Mumps has been known to cause unilateral sensorineural hearing loss, referred to as mumps deafness. Even subclinical mumps may be associated with hearing loss. The incidence of mumps deafness has been reported to be 0.005%. Recently, however, several reports have suggested that the incidence is much higher. Hearing loss associated with mumps is so severe that in most cases, it is refractory to any treatment. Thus, cochlear implantation is performed for cases of mumps deafness with bilateral severe hearing loss. There are a few reports of cases of deteriorated hearing in which hearing could be restored by administration of steroids and/or vitamins. However, it is still unclear as to which subset of patients could be successfully treated conservatively and which treatments might be effective. Mumps is a vaccine-preventable disease. Thus, vaccination is also the most effective way to prevent mumps deafness. However, the MMR vaccination program in our country has failed because of the high incidence of side effects (high incidence of aseptic meningitis). A new and more effective mumps vaccination program using a safer vaccine strain would, therefore, be needed in the near future.
Newborn hearing screening (NHS) programs have advanced nationally in Japan, however, differences have been seen in the funding, availability of equipment and rates of enforcement among prefectures. We investigated the current status of NHS in Aomori Prefecture by conducting a questionnaire survey of 36 obstetric institutions. About 60% performed NHS using automated auditory brainstem response (AABR) or otoacoustic emission (OAE) in equal numbers, while some institutions using both types of testing. Differences in the availability of testing devices were seen among institutions. About 3, 000 (25% of all) neonates were screened annually in 2004 and 2005. Compared to the national median, this is a low percentage. Institutions that lacked NHS devices indicated that they had no plans to purchase the equipment either, because of lack of funds and/or shortage of manpower. Early identification of hearing impairment is important for language development. To increase the rate of NHS in Aomori prefecture, we believe that it is necessary for otorhinolaryngologists to gain the cooperation of obstetricians and pediatricians and encourage institutions with the facilities to perform testing on all the neonates born at the institutions, as well as facilitate the transfer of newborns from institutions without facilities for NHS to those that are equipped, so that these neonates can also undergo screening.
We evaluated the audiological and speech performance of pediatric cochlear implant patients with inner ear malformations. Fourteen pediatric cochlear implant patients with inner ear malformations diagnosed by high-resolution computed tomography (HRCT) of the temporal bone were examined. Seven of the patients had an incomplete partition (IP), with two patients also exhibiting bilateral narrow internal auditory canals (IAC), and one also exhibiting bilateral enlarged vestibular aqueducts (EVA). One patient had partial semicircular canal aplasia, four had bilateral enlarged vestibular aqueducts (EVA), and two had a common cavity deformity (CC). None of the patients experienced postoperative complications, such as facial palsy, meningitis, or electrode extrusion. Children with bilateral narrow IACs demonstrated exhibited the poorest performance in all of the postoperative speech perception tests; therefore, they encouraged to use sign language to develop their language skills. Among two cases of common cavity deformity (CC), one began to perform well in postoperative speech perception and language development, while the other showed poor language acquisition. Because children with IP, partial semicircular canal aplasia, or EVA showed a significant improvement in speech perception, they are considered to be good candidates for cochlear implantation.
The participants were 100 children who were referred to the Kitasato University Hospital after Newborn Hearing Screening. We investigated the coincidence rate of the diagnosis of hearing impairment?? with the results of Newborn Hearing Screening and complete hearing check-up, and compared the results for the 53 well-born babies and the 47 high-risk babies. Both well-born babies and high-risk babies had undergone a complete hearing checkup within 3 months of birth. Through such checkup, 30% of the well-born babies were diagnosed to have normal hearing, while 22% were diagnosed to have bilateral hearing loss. On the other hand, 26% of the high-risk babies were diagnosed to have normal hearing, and 26% to have bilateral hearing loss. The coincidence rate of the babies who were referred bilateral who were diagnosed to have bilateral hearing loss by AABR was 71%, while that of those who were referred bilateral who were diagnosed to have bilateral hearing loss by OAF was 40%. The coincidence rates appeared to be higher for the well-born babies than for the high-risk babies. The Newborn Hearing Screening allowed not only severe-to-profound hearing loss, but also mild-to-moderate hearing loss to be diagnosed early. Future tasks to realize these advantages of Newborn Hearing Screening include an increase of the enforcement rate of the screening and construction of a system that would connect Newborn Hearing Screening results with those of medical checkup.
The purpose of this study was to develop a strategy for verifying the gain/frequency characteristics of nonlinear hearing aids used by infants, by converting their thresholds to 2cm3 coupler SPL. Twenty-three infants (age: 13 to 30 months) with hearing impairment (45 ears) were tested by visual reinforcement audiometry using ER-3A insert earphones coupled with custom earmolds to measure the MRTs (minimum response thresholds) across frequencies in dBHL. To convert dBHL to 2cm3 coupler SPL, the CDD (coupler-to-dial difference) values were added to the MRTs, which could display the MRTs on the 2cm3 SPL-gram developed by Ohwada. The strategy was based on the theory that the RECD (real-ear-to-coupler difference) values of wearing a hearing aid would be equal to those of inserting the ER-3A, because of the coupling with the same custom earmold. For verification of the hearing aid characteristics, the converted MRTs were compared to the output levels of nonlinear hearing aids measured in a 2cm3 HA-2 coupler with input levels of 50dB, 65dB and 80dBSPL. Strong correlations (r>.86) were found among them in the 500Hz, 1000Hz and 2000Hz range. In conclusion, comparison of the converted MRTs with the output levels of hearing aids on a 2cm3 SPL-gram was useful for verifying the suprathresholds characteristics of nonlinear hearing aids for infants.