Audx pro

The children were assessed with a standard clinical test battery composed of otoscopy examination, tympanometry, middle ear muscle reflexes (MEMR), distortion product otoacoustic emissions (DPOAEs; Bio-Logic AuDX Pro), auditory brainstem responses (ABRs), and behavioral tests (pure tone audiometry, speech awareness and recognition thresholds and speech discrimination scores). Several of these tests were repeated over time to monitor the progression of hearing loss. The ABRs were performed during natural sleep and/or under sedation using a 4-electrode 2-channel montage with insert earphones to present air conduction clicks (Vivosonic Integrity, Toronto, ON, Canada). The initial rate of stimulation was 27.5/sec or 37.7 and reduced to 7.6/sec in some occasions.

Our study was approved by the Seattle Children’s Hospital and University of Washington institutional review boards. All studies complied with relevant ethical regulations. Patients were recruited during routine appointments in otolaryngology and craniofacial clinics. Parental permission was obtained for participants under the age of 18 years. Children age 7 to 17 years provided written assent. Assent was obtained after parental permission was granted. Children age 7 to 12 years signed a simple assent form, and children age 13 to 17 years signed a consent form. Parents co-signed the consent form. Participants 18 years and older signed a consent form. We excluded patient ears where the patient was unable to complete the testing. Investigators were not blinded. In the study, the commercial OAE device used for testing was the AudX Pro (Bio-logic, 2006).