Table 1. Remote Microphone Technology Options for Children with Normal-Hearing Sensitivity, Mild Hearing Loss, and Unilateral Hearing Loss.
Personal RM Systems Transmitter & Receiver | Design Integrated | • FM/DM receiver connects to dedicated device • Pros: Good connection; small • Cons: Works with only one specific HA; expensive for schools if student moves out of area |
Universal | • FM/DM receiver for HA device with a device-specific adaptor (e.g., audio shoe) • Pros: Small; works with all devices • Cons: Adaptor susceptible to malfunction/ connection issues |
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Stand-Alone for Normal-Hearing Sensitivity (Transparent) | • FM/DM limited-gain receiver designed for normal pure-tone thresholds, but processing problems • Pros: Small; improves speech recognition in multiple populations; non-occluding • Cons: Children with tactile issues may not tolerate |
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Electromagnetic/Near Field Magnetic Imaging | • FM/DM/Infrared; requires neckloop & special receiver or ID with receiver • Pros: One receiver/ID sends to both HAs or earphones/buds; less expensive • Cons: May not have advanced signal processing; personal device must have telecoil or NFMI capability |
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Personal RM Accessory | Accessory Microphone | • DM; manufacturer-specific microphone; may be used with ID • Pros: No receiver if it's built into the HA (e.g., 2.4-GHz radio antenna); less expensive than RM systems • Cons: May use with only one manufacturer's HAs; may not contain advanced signal processing |
Soundfield Systems | Desktop | • FM, Small speaker placed on child's desk • Pros: No equipment for child; less expensive than RM systems • Cons: Minimal gain, portability limited for young children; does not address classroom reverberation |
Single-Speaker Classroom | • FM/DM, single loudspeaker placed in corner of room • Pros: No equipment for child; some improvement to SNR; less expensive than RM systems • Cons: Less gain than desktop; sound may not be equally distributed across room; does not address classroom reverberation; limited portability |
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Multiple-Speaker Classroom | • FM/DM, multiple loudspeakers placed around room • Pros: No equipment for child; some improvement to SNR; less expensive than RM systems • Cons: Less gain than desktop; unequal distribution of sound if installed incorrectly; does not address classroom reverberation; limited portability |
Abbreviations: DM = digital modulation transmission; HA = hearing aid; FM = frequency modulation transmission; ID = intermediary device; NFMI = near field magnetic induction; RM = remote microphone; SNR = signal-to-noise radio.