Exploring Use of the Coordinate Response Measure in a Multitalker Babble Paradigm.

Purpose: Three experiments examined the use of competing coordinate response measure (CRM) sentences as a multitalker babble. Method: In Experiment I, young adults with normal hearing listened to a CRM target sentence in the presence of 2, 4, or 6 competing CRM sentences with synchronous or asynchronous onsets. In Experiment II, the condition with 6 competing sentences was explored further. Three stimulus conditions (6 talkers saying same sentence, 1 talker producing 6 different sentences, and 6 talkers each saying a different sentence) were evaluated with different methods of presentation. Experiment III examined the performance of older adults with hearing impairment in a subset of conditions from Experiment II. Results: In Experiment I, performance declined with increasing numbers of talkers and improved with asynchronous sentence onsets. Experiment II identified conditions under which an increase in the number of talkers led to better performance. In Experiment III, the relative effects of the number of talkers, messages, and onset asynchrony were the same for young and older listeners. Conclusions: Multitalker babble composed of CRM sentences has masking properties similar to other types of multitalker babble. However, when the number of different talkers and messages are varied independently, performance is best with more talkers and fewer messages.

A comparison between the Dutch and American-English digits-in-noise (DIN) tests in normal-hearing listeners.

OBJECTIVE: The Dutch digits-in-noise test (NL DIN) and the American-English version (US DIN) are speech-in-noise tests for diagnostic and clinical usage. The present study investigated differences between NL DIN and US DIN speech reception thresholds (SRTs) for a group of native Dutch-speaking listeners. DESIGN: In experiment 1, a repeated-measures design was used to compare SRTs for the NL DIN and US DIN in steady-state noise and interrupted noise for monaural, diotic, and dichotic listening conditions. In experiment 2, a subset of these conditions with additional speech material (i.e. US DIN triplets without inter-digit coarticulation/prosody) was used. STUDY SAMPLE: Experiment 1 was conducted with 16 normal-hearing Dutch students. Experiment 2 was conducted with nine different students. RESULTS: No significant differences between SRTs measured with the NL DIN and US DIN were found in steady-state noise. In interrupted noise the US DIN SRTs were significantly better in monaural and diotic listening conditions. Experiment 2 demonstrated that these better SRTs cannot be explained by the combined effect of inter-digit coarticulation and prosody in the American-English triplets. CONCLUSIONS: The NL DIN and US DIN are highly comparable and valuable tests for measuring auditory speech recognition abilities. These tests promote across-language comparisons of results.

Validation of a screening test of auditory function using the telephone.

BACKGROUND: Several European countries have demonstrated successful use of telephone screening tests for auditory function. The screening test consists of spoken three-digit sequences presented in a noise background. The speech-to-noise ratios of the stimuli are determined by an adaptive tracking method that converges on the level required to achieve 50% correct recognition. PURPOSE: A version of the three-digit telephone screening protocol for the United States was developed: the US National Hearing Test (NHT). The objective of the current study was to determine the sensitivity and specificity as well as the feasibility of the NHT for use within the Department of Veterans Affairs (VA). Research Design and Study Sample: Using a multisite study design with convenience sampling, we used the NHT to collect data from 693 participants (1379 ears) from three geographical areas of the United States (Florida, Tennessee, and California). DATA COLLECTION AND ANALYSIS: The NHT procedures were as follows: the participants (1) called a toll-free telephone number, (2) entered their assigned ear-specific identification code, (3) listened to 40-sets of digit triplets presented in speech-spectrum background noise, and (4) entered in the numbers that they heard on the telephone key pad. The NHT was performed on each ear, either at home or in a VA clinic. In addition to collecting data from the experimental task, we gathered demographic data and the data from other standard-of-care tests (i.e., audiometric thresholds and speech recognition tests in quiet and in noise). RESULTS: A total of 505 participants completed the NHT at a VA clinic, whereas 188 completed the test at home. Although the ear-specific NHT and mean pure-tone threshold all correlated significantly (p < 0.001), there were more modest correlations in the low- and high-frequency ranges with the highest correlation seen with the 2000 Hz mean pure-tone threshold. When the NHT 50% point or threshold was compared with the three-frequency PTA at 500, 1000, and 2000 Hz, the sensitivity was 0.87 and specificity was 0.54. When comparing the NHT with the four-frequency PTA at 500, 1000, 2000, and 4000 Hz, the sensitivity was 0.81 and specificity increased to 0.65. The NHT also correlated strongly with other speech-in-noise measures. CONCLUSIONS: The NHT was found to correlate with other audiometric measures, including pure-tone thresholds and speech recognition tests in noise, at sufficiently high correlation values to support its use as a screening test of auditory function.

