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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
131

Development of a Speech-in-Multitalker-Babble Paradigm to Assess Word-Recognition Performance

Wilson, Richard H. 01 October 2003 (has links)
A simple word-recognition task in multitalker babble for clinic use was developed in the course of four experiments involving listeners with normal hearing and listeners with hearing loss. In Experiments 1 and 2, psychometric functions for the individual NU No. 6 words from Lists 2, 3, and 4 were obtained with each word in a unique segment of multitalker babble. The test paradigm that emerged involved ten words at each of seven signal-to-babble ratios (S/B) from 0 to 24 dB. Experiment 3 examined the effect that babble presentation level (70, 80, and 90 dB SPL) had on recognition performance in babble, whereas Experiment 4 studied the effect that monaural and binaural listening had on recognition performance. For listeners with normal hearing, the 90th percentile was 6 dB S/B. In comparison to the listeners with normal hearing, the 50% correct points on the functions for listeners with hearing loss were at 5 to 15 dB higher signal-to-babble ratios.
132

Role of Audiologists in Special Services

Bondurant, Lindsay 01 January 2015 (has links)
In most classrooms, where information is presented orally via spoken language, accurate knowledge of a student's hearing status is crucial so that the interdisciplinary team can ensure appropriate service provision. Audiologists play a key role on the interdisciplinary team to provide other professionals with information about children's hearing status, communication needs, device use, and intervention strategies. Conversely, audiologists gain valuable information and strategies from other team members.
133

The Homogeneity With Respect to Intelligibility of Recorded Word-Recognition Materials

Wilson, Richard H., McArdle, Rachel 01 January 2015 (has links)
Background: In developing the PB-50 word lists, J. P. Egan suggested five developmental principles, two of which were "equal average difficulty" and an "equal range of difficulty" among the lists (page 963). Egan was satisfied that each of the 20 PB-50 lists had equivalent ranges of recognition performances and that the lists produced the same average performances. This was accomplished in preliminary studies that measured the recognition performance of each word and eliminated words that were always or never correct. In preparing for studies of interrupted words, we needed to know the range of difficulty inherent in the speaker specific NU-6 and Maryland CNC materials we planned to use when those words were not interrupted. There were only a few studies in the literature that touched on the range of difficulty characteristic of the word-recognition materials in common usage. The paucity of this information prompted this investigation whose scope broadened to include the CID W-22, Maryland CNC, NU-6, and PB-50 materials spoken by a variety of speakers. Purpose: The purpose was to evaluate the homogeneity with respect to intelligibility of the words that comprise several of the common word-recognition materials used in audiologic evaluations. Research Design: Both retrospective (10) and prospective (3) studies were involved. Data from six of the retrospective studies were from our labs. The prospective studies involved both listeners with normal hearing for pure tones and listeners with sensorineural hearing loss. Study Sample: The sample sizes for the 13 data sets ranged from 24 to 1,030, with 24 the typical number for listeners with normal hearing. Data Collection and Analysis: The retrospective data were from published studies and archived data from our laboratories. The prospective studies involved presentation of the word-recognition materials to the listeners at a comfortable level. An item analysis was conducted on each data set with descriptive statistics used to characterize the data. Additionally, skewness coefficients were calculated on the distributions of word performances and the interquartile range was used to determine minor and major outliers within each set of 200 words and their component 50-word lists (300 words for the Maryland CNCs). Results: For listeners with normal hearing the majority of performances on the words within a 50-word list were better than the mean performance, which produced negatively skewed distributions with outlier performances in every list. For listeners with sensorineural hearing loss the performances on the words within a 50-word list were evenly distributed above and below the mean performance, which yielded essentially normal distributions with few outliers. There were a few words on which performances were better by the listeners with hearing loss. Conclusions: Every list of word-recognition materials has a few words on which recognition performances are noticeably poorer than performances on the majority of the remaining words. If the intention of an experiment is to evaluate performance at the word level, then identifying these "outliers" becomes a necessity. Although not evaluated in this report, the implications for 25-word lists are they should be based on recognition-performance data and not compiled arbitrarily.
134

Variables That Influence the Recognition Performance of Interrupted Words: Rise-Fall Shape and Temporal Location of the Interruptions

