| Summary: | 碩士 === 國立高雄師範大學 === 聽力學與語言治療研究所 === 103 === BACKGROUND AND PURPOSE: Most patients with sensorineural hearing loss (SNHL) are believed to have abnormalities of the membranous labyrinth that cannot be detected by conventional imaging techniques. Recently, some authors have reported previously unrecognized bony abnormalities of the inner ear in SNHL patients without cochlear malformation, such as hypoplasia of the bony cochlear nerve canal (BCNC). The aim of this study was to evaluate the diameters of the various bony canals of the inner ear (cochlear nerve, vestibular nerve, facial nerve and inner auditory canal (IAC)) under temporal bone computed tomography (CT) and try to find out the correlation of bony canal diameter and the degree of hearing loss.
PATIENTS AND METHODS: In our retrospective study, 253 patients (506 ears) were included and all received temporal bone CT scan and pure tone audiometry. We used CT scans to measure various bony canals of the inner ear in patients with or without SNHL (213 vs. 293 ears). The degree of hearing loss also was correlated with the diameters of these bony canals (IAC, cochlear nerve, vestibular nerve and facial nerve).
RESULTS: The SNHL is more severe in congenital SNHL group (213 ears, 65.06 dB) than non-congenital SNHL group (293 ears, 20.76 dB) (p < 0.001). The width and length of the BCNC was significantly wider and longer in non-congenital SNHL group than in congenital SNHL group (p < 0.001). Besides, the bony canal of vestibular nerve and IAC had the different width between these two groups (p < 0.001).The average hearing level of congenital hearing loss group revealed obvious negative correlation with the width of the BCNC (correlation coefficient: r = – 0.699, p < 0.001).
CONCLUSION: The result showed significantly smaller and shorter bony cochlear nerve canal, smaller vestibular nerve bony canal and IAC in the congenital hearing loss group. The width of BCNC had negative correlation with sensorineural hearing loss.
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