Effects of FM system fitted into normal hearing ear on speech-in-noise recognition in Japanese school-aged children with unilateral severe-to-profound hearing loss

Objectives : We examined speech recognition ability of elementary school-aged Japanese children with unilateral hearing loss under noisy environments and then examined the effects of the FM system fitted into their normal hearing ear on their speech recognition ability. Methods : Twelve children with severe-to-profound sensorineural hearing loss and ten age-matched children with bilateral normal hearing received speech recognition test in quiet and noisy environments. Other nine children with severe-to-profound sensorineural hearing loss received speech recognition test with or without the FM receiver fitted to the normal hearing ear in quiet and noisy environments. Results : Signal-to-noise ratio (SNR) in Japanese elementary school classrooms was estimated to be -6.9 dB at a preferential seat. In noisy environment of -5 dB SNR similar to working classrooms, the correct rates of speech recognition test in children with unilateral hearing loss were significantly lower, compared with those in children with bilateral normal hearing. In the noisy environment, the correct rates in children aided by the FM system with unilateral hearing loss were significantly better, compared with unaided ones. Conclusion : The results suggested that the FM system is recommended as an audiological management for improvement of speech recognition of children with unilateral hearing loss in noisy classrooms.

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本論文は，著者Aki Shimadaの学位論文として提出され，学位審査・授与の対象となっている。