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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.

Objective: Multiple auditory steady-state responses (ASSRs) to air- and bone-conduction stimuli were recorded in young children with otitis media with effusion (OME). After treatment for OME, differences between pre-treatment bone-conduction ASSR levels and post-treatment conditioned orientation reflex (COR) or air-conduction ASSR levels were examined, and compared with ASSR-estimated air-bone gap (ABG) before treatment. Methods: Navigator Pro with Master was used to assess the threshold of air- and bone-conduction ASSR in both ears at 500 Hz, 1000 Hz, 2000 Hz and 4000 Hz. For bone-conduction ASSR, RadioEar B-71 bone-vibrator placed on the mastoid was used with white-noise masking on the contralateral ear. Results: After ventilation tube placement, the thresholds of COR got closer to those of pre-treatment bone-conduction ASSR in young children with OME. Moreover, post-treatment air-conduction ASSR thresholds also got closer to those of pre-treatment bone-conduction ASSR. The differences between pre-treatment bone-conduction ASSR thresholds and post-treatment COR or air-conduction ASSR thresholds became much smaller than ASSR-estimated ABG before treatment. Conclusion: These findings suggest that bone-conduction ASSR can assess the normal or near normal cochlear sensitivity in young children with conductive hearing loss. It is also suggested that ASSR-estimated ABG can be used clinically to predict their accurate ABG.