Development and validation of an iPad-based Japanese language monosyllable speech perception test (iCI2004 monosyllable).

BACKGROUND: Speech perception tests are commonly used as indices reflecting hearing ability in daily life. In Japan, the CI-2004 test, first developed in 2004, is widely used as standard, but it was not validated against a large number of normal hearing controls and hearing loss patients. AIMS/OBJECTIVES: The primary objective of the present study was to develop and validate iPad-based software for the Japanese monosyllable speech perception test, 'iCI2004'. MATERIAL AND METHODS: Seven universities and two medical centers participated in this study. The hearing threshold and Japanese monosyllable speech perception test results of 77 people with normal hearing and 459 people with hearing loss were collected. RESULTS: All participants with normal hearing achieved almost perfect perception results both in quiet and in noise. For cochlear implant users, the average monosyllable speech perception score was 55.1 ± 19.6% in quiet and 40.3 ± 19.2% in noise (SNR + 10dB). CONCLUSIONS AND SIGNIFICANCE: We developed iPad-based Japanese monosyllable speech perception test software and validated it by testing a large number of controls and hearing loss patients with cochlear implants or hearing aids. The developed monosyllable speech perception test has a sufficiently large dynamic range for assessing improvement in speech perception in Japanese cochlear implant users.

Assessing binaural/bimodal advantages using auditory event-related potentials in subjects with cochlear implants.

OBJECTIVE: To assess the advantage of binaural and bimodal hearing for subjects with cochlear implant (CI) using auditory event-related potentials as well as speech perception tests. SUBJECTS AND METHODS: The subjects comprised four binaural CI users (CI/CI group) and eleven bimodal CI users, who wore a hearing aid (HA) contralaterally (CI/HA group). All subjects had used binaural or bimodal fitting for over 6 months. Their speech perception was examined in a quiet environment using monosyllabic words. Late cortical waves were measured while subjects were engaged in an oddball task of 1kHz frequent and 2kHz rare tone stimuli. The latencies of event-related potential (N1, N2, P3) were compared for monaural, binaural, and bimodal hearing conditions. RESULTS: Significantly (p<0.01, paired t-test) better speech perception for monosyllabic words was found for both binaural and bimodal hearing than monaural hearing. The latency of N1 did not significantly change for either binaural or bimodal hearing. On the other hand, the latency of N2 was significantly (p<0.01, paired t-test) shorter for binaural and bimodal hearing than for monaural hearing. The latency of P3 was shorter for binaural and bimodal hearing than monaural hearing in all subjects, and the difference was statistically significant in both CI/CI and CI/HA groups (p<0.01, paired t-test). CONCLUSIONS: Better speech perception was obtained for binaural and bimodal hearing than for monaural hearing in CI subjects. The results obtained in the comparison of P3 latency agreed with that of speech perception. Thus, using bilateral hearing devices is recommended for CI subjects. We also found that event-related potentials were useful as an objective tool to assess the advantage of binaural and bimodal hearing for CI subjects.

[Implantation of a vibratory mass transducer on the round window: a report of two cases].

The Vibrant Soundbridge (VSB, Med-El, Austria) is a semiimplantable hearing aid usually attached to the long process of the incus to vibrate the ossicular chain in patients with moderate to severe mixed hearing loss. We implanted a VSB vibratory transducer on the round window membrane of the left ear in two cases not treated effectively by tympanoplastic surgeries. Pure tone audiography did not differ significantly in the two cases pre- or postoperatively, indicating that the small mass transducer does not adversely affect middle-ear vibration. Postoperative hearing thresholds with VSBs were similar to those when patient 1 wore an air-conductive hearing aid and patient 2 wore a bone-anchored hearing aid (BAHA). VSB implantation on the round window could thus potentially benefit many patients with mixed hearing loss.

Bimodal studies using adaptive dynamic range optimization (ADRO) technology.

This study investigated the effects of adaptive dynamic range optimization (ADRO) processing for six bimodal listeners who used a hearing aid in one ear and a cochlear implant in the other. 'Bimodal' refers to the use of acoustic and electrical stimulation together. Bimodal speech recognition thresholds with the Japanese hearing in noise test were significantly lower for two ADRO devices than two non-ADRO devices in quiet, in noise from the front, and in noise from the implanted side. When the noise was presented from the non-implanted side there was no significant difference between the ADRO and non-ADRO conditions. The hearing aid measure of contrast questionnaire indicated that participants preferred ADRO in 77.3% of situations. ADRO was especially preferred in more difficult situations. The ADRO processing was designed for use in bimodal prostheses, and this study confirmed that speech intelligibility and sound quality improvements are obtainable by using ADRO in a bimodal context.

