A Study About Mechanism Of Tinnitus Patients With Normal Hearing By Clinical Audiology Examination

[Objective] Tinnitus is very popular in the people. We studied the characteristics of middle ear muscle reflexes , the tone decay test, matching test, acoustic emission (OAE), auditory brainstem response(ABR) in patients with complaints of tinnitus, explored causes of tinnitus and evaluated clinical value in diagnosis of the patients with tinnitus.[Methods] We evaluated 51 patients (73 ears) with tinnitus and normal hearing. We divided all tinnitus patients into two groups by the matching test .The patients in the first group with low tone tinnitus (34 ears ) ,the other patient with high tone tinnitus (39 ears ) . The inclusion criterion that was to have thresholds of 25 dB or less in each frequency at tonal audiometry. Normal middle ear function, as a prerequisite for the validity of all other tests, is established by tympanometry. Stapedial reflex threshold , Stapedial reflex decay, DPOAE, TEOAE ,SOAE ,ABR were performed in each patient respectively. 50 normal subjects (100 ears) were chosen as control .The result was analyzed by the SPSS 11.5 for windows. [Results] The patients of the low tone tinnitus groups the prevalence of TEOAE was low compared to that in control group (P<0.05) . The patients with high tone tinnitus have a lower amplitudes of DPOAE between 2000~8000Hz than that in control group (P<0.05 ) . The patients with low tone tinnitus have a lower amplitudes of DPOAE between 500~2000Hz than that in control group (P<0.05 ) . The prevalence of SOAE of the two tinnitus groups patients were low compared to that in controlgroup(P<0.05). One patient had no contralateral suppression of DPOAE, whereas middle ear muscle reflexes ,the tone decay test and ABR test were abnormal. After two weeks therapy with drug, the DPOAE amplitudes of the patients with not good cochlear function before thetherapy the OAE test had more increase than patients with good cochlear function.[Conclusion] These results suggest that OAE could reflect cochlear lesion in early stage. The functional examination of cochlear and ABR test were used as important diagnostic tests for patients with tinnitus and normal hearing, and might be helpful for the location diagnosis of tinnitus.