Wilson, Richard H. 01 January 2014 (has links)
Background: The abrupt transition of a signal from off to on and vice versa typically produces spectral splatter that can mask other signals that are spectrally removed from the nominal signal frequency. Both the Miller and Licklider (1950) and Cherry (1953) studies of interrupted speech and alternated speech, respectively, acknowledged the generation of extraneous noise by the rapid on and off characteristics of their unshaped signals but noted for slower interruption rates (e.g., 10 interruptions per second); the masking effects were minimal. Recent studies of interrupted speech have avoided this issue by shaping the rise-fall times with a digital algorithm (e.g., Jin and Nelson, 2010; Wang and Humes, 2010). A second variable in the interrupted speech paradigm is the temporal location or placement of the interruptions (i.e., where in the waveform the interruptions occur). Here the issue is this: what parts of an utterance are necessary to enable intelligibility (e.g., Fogerty and Kewley-Port, 2009)? Interruptions may or may not disturb these necessary cues. Purpose: Here is the prompting question: do shaped and unshaped rise-fall characteristics of the on-segments of interrupted speech produce the same or different recognition performances? A second question arises: are recognition performances on complementary halves of an interrupted signal the same or different? Research Design: This study used a mixed-model design with two within-subject variables (unshaped and shaped rise-fall characteristic, complementary halves) and one between-subjects variable (listener group). Study Sample: A total of 12 young listeners (age range: 19-29 yr) with normal hearing and 12 older listeners (age range: 53-80 yr) with hearing loss for pure tones participated. Data Collection and Analysis: A total of 95 consonant-vowel nucleus-consonant words were interrupted (10 interruptions per second; 50% duty cycle) by parsing alternate 50 msec segments to separate files, which provided complementary temporal halves of the target word referenced to word onset; the first on-segment of the 0 msec condition started at word onset, whereas the first on-segment of the 50 msec condition started 50 msec after word onset. The interruption routine either applied no shaping of the 4 msec rise-fall times or a cos2 shape. Each listener received 25 practice words then a unique randomization of 280 interrupted words (70 words, 2 rise-fall shapes, and 2 interrupt onset conditions). Results: The listeners with normal hearing performed 8-16% better on the various comparable conditions than did the older listeners with hearing loss. The mean performance differences between shaped and unshaped rise-fall characteristics ranged from <1-3% and were not significant. Performance was significantly 10-17% better on the 0 msec condition than on the 50 msec condition. There was no significant interaction between the two main variables, rise-fall shape, and onset time of the interruptions. Conclusions: The rise-fall shape of the onset and offset of the on-segment of the interruption cycle does not affect recognition performance of words. The location of the interruptions in a word can have a significant effect on recognition performance.
135

The Revised Speech Perception in Noise Test (R-Spin) in a Multiple Signal-to-Noise Ratio Paradigm

