PMID- 17204898
OWN - NLM
STAT- MEDLINE
DCOM- 20070620
LR  - 20191210
IS  - 0196-0202 (Print)
IS  - 0196-0202 (Linking)
VI  - 28
IP  - 1
DP  - 2007 Feb
TI  - Predictive measures of directional benefit part 2: verification of different 
      approaches to estimating directional benefit.
PG  - 46-61
AB  - OBJECTIVE: In this investigation, the relation between various directivity 
      measures and subject performance with directional microphone hearing aids was 
      determined. DESIGN: Test devices included first- and second-order directional 
      microphones. Recordings of sentences and noise (Hearing in Noise Test, HINT) were 
      made through each test device in simple, complex, and anisotropic background 
      noise conditions. Twenty-six subjects, with normal hearing, were administered the 
      HINT test recordings and directional benefit was computed. These measures were 
      correlated to theoretical, free-field, and Knowles Electronic Manikin for 
      Acoustic Research (KEMAR) directivity index (DI) values, as well as front-to-back 
      ratios (FBR), in situ signal-to-noise ratios (SNR), and a newly proposed Db SNR, 
      wherein a predictive value of the SNR improvement is calculated as a function of 
      the noise source incidence. RESULTS: The different predictive scores showed high 
      correlation to the measured directional benefit scores in the complex 
      (diffuse-like) background noise condition (r = 0.89 to 0.97, p < 0.05) but not 
      across all background noise conditions (r = 0.45 to 0.97, p < 0.05). The Db SNR 
      approach and the in situ SNR measures provided excellent prediction of subject 
      performance in all background noise conditions (0.85 to 0.97, p < 0.05). None of 
      the predictive measures could account for the effects of reverberation on the 
      speech signal (r = 0.35 to 0.40, p < 0.05). CONCLUSIONS: For environments that 
      included a discrete number of noise sources, the in situ SNR and Db SNR estimates 
      were most predictive of subject performance. No predictive approach was 
      indicative of the directional benefit achieved when the speech was also subjected 
      to reverberation (temporal distortion). This finding has implications for 
      real-world estimates of directional benefit.
FAU - Dittberner, Andrew B
AU  - Dittberner AB
AD  - Department of Speech Pathology and Audiology, The University of Iowa, Iowa City, 
      Iowa, USA. adittberner@gnresound.com
FAU - Bentler, Ruth A
AU  - Bentler RA
LA  - eng
PT  - Journal Article
PT  - Validation Study
PL  - United States
TA  - Ear Hear
JT  - Ear and hearing
JID - 8005585
SB  - IM
MH  - *Acoustics
MH  - Adult
MH  - *Amplifiers, Electronic
MH  - Analysis of Variance
MH  - Anisotropy
MH  - Audiometry, Speech
MH  - Female
MH  - *Hearing Aids/standards
MH  - Humans
MH  - Male
MH  - *Models, Theoretical
MH  - Noise
MH  - Reference Values
MH  - Speech Perception
EDAT- 2007/01/06 09:00
MHDA- 2007/06/21 09:00
CRDT- 2007/01/06 09:00
PHST- 2007/01/06 09:00 [pubmed]
PHST- 2007/06/21 09:00 [medline]
PHST- 2007/01/06 09:00 [entrez]
AID - 00003446-200702000-00005 [pii]
AID - 10.1097/01.aud.0000250019.01125.dc [doi]
PST - ppublish
SO  - Ear Hear. 2007 Feb;28(1):46-61. doi: 10.1097/01.aud.0000250019.01125.dc.