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The present study incorporated an ear canal temperature-gradient sensitivity model and evaluated its effects on predicted hearing aid output and speech audibility at sea level (0\u2009m) and 4572\u2009m using two representative hearing-loss profiles fitted with the National Acoustic Laboratories\u2014Non-Linear Version 2 prescription. Across all temperature-gradient conditions, peak attenuation was reduced to less than 3\u2009dB, compared with approximately 5.7\u2009dB in the original uniform-temperature model, and decreased further to approximately 1.8\u20131.9\u2009dB under the strongest thermal-regulation condition. A finer-resolution 18-band American National Standards Institute-style Speech Intelligibility Index analysis showed only small between-model differences, with maximum absolute differences at 4572\u2009m of approximately 0.011 for the N3 audiogram and 0.002 for the N6 audiogram. These findings suggest that incorporating the temperature-gradient model substantially reduces predicted altitude-related resonance effects without producing a correspondingly large change in predicted speech audibility.<\/jats:p>","DOI":"10.1121\/10.0046668","type":"journal-article","created":{"date-parts":[[2026,9,23]],"date-time":"2026-09-23T12:07:00Z","timestamp":1790165220000},"page":"2504-2513","update-policy":"https:\/\/doi.org\/10.1063\/aip-crossmark-policy-page","source":"Crossref","is-referenced-by-count":0,"title":["Effects of ear canal temperature gradients on altitude-related resonance shifts and hearing aid output"],"prefix":"10.1121","volume":"160","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-4986-1891","authenticated-orcid":false,"given":"Donghyeon","family":"Yun","sequence":"first","affiliation":[{"name":"Department of Speech, Language and Hearing Sciences, University of Colorado Boulder , Boulder, Colorado 80309,","place":["USA"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"231","published-online":{"date-parts":[[2026,9,23]]},"reference":[{"key":"2026092308065556400_c1","article-title":"Deafness and hearing loss (fact sheet)","author":"World Health Organization","year":"2025"},{"key":"2026092308065556400_c2","unstructured":"National Institute on Deafness and Other Communication Disorders, \u201cQuick statistics about hearing,\u201d Report, National Institute on Deafness and Other Communication Disorders, Bethesda, MD (2022)."},{"key":"2026092308065556400_c3","doi-asserted-by":"publisher","first-page":"e2436140","DOI":"10.1001\/jamanetworkopen.2024.36140","article-title":"Hearing aid use trends among older adults by income and metropolitan vs nonmetropolitan residence","volume":"7","year":"2024","journal-title":"JAMA Netw. 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