Telephone screening tests for functionally impaired hearing: current use in seven countries and development of a US version.

BACKGROUND: An estimated 36 million US citizens have impaired hearing, but nearly half of them have never had a hearing test. As noted by a recent National Institutes of Health/National Institute on Deafness and Other Communication Disorders (NIH/NIDCD) Working Group, "In the United States (in contrast to many other nations) there are no readily accessible low cost hearing screening programs…" (Donahue et al, 2010, p. 2). Since 2004, telephone administered screening tests utilizing three-digit sequences presented in noise have been developed, validated, and implemented in seven countries. Each of these tests has been based on a test protocol conceived by Smits and colleagues in The Netherlands. PURPOSE: Investigators from Communication Disorders Technology, Inc., Indiana University, and VU University Medical Center of Amsterdam agreed to collaborate in the development and validation of a screening test for hearing impairment suitable for delivery over the telephone, for use in the United States. This test, utilizing spoken three-digit sequences (triplets), was to be based on the design of Smits and his colleagues. RESEARCH DESIGN: A version of the digits-in-noise test was developed utilizing digit triplets spoken in Middle American dialect. The stimuli were individually adjusted to speech-to-noise ratio (SNR) values yielding 50% correct identification, on the basis of data collected from a group of 10 young adult listeners with normal hearing. A final set of 64 homogeneous stimuli were selected from an original 160 recorded triplets. Each test consisted of a series of 40 triplets drawn at random, presented in a noise background. The SNR threshold for 50% correct identification of the triplets was determined by a one-down, one-up adaptive procedure. The test was implemented by telephone, and administered to listeners with varying levels of hearing impairment. The listeners were then evaluated with pure-tone tests and other audiometric measures as clinically appropriate. STUDY SAMPLE: Ninety participants included 72 who were volunteers from the regular client population at the Indiana University Hearing Clinic, and 18 who were recruited with a newspaper ad offering a free hearing test. Of the 90 participants, 49 were later determined to have mean pure-tone thresholds greater than 20 dB hearing level (HL). DATA COLLECTION AND ANALYSIS: The primary data analyses were correlations between telephone test thresholds and other measures, including pure-tone thresholds and speech recognition tests, collected for the same participants. RESULTS: The correlation between the telephone test and pure-tone thresholds (r = 0.74) was within the range of correlations observed with successful telephone screening tests in use in other countries. Thresholds based on the average of only 21 trials (trials five through 25 of the 40-trial tracking history) yielded sensitivity and specificity values of 0.80 and 0.83, respectively, using pure-tone average((0.5, 1.0, 2.0 kHz)) >20 dB HL as the criterion measure. CONCLUSIONS: This US version of the digits-in-noise telephone screening test is sufficiently valid to be implemented for use by the general public. Its properties are quite similar to those telephone screening tests currently in use in most European countries. Telephone tests provide efficient, easy to use, and valid screening for functional hearing impairment. The results of this test are a reasonable basis for advising those who fail to seek a comprehensive hearing evaluation by an audiologist.

Individual differences in auditory abilities.

Performance on 19 auditory discrimination and identification tasks was measured for 340 listeners with normal hearing. Test stimuli included single tones, sequences of tones, amplitude-modulated and rippled noise, temporal gaps, speech, and environmental sounds. Principal components analysis and structural equation modeling of the data support the existence of a general auditory ability and four specific auditory abilities. The specific abilities are (1) loudness and duration (overall energy) discrimination; (2) sensitivity to temporal envelope variation; (3) identification of highly familiar sounds (speech and nonspeech); and (4) discrimination of unfamiliar simple and complex spectral and temporal patterns. Examination of Scholastic Aptitude Test (SAT) scores for a large subset of the population revealed little or no association between general or specific auditory abilities and general intellectual ability. The findings provide a basis for research to further specify the nature of the auditory abilities. Of particular interest are results suggestive of a familiar sound recognition (FSR) ability, apparently specialized for sound recognition on the basis of limited or distorted information. This FSR ability is independent of normal variation in both spectral-temporal acuity and of general intellectual ability.