant statistics difference was found in multiple comparison(P<0.05) except the group of steep drop type and the group of slow drop type. (2) The average tinnitus intensity of all the patients is 6.8 dBSL. The average tinnitus intensity of the three groups is respectively 5.7 dBSL (steep drop type), 6.2 dBSL (slow drop type), 9.2 dBSL (flat type). The comparison of the average tinnitus intensity among the three groups was statistically Significant(P<0.05). The significant statistics difference was found in multiple comparison(P<0.05) except the group of steep drop type and the group of slow drop type. (3) The percentage of the patients with the convergence & congruence tinnitus masking curves is respectively 64.4%(steep drop type), 40%(slow drop type), 16.7%(flat type).There is a significant difference in the distribution of the masking curves among the 3 groups (P <0.05). The significant statistics difference was found in multiple comparison(P<0.0125) only between the group of steep drop type and the group of flat type. (4) The percentage of the patients with the positive residual inhibition is respectively 89.3%(steep drop type), 75%(slow drop type), 36.6%(flat type). There is a significant difference in the distribution of the residual inhibition among the 3 groups (P <0.05). The significant statistics difference was found in multiple comparison(P<0.0125) only between the group of steep drop type and the group of flat type.(5)The effective rate (cure rate plus obvious effective rate) of the masking therapy is respectively 89.2%(steep drop type), 55%(slow drop type), 11.1%(flat type). The comparison of the effective rate among the three groups was statistically significant(P<0.05). The significant statistics difference was found in multiple comparison(P<0.0125).Conclusion: (1) Tinnitus with steep drop type manifest as low intensity (average intensity: 5.7 dBSL); high frequency(average frequency: 4559Hz); residual inhibition are almost positive; and is usually consistent with convergence & congruence tinnitus masking curves; masking therapy has better effect in the treatment of this type of tinnitus . (2) Tinnitus with slow drop type manifest as low intensity (average intensity: 6.2dBSL); high frequency(average frequency: 4016Hz); the distribution of residual inhibition and tinnitus masking curves has no obviously characteristics; The effective rate of masking therapy of this type of tinnitus was higher than tinnitus with flat type but low than that of tinnitus with steep drop type. (3) The intensity of tinnitus with flat type (average intensity: 9.2 dBSL) is higher than the previous groups. The distribution of frequency of this type has no obviously characteristics; residual inhibition are almost negative; and is usually consistent with divergence & persistence tinnitus masking curves; masking therapy has unsatisfactory curative effect in the treatment of this type of tinnitus . (4) For the tinnitus patients with steep drop type audiometric curve, we recommend masking therapy; For the tinnitus patients with slow drop type audiometric curve, we may attempt to perform masking therapy; For the tinnitus patients with flat type audiometric curve, we do not recommend masking therapy.