Wilson, Richard H., McArdle, Rachel, Watt, Kelly L., Smith, Sherri L. 01 September 2012 (has links)
Background: The Revised Speech Perception in Noise Test (R-SPIN; Bilger, 1984b) is composed of 200 target words distributed as the last words in 200 low-predictability (LP) and 200 high-predictability (HP) sentences. Four list pairs, each consisting of two 50-sentence lists, were constructed with the target word in a LP and HP sentence. Traditionally the R-SPIN is presented at a signal-to-noise ratio (SNR, S/N) of 8 dB with the listener task to repeat the last word in the sentence. Purpose: The purpose was to determine the practicality of altering the R-SPIN format from a single SNR paradigm into a multiple SNR paradigm from which the 50% points for the HP and LP sentences can be calculated. Research Design: Three repeated measures experiments were conducted. Study Sample: Forty listeners with normal hearing and 184 older listeners with pure-tone hearing loss participated in the sequence of experiments. Data Collection and Analysis: The R-SPIN sentences were edited digitally (1) to maintain the temporal relation between the sentences and babble, (2) to establish the SNRs, and (3) to mix the speech and noise signals to obtain SNRs between -1 and 23 dB. All materials were recorded on CD and were presented through an earphone with the responses recorded and analyzed at the token level. For reference purposes the Words-in-Noise Test (WIN) was included in the first experiment. Results: In Experiment 1, recognition performances by listeners with normal hearing were better than performances by listeners with hearing loss. For both groups, performances on the HP materials were better than performances on the LP materials. Performances on the LP materials and on the WIN were similar. Performances at 8 dB S/N were the same with the traditional fixed level presentation and the descending presentation level paradigms. The results from Experiment 2 demonstrated that the four list pairs of R-SPIN materials produced good first approximation psychometric functions over the -4 to 23 dB S/N range, but there were irregularities. The data from Experiment 2 were used in Experiment 3 to guide the selection of the words to be used at the various SNRs that would provide homogeneous performances at each SNR and would produce systematic psychometric functions. In Experiment 3, the 50% points were in good agreement for the LP and HP conditions within both groups of listeners. The psychometric functions for List Pairs 1 and 2, 3 and 4, and 5 and 6 had similar characteristics and maintained reasonable separations between the HP and LP functions, whereas the HP and LP functions for List Pair 7 and 8 bisected one another at the lower SNRs. Conclusions: This study indicates that the R-SPIN can be configured into a multiple SNR paradigm. A more in-depth study with the R-SPIN materials is needed to develop lists that are systematic and reasonably equivalent for use on listeners with hearing loss. The approach should be based on the psychometric characteristics of the 200 HP and 200 LP sentences with the current R-SPIN lists discarded. Of importance is maintaining the synchrony between the sentences and their accompanying babble.
136

The Words-in-Noise Test (WIN), List 3: A Practice List

Wilson, Richard H., Watts, Kelly L. 01 February 2012 (has links)
Background: The Words-in-Noise Test (WIN) was developed as an instrument to quantify the ability of listeners to understand monosyllabic words in background noise using multitalker babble (Wilson, 2003). The 50% point, which is calculated with the Spearman-Kärber equation (Finney, 1952), is used as the evaluative metric with the WIN materials. Initially, the WIN was designed as a 70-word instrument that presented ten unique words at each of seven signal-to-noise ratios from 24 to 0 dB in 4 dB decrements. Subsequently, the 70-word list was parsed into two 35-word lists that achieved equivalent recognition performances (Wilson and Burks, 2005). This report involves the development of a third list (WIN List 3) that was developed to serve as a practice list to familiarize the participant with listening to words presented in background babble. Purpose: To determine - on young listeners with normal hearing and on older listeners with sensorineural hearing loss - the psychometric properties of the WIN List 3 materials. Research Design: A quasi-experimental, repeated-measures design was used. Study Sample: Twenty-four young adult listeners (M=21.6 yr)with normal pure-tone thresholds (≤20 dB HL at 250 to 8000 Hz) and 24 older listeners (M=65.9 yr) with sensorineural hearing loss participated. Data Collection and Analysis: The level of the babble was fixed at 80 dB SPL with the level of the words varied from 104 to 80 dB SPL in 4 dB decrements. Results: For listeners with normal hearing, the 50% points for Lists 1 and 2 were similar (4.3 and 5.1 dB S/N, respectively), both of which were lower than the 50% point for List 3 (7.4 dB S/N). A similar relation was observed with the listeners with hearing loss, 50% points for Lists 1 and 2 of 12.2 and 12.4 dB S/N, respectively, compared to 15.8 dB S/N for List 3. The differences between Lists 1 and 2 and List 3 were significant. The relations among the psychometric functions and the relations among the individual data both reflected these differences. Conclusions: The significantz3 dB difference between performances on WIN Lists 1 and 2 and on WIN List 3 by the listeners with normal hearing and the listeners with hearing loss dictates caution with the use of List 3. The use of WIN List 3 should be reserved for ancillary purposes in which equivalent recognition performances are not required, for example, as a practice list or a stand alone measure.
137

