Speech perception benefits of FM and infrared devices to children with hearing aids in a typical classroom

Children typically learn in classroom environments that have background noise and reverberation that interfere with accurate speech perception. Amplification technology can enhance the speech perception of students who are hard of hearing. Purpose: this study used a single-subject alternating treatments design to compare the speech recognition abilities of children who are hard of hearing when they were using hearing aids with each of three frequency modulated (FM) or infrared devices. Method: Eight 9-12-year-olds with mild to severe hearing loss repeated Hearing in Noise Test (HINT) sentence lists under controlled conditions in a typical kindergarten classroom with a background noise level of +10 dB signal-to-noise (S/N) ratio and 1.1-s reverberation time. Participants listened to HINT lists using hearing aids alone and hearing aids in combination with three types of S/N-enhancing devices that are currently used in mainstream classrooms: (as) FM systems lined to personal hearing aids (b) infrared sound field systems with speakers placed throughout the classroom, and (c) desktop personal sound field FM systems. Results: The infrared ceiling sound field system did not provide benefit beyond that provided by hearing aids alone. Desktop and personal FM systems in combination with personal hearing aids provided substantial improvements in speech recognition. Clinical Implications: This information can assist in making S/N-enhancing device decisions for students using hearing aids. In a reverberant and noisy classroom setting, classroom sound field devices are not beneficial to speech perception for students with hearing aids, whereas either personal FM or desktop sound field systems provide listening benefits.