Modernising speech audiometry: using a smartphone application to test word recognition.

OBJECTIVE: This study aimed to develop and assess a method to measure word recognition abilities using a smartphone application (App) connected to an audiometer. DESIGN: Word lists were recorded in South African English and Afrikaans. Analyses were conducted to determine the effect of hardware used for presentation (computer, compact-disc player, or smartphone) on the frequency content of recordings. An Android App was developed to enable presentation of recorded materials via a smartphone connected to the auxiliary input of the audiometer. Experiments were performed to test feasibility and validity of the developed App and recordings. STUDY SAMPLE: Participants were 100 young adults (18-30 years) with pure tone thresholds ≤15 dB across the frequency spectrum (250-8000 Hz). RESULTS: Hardware used for presentation had no significant effect on the frequency content of recordings. Listening experiments indicated good inter-list reliability for recordings in both languages, with no significant differences between scores on different lists at each of the tested intensities. Performance-intensity functions had slopes of 4.05%/dB for English and 4.75%/dB for Afrikaans lists at the 50% point. CONCLUSIONS: The developed smartphone App constitutes a feasible and valid method for measuring word recognition scores, and can support standardisation and accessibility of recorded speech audiometry.

Development and validation of a smartphone-based digits-in-noise hearing test in South African English.

OBJECTIVE: The objective of this study was to develop and validate a smartphone-based digits-in-noise hearing test for South African English. DESIGN: Single digits (0-9) were recorded and spoken by a first language English female speaker. Level corrections were applied to create a set of homogeneous digits with steep speech recognition functions. A smartphone application was created to utilize 120 digit-triplets in noise as test material. An adaptive test procedure determined the speech reception threshold (SRT). Experiments were performed to determine headphones effects on the SRT and to establish normative data. STUDY SAMPLE: Participants consisted of 40 normal-hearing subjects with thresholds ≤15 dB across the frequency spectrum (250-8000 Hz) and 186 subjects with normal-hearing in both ears, or normal-hearing in the better ear. RESULTS: The results show steep speech recognition functions with a slope of 20%/dB for digit-triplets presented in noise using the smartphone application. The results of five headphone types indicate that the smartphone-based hearing test is reliable and can be conducted using standard Android smartphone headphones or clinical headphones. CONCLUSION: A digits-in-noise hearing test was developed and validated for South Africa. The mean SRT and speech recognition functions correspond to previous developed telephone-based digits-in-noise tests.

[Testing the comparability of free-field and HDA200 headphone measurements for the Freiburg speech test]. / Überprüfung der Vergleichbarkeit von Freifeld- und HDA200-Kopfhörermessungen für den Freiburger Sprachtest.

BACKGROUND: In clinical practice, the standardized Freiburg speech test is presented via headphones as well as via loudspeakers. To achieve comparable results with both presentation modes, the headphone measurements are equated to the free-field situation. The free-field correction is determined by subjective loudness balance measurements and realized by a free-field equalizer network and a broadband frequency correction value during headphone calibration. Using the Freiburg speech test, this study tested the comparability of free-field and HDA200 headphone measurements. PATIENTS AND METHODS: In 15 normal hearing subjects, the Freiburg speech intelligibility test was performed using both loudspeakers and HDA200 headphones. RESULTS: The 50% speech reception threshold measured using HDA200 headphones was on average 5.1 dB lower than for loudspeakers and lay below the standardized reference values. CONCLUSION: The desired comparability to free-field measurements could not be shown for the HDA200 headphones. The improved intelligibility via HDA200 is probably caused by the fact that the calibration correction factor of 4 dB is too high. This should be checked by the PTB.

The effect of bone conduction microphone placement on intensity and spectrum of transmitted speech items.

Speech signals can be converted into electrical audio signals using either conventional air conduction (AC) microphone or a contact bone conduction (BC) microphone. The goal of this study was to investigate the effects of the location of a BC microphone on the intensity and frequency spectrum of the recorded speech. Twelve locations, 11 on the talker's head and 1 on the collar bone, were investigated. The speech sounds were three vowels (/u/, /a/, /i/) and two consonants (/m/, /∫/). The sounds were produced by 12 talkers. Each sound was recorded simultaneously with two BC microphones and an AC microphone. Analyzed spectral data showed that the BC recordings made at the forehead of the talker were the most similar to the AC recordings, whereas the collar bone recordings were most different. Comparison of the spectral data with speech intelligibility data collected in another study revealed a strong negative relationship between BC speech intelligibility and the degree of deviation of the BC speech spectrum from the AC spectrum. In addition, the head locations that resulted in the highest speech intelligibility were associated with the lowest output signals among all tested locations. Implications of these findings for BC communication are discussed.

