摘要:

Objective:The purpose of the present studies was to assess the validity of using closed-set response formats to measure two cognitive processes essential for recognizing spoken words-perceptual normalization (the ability to accommodate acoustic-phonetic variability) and lexical discrimination (the ability to isolate words in the mental lexicon). In addition, the experiments were designed to examine the effects of response format on evaluation of these two abilities in normal-hearing (NH), noise-masked normal-hearing (NMNH), and cochlear implant (CI) subject populations.Design:The speech recognition performance of NH, NMNH, and CI listeners was measured using both open- and closed-set response formats under a number of experimental conditions. To assess talker normalization abilities, identification scores for words produced by a single talker were compared with recognition performance for items produced by multiple talkers. To examine lexical discrimination, performance for words that are phonetically similar to many other words (hard words) was compared with scores for items with few phonetically similar competitors (easy words).Results:Open-set word identification for all subjects was significantly poorer when stimuli were produced in lists with multiple talkers compared with conditions in which all of the words were spoken by a single talker. Open-set word recognition also was better for lexically easy compared with lexically hard words. Closed-set tests, in contrast, failed to reveal the effects of either talker variability or lexical difficulty even when the response alternatives provided were systematically selected to maximize confusability with target items.Conclusions:These findings suggest that, although closed-set tests may provide important information for clinical assessment of speech perception, they may not adequately evaluate a number of cognitive processes that are necessary for recognizing spoken words. The parallel results obtained across all subject groups indicate that NH, NMNH, and CI listeners engage similar perceptual operations to identify spoken words. Implications of these findings for the design of new test batteries that can provide comprehensive evaluations of the individual capacities needed for processing spoken language are discussed.

ISSN:0196-0202    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

Objective:The study was conducted to determine the relationship between measures of auditory performance in elderly individuals. Specifically, its goal was to uncover a set of measures correlated with the set of measures of speech understanding under specific conditions of interference to gain a better understanding of decline of the "cocktail party effect" in aging.Design:Audiological status and auditory performance of a group of elderly (60- to 81-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, despite the nearly normal hearing levels that characterized much of the subject group, auditory sensitivity measures showed persistent correlation to all other measures, with the exception of auditory resolution regarding frequency, time, and space. As a set, sensitivity measures accounted for more than 85% of the variance. When auditory sensitivity was controlled for, other factors underlying speech processing in the presence of interfering stimuli were uncovered, factors most likely related to the ability to perceptually segregate one speech signal from another.Conclusions:The findings suggest that, to determine the relationship between audiological/auditory test results of an elderly population, it is important to remove the effects of hearing loss through appropriate statistical methods.

ISSN:0196-0202    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

Objective:The purpose of this study is to present descriptive results from an audiometric examination of a male twin sample, compare the values with normative databases, and explore whether there are age differences in genetic and environmental contributions to variation in hearing.Design:Audiometric and questionnaire data were collected on a subsample of male twins who were identified through the population-based Swedish Twin Registry. Hearing examinations were completed for a total of 557 intact pairs, comprised of 250 identical (monozygotic [MZ]) pairs and 307 fraternal(dizygotic [DZ]) pairs aged 36 to 80 yr. A scale measuring hearing in the high-tone ranges was constructed by calculating the mean for the hearing threshold values obtained for both ears combined at 3000, 4000, 6000, and 8000 Hz for air conduction.Results:To assess whether the twin values are representative of general hearing function, the hearing thresholds were compared with values from two normative databases. Results suggest that these twin data provide a valid representation of hearing function in a cross-section of the Swedish male population, aged 35 and older. The mean values for hearing ability decreased across age, and variation increased. Twin similarity, estimated across four age groups using intraclass correlations, decreased from 0.716 to 0.516 for the MZ pairs and increased from 0.131 to 0.279 for the DZ pairs. These results suggest that variation in hearing ability in the high ranges is due to genetic and environmental factors and that environmental effects become more important with age.Conclusions:These data reflect typical age-related deterioration in hearing ability accompanied by greater individual differences in hearing function with age. Across all ages, genetic and environmental effects are important sources of variation in hearing. However, preliminary analyses suggest that the relative influence of environment increases with age. These environmental effects are of the nonshared type that are not associated with shared family environments but rather are explained by unique exposures.

ISSN:0196-0202    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

Objective:The recently developed technique of recording transient evoked otoacoustic emissions (TEOAEs) using clicks presented according to maximum length sequences (MLSs) enables very high stimulation rates to be used. The aim of this study was to provide normative data on the relationship between TEOAEs recorded conventionally (at 40 clicks/sec) and those recorded using the MLS technique (at 11 maximum rates between 100 and 5000 clicks/sec) to establish a baseline for future clinical studies.Design:TEOAEs were recorded at 12 rates from 12 normally hearing adult ears at click levels decreasing in 5 dB steps from 68 dB peSPL.Results:The morphology of the waveforms and the pattern of the input/output functions with latency were similar for conventional and MLS TEOAEs. The only major difference between TEOAEs recorded at the different rates was in their absolute amplitude. As the click rate was increased from 40 clicks/sec there was a reduction in amplitude that reached a near asymptote at approximately 1500 clicks/sec. When expressed as a percentage reduction in amplitude compared with that recorded at 40 clicks/sec, this MLS "rate effect" was independent of stimulus level over all but the lowest test level (38 dB peSPL).Conclusion:Over a wide range of amplitudes of conventionally recorded TEOAEs (21 to 450 µPa for the 9 to 13 msec section of the otoacoustic emission), the mechanism involved in the MLS rate effect seems to act in a way that reduces the amplitude by an almost constant proportion, whatever its original size.