Speech-in-Noise Measures: Variable Versus Fixed Speech and Noise Levels

Wilson, Richard H., McArdle, Rachel 01 September 2012 (has links)
Objective: The purpose was to determine if speech-recognition performances were the same when the speech level was fixed and the noise level varied as when the noise level was fixed and the speech level varied. Design: A descriptive/quasi-experimental experiment was conducted with Lists 3 and 4 of the revised speech perception in noise (R-SPIN) test, which involves high predictability (HP) and low predictability (LP) words. The R-SPIN was modified into a multiple signal-to-noise paradigm (23- to -1-dB in 3-dB decrements) from which the 50% points were calculated with the Spearman-Kärber equation. Study sample: Sixteen young listeners with normal hearing and 48 older listeners with pure-tone hearing losses participated. Results: The listeners with normal hearing performed better than the listeners with hearing loss on both the HP and LP conditions. For both groups of listeners, (1) performance on the HP sentences was better than on the LP sentences, and (2) the mean 50% points were 0.1 to 0.4 dB lower (better) on the speech-variable, babble-fixed condition than on the speech-fixed, babble-variable condition. Conclusions: For practical purposes the ≤0.4-dB differences are not considered noteworthy as the differences are smaller than the decibel value of one word on the test (0.6 dB).
138

A Comparison of Two Word-Recognition Tasks in Multitalker Babble: Speech Recognition in Noise Test (SPRINT) and Words-in-Noise Test (WIN)

Wilson, Richard, Cates, Wendy B. 01 December 2008 (has links)
Background: The Speech Recognition in Noise Test (SPRINT) is a word-recognition instrument that presents the 200 Northwestern University Auditory Test No. 6 (NU-6) words binaurally at 50 dB HL in a multitalker babble at a 9 dB signal-to-noise ratio (S/N) (Cord et al, 1992). The SPRINT was developed by and used by the Army as a more valid predictor of communication abilities (than pure-tone thresholds or word-recognition in quiet) for issues involving fitness for duty from a hearing perspective of Army personnel. The Words-in-Noise test (WIN) is a slightly different word-recognition task in a fixed level multitalker babble with 10 NU-6 words presented at each of 7 S/N from 24 to 0 dB S/N in 4 dB decrements (Wilson, 2003; Wilson and McArdle, 2007). For the two instruments, both the babble and the speakers of the words are different. The SPRINT uses all 200 NU-6 words, whereas the WIN uses a maximum of 70 words. Purpose: The purpose was to compare recognition performances by 24 young listeners with normal hearing and 48 older listeners with sensorineural hearing on the SPRINT and WIN protocols. Research Design: A quasi-experimental, mixed model design was used. Study Sample: The 24 young listeners with normal hearing (19 to 29 years, mean = 23.3 years) were from the local university and had normal hearing (≤20 dB HL; American National Standards Institute, 2004) at the 250-8000 Hz octave intervals. The 48 older listeners with sensorineural hearing loss (60 to 82 years, mean = 69.9 years) had the following inclusion criteria: (1) a threshold at 500 Hz between 15 and 30 dB HL, (2) a threshold at 1000 Hz between 20 and 40 dB HL, (3) a three-frequency pure-tone average (500, 1000, and 2000 Hz) of ≤40 dB HL, (4) word-recognition scores in quiet ≥40%, and (5) no history of middle ear or retrocochlear pathology as determined by an audiologic evaluation. Data Collection and Analysis: The speech materials were presented bilaterally in the following order: (1) the SPRINT at 50 dB HL, (2) two half lists of NU-6 words in quiet at 60 dB HL and 80 dB HL, and (3) the two 35-word lists of the WIN materials with the multitalker babble fixed at 60 dB HL. Data collection occurred during a 40-60 minute session. Recognition performances on each stimulus word were analyzed. Results: The listeners with normal hearing obtained 92.5% correct on the SPRINT with a 50% point on the WIN of 2.7 dB S/N. The listeners with hearing loss obtained 65.3% correct on the SPRINT and a WIN 50% point at 12.0 dB S/N. The SPRINT and WIN were significantly correlated (r = -0.81, p < .01), indicating that the SPRINT had good concurrent validity. The high-frequency, pure-tone average (1000, 2000, 4000 Hz) had higher correlations with the SPRINT, WIN, and NU-6 in quiet than did the traditional three-frequency pure-tone average (500, 1000, 2000 Hz). Conclusions: Graphically and numerically the SPRINT and WIN were highly related, which is indicative of good concurrent validity of the SPRINT.
139

Predicting Word-Recognition Performance in Noise by Young Listeners With Normal Hearing Using Acoustic, Phonetic, and Lexical Variables

