Medial Olivocochlear Modulation in Children With Cleft Lip and Palate: Evidence From Contralateral Suppression of...

ObjectiveTo investigate the potential impact of a history of cleft lip and/or palate (CL/P) on medial olivocochlear (MOC) efferent system modulation in children.DesignCross-sectional study.SettingUniversity-affiliated audiology research laboratory under controlled acoustic conditions.ParticipantsFifty-two children aged 9 to 15 years with typical hearing participated, including 26 children with surgically repaired, non-syndromic CL/P (CL/P group) and 26 typically developing peers (control group).InterventionMOC modulation was assessed using a dual-probe, linear-mode protocol with the Otodynamics ILO292-II system. Transient-evoked otoacoustic emissions (TEOAEs) were recorded in quiet at 1, 1.5, 2, 3, and 4 kHz using a 65 dB peSPL stimulus. Contralateral suppression of TEOAEs was subsequently measured at the same frequencies by presenting 65 dB SPL broadband noise to the contralateral ear.Main Outcome MeasuresTEOAE amplitudes and contralateral suppression amplitudes across the 1 to 4 kHz frequency range.ResultsThe CL/P group exhibited significantly reduced TEOAE amplitudes and significantly lower contralateral suppression amplitudes across the entire 1 to 4 kHz frequency range compared with the control group.ConclusionThe results suggest that typically hearing children with a history of CL/P may show subtle differences in cochlear output and MOC efferent modulation, potentially associated with early life auditory challenges. The observed MOC modulation differences may be partially influenced by reduced TEOAE amplitudes and/or reflect independent efferent regulatory mechanisms. Further investigation is required to clarify the relative contributions of these factors and their potential functional implications.