Audiometric configurations of hearing impaired children in Hong Kong: implications for amplification

Children with hearing loss who require special school placement may have a wide range of audiometric configurations. Since such children will vary in auditory status their amplification requirements may also be diverse. This study examined the audiological records of 231 children attending four schools for hearing impaired children in Hong Kong to gain an understanding of common audiometric patterns found in the school children and their auditory rehabilitation needs.

Data on the children's aetiology of hearing loss, hearing status, tympanometric findings and the electroacoustic characteristics of their hearing aids were obtained. For 424 children's ears considered having essentially sensorineural hearing loss, k-means cluster analysis methods were used to categorize audiometric configuration groups.

Cluster analysis that indicated that five distinct audiometric configurations could be found among the school children. Different clusters contained children who had differing amplification needs. The study analysed a number of parameters to check fitting outcomes, including average prescribed gain, frequency-specific measured versus prescribed gain, prescribed frequency response, measured versus prescribed frequency response and the predicted aided thresholds for the children.

The amplification needs associated with these five configurations, including recommended prescription gain, maximum power output and possible signal processing strategies, were considered. The clustering algorithm approach proved useful as a means of grouping distinctive audiometric profiles.