www.diyhearingaids.com - Add to Cart. DiY hearing aids include ITE, ITC and BTE Hearing aids for the Open Fit technology. Now with self programmable hearing instruments you can adjust ITE, ITC and BTE hearing aids at home. With DiY's discount hearing aids, a hearing aid repair may not be necessary.

A+ and A++ Directional Microphone add on feature

Click to enlarge image(s)

INTRODUCTION

Sensorineural hearing loss (SNHL) is a disability affecting an estimated 25 million Americans. Hearing loss is one of the most common disabilities experienced by the aging veteran population. Aside from causing a loss of sensitivity to speech and other sounds, hearing loss may affect mental and social well-being, which in turn significantly affects an individual's overall quality of life. The use of hearing aids, particularly in quiet environments, has been shown to not only effectively improve speech understanding over unaided listening but also significantly improve quality of life.

Although hearing aids usually allow for better audibility of speech sounds, individuals with hearing impairment continue to have particular difficulty in background noise [6-10]. Background noise negatively affects the hearing aid wearer's understanding of speech, listening comfort, and overall hearing aid benefit [11-13]. One investigation indicated that 25 percent of individuals who own hearing aids but do not wear them cite poor performance in background noise as the reason for hearing aid rejection [14].

The signal-to-noise ratio (SNR) is the primary factor that affects speech understanding in noise [6,15-16]. The SNR describes the intensity differences between the signal of interest (in any given environment) and competing stimuli. For an individual's speech intelligibility in noise to improve, the SNR must be improved. In general, omnidirectional hearing aids do not improve the SNR in comparison with the unaided ear, and in some cases, the SNR can be worsened by amplification [17-19]. Directional hearing aids incorporate multiple microphones (or microphone ports) to improve SNR based on the spatial location of the signal of interest (front hemisphere) relative to unwanted signals (usually the rear hemisphere). The SNR is improved by providing more gain for sounds arriving from frontal azimuths than for those arriving from rear azimuths. The improvement in SNR relative to omnidirectional hearing aid fittings can lead to improved speech intelligibility in noisy environments [18,20-23].

CONCLUSION

Ninety-four subjects completed the double-blinded trial with omnidirectional and directional settings programmed into the experimental hearing aids. Subjects in the three hearing loss groups wore the aids in each of the two experimental settings for 1 month before returning for speech-in-noise testing and laboratory-administered self-assessment questionnaires. The objective measures of speech understanding in noise strongly favored the directional setting for both tests across all hearing loss groups. The lack of significant interaction effects indicated that the degree of benefit from the directional-microphone hearing aids was consistent across the mild, moderate, and severe hearing loss groups. These data support the use of directional-microphone hearing aids for all degrees of hearing loss included in this study. Specifically, the severe-to-profound group showed significant improvements in speech intelligibility in noise with directional microphones.

The results of the subjective measurements demonstrated a considerable halo effect related to the experimental hearing aids. Subjective data did not strongly support an exceptional real-world advantage to directional setting within the experimental hearing aid conditions. These findings are consistent with previous research, suggesting that general subjective measures may lack the sensitivity to capture the differences in speech understanding in noise between the two experimental hearing aid settings. Despite this argument, frequency-response differences between the programs, experimental and placebo effects, and the potential failure of subjects to properly use/position themselves with the hearing aids in background noise may have also contributed to this finding.

Taken together, the objective and subjective data indicate the potential for significant improvements in speech understanding in noise with directional-microphone hearing aids for clinical patients with varying degrees of hearing loss. The lack of significant differences in subjective data, however, indicates that either our measures do not directly address situations where directional microphones are advantageous or our investigators failed to effectively instruct patients in the proper use of directional hearing aids. Clinically, we recommend the use of directional hearing aids when possible for patients with varying degrees of hearing loss and strongly recommend counseling patients on the best practices and positioning when using these devices.

To read the full clinical trial outcome see: http://www.rehab.research.va.gov/jour/09/46/5/gnewikow.html