Causal diagnosis of hearing impairment in children can potentially lead to proper provisions for the future of a child with hearing impairment. Despite its importance, the homogeneity of audiological features frequently hampers further causal diagnosis of hearing impairments. The two major causes of pediatric hearing impairment, namely, 1) genetic causes and 2) environmental causes, are discussed in this review. Particular attention was paid to the clinical/audiological features of known causes of hearing impairment, because clinical suspicion with typical stigmata/symptom are of primary importance for clinicians.

View full abstract

A behavioral observation audiometry (BOA) was conducted at 1kHz and 3kHz at the hearing level of 50dB and 70dB on 208 babies who were first seen at less than 2 months old for newborn hearing screening. A comparative review was made between the results of the BOA and the subsequent definitive diagnosis.
Almost 100% of the cases who responded to 50dB and approximately 90% of those who responded to 70dB were found to have unilateral or bilateral normal hearing at definitive diagnosis and a high-level of profound deafness was rare. However, 26.5% of the cases with unilateral/bilateral normal hearing did not respond to the BOA. As for the level of the subjects' sleep, more responses were obtained when the babies were tested at the onset of sleep rather than when they were awake or sleeping.
Although it is impossible to detect deafness or estimate the level of deafness when infants show no response to the BOA before 2 months of age , if any response is obtained, it serves as good reference material for extensive testing and diagnosis, as well as being useful information for educating the parents.

View full abstract

“CI-2004 (tentative)” has been developed to evaluate speech recognition in cochlear implant (CI) users. It is an open-set test battery in Japanese and consists of consonants, monosyllables, words and everyday-life sentences. The lists of words and sentences are available both in quiet and in noise.
The purpose of this study was to evaluate the performance of CI-2004 and to examine whether CI-2004 might be useful and profitable for evaluating speech recognition in CI users with auditory alone.
We examined the speech perception performance of 50 postlingually deafened adults with CI, after 6 months of implant use. The mean correct sentence recognition score was 78%, close to the results reported for HINT by Arndt et al.
Furthermore, classification of the listening performance changes made it possible to give CI users appropriate auditory training and directions to make the most of their CIs in everyday life. From that perspective, it was also useful for preparing individual auditory rehabilitation programs to allow hearing in more realistic listening situations.

View full abstract

MB11 with BERAphone^® is a newborn hearing screening device which is sometimes used with Natus ALGO^®, mainly in the obstetric field in Japan. This device is considered to reduce both the labor and cost as compared with conventional screening devices. We evaluated the usefulness of MB11 as a screening device. The results revealed a sensitivity of MB11 of 92.0% (23/25 ears), and specificity of 100% (65/65 ears). The mean test time was only 2 minutes and 12 seconds, facilitating rapid diagnosis. Each test costs about 20 yen, for the conductive gel, indicating good cost performance. This device could become more widely applicable, although further studies are necessary.

View full abstract

Auditory neuropathy spectrum disorder (ANSD) is a hearing disorder caused by desynchronized neural discharges of the auditory nerve. It is a retrocochlear hearing disorder identified by abnormal or complete absence of auditory brainstem responses (ABR) and presence of evoked acoustic otoemissions (OAE). Some reports have shown that cochlear implantation may be successful for rehabilitation of children with ANSD. One report has shown that mutations of the OTOF gene, which encodes otoferlin, cause non-syndromic ANSD. Herein, we report on three children with ANSD who underwent cochlear implantation at the National Center for Child Health and Development (Japan). We report the patient characteristics, preoperative audiological profiles, and postoperative performances of the children with cochlear implants. They were diagnosed as having ANSD based on the detection of normal DPOAE, but absent ABR. Mutation of the OTOF gene was also detected. They had no or very poor open-set speech recognition, both with and without appropriate hearing aids, and benefited from cochlear implantation. Cochlear implantation is expected to be a useful modality for language development in ANSD children with mutation of the OTOF gene.

View full abstract