Authors: Lina Motlagh Zadeh¹, Diala Izhiman², Chelsea Blankenship³, David Moore³, Dawn Konrad Martin⁴, Angela Garinis⁵, Patrick Feeney⁵, Lisa Hunter³
¹University of Cincinnati; ²University of Texas at Dallas; ³Cincinnati Children’s Hospital Medical Center; ⁴National Center for Rehabilitative Auditory Research, VA Portland Health Care System; ⁵Oregon Health & Science University
Background: Patients with cystic fibrosis (CF) frequently receive aminoglycosides (AGs) for pulmonary infections, increasing their risk for ototoxicity. While extended-high-frequency (EHF; 9–16 kHz) hearing loss is a known early indicator of AG damage, its impact on speech-in-noise (SiN) perception is unclear. This study investigated whether SiN difficulties in CF individuals reflect cochlear damage (EHF and standard frequency) or neural dysfunction (measured via middle-ear muscle reflexes).
Method: We enrolled 185 participants: 101 individuals with CF treated with intravenous AGs and 84 age- and sex-matched controls. The assessment battery included EHF and standard frequency (SF) pure-tone audiometry (PTA), Bamford-Kowal-Bench (BKB)-SIN testing, transient-evoked otoacoustic emissions (TEOAEs) up to 14.7 kHz, and wideband middle-ear muscle reflex (MEMR) thresholds and growth functions.
Results: Surprisingly, reduced EHF sensitivity (PTA and TEOAEs) was not associated with impaired SiN performance in the CF group. Instead, SF hearing was identified as the primary predictor of SiN outcomes. Furthermore, neural contributions were evident, as increased MEMR growth was significantly associated with poorer SiN performance.
Conclusion: SiN deficits in patients with CF are primarily driven by impairment within the standard frequency range and altered neural reflex function, rather than EHF loss alone. These results suggest that listening difficulties following AG exposure arise from an integrated sensory and neural mechanism, highlighting the need for comprehensive monitoring beyond EHF audiometry.
