Development of speech reception threshold materials for speakers of Taiwan Mandarin

Validating Four Hmong Word Recognition Tests With Normal-Hearing Bilingual Hmong Individuals

Purpose:

The purpose of this study was to validate four digitally recorded and phonetically balanced 50-word recognition lists in the White Hmong dialect with normal-hearing bilingual Hmong adults.

Method:

Using a randomized, incomplete-block design, each participant listened to and repeated four unique Hmong lists delivered by a female and a male talker. Participants were also tested with an English word list—List 1A of the Northwestern University Auditory Test No. 6. Participants' correct pronunciation of each word was scored. A nonparametric Mann–Whitney U Location Difference Test for Equivalence using two one-sided tests equivalence hypothesis: −0.02 < [(List_1) – (List_2)] < 0.02 was conducted to assess equivalence among all four Hmong and the English lists.

Results:

Seventy Hmong speakers participated in this study (35 women, 35 men; M age = 29.5 years, SD = 7.1). In all four Hmong lists, 93.5% (187/200) words met the validation criteria for ≥ 92% correct pronunciation. The 13 difficult words were deemed adequate by a Hmong panel and, therefore, were included to maintain four unique, balanced word lists. The test revealed that the Hmong and English word lists were considered equivalent at the 2% bound.

Conclusion:

The four Hmong word lists were validated to ensure an equal range of word difficulty across the lists.

Combination and Comparison of Sound Coding Strategies Using Cochlear Implant Simulation With Mandarin Speech

Three cochlear implant (CI) sound coding strategies were combined in the same signal processing path and compared for speech intelligibility with vocoded Mandarin sentences. The three CI coding strategies, biologically-inspired hearing aid algorithm (BioAid), envelope enhancement (EE), and fundamental frequency modulation (F0mod), were combined with the advanced combination encoder (ACE) strategy. Hence, four singular coding strategies and four combinational coding strategies were derived. Mandarin sentences with speech-shape noise were processed using these coding strategies. Speech understanding of vocoded Mandarin sentences was evaluated using short-time objective intelligibility (STOI) and subjective sentence recognition tests with normal-hearing listeners. For signal-to-noise ratios at 5 dB or above, the EE strategy had slightly higher average scores in both STOI and listening tests compared to ACE. The addition of EE to BioAid slightly increased the mean scores for BioAid+EE, which was the combination strategy with the highest scores in both objective and subjective speech intelligibility. The benefits of BioAid, F0mod, and the four combinational coding strategies were not observed in CI simulation. The findings of this study may be useful for the future design of coding strategies and related studies with Mandarin.

The validity of an isiZulu speech reception threshold test for use with adult isiZulu speakers

Background

This study continued the development of an isiZulu speech reception threshold (zSRT) test for use with first language, adult speakers of isiZulu.

Objectives

The objective of this study was to determine the convergent and concurrent validity of the zSRT test.

Methods

One hundred adult isiZulu first-language speakers with normal hearing and 76 first-language, adult isiZulu speakers with conductive or sensorineural hearing losses ranging from mild to severe were assessed on pure tone audiometry and a newly developed isiZulu SRT test. Convergent validity was established through agreement of the zSRT scores with pure tone average (PTA) scores. Concurrent validity was assessed by examining the steepness of the psychometric curve for each word in the zSRT test for each type and degree of hearing loss.

Results

Intraclass correlation coefficient analyses showed zSRT scores were in substantial to very high agreement with PTA scores for the normal hearing and hearing loss groups (NH – right ear ICC consistency = 0.78, left ear ICC = 0.67; HL – right ear ICC consistency = 0.97, left ear ICC consistency = 0.95). The mean psychometric slope (%/dB) at 50% correct perception for all words in the zSRT test was 4.92%/dB for the mild conductive hearing loss group, 5.26%/dB for the moderate conductive hearing loss group, 2.85%/dB for the moderately severe sensorineural hearing loss group and 2.47%/dB for the severe sensorineural hearing loss group. These slopes were appropriate for the degree of hearing loss observed in each group.

Conclusion

The zSRT test showed convergent and concurrent validity for assessing SRT in first language, adult speakers of isiZulu.

The Effect of Dialect on Speech Audiometry Testing

Purpose

In this study, the authors examined the validity of using materials from 2 nonregional yet mutually intelligible dialects to evaluate an individual's speech recognition threshold (SRT) and word recognition (WR) abilities and whether a speaker of 1 dialect could accurately administer and score materials in the other dialect.

Method

Previously created SRT and WR materials were presented to 32 Mandarin listeners with normal hearing: 16 speakers of Mainland Mandarin and 16 speakers of Taiwan Mandarin. Hearing abilities were examined using SRT and WR materials created for speakers from 2 different regional dialects. Presentation of the materials occurred during 2 test sessions, counterbalanced across material and listener dialect. Listener responses were evaluated by 2 judges; 1 spoke Mainland Mandarin, and the other spoke Taiwan Mandarin.

Results

For the SRT and WR results, differences in listener performance were statistically significant across material and listener dialect, with threshold differences of less than 2 dB HL when collapsed across session. The interscorer percentage of agreement was 99.5% for SRT and 99.1% for WR testing.

Conclusion

Testing with materials in a different regional dialect does have a measurable impact on SRT and WR performance. However, this difference, though reliable, is small enough to have a negligible impact on clinical findings.

Word Recognition Materials for Native Speakers of Taiwan Mandarin

Purpose

To select, digitally record, evaluate, and psychometrically equate word recognition materials that can be used to measure the speech perception abilities of native speakers of Taiwan Mandarin in quiet.

Method

Frequently used bisyllabic words produced by male and female talkers of Taiwan Mandarin were digitally recorded and subsequently evaluated using 20 native listeners with normal hearing at 10 intensity levels (−5 to 40 dB HL) in increments of 5 dB.

Results

Using logistic regression, 200 words with the steepest psychometric slopes were divided into 4 lists and 8 half-lists that were relatively equivalent in psychometric function slope. To increase auditory homogeneity of the lists, the intensity of words in each list was digitally adjusted so that the threshold of each list was equal to the midpoint between the mean thresholds of the male and female half-lists.

Conclusions

Digital recordings of the word recognition lists and the associated clinical instructions are available on CD upon request.