Communications Biophysics

Contains reports on seven research projects split into three sections, with research objective for the final section.National Institutes of Health (Grant 2 PO1 NS 13126)National Institutes of Health (Grant 5 RO1 NS 18682)National Institutes of Health (Grant 1 RO1 NS 20322)National Institutes of Health (Grant 1 RO1 NS 20269)National Institutes of Health (Grant 5 T32 NS 07047)Symbion, Inc.National Institutes of Health (Grant 5 RO1 NS10916)National Institutes of Health (Grant 1 RO1 NS16917)National Science Foundation (Grant BNS83-19874)National Science Foundation (Grant BNS83-19887)National Institutes of Health (Grant 5 RO1 NS12846)National Institutes of Health (Grant 5 RO1 NS21322)National Institutes of Health (Grant 5 RO1 NS 11080

Communications Biophysics

Contains research objectives and reports on eight research projects split into three sections.National Institutes of Health (Grant 2 PO1 NS13126)National Institutes of Health (Grant 5 RO1 NS18682)National Institutes of Health (Grant 5 RO1 NS20322)National Institutes of Health (Grant 1 RO1 NS 20269)National Institutes of Health (Grant 5 T32 NS 07047)Symbion, Inc.National Institutes of Health (Grant 5 R01 NS10916)National Institutes of Health (Grant 1 RO NS 16917)National Science Foundation (Grant BNS83-19874)National Science Foundation (Grant BNS83-19887)National Institutes of Health (Grant 5 RO1 NS12846)National Institutes of Health (Grant 1 RO1 NS21322-01)National Institutes of Health (Grant 5 T32-NS07099-07)National Institutes of Health (Grant 1 RO1 NS14092-06)National Science Foundation (Grant BNS77-21751)National Institutes of Health (Grant 5 RO1 NS11080

Communications Biophysics

Contains reports on seven research projects split into three sections.National Institutes of Health (Grant 5 PO1 NS13126)National Institutes of Health (Grant 1 RO1 NS18682)National Institutes of Health (Training Grant 5 T32 NS07047)National Science Foundation (Grant BNS77-16861)National Institutes of Health (Grant 1 F33 NS07202-01)National Institutes of Health (Grant 5 RO1 NS10916)National Institutes of Health (Grant 5 RO1 NS12846)National Institutes of Health (Grant 1 RO1 NS16917)National Institutes of Health (Grant 1 RO1 NS14092-05)National Science Foundation (Grant BNS 77 21751)National Institutes of Health (Grant 5 R01 NS11080)National Institutes of Health (Grant GM-21189

Communication Biophysics

Contains reports on six research projects.National Institutes of Health (Grant 5 PO1 NS13126)National Institutes of Health (Grant 5 RO1 NS18682)National Institutes of Health (Grant 5 RO1 NS20322)National Institutes of Health (Grant 5 R01 NS20269)National Institutes of Health (Grant 5 T32NS 07047)Symbion, Inc.National Science Foundation (Grant BNS 83-19874)National Science Foundation (Grant BNS 83-19887)National Institutes of Health (Grant 6 RO1 NS 12846)National Institutes of Health (Grant 1 RO1 NS 21322

The Effects of Aging on Binaural and Spatial Hearing

As the size of the older adult population continues to grow, so too does the need to better understand the complex effects of aging on everyday listening tasks involving binaural and spatial hearing. It is well known that older individuals with and without hearing loss often complain of difficulty hearing and understanding speech. In this article the results of recent studies evaluating the effects of aging on various binaural and spatial tasks are summarized and discussed, and an attempt is made to identify the difficulties encountered in daily living by older adults because of problems processing binaural and spatial information. The results of most of the studies reviewed here indicate that the ability of older listeners to localize sound sources, to obtain a gain in speech intelligibility in noise when speech and noise sources are separated, to improve the detection of signals in noise by using binaural cues (as measured with a masking level difference task), and to discriminate interaural differences in time and intensity decline with increasing age. These decreases in performance on binaural and spatial tasks are generally observed even when the effects of hearing loss are taken into account

A Procedure for Testing Speech Intelligibility in a Virtual Listening Environment

Objective: The development of a test of virtual speech intelligibility in noise that enables assessment in typical, everyday listening situations. To eliminate extraneous confounding factors, digital signal processing was incorporated to simulate listening environments and source locations and allow presentation of stimuli via earphones. Design: Source-to-eardrum transfer functions measured on KEMAR for various source locations in anechoic and reverberant environments were used to process monosyllabic words and speech-spectrum noise. Speech intelligibility was measured for three speech and noise configurations in two environments using an adaptive procedure to determine the signal-to-noise (S/N) ratio for 50% intelligibility. Results: Normal-hearing listeners achieved 50% intelligibility of monosyllabic words at significantly lower S/N ratios in a virtual anechoic environment than in a virtual reverberant environment. Speech intelligibility improved significantly in both environments when the speech and noise sources were separated, but the intelligibility gain in the anechoic environment was four times larger than in the reverberant environment. Conclusions: This test is easy to administer and score, and it provides a means for measuring: 1) the effects of separating speech and noise sources and 2) the effects of reverberation on speech intelligibility in noise while eliminating confounding factors such as calibration

