Benefit From Directional Microphone Hearing Aids: Objective and Subjective Evaluations.
OBJECTIVE
The aims of this study were to find and compare the effect of directional (DIR) processing of two different hearing aids via both subjective and objective methods, to determine the association between the results of the subjective and objective evaluations, and to find out individual predictive factors influencing the DIR benefit.


METHODS
Twenty-six hearing aid users fitted unilaterally with each two different experimental hearing aid performed modified Korean Hearing in Noise Test (K-HINT) in three DIR conditions; omnidirectional (OMNI) mode, OMNI plus noise reduction feature, fixed DIR mode. In order to determine benefits from DIR benefit within a hearing aid and compare performance of the DIR processing between hearing aids, a subjective questionnaire was administrated on speech quality (SQ) and discomfort in noise (DN) domain. Correlation analysis of factors influencing DIR benefit was accomplished.


RESULTS
Benefits from switching OMNI mode to DIR mode within both hearing aids in K-HINT were about 2.8 (standard deviation, 3.5) and 2.1 dB SNR (signal to ratio; SD, 2.5), but significant difference in K-HINT results between OMNI and OMNI plus noise reduction algorithm was not shown. The subjective evaluation resulted in the better SQ and DN scores in DIR mode than those in OMNI mode. However, the difference of scores on both SQ and DN between the two hearing aids with DIR mode was not statistically significant. Any individual factors did not significantly affect subjective and objective DIR benefits.


CONCLUSIONS
DIR benefit was found not only in the objective measurement performed in the laboratory but also in the subjective questionnaires, but the subjective results was failed to have significant correlation with the DIR benefit obtained in the K-HINT. Factors influencing individual variation in perceptual DIR benefit were still hard to explain.
Hearing Research Laboratory, Samsung Medical Center, Seoul, Korea.
Hee-Sung
HS
Park
Hearing Research Laboratory, Samsung Medical Center, Seoul, Korea. ; Department of Otorhinolaryngology-Head and Neck Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
Il Joon
IJ
Moon
Hearing Research Laboratory, Samsung Medical Center, Seoul, Korea.
Sun Hwa
SH
Jin
Hearing Research Laboratory, Samsung Medical Center, Seoul, Korea. ; Department of Otorhinolaryngology-Head and Neck Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
Ji Eun
JE
Choi
Hearing Research Laboratory, Samsung Medical Center, Seoul, Korea. ; Department of Otorhinolaryngology-Head and Neck Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
Yang-Sun
YS
Cho
Hearing Research Laboratory, Samsung Medical Center, Seoul, Korea. ; Department of Otorhinolaryngology-Head and Neck Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
Sung Hwa
SH
Hong
Hearing Aids; Hearing Loss; Signal-To-Noise Ratio; Speech Intelligibility