The effects of aging on the preoperative hearing loss were assessed in 1182 patients with chronic otitis media (COM) or cholesteatoma (CHL). Analysis was performed to clarify the correlation between preoperative hearing loss and age by calculating the regression line and the second order polynomial regression analysis. Preoperative hearing loss was appreciably poor in the younger patients and increased with age, compared with physiological hearing loss in the old patients (presbyacusis). The regression lines for bone conduction in the patients and for normal data separated from each other after the age of 30 and hearing loss gradually accelerated with age in low-middle frequency. This was more dominant in the patients who had undergone type IV or plannd staged tympanoplasty (without ossiculoplasty) than those with type I, and in the patients with COM than with CHL. Labyrinthine function appeared to be aggravated with age in COM and CHL. Thus, the patients with COM and CHL recommended to undergo tympanoplasty at an early stage.
Multifrequency tympanometry in the ears with conductive loss (stapes fixation, 76 ears; ossicular discontinuity, 12 ears) and the normal ears (36 ears) was evaluated. The difference between the stapes fixation group and the other two groups (the normal and ossicular discontinuity group) was significant in regard to static compliance, but not significant between the normal and stapes fixation groups. On the other hand, the differences in resonant frequency among the three groups were significant. However, some values were shared by cases in each of the three groups. Diagnosis of the cause of conductive loss is difficult to determine using only multifrequency tympanometry. A negative relationship between resonant frequency and preoperative air-bone gap at 2 and 4kHz for the stapes fixation group was recognized.
Between January 1998 and March 2000, 28 patients with unilateral vestibular schwannomas received stereotactic gamma knife radiosurgery (GKR) at the Chiba Cardiovascular Center. Patients' age ranged from 29 to 81 years (medians=59). 15 patients underwent prior surgical resection. Median follow-up period was 13.3 months (range: 3-30 months). Tumor volume was measured by Gamma Plan using MRI. Tumor volume ranged from 257 to 10100mm3. The pure-tone auiometry and speech discrimination test were performed before GKR. Post-GKR, tumor volume measurement and audiometric testing were undertaken every 3 months in a year, then every 6 months. 17 of 28 patients have lost their hearing before GKR by tumor itself or prior surgery, and none of them was improved after GKR. In one patient, who had serviceable hearing before GKR, lost his hearing at 6 months. In two patients, hearing was gradually deteriorating in spite of the reduction of tumor volume. Hearing improvement occurred in 2 patients at 3 to 6 months. Preservation of some measurable hearing was obtained in 10 of 11 patients (90.9%), however, serviceable hearing was preserved in 3 of 5 patients (60%). The change of tumor volume did not correlate to hearing change.
The progressiveness of the noise-induced hearing loss, especially in relation to the aging, was studied. First, the cross-sectional analysis was done on the hearing of 727 employees of a metal mine with special reference to their working years and age. Second, the hearing status of 208 cases with occupational noise-induced hearing loss, including the retired members of advanced age, were analyzed in relation to their ages. It was concluded that the noise-induced hearing loss appears and progresses rapidly during the initial 15 years of exposure, then after it tended to slow down. The hearing deterioration, however, continues for the whole period of employment and even after retirement. The amount of hearing deterioration is not the result of a simple addition of the age-related hearing loss.
A retrospective study was conducted on 267 neonatal intensive care unit (NICU). Mean birth weight was 2019g and mean gestational age was 34 weeks. The auditory brainstem response was examined as a hearing screening procedure on these infants. One or two years later, hearing was tested by auditory free field responses, and language development was assessed using the Shinpan-K shiki scale. There was 0.4% profound sensorineural hearing loss and 2.6% moderate combined hearing loss in the assessed group. Twenty-three children (8.6%) had speech problems on long-term follow-up. Thus the overall incidence of hearing loss in this NICU population was low, but there was the significantly higher incidence of speech problem.