Using the speech understanding in noise (SUN) test for adult hearing screening1.

PURPOSE: To develop a novel speech-in-noise test for adult hearing screening-the Speech Understanding in Noise (SUN) test. The goal was to design a fast, automated, easy-to-use test to identify difficulties in speech communication. METHOD: The SUN test consists of a short list of intervocalic consonants in noise presented in a forced-choice paradigm by means of a touch screen. The SUN test was developed and evaluated in an overall population of >6,000 participants. The test is available in various languages (i.e., English, French, German, and Italian) and continues to be developed in others (e.g., Spanish, Portuguese, and Mandarin). RESULTS: Test time was <1 min/ear. Test-retest reliability was very good. The test showed good agreement with conventional clinical measures (e.g., pure-tone testing, speech-in-noise testing, and self-reported hearing handicap). The test's sensitivity and specificity to identify disabling hearing impairment were 84% and 75%, respectively. The same results were obtained in low and high ambient noise. CONCLUSION: The SUN test is fast, repeatable, easy to use, self-explanatory, specific to the impairment, and robust to ambient noise. It may be a viable approach for adult hearing screening in clinical as well as nonclinical settings.

Speech-in-noise tests for multilingual hearing screening and diagnostics1.

PURPOSE: New complementary multilingual speech-in-noise tests in Russian, Turkish, and Spanish for hearing self-screening purposes and follow-up hearing diagnostics are compared to the speech tests of the European project, HearCom (Hearing in the Communication Society). METHOD: The tests consist of spoken numbers (Digit Triplet Test; Smits, Kapteyn, & Houtgast, 2004) or sentences (Matrix Test; e.g., Hagerman, 1982) presented in a background noise and estimate the speech reception threshold, which is the signal-to-noise ratio that yields 50% speech intelligibility. All tests were developed according to the HearCom minimum quality standards for speech intelligibility tests. This report presents a cross-language comparison of reference speech intelligibility functions for monaural headphone measurements with normal-hearing listeners. The same model function was employed to describe the speech intelligibility functions for all of the tests. RESULTS: Reference speech intelligibility functions of the new versions of the Digit Triplet Test and Matrix Test show high comparability to the HearCom tests. In order to achieve the highest possible comparability across languages, language- and speaker-dependent factors in speech intelligibility should be compensated for. CONCLUSION: To date, several complementary tests for screening and diagnostics have been developed in several languages. Adhering to the HearCom standards, the tests are highly comparable across languages. For the Matrix Test, equal syntax and linguistic complexity were maintained across languages due to common methodological standards.

[Correlation of pure tone thresholds and hearing loss for numbers. Comparison of three calculation variations for plausibility checking in expertise]. / Korrelation von Tonschwellenaudiogramm und Hörverlust für Zahlen. Vergleich dreier Rechenvarianten zur gutachterlichen Plausibilitätsprüfung.

BACKGROUND: The present study analyzes the best combination of frequencies for the calculation of mean hearing loss in pure tone threshold audiometry for correlation with hearing loss for numbers in speech audiometry, since the literature describes different calculation variations for plausibility checking in expertise. Three calculation variations, A (250, 500 and 1000 Hz), B (500 and 1000 Hz) and C (500, 1000 and 2000 Hz), were compared. METHODS: Audiograms in 80 patients with normal hearing, 106 patients with hearing loss and 135 expertise patients were analyzed in a retrospective manner. Differences between mean pure tone audiometry thresholds and hearing loss for numbers were calculated and statistically compared separately for the right and the left ear in the three patient collectives. RESULTS: We found the calculation variation A to be the best combination of frequencies, since it yielded the smallest standard deviations while being statistically different to calculation variations B and C. The 1- and 2.58-fold standard deviation (representing 68.3% and 99.0% of all values) was ±4.6 and ±11.8 dB for calculation variation A in patients with hearing loss, respectively. CONCLUSIONS: For plausibility checking in expertise, the mean threshold from the frequencies 250, 500 and 1000 Hz should be compared to the hearing loss for numbers. The common recommendation reported by the literature to doubt plausibility when the difference of these values exceeds ±5 dB is too strict as shown by this study.

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.

Influence of compact disk recording protocols on reliability and comparability of speech audiometry outcomes: acoustic analysis.

