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Normative diameters and effects of aging on the cochlear and facial nerves in normal-hearing Korean ears using 3.0-tesla magnetic resonance imaging

Authors


  • The authors have no funding, financial relationships, or conflicts of interest to disclose.

Abstract

Objectives/Hypothesis:

To assess the normative size of the cochlear nerve (CN) and facial nerve (FN) in normal-hearing ears and to determine whether nerve size varies with age.

Study Design:

Cross-sectional.

Methods:

We included 169 ears with normal hearing between 2005 and 2010. The height, width, and cross-sectional area (CSA) of the CN and FN in the middle of the internal auditory canal were measured on oblique sagittal images of 3.0-T magnetic resonance imaging. Results were compared by age. Young subjects were divided into three age groups, 0–5, 6–10, and 11–15 years. Subjects over age 40 years were divided into groups at 10-year intervals.

Results:

Mean age was 32.6 years (range, 0.75–79 years). We found that the CN had significantly greater vertical (1.10 ± 0.21 mm vs. 0.95 ± 0.21 mm) and horizontal (1.11 ± 0.20 mm vs. 1.03 ± 0.22 mm) diameters than the FN. The CSA of the CN was larger than that of the FN (0.98 ± 0.33 mm2 vs. 0.79 ± 0.31 mm2). Except for the CN vertical diameter, there were no significant differences between right and left ears. Sex did not affect the nerve size. Although the CN was not affected by age, the FN vertical diameter and CSA of children <5 years were significantly smaller than those of children aged >5 years. The size of the two nerves did not differ among groups over age 40 years.

Conclusions:

The CN is not affected by age in normal-hearing ears. The FN vertical diameter and CSA of children <5 years are smaller than those of older children.

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