Hearing Aid Research 

Phase I: Study of the Interaction of Wireless Phones and Hearing Aids

Objectives 

- Survey existing literature

- Develop protocol for test

- Execute test plan

- Recommend solutions

Phase IIA: Development of a Laboratory Protocol for Interference Evaluat

Objective 

Develop and evaluate a repeatable test method for characterizing the audible interference of hearing aids with three phone technologies: CDMA (800 MHz), TDMA-50 Hz (800 MHz), and PCS-1900

 

Phase IIB: Clinical Determination of the Speech-to-Interference Ratio

Objective 

Measure speech recognition and annoyance of 24 hearing aid wearers with five levels of the IRIS signal for each phone technology mixed with speech at 65 dB SPL

 

Phase IIC

Objective 

Use a 900 MHz waveguide to test 34 hearing aids against a 900 MHz RF signal 80% amplitude modulated with a 1 kHz sine wave, and against a TDMA-50 Hz (800 MHz) phone.

 

Phase IIIA

Scope:

•  8 Hearing Aids (ranging from low to high immunity)
• 10 Wireless Phones (CDMA, TDMA-50 Hz, TDMA-217 Hz at 800 and 1900 MHz)
• 5 Power Levels (0, 6, 12, 18, and 24 dBm)

 Objective: 

Compare acoustic measurements of the interference between various combinations of wireless phones and hearing aids to the usability classification predicted by the C63.19 Hearing Aid - Wireless Phone Compatibility Standard. 

Phase IIIB

Objective 

The overall objective of the current research was to relate subjective ratings of speech intelligibility, usability, and annoyance to acoustic measurements of the interference between wireless phones and hearing aids.

 

CDG Study

Scope:

- 9 HA

- 4 CDMA Phones- 2 CDMA Manufacturers- 800 & 1900 MHz

Objective:

Investigate the effects of various phone puncture rates and transmission power levels to determine the power level at which interference becomes unacceptable