Auditory perception and speech production skills of children with cochlear implant assessed by means of questionnaire batteries.

OBJECTIVE: The aims of this study were to evaluate early auditory perception and speech production skills, and to compare the outcomes between two groups of children wearing the Nucleus cochlear implant (CI) and Clarion CI. METHODS: A total number of subjects were 68 prelingually deaf children who were implanted with a CI at our center, 31 subjects with the Nucleus CI (N-group), and 37 with the Clarion CI (C-group). The early time course of auditory perception and speech production skills were assessed by means of parental interviews using three kinds of questionnaires, the Listening in Progress (LIP) score, the Infant-Toddler Meaningful Auditory Integration Scale (IT-MAIS) and the Meaningful Use of Speech Scale (MUSS). RESULTS: The basement scores for all three test batteries before the use of CI were poorer for the C-group than the N-group. The scores improved rapidly over the initial 6 months and gradually reached a plateauover a 6- to 12-month period. The speech production skills evaluated by MUSS developed much more slowly and took over 3 years to reach a given level. CONCLUSIONS: Our pediatric CI users showed steady development of auditory perception and speech production skills after CI without any significant difference between the two groups.

[The change of the auditory function in children with cochlear implant].

OBJECTIVE: Study the change of the auditory function in children with cochlear implant in different periods. METHOD: This study compared the Nucleus group and the Clarion group in 47 children after cochlear implantation, discussed the auditory change in different periods after surgical procedures and by the Listening Progress Profile (LIP) of Nottingham University. RESULT: The average scores of LIP before the operation and after 3 months, 6 months and 12 months were (8.5 +/- 9.9), (35.0 +/- 8.6), (39.0 +/- 2.4), (40.0 +/- 2.9) in Nucleus group and (5.6 +/- .5), (28.1 +/- 13.4), (34.4 +/- 9.2), (39.8 +/- 3.5) in Clarion group respectively. The improvement of auditory function was significant in the initial 3 months after switch-on but slower from the 3rd to 12th month. CONCLUSION: The testing outcomes of auditory function in both Nucleus group and Clarion group are all close to the full score 1 year after switch-on. The auditory function can be improved in different degrees after the cochlear implantation in children with congenital deafness.

Neural mechanism of residual inhibition of tinnitus in cochlear implant users.

Residual inhibition is a transient suppression of tinnitus after auditory stimulation has stopped. We used positron emission tomography to study brain regions underlying residual inhibition in three tinnitus patients with cochlear implants and six normal hearing controls. Regional cerebral blood flow was measured and compared under two conditions: with tinnitus and during the residual inhibition of tinnitus. The right anterior middle and superior temporal gyri (Brodmann areas 21 and 38) were activated during residual inhibition, while the right cerebellum was activated during tinnitus perception in the tinnitus patients. No significant activation was observed in the normal controls. Our results suggest that tinnitus and residual inhibition are related to cortical networks of auditory higher-order processing, memory and attention.

Comparison of speech perception between monaural and binaural hearing in cochlear implant patients.

OBJECTIVE: To assess the advantages of binaural hearing for cochlear implant (CI) users using a hearing aid (HA) for the contralateral ear. MATERIAL AND METHODS: The subjects comprised 3 males and 3 females (age range 48-84 years). All of them had been using a CI and HA for > 6 months. Their speech perception was examined in quiet using monosyllables and Japanese Hearing in Noise Test (J-HINT) sentences. Speech perception in noise was examined using J-HINT sentences. Late cortical waves were measured while subjects listened to 1 kHz frequent and 2 kHz target tone stimuli. The latency of the event-related potential (P300) wave was compared for monaural and binaural hearing conditions. RESULTS: Three subjects showed significantly better results for binaural than monaural (CI alone) hearing for monosyllables and HINT sentences (p < 0.05; paired t-test). Subjects with better speech perception had been using an HA for longer than those with poor performance (18.3 vs 4.0 years). The overall average score was better for binaural than monaural hearing in the speech perception test under quiet and noisy conditions. Comparison of the latency of the P300 wave under monaural and binaural hearing conditions showed a significantly shorter latency for the latter (p = 0.02; paired t-test). CONCLUSIONS: Although the use of an HA alone showed marginal benefit for CI users, binaural hearing (CI+HA) resulted in a significant improvement in speech perception under various circumstances.

Cortical processing of tactile language in a postlingually deaf-blind subject.

