Tone perception in Mandarin-speaking children with cochlear implants.

OBJECTIVE: To evaluate the effects of implant age and duration of implantation on development of Mandarin tone perception in paediatric cochlear implant recipients. DESIGN: Retrospective cross-sectional evaluation of tone perception, as assessed with the Mandarin Early Speech Perception test at 3, 6, 12, 24, 36 and 48 months after activation. STUDY SAMPLE: A total of 143 subjects, 60 girls and 83 boys unilaterally implanted at 1-4 years of age comprised the sample. All the subjects were implanted with devices from one of three manufacturers. RESULTS: Regardless of implant age, approximately 80% of the subjects obtained overall tone discrimination scores significantly above chance by 4 years after implantation, and average discrimination accuracy increased from approximately 68% to 79%. Acoustically distinct tones 1 and 4 were discriminated and recognised more accurately, while less distinct tones 2 and 3 were discriminated and recognised less accurately. Large individual differences in performance were evident. CONCLUSIONS: Most Mandarin-speaking paediatric CI recipients discriminate tones above chance at 5 years of age with accuracy comparable to that of children with normal hearing at 2 years of age. Modest benefits of early implantation are evident.

The effect of non-native and non-regional speech testing on a multi-lingual population.

OBJECTIVE: This study was conducted to evaluate the speech perception of Malaysian Chinese adults using the Taiwanese Mandarin HINT (MHINT-T) and the Malay HINT (MyHINT). DESIGN: The MHINT-T and the MyHINT were presented in quiet and noise (front, right and left) conditions under headphones. Results for the two tests were compared with each other and with the norms for each test. STUDY SAMPLE: Malaysian Chinese native speakers of Mandarin (N = 58), 18-31 years of age with normal hearing. RESULTS: On average, subjects demonstrated poorer speech perception ability than the normative samples for these tests. Repeated measures ANOVA showed that speech reception thresholds (SRTs) were slightly poorer on the MHINT-T than on the MyHINT for all test conditions. However, normalized SRTs were poorer by 0.6 standard deviations for MyHINT as compared with MHINT-T. CONCLUSIONS: MyHINT and MHINT-T can be used as norm-referenced speech perception measures for Mandarin-speaking Chinese in Malaysia.

Initial classification of pediatric hearing impairment using behavioral measures of early prelingual auditory development.

OBJECTIVE: Determine the sensitivity, specificity, and accuracy of pediatric hearing loss classification using behavioral evidence of early prelingual auditory development (EPLAD). Validate behavioral measures of EPLAD. DESIGN: EPLAD was assessed in a prospective sample of hearing-impaired children using the infant-toddler meaningful auditory integration scale (ITMAIS/MAIS). Hearing losses were classified using tone-burst auditory brainstem response (ABR) and ITMAIS/MAIS scores. This process was repeated in a second retrospective sample. STUDY SAMPLE: The prospective sample was comprised of 139 hearing-impaired children under five years of age. Approximately equal proportions of mild-moderate, severe, and profound losses were included. The second retrospective sample was comprised of case records for 144 hearing-impaired children meeting the same selection criteria. This sample contained more than 80% profound losses. RESULTS: EPLAD trajectories reached different asymptotes after two years of age, depending on the severity of hearing loss, allowing children over this age to be classified. The sensitivity of EPLAD classifications was over 90%; specificity was over 82%; and accuracy was over 88%. CONCLUSIONS: Behavioral evidence of EPLAD provides an initial means of classifying pediatric hearing losses which can facilitate initial treatment options prior to diagnostic evaluation with tone-burst ABR.

Characterization of speech understanding in various types of noise.

This study examined (1) the effects of noise on speech understanding and (2) whether performance in real-life noises could be predicted based on performance in steady-state speech-spectrum-shaped noise. The noise conditions included a steady-state speech-spectrum-shaped noise and six types of real-life noise. Thirty normal-hearing adults were tested using sentence materials from the Cantonese Hearing In Noise Test (CHINT). To achieve the first aim, the performance-intensity function slopes in these noise conditions were estimated and compared. Variations in performance-intensity function slopes were attributed to differences in the amount of amplitude fluctuations and the presence of competing background speech. How well the data obtained in real-life noises fit the performance-intensity functions obtained in steady-state speech-spectrum-shaped noises was examined for the second aim of the study. Four out of six types of noise yielded performance-intensity function slopes similar to that in steady-state speech-spectrum-shaped noise. After accounting for individual differences in sentence reception threshold (SRT) and the offset between the signal-to-noise ratio for 50% intelligibility across different types of noise, performance in steady-state speech-spectrum-shaped noise was found to predict well the performance in most of the real-life noise conditions.

Outcome assessment alternatives for young children during the first 12 months after pediatric hearing-aid fittings.

OBJECTIVE: Perform longitudinal evaluations of young children during the first 12 months after initial hearing-aid fitting. Document evidence of early prelingual auditory development (EPLAD), identify factors that affect EPLAD, and define performance milestones that can guide best practices. DESIGN: Unblinded, prospective, within-subject, repeated-measures design. Audiological measures and measures of EPLAD were taken at baseline, 3, 6, and 12 months after hearing-aid fitting. STUDY SAMPLE: Subjects were 45 pediatric patients initially fitted with hearing aids between 1 and 5.5 years of age. Four groups were formed for analysis purposes based on severity of hearing loss (moderate-to-severe and profound) and initial fitting age (≤ 30 months and > 30 months). RESULTS: All groups exhibited statistically significant increases in EPLAD within six months of hearing-aid fitting, and those with profound losses exhibited further statistically significant improvement between six and 12 months. Similar EPLAD levels were reached at 12 months regardless of severity of hearing loss. The EPLAD trajectory is similar to that following early cochlear implantation. CONCLUSIONS: Measures of EPLAD provide a means of evaluating outcomes following early pediatric hearing-aid intervention, supplementing behavioral audiological measures.

