Normative data for diagnosing auditory processing disorder in Norwegian children aged 7-12 years.

OBJECTIVE: The main purpose of this research was to obtain normative data for auditory processing tests for Norwegian speaking children. DESIGN: Participants were administered routine audiological tests and an auditory processing test-battery consisting of Filtered Words, Competing Words, Dichotic Digits, Gaps In Noise, Duration- and Frequency Pattern, Binaural Masking Level Difference and HIST Speech in Noise test. A group of 10-year-old children were retested after two weeks. The effects ear, age and gender and the test-retest reliability were investigated. STUDY SAMPLE: There were 268 normal hearing children aged 7-12 years who participated in the study. RESULTS: Results revealed no differences between genders. The children showed improving performance by age on all tests, except from the Gaps In Noise and Binaural Masking Level Difference. As expected, the children showed a right ear advantage on dichotic speech tests that decreased with age. The test-retest reliability for the tests was good, with a small learning effect on the Filtered Words test. CONCLUSION: Normative data were established and the preferred tests for diagnosing Auditory Processing Disorder were suggested for Norwegian children aged 7-12 years.

The clinical use of Arthur Boothroyd (AB) word lists in Australia: exploring evidence-based practice.

OBJECTIVE: Limited empirical investigation exists validating the use of Arthur Boothroyd (AB) word recognition materials within the Australian clinical context. The current research was undertaken to examine the evidence base and clinical implementation/interpretation of AB words in Australia. DESIGN: An on-line 22-question survey was e-mailed to members of the peak audiology professional body in Australia. STUDY SAMPLE: Three hundred and twelve responses were recorded between April and June 2015 from audiologists of a range of ages, working in various clinical settings. RESULTS: The survey results suggested audiologists use AB words on a wide range of clients from children <5 to adults ≥80 years, for diverse purposes including diagnosis of retrocochlear pathology, candidacy and validation of rehabilitative options, and client counselling. A majority of respondents reported typically administering one or two word lists per ear, and over 99% of audiologists utilised phonemic scoring. There was no consensus regarding what constitutes a significant difference between any two given scores. CONCLUSIONS: Wide variation exists in the administration and interpretation of AB words in Australia. There appears to be a mismatch between clinical utilisation of AB words and existing evidence-based empirical data. Further research is required to improve evidence-based audiologist training, and thereby current clinical use of AB words.

Internationally comparable screening tests for listening in noise in several European languages: the German digit triplet test as an optimization prototype.

OBJECTIVE: A review is given of internationally comparable speech-in-noise tests for hearing screening purposes that were part of the European HearCom project. This report describes the development, optimization, and evaluation of such tests for headphone and telephone presentation, using the example of the German digit triplet test. In order to achieve the highest possible comparability, language- and speaker-dependent factors in speech intelligibility should be compensated for. MATERIALS AND METHODS: The tests comprise spoken numbers in background noise and estimate the speech reception threshold (SRT), i.e. the signal-to-noise ratio (SNR) yielding 50% speech intelligibility. RESULTS: The respective reference speech intelligibility functions for headphone and telephone presentation of the German version for 15 and 10 normal-hearing listeners are described by a SRT of -9.3 ± 0.2 and -6.5 ± 0.4 dB SNR, and slopes of 19.6 and 17.9%/dB, respectively. Reference speech intelligibility functions of all digit triplet tests optimized within the HearCom project allow for investigation of the comparability due to language specificities. CONCLUSIONS: The optimization criteria established here should be used for similar screening tests in other languages.

The development of psychometrically equivalent Cantonese speech audiometry materials.

OBJECTIVE: The aim of this study was to develop and psychometrically evaluate speech audiometry materials that can be used to measure word recognition (WR) and speech recognition testing (SRT) in quiet for native speakers of Cantonese. STUDY SAMPLE: Commonly used bisyllabic and trisyllabic Cantonese words were digitally recorded by native male and female talkers and then evaluated by twenty normal-hearing Cantonese listeners. DESIGN: The recorded bisyllabic words were psychometrically evaluated and arranged into four WR lists and eight half-lists that are relatively homogeneous in audibility. Using logistic regression, SRT materials were developed by selecting 28 trisyllabic words with relatively steep psychometric functions and digitally adjusting their intensity to match the listeners' mean pure-tone average. RESULT: The mean psychometric slopes for the WR materials were 7.5%/dB for the male talker and 7.6%/dB for the female talker, with no statistically significant differences between the lists or half-lists. At intensity levels required for 50% intelligibility, the mean psychometric slopes of the male and female talker SRT materials were 14.5%/dB and 14.9 %/dB, respectively. CONCLUSION: High-quality digital recordings of Cantonese speech audiometric WR and SRT materials were developed and validated in this study. These materials are available on compact disc, indexed by talker gender.

Free-field correction values for Interacoustics DD 45 supra-aural audiometric earphones.

OBJECTIVE: This paper reports free-field correction values for the Interacoustics DD 45 audiometric earphone. The free-field correction values for earphones provide the loudness based equivalence to loudspeaker presentation. Correction values are especially used for the calibration of audiometric equipment for speech audiometry performed with headphones. Calibration values may be found in, e.g. the ISO 389 series of standards. DESIGN: The free-field correction values were determined by means of loudness balance measurements of one-third octave noises (centre frequencies 125 Hz to 8000 Hz) presented alternately from a loudspeaker in a free field and from the earphones. The procedure was essentially in accordance with the free-field frequency response procedure described in IEC 60268-7: Headphones and earphones. STUDY SAMPLE: Four earphones and 14 test subjects. RESULTS: Free field correction values are reported for the acoustic coupler IEC 60318-3 (NBS 9-A) and for the ear simulator IEC 60318-1. The results are in good agreement with the results of another independent investigation. CONCLUSIONS: The reported free-field correction values may be used as part of the basis for future standardization of the DD 45 earphone.

