Udit Saxena1, Hansapani Rodrigo2, Srikanta Mishra3
1Department of Audiology & Speech Language Pathology, GMES Medical College & Hospital, Ahmedabad, India
2School of Mathematical and Statistical Sciences, The University of Texas Rio Grande Valley, Edinburg, USA
3Department of Communication Sciences & Disorders, University of Texas Rio Grande Valley, Edinburg, USA
Humans can hear up to 20 kHz. Compared to adults, children have excellent hearing in the extended high frequencies (EHFs). Emerging reports suggest that EHFs contribute to speech-in-noise recognition in children who have normal hearing in the standard frequencies (0.25 through 8 kHz) and EHFs (10-16 kHz). However, the effect of EHF hearing impairment in children remains unclear. This case-control study aimed to answer how EHF hearing loss in children is related to cochlear function in lower frequencies and speech-in-noise perception. We measured hearing thresholds in the standard frequencies and EHFs, distortion product otoacoustic emissions, and digit triplets in noise in children (n=542; 4-19 years) with clinically normal audiograms. Thirty-eight children had some degree of impairment (>15 dB HL) for at least one EHF. Children with EHF impairment had relatively higher thresholds in the standard frequencies even though they had clinically normal audiograms. Otoacoustic emissions in the 2-5 kHz region predicted EHF hearing status and were lower for EHF-impaired children than children with no EHF impairment. EHF impairment had a small but statistically significant effect on the speech recognition threshold, when age effects were adjusted using a linear mixed-effects model. There was no effect of otitis media history, although a history of pressure equalization tube surgery excluded from participation. These findings suggest that despite a normal audiogram, EHF hearing impairment is common in children and is associated with pre-clinical cochlear deficits and poor speech-in-noise recognition. The results will be discussed in detail.