Effects of age and hearing mechanism on spectral resolution in normal hearing and cochlear-implanted listeners.

Spectral resolution limits speech perception with a cochlear implant (CI) in post-lingually deaf adults. However, the development of spectral resolution in pre-lingually deaf implanted children is not well understood. Acoustic spectral resolution was measured as a function of age (school-age versus adult) in CI and normal-hearing (NH) participants using spectral ripple discrimination (SRD). A 3-alternative forced-choice task was used to obtain SRD thresholds at five ripple depths. Effects of age and hearing method on SRD and spectral modulation transfer function (SMTF) slope (reflecting frequency resolution) and x-intercept (reflecting across-channel intensity resolution) were examined. Correlations between SRD, SMTF parameters, age, and speech perception in noise were studied. Better SRD in NH than CI participants was observed at all depths. SRD thresholds and SMTF slope correlated with speech perception in CI users. When adjusted for floor performance, x-intercept did not correlate with SMTF slope or speech perception. Age and x-intercept correlations were positive and significant in NH but not CI children suggesting that across-channel intensity resolution matures during school-age in NH children. No evidence for maturation of spectral resolution beyond early school-age in pre-lingually deaf implanted CI users was found in the present study.

Interrater reliability of a phenotypic assessment tool for the ear morphology in microtia.

The Elements of Morphology Standard Terminology working group published standardized definitions for external ear morphology. The primary objective of our study was to use these descriptions to evaluate the interrater reliability for specific features associated with microtia. We invited six raters from three different subspecialities to rate 100 ear photographs on 32 features. We calculated overall and within specialty and professional experience intraclass correlation coefficients (ICC) and 95% confidence intervals. A total of 600 possible observations were recorded for each feature. The overall interrater reliability ranged from 0.04 (95% CI: 0.00-0.14) for the width of the antihelix inferior crus to 0.93 (95% CI: 0.91-0.95) for the presence of the inferior crux of the antihelix. The reliability for quantitative characteristics such as length or width of an ear structure was generally lower than the reliability for qualitative characteristics (e.g., presence or absence of an ear structure). Categories with very poor interrater reliability included anti-helix inferior crux width (0.04, 95% CI: 0.00-0.14), crux helix extension (0.17, 95% CI 0.00-0.37), and shape of the incisura (0.14, 95% CI: 0.01-0.27). There were no significant differences in reliability estimates by specialty or professional experience for most variables. Our study showed that it is feasible to systematically characterize many of structures of the ear that are affected in microtia. We incorporated these descriptions into a standardized phenotypic assessment tool (PAT-Microtia) that might be used in multicenter research studies to identify sub-phenotypes for future studies of microtia.