Reference sound pressure level for Korean speech audiometry.

OBJECTIVE: The purpose of this study was to examine the reference sound pressure level (RSPL) for Korean speech audiometry which was defined as the reference speech recognition threshold level (RSRTL) equivalent to 0 dB HL at the audiometer. STUDY SAMPLE: Subjects consisted of 20 adults (40 ears) with normal hearing sensitivity. DESIGN: Puretone thresholds (PTs) were obtained in 2 dB steps at each octave band. The newly developed Korean bisyllabic words were used to establish the speech recognition thresholds (SRTs). The SRT was the level at 50% correct responses based on the psychometric function performed from -8 dB HL (12 dB SPL) up to the level at or above 90% correct responses in 2 dB steps. RESULTS CONCLUSIONS: The mean SRT was 23.44 dB SPL for sets comprised of 36 Korean bisyllabic words. Thus, the difference between English and Korean RSRTLs was about 3.44 dB. We recommend further study to recalculate the RSRTL for Korean speech audiometry with more subjects.

Development of the Cantonese Hearing In Noise Test (CHINT).

OBJECTIVE: To develop a Cantonese version of the Hearing In Noise Test (CHINT) with the same features as the English Hearing In Noise Test (HINT) (Nilsson, Soli, & Sullivan, 1994). DESIGN: The CHINT was developed in five separate studies: (1) evaluation of initial materials; (2) creation of sentence materials; (3) equalization of sentence difficulty; (4) creation of sentence lists; and (5) evaluation of response variability, inter-list reliability, and establishment of norms. Using the CHINT material, reception thresholds for sentences were measured under four headphone test conditions: Quiet, and in noise with noise simulated as originating from 0 degrees (noise front), 90 degrees (noise right), and 270 degrees (noise left). The speech source was located at 0 degrees in all conditions. The locations of the speech and noise sources were simulated using virtual audio processing, as with the English HINT. The noise conditions consisted of listening with noise fixed at 65 dBA with the level of speech varied in an adaptive procedure. A total of 142 subjects with normal hearing thresholds participated in the five studies. RESULTS: Two versions of the test materials, twenty-four 10-sentence lists and twelve 20-sentence lists, were created from a single set of 240 sentences containing 10 syllables per sentence. Using the twenty-four 10-sentence lists, mean thresholds under earphones in quiet were measured at 19.4 dBA and reception thresholds for sentences of -3.9 dB for noise front, -10.6 dB for noise right, and -10.5 dB for noise left. Similar results were obtained using the 20-sentence lists (19.4, -4.0, -10.9, and -11.0 dB, respectively, for quiet, noise front, noise right, and noise left conditions). There was low response variability within each list. High inter-list reliability suggests that consistent results could be obtained using any list. Confidence intervals are reported. The CHINT norms for listening in quiet and noise conditions were comparable to those for the English HINT. CONCLUSIONS: The CHINT is the first standardized Cantonese sentence speech intelligibility test. The CHINT was developed using the same rationale as the English HINT, allowing norm reference results from the two tests to be compared directly across languages. Results showed the CHINT is a reliable test. The CHINT would benefit from further evaluation of validity.

Band importance functions for audiological applications.

Recently, band importance functions have been developed for a number of speech tests used in audiology. These functions, as well as the importance functions for average (everyday) speech, are also being considered for the inclusion in the revised Articulation Index standard (submitted for vote to the Acoustical Society of America). In this paper, the band importance functions for different speech materials (usually reported in literature for 1/3 octave bands) have been recalculated to correspond to frequency bands normally used in audiological applications. In addition, criteria for selecting appropriate importance functions and transfer functions are discussed.

A model to evaluate and maximize hearing aid performance by integrating the articulation index across listening conditions.

A method for integrating the articulation index (AI) across listening conditions was developed and applied to a preliminary model for evaluating and optimizing prescriptions of hearing aid characteristics. The model takes hearing threshold, masking of noise, self-masking of speech, high level cochlear distortion, and the peak-clipping effects of a hearing aid into account. The integrated AI (IAI) across a range of listening conditions is used as a criterion for evaluating a specific hearing aid response characteristic and calculating an optimal frequency-gain characteristic that maximizes the IAI. For a high-frequency hearing loss, the frequency-gain characteristics and IAI's derived from an optimal IAI (OIAI), POGO, and NAL prescriptions are compared for two of listening situations: a quiet setting and a setting with a signal-to-noise ratio of -3 dB. The results predict that, in quiet, the OIAI prescription is not significantly different from the well-established prescriptive procedures such as the POGO and the NAL. For the noise condition, however, the optimal IAI model is predicted to be better in terms of speech intelligibility.

Prediction of aided preferred listening levels for hearing aid gain prescription.

Relative accuracy was assessed for two methods for predicting preferred listening levels as estimated by measurements of the upper limit of the comfortable loudness range (ULCL). Sixteen hearing-impaired subjects provided ULCL data for eight test stimuli on each of five occasions. The stimuli were four narrow bands of noise centered at 500, 1000, 2000, and 4000 Hz and four narrow bands of speech babble also centered at 500, 1000, 2000, and 4000 Hz. Best estimates of ULCL were determined to be the means of the five measurements for each subject for each of the eight test signals. Results revealed that the mean ULCL for each speech-band stimulus was predicted more accurately from that subject's first measurement of ULCL for that speech-band than from his/her threshold for the same signal. However, the accuracy with which noise-band ULCLs could be used to predict the mean speech-band ULCL varied with frequency and with the number of trials averaged. Relationship of ULCL to preferred listening levels was explored by comparing results obtained in this study with work of previous investigators. Implications of the results for hearing aid gain prescription are discussed.