We compared neural activation detected by magnetoencephalography (MEG) during tactile presentation of words and non-words in a postlingually deaf-blind subject and six normal volunteers. The left postcentral gyrus, bilateral inferior frontal gyri, left posterior temporal lobe, right anterior temporal lobe, bilateral middle occipital gyri were activated when tactile words were presented to the right hand of the deaf-blind subject. This set of activated regions was not observed in the normal volunteers, although activation of several combinations of these regions was detected. Positron emission tomography confirmed the location of the MEG-activated areas in the deaf-blind subject. Our results demonstrated that the deaf-blind subject is heavily involved in interpreting tactile language by enhancing cortical activation of cognitive and semantic processing.

[Binaural advantage on usage of hearing aid together with cochlear implant--examination on speech perception (Japanese monosyllable word list 67-S and Japanese HINT)].

Six cochlear implant recipients with hearing aids in the opposite ear were studied to survey binaural advantage. They were examined in separate tests by using a hearing aid alone, cochlear implant alone, and by using both devices (bimodal condition). Test items used were the Japanese monosyllable word list 67--S and Japanese HINT. Statistically significantly results were obtained in the bimodal condition, three out of six subjects were successful in the monosyllable word test and all successful in the Japanese HINT. We conclude that all subjects enjoyed binaural advantage in speech perception in bimodal condition with no conflict at the recognition level; even when different sounds from cochlear implant and contralateral hearing aid were received. The plasticity of the brain is thought to be of importance in the bimodal condition.

[Audiological assessment of hearing-impaired children under age 3 and their later pure tone audiometry].

We analyzed the first audiological assessment and latest pure tone audiometry (PTA) in 29 hearing-impaired children (58 ears) visiting Osaka University for their first audiological assessment at the ages of 0, 1, and 2. We evaluated their hearing thresholds with PTA during follow-up and compared them to their first assessments. We combined auditory brain-stem response (ABR), behavioral audiometry, and conditioned orientation reflex (COR) for audiological evaluation of infants. Hearing thresholds assessed by 2 or 3 of these methods were sufficiently precise for hearing aid fitting. Thresholds of recorded ABR waves in 14 ears at loud sound pressure correlated well with later pure tone thresholds at high frequencies. Pure tone thresholds of those in whom no ABR waves were observed at 100 dB, were often out of scale at high frequencies--14% at 4000 Hz and 73% at 8000 Hz. Because of residual hearing at low frequencies, 4-frequency-averaged hearing at 500 Hz, 2 x 1000 Hz, 2000 Hz was better than 100 dB in 7 of 44 ears (16%), and 4 of 22 children (18%) did not fit the severest rank, 2, of the Disabled Persons, Welfare Law in Japan.

Successful cochlear implantation in prelingual profound deafness resulting from the common 233delC mutation of the GJB2 gene in the Japanese.

OBJECTIVES: Recently, we identified three novel mutations of the GJB2 gene in Japanese families with autosomal-recessive non-syndromic deafness.1 Seven of 11 mutated chromosomes (63.6%) contained a 233delC allele, suggesting that the 233delC mutation is the most common mutation of the GJB2 gene in the Japanese population. After it was recognized that cochlear implantation (CI) is of benefit to children with prelingual deafness, we have had a number of prelingual pediatric CI patients. Because children carrying the homozygous 233delC mutation show bilateral prelingual profound deafness, they could be enrolled in the CI program at Osaka University Graduate School of Medicine. The purposes of this study were 1) to analyze the occurrence of the GJB2 mutations in our 15 prelingual pediatric CI patients in whom the cause of non-syndromic deafness was unknown, and 2) to evaluate the auditory function and postoperative speech perception with CI of those GJB2-related deaf subjects. STUDY DESIGN: Retrospective analysis. METHODS: Mutation analysis of the GJB2 gene by direct sequencing was performed with genomic DNA from 15 children born profoundly deaf as a result of unknown causes and implanted with CI. Intraoperative electrically evoked auditory brainstem response (EABR) and intra-/postoperative EAP were measured. The speech perception was evaluated with Infants and Toddlers Meaningful Auditory Integration Scale (IT-MAIS). RESULTS AND CONCLUSIONS: We identified 4 CI patients (26.7%) out of 15 children carrying the homozygous 233delC mutation. Intra- and postoperative evaluation of the auditory system revealed almost intact cochlear and retrocochlear auditory function in these 4 patients. Postoperative auditory testing indicates that their speech perception had become significantly higher in comparison with that of other prelingual CI patients. These results suggest that prelingual deaf children carrying the homozygous 233delC mutation of the GJB2 gene can benefit from CI.