Document Detail


Spatial benefit of bilateral hearing AIDS.
MedLine Citation:
PMID:  19194292     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
OBJECTIVES: To assess the extent to which hearing aids improve spatial benefit by restoring the availability of interaural difference cues, the benefit attributable to spatial separation of speech and babble with and without bilateral hearing aids was measured as a function of low-pass cutoff frequency. DESIGN: Twenty-one older adults with sloping high-frequency hearing loss were provided commercially available bilateral hearing aids. After a 3 to 6 month acclimatization period, speech levels corresponding to 50% correct recognition of sentences from the Hearing in Noise Test (HINT) were measured in a 65-dB SPL babble, with speech and babble low-pass filtered at 1.8, 3.6, and 5.6 kHz. Sentences were always at 0 degrees azimuth, and babble was at either 0 degrees or 90 degrees . Speech and babble spectra for all conditions were digitally recorded using a probe microphone placed in each ear canal of each subject. Spectra and levels of speech and babble and unaided thresholds for narrowband noises were used to calculate the aided audibility index and provide predictions of unaided and aided thresholds for HINT sentences, hearing aid benefit, and spatial benefit for each cutoff frequency. In addition, subjects' willingness to tolerate background noise with and without amplification was measured in the spatially coincident and spatially separated conditions using the Acceptable Noise Level (ANL) procedure. RESULTS: Thresholds for HINT sentences in babble and ANL improved significantly when aided and when speech and babble were spatially separated. Specifically, hearing aid benefit improved significantly as cutoff frequency increased from 1.8 to 3.6 kHz but only when speech and babble were spatially separated; likewise, spatial benefit improved significantly from 1.8 to 3.6 kHz but only in the aided condition. No further improvement in hearing aid or spatial benefit was observed when cutoff frequency was increased from 3.6 to 5.6 kHz, although improvement in hearing aid benefit was predicted. CONCLUSIONS: Hearing aid benefit, although significant, was poorer than predicted, suggesting that these older adults with high-frequency hearing loss did not take full advantage of the increase in audible speech information provided by amplification. Hearing aid benefit was also limited because hearing aids for some subjects did not restore speech audibility across the full bandwidth of speech. Unaided and aided spatial benefit was significantly greater than predicted, and aided spatial benefit was greater than unaided. This suggests that these older adults were able to take advantage of interaural level and time difference cues to improve speech recognition in babble and that they benefited from these cues to a greater extent with than without bilateral hearing aids. Finally, in contrast to results of previous studies, ANL may vary for an individual depending on the listening condition.
Authors:
Jayne B Ahlstrom; Amy R Horwitz; Judy R Dubno
Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Ear and hearing     Volume:  30     ISSN:  1538-4667     ISO Abbreviation:  Ear Hear     Publication Date:  2009 Apr 
Date Detail:
Created Date:  2010-06-16     Completed Date:  2010-09-29     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  8005585     Medline TA:  Ear Hear     Country:  United States    
Other Details:
Languages:  eng     Pagination:  203-18     Citation Subset:  IM    
Affiliation:
Department of Otolaryngology-Head and Neck Surgery, Medical University of South Carolina, Charleston, South Carolina 29425-5500, USA. ahlstrjb@musc.edu
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MeSH Terms
Descriptor/Qualifier:
Acoustic Stimulation
Adaptation, Physiological / physiology
Aged
Aged, 80 and over
Audiometry, Pure-Tone
Auditory Threshold / physiology
Hearing Aids*
Hearing Loss, Sensorineural / physiopathology*,  rehabilitation*
Humans
Noise
Patient Satisfaction
Phonetics
Predictive Value of Tests
Psychoacoustics*
Questionnaires
Sound Localization / physiology*
Speech Perception / physiology
Grant Support
ID/Acronym/Agency:
C06 RR14516/RR/NCRR NIH HHS; M01 RR01070/RR/NCRR NIH HHS; P50 DC00422/DC/NIDCD NIH HHS; R01 DC00184/DC/NIDCD NIH HHS

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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