ISSN:0196-0202    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

Objective:To investigate acclimatization to hearing aids.Design:Forty-eight subjects took part in a study in which hearing aid benefit was measured four times over the initial 3 mo of participation. At the start, 24 subjects were experienced hearing aid users and 24 had never worn a hearing aid before. Subjects wore one of three models of hearing aid with one of six different configurations (combination of frequency response and method of output limiting). Hearing aid benefit was measured with CID W-1 spondees and the Hearing in Noise Test (HINT) test. Testing took place on Days 0 (day of fitting), 30, 60, and 90. Analyses of variance were used to determine whether hearing aid benefit changed over time as a function of hearing aid user status, hearing aid configuration, and hearing aid volume setting.Results:There were small, nonsignificant changes in hearing aid benefit over the test sessions with both sets of test materials. There were no interactions between hearing aid benefit over time and hearing aid user status or hearing aid volume setting. There was an interaction between benefit over time and hearing aid configuration on one test measure only.Conclusions:The data showed little evidence of acclimatization over the 3 mo of hearing aid use. The test materials used here were low- to mid-frequency sensitive, and, therefore, it is concluded that if acclimatization did occur, it did so primarily at high frequencies. Because the HINT test has good face validity to everyday listening situations, it is suggested that the clinical ramifications of acclimatization are probably small.

ISSN:0196-0202    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

Objective:To evaluate hearing aid user preference for Linear Class D or Class D with K-Amp™ circuit.Design:Eighteen subjects, experienced with Class A hearing aid use, were given a choice of binaural hearing aids with either Linear Class D circuits or Class D with K-Amp™ circuits after consecutive 30 day trial periods with each set of instruments. The patients also rated the benefit obtained from each circuit using the Profile of Hearing Aid Benefit (PHAB).Results:There was no significant difference in the number of subjects who chose one or the other of the circuits. Further, the PHAB scores showed no statistically significant differences between the two circuits. In most cases, the instruments rated highest on each of the subscales by an individual subject were also the ones preferred based on the 30 day trial.Conclusions:Hearing aids with either Class D Linear or Class D with K-Amp™ circuits provided significant benefit in many everyday listening environments for individuals with a mild to moderate degree of hearing loss. Subjective choice between the Linear Class D and the K-Amp™ circuits was relatively evenly divided.

ISSN:0196-0202    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

Objective:To assess changes in speech intelligibility as a function of signal processing strategy and as a function of time for one of the first two Ineraid patients in the United States fitted with a continuous interleaved sampling (CIS) signal processor.Design:In Experiment 1, the patient was fitted with a CIS processor and measures of speech intelligibility were taken over a period of 4 mo. These data were compared with data collected with the Ineraid. In Experiment 2, three new signal processing strategies were tested. Measures of speech intelligibility were taken at fitting and after a week's use of the processor. In Experiment 3, the number of channels in the processor was reduced to 5, 4, and 3. Each processor was tested at fitting and after a week's use of the processor.Results:In Experiment 1, immediately on fitting, the CIS processor produced better speech intelligibility for consonants, vowels, and the CID sentences than did the Ineraid. Performance improved over periods ranging from 1 to 4 mo depending on the test material. In Experiment 2, two processors produced significantly better speech intelligibility than did other processors. Most generally, performance dropped slightly when a new processor was fitted and then improved over the course of a week. All of the processors produced better speech intelligibility than did the Ineraid. In Experiment 3, five channels allowed similar levels of performance as did six channels. The effect of four and three channels varied as a function of test material. Four CIS channels allowed better performance than did the four analogue channels of the Ineraid.Conclusions:We conclude 1) that CIS processors can provide much better speech intelligibility than can the analogue processor of the Ineraid; 2) that many CIS strategies, not just one, will produce better speech intelligibility than will the Ineraid; 3) that for this patient, five channels can allow as high a level of word intelligibility as can six channels; 4) that when the number of CIS and analogue channels are equated (at four), the CIS strategy provides better speech intelligibility than does the Ineraid; and 5) that speech intelligibility with CIS processors improves over periods as short as a week and as long as several months after fitting of the processor.

ISSN:0196-0202    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

Objective:The aim was to determine the effect of loudness imbalance between electrodes in patients using the 22-electrode cochlear implant (Cochlear Pty Ltd). It was hypothesized that speech perception scores would be greater when the loudness of electrodes was balanced at the comfort (C) levels than when the C levels were unbalanced.Design:Ten adult patients received a monosyllabic word test (CNC words) in quiet and a sentence test (CUNY sentences) in noise under two conditions: with C levels balanced for equal loudness and with unbalanced C levels.Results:When the C levels across electrodes were pseudo-randomly unbalanced by 0 to ±20% of the electrodes' dynamic ranges (20% unbalancing), 6 of the 10 subjects showed a significant drop in sentence perception scores. Of these patients, none had a significant decrease in perception when the degree of unbalancing was halved. Of the four patients who showed no change with 20% unbalancing, three revealed a significant decline in sentence perception when the degree of unbalancing was doubled. There also were significant group effects for phonemes on the word test as well as for sentences in noise for the 20% unbalancing.Conclusions:The implications for clinical practice are that it is important to balance the C levels and that clinicians should be encouraged to refine methods for setting C levels in very young children, who may be using unbalanced MAPs. Nevertheless, although most patients revealed a statistically significant drop in sentence perception with 20% imbalance of the C levels, the changes in percentage scores often were only small.

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