Audiological Analysis of Patients with Intact Tympanic Membranes and Conductive or Mixed Hearing Loss / 听力学及言语疾病杂志

ABSTRACT

Objective To investigate audiological characteristics of patients with intact tympanic membranes and conductive or mixed hearing loss .Methods A retrospective study was carried out among 30 patients (42 ears) with intact tympanic membranes and conductive or mixed hearing loss who underwent exploratory tympanotomy . The preoperative outcomes of pure tone audiometry ,tympanometry ,resonant frequency of middle ear and temporal bone CT scan were analyzed .Results Among 42 ears ,30 ears with otosclerosis and 12 ears with ossicular chain dis-ruption were confirmed in exploratory tympanotomy ,but only 5 ears showed positive findings in CT scan .The mean thresholds of bone conduction ,air conduction and air -bone gap at frequencies of 0 .5 ,1 and 2 kHz were 27 .5 ± 1 .3 dB HL ,67 .0 ± 1 .8 dB HL ,39 .5 ± 1 .1 dB HL ,respectively .An analysis of tympanometric data of all patients re-vealed that 50% of all ears (21/42) were type A tympanograms ,42 .9% (18/42) were type As tympanograms ,and 7 .1% (3/42) were type Ad tympanograms .The mean of the resonant frequency of the middle ear in otosclerositic patients (1 079 .0 ± 67 .4 Hz) was significantly higher than ossicular chain disruption patients (633 .3 ± 43 .6 Hz) . Conclusion Otosclerosis is the most common in the patients with intact tympanic membranes and conductive or mixed hearing loss .The middle ear resonant frequency of otosclerositic patients is significantly higher than that of ossicular chain disruption patients .