Abstract:
Introduction: Previous research showing associations between normal hearing level, psychosocial variables, and growth rates in teenagers hypothesised that the associations observed may in part be driven by variations in the capacity to express IGF-1. The aim of this project will be to test this association directly. An observed correlation between IGF-1 levels and hearing, can potentially explain the background for poor Auditory Processing Disorder (APD) scores among children with normal hearing. IGF-1 plays an important role in maturation of the cochlea, which is the hearing organ in the inner ear. Aim: The aim of the research was to investigate the relationship between variations in hearing and APD with serum IGF-1 in teenagers between the age of around 14-16 years with normal hearing. Other variables, such as height and age were also correlated against hearing thresholds. Hypothesis: Variation in IGF-1 expression may have impact on variations in hearing and APD scores. Methods: Eight participants were recruited and underwent two separate sessions for the study, the first one for audiological assessment including pure tone audiometry, tympanometry, speech audiometry and four auditory processing assessments (dichotic digits test, frequency pattern test, random gap detection test and forward digit span test). The second part of the study was IGF-1 assessment, where the participants visited Labtest Clinics for the blood collection and the analysis of IGF-1. Results: All participants had normal hearing. There was a correlation seen between IGF-1 and the average hearing threshold in that participants with better normal hearing tended to have higher concentrations of serum IGF-1. There were no correlations between IGF-1 and hearing thresholds with APD scores or other variables such as height and age. Conclusion: Children with higher IGF-1 have better hearing thresholds, and neither hearing sensitivity nor IGF-1 concentration had an association with processing ability of sound.
