S J Daniel1, M McIntosh2, O V Akinpelu3, C V Rohlicek2. 1. Department of Otolaryngology - Head and Neck Surgery, Montreal Children's Hospital - McGill University Health Centre, Quebec, Canada. 2. Division of Cardiology, Montreal Children's Hospital - McGill University Health Centre, Quebec, Canada. 3. McGill Auditory Sciences Laboratory, Montreal Children's Hospital - McGill University Health Centre, Quebec, Canada.
Abstract
Objective: To determine the effect of experimentally induced hypoxia, in the first 10 days of life, on physiological hearing in a Sprague-Dawley rat model. Methods: A prospective, controlled animal study was carried out using 22 male rat pups. The rats in the hypoxic group (n = 12) were reared in hypoxia for the first 10 days of life, and subsequently reared in normoxia, while those in the control group (n = 10) were reared in normoxia for the duration of the experiment. Hearing was assessed using auditory brainstem response testing at approximately 72 days of age. Results: The hypoxia group had higher auditory brainstem response thresholds for all frequencies tested (more pronounced at 16 kHz), compared with controls. Wave I-V inter-peak latencies were more prolonged in the hypoxic rats, while both groups had similar wave I latencies. Conclusion: Chronic postnatal hypoxia induced permanent hearing loss in this Sprague-Dawley rat model. Prolonged wave I-V inter-peak latencies suggested functional abnormality in the central auditory pathway.
Objective: To determine the effect of experimentally induced hypoxia, in the first 10 days of life, on physiological hearing in a Sprague-Dawley rat model. Methods: A prospective, controlled animal study was carried out using 22 male rat pups. The rats in the hypoxic group (n = 12) were reared in hypoxia for the first 10 days of life, and subsequently reared in normoxia, while those in the control group (n = 10) were reared in normoxia for the duration of the experiment. Hearing was assessed using auditory brainstem response testing at approximately 72 days of age. Results: The hypoxia group had higher auditory brainstem response thresholds for all frequencies tested (more pronounced at 16 kHz), compared with controls. Wave I-V inter-peak latencies were more prolonged in the hypoxic rats, while both groups had similar wave I latencies. Conclusion: Chronic postnatal hypoxia induced permanent hearing loss in this Sprague-Dawley rat model. Prolonged wave I-V inter-peak latencies suggested functional abnormality in the central auditory pathway.