iHear: Canadian medical student based hearing assessment program for grade school children using a tablet audiometer.

PURPOSE: To evaluate the progress and challenges of a hearing screening program as well as review the incidence of pediatric hearing loss in grade school children participating in this program. METHODS: Medical students from the University of Ottawa established iHear, a grade school hearing assessment program that uses novel tablet audiometry. Over 3 years, children in grades 1 and 2 were assessed and those found to have abnormal results on iHear assessment were then referred to audiology for formal testing, and to otolaryngology if needed. RESULTS: From 2014 to 2017, 753 children aged 5-9 years old were assessed for hearing loss. Mean age of participants was 6.7 years, 51.9% of whom were female. Of the children assessed, 86 (11.4%) had abnormal results and 6 (0.8%) had inconsistent results, necessitating 92 referrals for assessment by a professional audiologist. Of the 65 participants who completed secondary audiologic assessment, 54 (83.1%) were normal and 11 (16.9%) had a definitive hearing loss or abnormal tympanometry. A total of 32 children were lost to follow-up. A total of 118 medical students were involved in the iHear program. CONCLUSIONS: Hearing loss in grade school populations continues to go undetected across Canada. Programs such as iHear demonstrate that gaps in the provision of hearing assessment can be filled effectively by medical students equipped with tablet audiometry. Medical student exposure to audiology and otolaryngology increased through the iHear program.

Mechanisms of neurodegeneration after severe hypoxic-ischemic injury in the neonatal rat brain.

PURPOSE: Apoptosis is implicated in mild-moderate ischemic injury. Cell death pathways in the severely ischemic brain are not characterized. We sought to determine the role of apoptosis in the severely ischemic immature brain. METHODS: Seven-day old rats were randomly assigned to mild-moderate or severe cerebral hypoxia-ischemia (HI) group. After ligating the right common carotid artery, animals were subjected to hypoxia for 90min in the mild-moderate HI or 180min in the severe HI. The core and peri-infarct area were measured in H&E stained brain sections using NIS Elements software. Brain sections were processed for caspase-3, AIF and RIP3 immuno-staining. Number of positive cells were counted and compared between the two groups. RESULTS: The core constituted a significantly higher proportion of the ischemic lesion in the severely compared to the moderately injured brain (P<0.04) up to 7 days post-injury. Apoptotic cell death was significantly higher (P<0.05) in the core than the peri-infarct of the severe HI brain. In the peri-infarct area of severe HI, AIF-induced cell death increased over time and caspase-3 and AIF equally mediated neuronal death. Necroptosis was significantly higher (P=0.02) in the peri-infarct of the severe HI lesion compared to the moderate HI lesion. In males, but not in females, apoptosis was higher in moderate compared to severe HI. CONCLUSIONS: Caspase-independent cell death plays an important role in severe ischemic injury. Injury severity, timing of intervention post-injury and sex of the animal are important determinants in designing neuroprotective intervention for the severely ischemic immature brain.