McArdle, Rachel, Wilson, Richard H. 01 December 2008 (has links)
Purpose: To analyze the 50% correct recognition data that were from the Wilson et al (this issue) study and that were obtained from 24 listeners with normal hearing; also to examine whether acoustic, phonetic, or lexical variables can predict recognition performance for monosyllabic words presented in speech-spectrum noise. Research Design: The specific variables are as follows: (a) acoustic variables (i.e., effective root-mean-square sound pressure level, duration), (b) phonetic variables (i.e., consonant features such as manner, place, and voicing for initial and final phonemes; vowel phonemes), and (c) lexical variables (i.e., word frequency, word familiarity, neighborhood density, neighborhood frequency). Data Collection and Analysis: The descriptive, correlational study will examine the influence of acoustic, phonetic, and lexical variables on speech recognition in noise performance. Results: Regression analysis demonstrated that 45% of the variance in the 50% point was accounted for by acoustic and phonetic variables whereas only 3% of the variance was accounted for by lexical variables. These findings suggest that monosyllabic word-recognition-in-noise is more dependent on bottom-up processing than on top-down processing. Conclusions: The results suggest that when speech-in-noise testing is used in a pre- and post-hearing-aid-fitting format, the use of monosyllabic words may be sensitive to changes in audibility resulting from amplification.
140

A Comparison of Recognition Performances in Speech-Spectrum Noise by Listeners With Normal Hearing on PB-50, CID W-22, Nu-6, W-1 Spondaic Words, and Monosyllabic Digits Spoken by the Same Speaker

Wilson, Richard, McArdle, Rachel, Roberts, Heidi 01 December 2008 (has links)
Background: So that portions of the classic Miller, Heise, and Lichten (1951) study could be replicated, new recorded versions of the words and digits were made because none of the three common monosyllabic word lists (PAL PB-50, CID W-22, and NU-6) contained the 9 monosyllabic digits (1-10, excluding 7) that were used by Miller et al. It is well established that different psychometric characteristics have been observed for different lists and even for the same materials spoken by different speakers. The decision was made to record four lists of each of the three monosyllabic word sets, the monosyllabic digits not included in the three sets of word lists, and the CID W-1 spondaic words. A professional female speaker with a General American dialect recorded the materials during four recording sessions within a 2-week interval. The recording order of the 582 words was random. Purpose: To determine - on listeners with normal hearing - the psychometric properties of the five speech materials presented in speech-spectrum noise. Research Design: A quasi-experimental, repeated-measures design was used. Study Sample: Twenty-four young adult listeners (M = 23 years) with normal pure-tone thresholds (≤20-dB HL at 250 to 8000 Hz) participated. The participants were university students who were unfamiliar with the test materials. Data Collection and Analysis: The 582 words were presented at four signal-to-noise ratios (SNRs; -7-, -2-, 3-, and 8-dB) in speech-spectrum noise fixed at 72-dB SPL. Although the main metric of interest was the 50% point on the function for each word established with the Spearman-Kärber equation (Finney, 1952), the percentage correct on each word at each SNR was evaluated. The psychometric characteristics of the PB-50, CID W-22, and NU-6 monosyllabic word lists were compared with one another, with the CID W-1 spondaic words, and with the 9 monosyllabic digits. Results: Recognition performance on the four lists within each of the three monosyllabic word materials were equivalent, ±0.4 dB. Likewise, word-recognition performance on the PB-50, W-22, and NU-6 word lists were equivalent, ±0.2 dB. The mean recognition performance at the 50% point with the 36 W-1 spondaic words was ∼6.2 dB lower than the 50% point with the monosyllabic words. Recognition performance on the monosyllabic digits was 1-2 dB better than mean performance on the monosyllabic words. Conclusions: Word-recognition performances on the three sets of materials (PB-50, CID W-22, and NU-6) were equivalent, as were the performances on the four lists that make up each of the three materials. Phonetic/phonemic balance does not appear to be an important consideration in the compilation of word-recognition lists used to evaluate the ability of listeners to understand speech. A companion paper examines the acoustic, phonetic/phonological, and lexical variables that may predict the relative ease or difficulty for which these monosyllable words were recognized in noise (McArdle and Wilson, this issue).

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