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The Length of the Organ of Corti in Humankind: A Meta-Analysis
23 Pages Posted: 13 Aug 2020
More...Abstract
Background: The aim of this study is to determine the global average size of normal hearing and congenital severe hearing loss human cochlea and evaluate the effect of common variables on heterogeneity.
Methods: Cochrane, PubMed, Web of Science, and Scopus were systematically searched using the terms ‘cochlear length’, ‘cochlear measurement’, ‘cochlear A value’, and ‘cochlear dimensions’ to retrieve studies published from 1938 to the end of 2019. Studies containing the mean and standard deviation measurements of the cochlear lateral wall length (LW), length of the organ of Corti (OC), and the cochlear basal diameter (A value) were included in the meta-analysis. Study-level characteristics, such as gender, age, hearing status, country, continent, material, method, and subtype of method were determined as predictor covariates. The quality assessment of the studies was carried out individually by two researchers using the form provided by the Joanna Briggs Institute. The data were pooled with the random-effects model. Meta-regression and subgroup analyses were conducted. This meta-analysis was organized using the PRISMA statement. Estimation of the overall effect for the length of OC, LW, and the A value.
Findings: The meta-analysis consisted of 53 studies with a total of 4,580 materials. The first model based on age and gender were found to have no effect on the outcomes. In the second model, hearing status and method were predictors of outcomes. The ratio of residual variance due to heterogeneity was I2 = 0%. These results were not significant. The coefficient of determination of the second model was R2 = 100% (p = 0.038). The overall effect value for OC was 33.088 (95% CI: 32.636 – 33.539) mm. For the third model, in which studies conducted with patients having congenital sensorineural hearing loss were excluded, the OC length was 33.291 (95% CI: 32.824 – 33.758) mm.
Interpretation: The length of OC shows a wide global variation in humankind. This meta-analysis suggests that the cochlea of patients with congenital sensorineural hearing loss is significantly shorter.
Funding Statement: None.
Declaration of Interests: We declare no competing interests.
Ethics Approval Statement: The study protocol was approved by the Clinical Research Ethics Committee of Istanbul Medeniyet University Goztepe Training and Research Hospital (April, 020/0195).
Keywords: Cochlea; size; humankind; cochlear lateral wall length; length of the organ of Corti; the cochlear basal diameter; meta-analysis
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