Clinical evaluation of a new hearing aid anti-cardioid directivity pattern

Area of Science:

• Audiology
• Signal Processing
• Hearing Aid Technology

Background:

• Background noise and sound source directionality pose significant challenges for hearing aid users.
• Traditional hearing aid microphone patterns may not optimally address speech signals originating from behind the user.

Purpose of the Study:

• To evaluate a novel directional hearing aid algorithm designed to automatically adopt an anti-cardioid pattern.
• To assess the algorithm's effectiveness in improving speech recognition when speech originates from behind the user amidst background noise.

Main Methods:

• The study utilized the Hearing-In-Noise-Test (HINT) in a soundfield setup.
• Participants (n=21) with sensorineural hearing loss were tested with three hearing aid conditions: omnidirectional, conventional adaptive directional, and the new adaptive directional with anti-cardioid algorithm.
• Speech stimuli were presented from the rear (180°), while competing noise originated from the front (0°).

Main Results:

• A significant effect of hearing aid microphone setting was observed (p < .0001).
• The anti-cardioid algorithm yielded the best results, with a mean speech recognition score of -5.7 dB.
• Conventional adaptive directional and omnidirectional settings resulted in scores of 4.2 dB and -0.1 dB, respectively.

Conclusions:

• The signal classification system successfully guided the algorithm to adopt the anti-cardioid pattern.
• The anti-cardioid polar pattern demonstrably enhanced speech recognition in challenging background noise conditions for sounds originating from behind.
• This technology shows promise for improving audibility in specific, difficult listening environments.