摘要:

Objective:The present study sought to determine whether benefit derived from hearing aid use increases with hearing aid experience. This question is of considerable interest to both researchers and clinicians. Several previous investigations recently published have obtained mixed results.Design:Control conditions were provided to address the potential influences of practice effects and changes in preferred hearing aid gain. The experimental group consisted of 13 hearing-impaired listeners about to be fit with their first hearing aid. The control group consisted of 13 hearing aid users with at least 1 yr's experience with their hearing aids. The control group permitted examination of practice effects that may have confounded previous results showing increases in benefit with experience. Hearing aid benefit was defined as aided speech recognition ability minus unaided speech recognition ability and was assessed repeatedly over 18 wk. Two measures of hearing aid benefit were employed: an objective syllable recognition task and a subjective questionnaire. For the objective measure, hearing aid benefit was assessed for the condition of fixed hearing aid gain and also for the condition of subject-adjusted hearing aid gain to examine effects of changes in audibility that may have influenced benefit and confounded previous results.Results:The objective measure of group mean hearing aid benefit increased significantly over time for both gain conditions for the new hearing aid users, but did not increase for the long-standing control group. Subjective benefit increased over time, but without statistical significance for the new hearing aid users, and was essentially unchanged for the long-standing control group.Conclusions:Results suggest that the observed improvements in speech recognition are not due to increases in audibility nor to simple practice effects. The overall improvements in benefit over time were of statistical significance and also practical importance for studies of group differences. However, the improvements are too small to be observed consistently for individual hearing aid users.

ISSN:0196-0202    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

Objective:In a series of experiments with a wearable binaural digital hearing aid, two hearing aid processing algorithms were compared. Both algorithms provided individual frequency shaping via a seven-band filterbank with compression limiting in the high-frequency channel. They differed in the processing of the low-frequency channel, using dynamic range compression for one (DynEar) and linear processing with compression limiting for the other (LinEar). In a pilot field test we found that LinEar/DynEar preference based on use time could be predicted from auditory dynamic range data. For the subjects who preferred DynEar, the mean dynamic range was broader for low and mid frequencies and narrower for high frequencies, as compared with the LinEar preference subjects. These groupings were tested as predictors of user preference and performance in a main field test.Design:The main study included 26 hearing aid users with symmetrical sensorineural losses. The algorithms were compared in a one-mo-long blind field test. A data logger function was included for objective recording of the total time each algorithm was used and how the volume controls were used. The preference was based on the time used for each algorithm and on subjective statements. Threshold signal-to-noise ratio (S/N-threshold) for speech was tested, and sound quality ratings were obtained through a questionnaire. We also tested the S/N-thresholds for the subjects' conventional (own) aids.Results:The preference was correctly predicted by the dynamic range data on 12 out of 15 new cases. S/N-thresholds were lower for the preferred fittings compared with the nonpreferred fittings and with the subjects' own aids. In the questionnaire the preferred fittings were rated significantly higher in terms of overall impression and clearness. Because of the systematic way the DynEar-preference subjects adjusted the high-frequency DynEar gain, we speculate that upward spread of masking may have been a factor in preference and performance. Additionally, LinEar-preference subjects' preference and performance might have been influenced by excessive compression ratios with the DynEar processing in these cases.Conclusions:1. Preference for DynEar versus LinEar depends on the auditory dynamic range. 2. S/N-thresholds for speech were better for the preferred fittings, which also were rated higher in terms of overall impression of sound quality and clearness.

ISSN:0196-0202    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

Objective:Multichannel syllabic compressors have not yet shown clear advantages for speech perception. New multichannel syllabic nonlinear processors are designed and evaluated in this study to test whether they enhance speech perception scores.Design:Nonsense consonant-vowel-consonant words have been processed in real time with two syllabic nonlinear methods in nine different frequency channels: 1) 30 dB of speech information is mapped into the residual dynamic range (DR) of the subjects with hearing impairment using either compression of expansion; 2) speech levels above the rms level are compressed with a ratio of 3:1, and input levels below the rms level are mapped into the reduced DR of the subjects. The overall frequency spectrum of speech is tilted with more high-frequency output for this condition. The two syllabic nonlinear processors were compared with two linear reference systems (one of them with the same spectral tilt as the second nonlinear condition) for seven hearing-impaired subjects.Results:On average, the syllabic nonlinear processors show scores similar to one of the linear systems. The linear reference with tilt has, on average, 3% higher scores, mainly due to improved vowel identification.Conclusions:No negative effects were shown on average for the syllabic nonlinear processors, but no positive effects were demonstrated either. Tilting of the overall speech spectrum was advantageous.