OBJECTIVE: To assess whether different compact disk recording protocols, used to prepare speech test material, affect the reliability and comparability of speech audiometry testing. MATERIAL AND METHODS: We conducted acoustic analysis of compact disks used in clinical practice, to determine whether speech material had been recorded using similar procedures. To assess the impact of different recording procedures on speech test outcomes, normal hearing subjects were tested using differently prepared compact disks, and their psychometric curves compared. RESULTS: Acoustic analysis revealed that speech material had been recorded using different protocols. The major difference was the gain between the levels at which the speech material and the calibration signal had been recorded. Although correct calibration of the audiometer was performed for each compact disk before testing, speech recognition thresholds and maximum intelligibility thresholds differed significantly between compact disks (p < 0.05), and were influenced by the gain between the recording level of the speech material and the calibration signal. CONCLUSION: To ensure the reliability and comparability of speech test outcomes obtained using different compact disks, it is recommended to check for possible differences in the recording gains used to prepare the compact disks, and then to compensate for any differences before testing.

Comparison of vu-meter-based and rms-based calibration of speech levels.

A difference of approximately 5 dB exists between the level of spoken English determined using the ANSI standard vu-meter method compared to the common root-mean-square (rms) method. If the rms method is substituted for the present ANSI standard method for calibrating a speech audiometer, for example, the reported speech reception thresholds will improve 5 dB: Speech levels read approximately 5 dB less using rms. Similarly, the reported signal-to-noise ratio required to understand speech in a speech-spectrum noise will be 5 dB better using rms. A simple method for obtaining a close approximation to traditional calibrations using a modified rms method is given.

Psychometrically equivalent Russian speech audiometry materials by male and female talkers.

Despite the large number of individuals who speak Russian, only a limited number of high-quality speech audiometry materials are available in a standard dialect of Russian. Thus, the purpose of this study was to develop and evaluate speech audiometry materials that can be used to measure word recognition and SRT testing in quiet for native speakers of Russian. Familiar monosyllabic and bisyllabic words were digitally recorded by male and female talkers of Russian and subsequently evaluated by native listeners. Using logistic regression, psychometric functions were then calculated for all words. Selected monosyllabic words were digitally adjusted to create word recognition lists which are relatively homogeneous with respect to audibility and psychometric slope. Speech reception threshold materials were developed by selecting twenty-five bisyllabic words with relatively steep psychometric function slopes (12.1%/dB and 9.9 %/dB) and digitally equating their intensity to match the mean PTA of the native listeners. Digital recordings of the resulting psychometrically equivalent speech audiometry materials are available on compact disc.

[Polish language dychotomic tests for speech audiometry Part 2: A study of people with normal hearing from various age groups]. / Testy utrudnione w audiometrii mowy dla jezyka polskiego (czesc II). Badania osób z prawidlowym sluchem w róznych grupach wiekowych.

INTRODUCTION: Evaluation of the objective results in the clinical examination of central auditory disorders requires the use of reliable language tests which provide the means for the estimation of patients' audio-verbal communicative skills. MATERIALS AND METHODS: The authors present a new set of more difficult language tests in Polish, including a filtered speech test, numeral and verbal dichotic tests and the normal Calearo test. The tests were evaluated on a group of people with good hearing from various age groups. CONCLUSIONS: The presented tests are the only existing ones created for the Polish language which expand the diagnostic possibilities in the case of central auditory processing disorders. It was found that there is a right ear predominance in dichotic tests, which grows together with the patient's age. This observation can be very beneficial in practice, allowing for hearing aids to be better fitted.

Evaluation of equivalency in two recordings of monosyllabic words.

Thirty "new" lists of monosyllabic words were created at the University of Melbourne and recorded by Australian and American English speakers. These new lists and the ten original CNC lists (Peterson and Lehiste, 1962) were used during the feasibility study of the Nucleus Research Platform 8 Cochlear Implant System (Holden et al, 2004). Performance was similar across original and new lists for six implanted Australian subjects; for four implanted U.S. subjects, mean performance was 23 percentage points lower with the new than with the original lists. To evaluate differences between original and new lists for the American English recording, 22 CI recipients were administered all 40 CNC lists (30 new and 10 original lists). The overall mean word score for the new lists was significantly lower (22.3 percentage points) than for the original lists. Acoustic analysis revealed that decreased performance was most likely due to reduced amplitudes of certain initial and final consonants. The new CNC lists can be used as more difficult test material for clinical research.

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.

The benefit method: fitting hearing aids in noise.