Assessment of Binaural and Spatial Hearing

Recent research in the area of binaural and spatial hearing has been marked by the introduction of a number of new test procedures and test systems. The development of these systems and procedures to evaluate sound source localization in quiet and in noise, speech intelligibility in noise, and signal detection in quiet and in noise has been motivated by the need for better clinical tools and improved theoretical models. Several of these new tests are described in this review, and, if it has been tested, their sensitivity to the effects of hearing loss and/or auditory pathology is reported. Some of these tests are currently being evaluated for routine clinical use; others were designed strictly for measuring binaural sensitivity in a laboratory setting. The contribution of these tests to the current audiologic test battery and the use of the test results for developing focused rehabilitation strategies for individual patients is also discussed

A Test of Virtual Auditory Localization

Objective: The purpose of this study was to evaluate a test of virtual auditory localization including assessment of its ease of administration and its sensitivity to differences in binaural performance in children and adults. This test eliminates many potential problems inherent in any free-field localization test such as calibration problems, problems replicating source and listener locations, and issues associated with head movements. Design: Binaural performance was measured using the virtual localization test and a simple binaural detection task, the masking-level difference (MID), for three groups of subjects: adults, children with a negative history of otitis media, and children with a positive history of otitis media. There were five subjects in each group. The adults were all student volunteers; the children were recruited first and subsequently placed into groups based on their medical histories obtained from their physicians and parental reports. Results: Results indicate that this test of virtual auditory localization is useful for measuring binaural performance in children and adults and is sensitive to differences in binaural processing. Performance of the adults and children with a negative history of otitis media was comparable on both of the binaural tests, and on the binaural detection task, was similar to that reported in the literature for normal-hearing listeners; but the children with a positive history of otitis media performed more poorly on both tests. Conclusions: The results of this study indicate that the virtual localization test described here is easy to administer to children and adults. The signal processing techniques used in this virtual auditory localization test lend themselves to straightforward comparisons across different laboratories and clinics and make this test a potentially useful clinical tool. The development of such a clinical test is currently under study

Effects of Roving Level Variation on Monaural Detection with a Contralateral Cue

Monaural detection with a contralateral cue (MDCC) was measured with and without a 20-dB overall roving level to determine the contribution of loudness to performance on this task. Psychometric functions were obtained for three normal-hearing subjects as a function of the signal-to-noise ratio for pure-tone and 1/3-oct noiseband signals at 500 and 4000 Hz with a wideband noise masker. At 4000 Hz, the roving level degrades performance for the narrow-band noise signal by about 5.3 dB. In addition, the presence of the contralateral cue degrades performance for both the pure-tone and narrow- band noise signals at 4000 Hz by 3 to 6 dB. At 500 Hz, however, performance is not affected by the roving level, and is improved by 3 to 6 dB by the contralateral cue. These results indicate that loudness is being used as a cue only for detection of the 4000-Hz narrow-band noise

The effects of reverberation on a listener\u27s ability to recognize target sentences in the presence of up to three synchronized masking sentences.

Objective: To determine the effects of room reverberation on target sentence recognition in the presence of 0-to-3 synchronous masking sentences. Design: Target and masker sentences were presented through four loudspeakers (± 90° and ± 45° azimuth; 1m from the listener) in rooms having reverberation times (RT) of 0.2, 0.4, 0.6, and 1.1 s. Study Sample: Four groups of 13 listeners each participated in the study (N = 52).RESULTS: In rooms with RTs of 0.2, 0.4, and 0.6 s, mean speech recognition scores (SRSs) were similar, with scores ranging from 96-100%, 90-95%, 75-80%, and 53-60%, when 0, 1, 2, and 3 competing sentences were present, respectively. However, in the room with a RT = 1.1 s, SRSs deteriorated significantly faster as the number of competing sentences increased; mean scores were 93%, 73%, 26%, and 10%, in the 0, 1, 2, 3, competing sentence condition, respectively. The majority of errors in SRSs (98%) resulted from listeners reporting words presented in masking sentences along with those in target sentences (mixing errors). Conclusions: Results indicate that reverberation has a similar influence on SRSs measured in multi-talker environments, when room reverberation is ≤ 0.6 s. However, SRSs are dramatically reduced in the room with a RT = 1.1 s, even when only one competing talker is present. (PsycINFO Database Record (c) 2016 APA, all rights reserved