ISSN:0196-0202    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

One of the most important parameters of a hearing aid is its gain characteristics. Under ideal circumstances, the gain and the functional gain(FG) are the same for an air conduction device. This is not the case, however, with bone conduction devices, e.g., the bone-anchored hearing aid(BAHA). In this article, the relation between the gain and the FG is derived for bone conduction devices including the BAHA. Reference quantities used when measuring bone conduction devices also are presented.

ISSN:0196-0202    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

Objective:The study was conducted to answer two questions: 1) Which auditory measures detect impairments attributable to age rather than hearing loss? 2) Among the elderly, is there a lateral asymmetry of performance?Design:Audiological status and auditory performance of a group of elderly (60 to 81 yr old) and normal-hearing young (18 to 30 yr old) individuals were determined through a test battery. When present, the hearing loss of elderly subjects was symmetrical in the two ears and, at most, moderate. The battery included tests of speech intelligibility on the word and sentence levels, with and without the presence of interfering speech. In addition to pure-tone and speech reception thresholds, perception of spectrally or temporally distorted speech and auditory resolution of frequency, time, and space were tested. Two tests received special consideration: the Speech Perception In Noise Test and the Modified Rhyme Reverberation Test.Results:Results indicated that 1) hearing loss was a major factor differentiating auditory performance of elderly and young individuals, and 2) genuine age-related deficits were found in measures assessing auditory resolution and the ability to utilize spatial, temporal, and/or linguistic context information to perceptually separate a speech target from surrounding speech noise. Furthermore, the elderly group exhibited a right-ear advantage, caused by left-ear deficits, in tests measuring central auditory processing and a slight left-ear advantage in tests measuring peripheral auditory resolution.Conclusions:The findings suggest that, after controlling for the effect of hearing loss, there are a number of test measures in which performance of elderly and young listeners differs. Regarding lateral asymmetry, a disproportionate decline in auditory processing in the left ear of elderly individuals has been demonstrated. The major clinical conclusion is that, when testing an elderly group's performance regarding any given auditory function, the influence of pure-tone threshold elevations, no matter how mild, cannot be disregarded.

ISSN:0196-0202    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

Objective:To investigate the effects of a history of otitis media (OM) in childhood on the acoustic reflex threshold (ART) in young adults.Design:Questionnaire responses on childhood ear and hearing problems were obtained from populations of university students. In Study 1, 31 students reporting histories of persistent childhood OM and 34 students with no known OM histories were identified. They received pure-tone audiometry, otomicroscopy, and measurement of ARTs for a 500 Hz pure tone. In Study 2, 20 students with OM histories and 20 students with no known OM histories received pure-tone audiometry, otomicroscopy, and measurement of ARTs for a broadband noise.Results:Subjects with OM histories had higher ARTs than did subjects with no known OM histories. Multiple regression analyses showed that the main variables contributing to elevated reflex thresholds were raised hearing thresholds on the activator ear and tympanic membrane abnormalities on the probe ear.Conclusions:The elevated ARTs in adults with histories of childhood OM result from peripheral sequelae of OM. Further evidence is required to determine any functional significance of these raised reflex thresholds.

ISSN:0196-0202    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

Objective:The effect of level-dependent hearing protection devices (HPDs) on subjects' ability to identify real-life environmental sounds was investigated.Design:Eighteen subjects with no hunting experience attempted to identify sounds(crow, duck, turkey, deer, owl, goose, and person) recorded at various distances in the presence of the SoundScope and Sonic II level-dependent HPDs as well as in an open ear condition. Knowles Electronic's Manikin for Auditory Research was employed in making the experimental recordings. The Sonic II accomplishes level-dependent attenuation via a passive mechanism, whereas the SoundScope employs active circuitry that attenuates loud sounds while providing a small amount of high frequency amplification for soft sounds. Both devices are commercially available and are advertised for hunters/shooters. Sound identification scores (SISs) were determined for each condition.Results:Mean SISs differed significantly among the three earplug conditions, collapsed over type of sound and distance, with the best SIS obtained under the open ear condition (96.43%) and the worst under the Sonic II condition(84.13%). Further analysis revealed that the listening conditions differed significantly only at the 100 yard distance.Conclusions:Auditory awareness was not maintained by either device investigated during the 100 yard condition. However, auditory awareness was maintained by both devices at a distance of 75 yards or closer. These devices may be appropriate for use in certain hunting/shooting situations depending on several factors including type of game being hunted, environment, and shooting range of the weapon. Further support also is provided for the usage of level-dependent HPDs during recreational shooting activities (i.e., at a shooting range).

ISSN:0196-0202    

出版商:OVID    

年代:1997

数据来源: OVID

ISSN:0196-0202    

出版商:OVID    

年代:1997

数据来源: OVID

ISSN:0196-0202    

出版商:OVID    

年代:1997

数据来源: OVID

ISSN:0196-0202    

出版商:OVID    

年代:1997

数据来源: OVID