The most common complaint among individuals with hearing impairment is the inability to follow a conversation when several people are talking simultaneously, a noisy listening situation which is completely different from the quiet surrounding of the conventional pure tone audiometry used as basis for the hearing aid settings. The purpose of this report was to present important characteristics of the BeneFit Method (BFM), a procedure that fits the hearing aid under simulated conditions of competing speech and also a clinical pilot evaluation study comparing the BFM to the NAL-R recommendations and also to the Logic procedure, a GN resound proprietary fitting algorithm representing a modern digital hearing aid fitting procedure. Speech recognition scores in noise (SRSN) using monosyllabic words presented under different background noise levels were evaluated on 21 randomly selected subjects with hearing impairment. The subjects were fitted with the same type of hearing aid Danalogic 163D according to the BFM procedure as well as the logic procedure, the latter developed and recommended by the manufacturer. A comparison of the SRSN when using the subjects' current hearing aid fitted according to the NAL-R procedure was also made. Only the BFM procedure provided a significant SRSN improvement compared to the unaided condition (P< 0.01) in a signal/speech-noise level of 75/65 dB corresponding to a normal cocktail party condition. Moreover, patients performed significantly higher SRSN when fitted according to the BFM, than when fitted according the Logic or NAL-R procedures. The BFM procedure, which is based on individual and functional detection of hearing thresholds in noise levels corresponding to a cocktail party condition, can improve SRSN significantly. Hearing aids should be fitted under conditions similar to those when the hearing disability is perceived the most, i.e, in an environment with background noise.

The viability of speech-in-noise audiometric screening using domestic audio equipment.

Speech-in-noise audiometry has potential application as a low-cost, self-screening test for sensorineural hearing loss. To realize this potential, the influence of variations in audio equipment and listening environment need assessment. The present study assessed: 1) the frequency response and distortion produced by a wide range of commercially available audio equipment; 2) the effects of such variations upon test results with normally hearing subjects using a simple, open-set, word-identification test; 3) the effect of distortion on the speech reception threshold using digitally applied distortion; and 4) the reliability of the test in listening environments with different levels of reverberation. In addition, preliminary tests were conducted with elderly listeners. The results indicate that variations in equipment have negligible effects on speech-in-noise audiometry. The only factor that substantially elevated normally hearing listeners' thresholds was high levels of room reverberation when using loudspeaker presentation. Variations in equipment and environment thus present no significant obstacle to the development of a self-administered audiometric screening test based on speech in noise.

The performance of South African English first language child speakers on a "low linguistically loaded" central auditory processing test protocol.

The lack of standardized tests for central auditory processing disorders (CAPD) in South Africa (SA) led to the formation of a SA CAPD Taskforce, and the interim development of a "Low Linguistically Loaded" CAPD test protocol using test recordings from the 'Tonal and Speech Materials for Auditory Perceptual Assessment Disc 2.0'. This study compared the performance of 50 SA English first language child speakers (aged 8 to 12 years of age) on this protocol, with the previously published American normative data of Bellis (1996, 2003). Results with respect to predicted pass criteria as calculated by mean-2SD cutoffs, suggested that the SA speakers performed of a lower level than the American speakers by an average of 5.3% per ear for the two pair dichotic digits test, 1.9 dB for the masking level difference test, 8.8% per ear for the frequency pattern test--humming report, 14.5% per ear for the frequency patterns test--verbal report, and 39.7% per ear for the low pass filtered speech test. Consequently, the Bellis (1996, 2003) data was not considered appropriate for immediate use as normative data in SA. Instead, the preliminary data provided in this study was recommended as interim normative data for SA English first language child speakers until larger scale SA normative data can be obtained.

Picture naming by children with hearing loss: II. Effect of phonologically related auditory distractors.

Thirty children with hearing loss (HL) and 129 typically developing (TD) children representing comparable ages, vocabulary abilities, or phonology skills named pictures while attempting to ignore auditory distractors. The picture-distractor pairs were constructed to represent phonologically congruent or conflicting onset relations, for example, the picture "duck" with distractors of /[symbol: see text]/or /[symbol: see text]/, respectively. In children with good phoneme discrimination, congruent distractors speeded naming and conflicting distractors slowed naming, relative to a control condition. Effects were similar in HL and TD subgroups. In children with poorer phoneme discrimination, conflicting distractors did not influence naming in the HL subgroup, regardless of discrimination status, and consistently slowed naming only for discriminated contrasts in the TD subgroup. Phonologic representations appear suitably fine-grained in HL children with good auditory perceptual abilities but may be less well specified, more holistic, and/or less auditory-linguistically based in HL children with poorer auditory perceptual abilities. Results are discussed in terms of the heterogeneous nature of phonologic processing in children with HL.