Hearing aid manufacturers are increasingly offering technology that claims to improve sound quality, hearing in noise, spatial awareness and automatic changes for directional microphone modes. While the benefits may be gleaned through subjective evaluation, objective verification of these features requires new protocols for real-ear and test box measures.
ReSound’s Stephen Hallenbeck, Au.D., and Tammara Stender, Au.D. presented at the 2013 AudiologyNOW! conference concepts and tools to objectively verify binaural features in hearing aids.
Why do we verify:
- To align expectations.
- To provide mental construct from which clinicians can develop effective counseling messages.
- To ensure proper function.
It is important to understand which features to verify. Binaural processing is a “buzz word” and some features may be easily verified and other extremely difficult. The ReSound template includes:
- Binaural Directionality: presence of speech or noise on one side will alter which hearing aid is in directional. With one test box we can establish that changing the stimulus on one side changes the other side.
- Comfort Phone: use a magnet to trigger the Comfort Phone in the HI outside the test box. The HI inside the test box should reduce by 6 dB and when the magnet is removed the hearing aid should return to baseline.
- Environmental Optimizer II: with both hearing aids in the test box and speech in noise we expect the output of the measured HI to increase by approximately 6 dB. With one HI out of the test box, we expect the difference in environments to cause the increase to be slightly reduced.
- Synchronized Softswitching: this is an environmentally dependent automatic change between omnidirectional and directional settings. The Synchronization ensures that these changes happen in both simultaneously and is difficult to visualize within a test box.