Cantonese tone recognition with enhanced temporal periodicity cues.

This study investigated the contributions of temporal periodicity cues and the effectiveness of enhancing these cues for Cantonese tone recognition in noise. A multichannel noise-excited vocoder was used to simulate speech processing in cochlear implants. Ten normal-hearing listeners were tested. Temporal envelope and periodicity cues (TEPCs) below 500 Hz were extracted from four frequency bands: 60-500, 500-1000, 1000-2000, and 2000-4000 Hz. The test stimuli were obtained by combining TEPC-modulated noise signals from individual bands. For periodicity enhancement, temporal fluctuations in the range 20-500 Hz were replaced by a sinusoid with frequency equal to the fundamental frequency of original speech. Tone identification experiments were carried out using disyllabic word carriers. Results showed that TEPCs from the two high-frequency bands were more important for tone identification than TEPCs from the low-frequency bands. The use of periodicity-enhanced TEPCs led to consistent improvement of tone identification accuracy. The improvement was more significant at low signal-to-noise ratios, and more noticeable for female than for male voices. Analysis of error distributions showed that the enhancement method reduced tone identification errors and did not show any negative effect on the recognition of segmental structures.

Development of the Mandarin pediatric speech intelligibility (MPSI) test.

The objective of this research was to create a Mandarin closed-set sentence recognition test based on the English pediatric speech intelligibility (PSI) test (Jerger & Jerger, 1984 ) for evaluation of speech perception in children as young as three years of age. Developmentally normal children (N = 93), 3-6 years of age, were administered the Mandarin PSI (MPSI) via a computer-controlled protocol. Perfect performance was observed for all children in quiet and at +10 and +5 dB signal-to-noise ratios (SNRs). Significant age and developmental trends were seen for the more difficult SNRs, 0 dB, -5 dB, and -10 dB, with 75% of 5-6 year olds reaching the most difficult SNR. Children who reached each of the more difficult SNRs, regardless of age, exhibited the same pattern of performance on all easier conditions, indicating that the final SNR achieved, rather than percent correct scores, may be a better descriptor of performance. The MPSI comprises part of a hierarchical assessment battery for pediatric speech perception for evaluation of intervention alternatives for Mandarin-speaking children with hearing impairment.

Treatment of mixed hearing losses via implantation of a vibratory transducer on the round window.

Early clinical findings are reported for subjects implanted with the Vibrant Med-El Soundbridge (VSB) device. The present criteria for the VSB, limiting its application to patients with normal middle ear function, have been extended to include patients with ossicular chain defects. Seven patients with severe mixed hearing loss were implanted with the transducer placed onto the round window. All had undergone previous surgery: six had multiple ossiculoplasties, and one had the VSB crimped on the incus with unsuccessful results. Round window implantation bypasses the normal conductive path and provides amplified input to the cochlea. Post-operative aided thresholds of 30 dB HL were achieved for most subjects, as compared with unaided thresholds ranging from 60-80 dB HL. Aided speech reception thresholds at 50% intelligibility were 50 dB HL, with most subjects reaching 100% intelligibility at conversational levels, while unaided thresholds averaged 80 dB HL, with only one subject reaching 100% intelligibility. These results suggest that round window implantation may offer a viable treatment option for individuals with severe mixed hearing losses who have undergone unsuccessful ossiculoplasties.

Adaptation of the HINT (hearing in noise test) for adult Canadian Francophone populations.

The HINT provides an efficient and reliable method of assessing speech intelligibility in quiet and in noise by using an adaptive strategy to measure speech reception thresholds for sentences, thus avoiding ceiling and floor effects that plague traditional measures performed at fixed presentation levels A strong need for such a test within the Canadian Francophone population, led us to develop a French version of the HINT. Here we describe the development of this test. The Canadian French version is composed of 240-recorded sentences, equated for intelligibility, and cast into 12 phonemically balanced 20-sentence lists. Average headphone SRTs, measured with 36 adult Canadian Francophone native speakers with normal hearing, were 16.4 dBA in quiet, -3.0 dBA SNR in a 65 dBA noise front condition and -11.4 dBA SNR in a 65 dBA noise side condition. Reliability was established by means of within-subjects standard deviation of repeated SRT measurements over different lists and yielded values of 2.2 and 1.1 dB for the quiet and noise conditions, respectively.

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.

Transcranial contralateral cochlear stimulation in unilateral deafness.

OBJECTIVES: The purpose of this study is to evaluate the effectiveness of Bone Anchored Cochlear Stimulator (BAHA) in transcranial routing of signal by implanting the deaf ear. Study design and settings Eighteen patients with unilateral deafness were included in a multisite study. They had a 1-month pre-implantation trial with a contralateral routing of signal (CROS) hearing aid. Their performance with BAHA was compared with the CROS device using speech reception thresholds, speech recognition performance in noise, and the Abbreviated Profile Hearing Benefit and Single Sided Deafness questionnaires. RESULTS: Patients reported a significant improvement in speech intelligibility in noise and greater benefit from BAHA compared with CROS hearing aids. Patients were satisfied with the device and its impact on their quality of life. No major complications were reported. Conclusion and significance BAHA is effective in unilateral deafness. Auditory stimuli from the deaf side can be transmitted to the good ear, avoiding the limitations inherent in CROS amplification.