Hearing Aid Phase II-A Study
[Executive Summary]
The goal of the Hearing Aid Phase II-A Study was to develop and evaluate a repeatable test method for characterizing the audible interference of hearing aids with three phone technologies: CDMA 800 MHz (IS-95), TDMA 800 MHz (IS-54) and PCS 1900 (J-STD-007). An Input Referenced Interference Spectrum (IRIS) approach was developed which examines the entire spectrum of interference and generates equivalent acoustical inputs to represent the interference of the specific phone technologies. The three IRIS patterns were found to be consistent across a variety of hearing aids and gain settings. Interference levels differed significantly with the separation distances and spatial orientations between the phone and hearing aid.
