Considering the anatomical and functional characteristics of the cerebral cortex, where each neuron receives massive synaptic inputs, on the order of 104 inputs, and information processing in the brain is highly recursive, we investigated how auditory perception is correlated with phase synchrony in the auditory cortex of rats. In this article, we first introduce the common indices of phase synchrony: inter-trial phase coherence (ITPC) and phase locking value (PLV). We then review our recent studies to discuss the functional roles of these phase synchronies in our auditory perception. Our experiments demonstrated that ITPC in the gamma band better explained the psychophysics of auditory streaming than the conventional properties of auditory evoked potentials. The PLV depended on the sound quality, such as consonance and tonality. These results support our hypotheses that phase synchrony in the auditory cortex is more closely related with subjective auditory perception as compared to conventional characterization of evoked potentials.
Most mothers caring for infants with disabilities tend to have anxiety about their children's future and stress from child-rearing. In this study, we investigated the degree of the mothers' stress using a questionnaire, as well as the relationship between the stress and potentially related factors.
We administered a questionnaire to 17 mothers caring for their hard-of-hearing infants (age 1-6 yrs.). The questionnaire prepared by us included 8 scales, including Parental Affliction, Anxiety about the Future of the Child, Social Isolation, Lack of Family Integration, Financial Problems, etc.
Our results showed that the scores for Parental Affliction and Anxiety about the Future of the Child were high, and those for Social Isolation and Lack of Family Integration were low. There were no significant correlations between the mother's stress and their children's age, degree of hearing, development, support periods, or presence of siblings.
We concluded that a variety of factors contribute to the mothers' stress. Therefore, appropriate support needs to be provided to parents caring for hard-of-hearing infants, including not only specific support in response to the children's development and environment, but also mental support, by listening carefully to the mothers' worries.
This study was conducted to compare the music perception abilities between electric acoustic stimulation (EAS) users and cochlear implant (CI) users. A total of 6 EAS users and 7 CI users participated in this study and were evaluated using three music tests: instrument identification, melody discrimination, and pitch discrimination. In addition, the 6 EAS users were also evaluated under electric stimulation (ES) conditions alone. In contrast to their results the best results were obtained in EAS users. We predicted that EAS users functioning under ES conditions alone are at a disadvantage as compared to CI users, due to the lack of stimulation in low frequencies for ES under ES conditions alone. Specifically, in EAS users perception occurs by slight acoustic stimulation in low frequencies and by electric stimulation in middle and high frequencies, while CI users perceive music by stable electric stimulation in all frequencies, from low to high. But there were actually no significant differences between EAS users operating under ES conditions alone and CI users. This indicates that slight acoustic stimulation contributes to improvement of the music perception ability.
Patients with single-sided deafness (SSD) often experience difficulties in hearing and have a reduced quality of life. In Europe, cochlear implantation is already performed for patients with SSD. We performed cochlear implantation in five patients with SSD from four facilities. We diagnosed one case of SSD at our department. Speech perception in noise, sound localization and tinnitus suppression with improved binaural hearing were observed four years after the cochlear implantation. We hope that cochlear implantation would come to be accepted in the future for enabling binaural hearing in patients with SSD.
We followed up with schools that enrolled children under 18 years of age who had undergone cochlear implantation between 1998 and 2016 while attending our hearing rehabilitation center during the same time period. There were 202 children who were of school age or older, with 144 attending regular schools. The rate of integration of our children with CIs was 71.3%. Except in the year 2015, when more than an average number of children were enrolled in regular kindergarten and nurseries, the rate of integration into regular schools over the last six years has been between 80% and 90%.
The main factors that account for the high rate of inclusion are newborn hearing screening, bilateral cochlear implantation, early detection of hearing loss caused by gene mutation and viral disease, preoperative auditory verbal/oral habilitation using hearing aids, surgery between 1 and 2 years of age, and ongoing interaction with the full-time speech-hearing-language therapist at the school for the deaf and at our center.
Having visited over 150 schools to follow how children with CIs have adapted to regular education, a discussion of the important aspects of school education that are needed to cater to these children follows.
To investigate the effect of tailor-made notched music training as a novel treatment for tinnitus, we created an iPhone application capable of 1) continuous frequency self-recording audiometry, 2) tinnitus pitch matching, 3) Tinnitus Handicap Index (THI) survey, 4) Visual Analog Scale (VAS) survey, and 5) playing music from the user's music library with a real-time band-stop filter. The results of the treatment can be uploaded to the cloud server and easily collected. This trial was planned to check the safety of the treatment and effectiveness of the evaluation. Eleven people took part in this 12-week trial. With pure-tone audiometry, the change in the hearing threshold between before and after the trial was within 5 dB for all frequencies in all participants. Evaluation by VAS was conducted every four weeks, but showed no consistent changes. Six participants in whom the initial THI was higher than 20 showed improvement of the THI after 12 weeks, however, the results failed to reach statistical significance, perhaps because of the small study sample. Some of the participants with initial THI values of lower than 20 showed worsening of the THI. The trial was a preliminary trial and no controls were set. Larger-scale, randomized controlled trials are needed.