The features of hearing loss in the elderly were elucidated and circumstances related to the fitting of hearing aids in this population were discussed. Hearing loss in the elderly has features related not only to hearing impairment but to the advanced age of the patient. As for fitting hearing aids in the elderly, in the case of each individual patient, it is very important be aware of specific features such as less awareness of actually being hard of hearing, refusal to use a hearing aid and decline of the patient's physical and mental function.
In recent years, many studies have been reported on the relationship between oxidative stress and various diseases. In this study, oxidative stress was assessed in 39 patients with sudden sensorineural hearing loss (SSNHL) using FRAS 4 (free radical analytical system 4). No statistical significance was observed for oxidative stress between SSNHL patients and 13 healthy volunteers (control), however, patients with mild hearing loss exhibited significantly higher values for oxidative stress than that of control, suggesting oxidative stress could be a risk factor for SSNHL, especially in the case of mild hearing loss.
The aim of this study was to evaluate the auditory steady-state response (ASSR) in children and to compare the ASSR thresholds with behavioral hearing thresholds and the click evoked auditory brain stem response (ABR). The ASSR of 39 infants and children with hearing loss between the ages of 0 to 75 months was examined. Both ears of all the subjects were tested with Audera (Grason-Stadler Corporation). The ASSR thresholds were 15 to 22dB higher than behavioral hearing thresholds, but significantly correlated with behavioral hearing thresholds. We investigated the ASSR thresholds in cases showing no response ABR at 105dBnHL. The ASSR thresholds were present in all cases, particularly in more than half of the ears at 500 and 1000Hz. These results were useful for detection and diagnosis of hearing loss and for the fitting of hearing aids. The ASSR is useful for performing objective measurements of the frequency-specific healing level. Furthermore, the ASSR may quantify hearing losses in the severe to profound range, and indicate some amount of residual hearing.
To assess the effect of measurement conditions of MASTER® on the threshold of the auditory steady-state response (ASSR) in adults, the ASSR using the multiple simultaneous stimulation technique with modulation frequencies (MFs) of around 40 and 82-98Hz, and pure-tone audiometry were performed in 6 adults (12ears) with normal hearing. The combinations of MFs and arousal states (waking and sleeping) were set at MF32-46Hz and MF82-98Hz while awake, and MF82-98Hz during sleep. In each combination of MF32-46Hz while awake and MF82-98Hz during sleep, the average differences between the ASSR threshold and the hearing level were smaller than those at MF82-98Hz while awake. These findings suggest that MASTER® using MF82-98Hz may not be recommended in awake adults.
The influence of recording time and noise level on the precision of the hearing thresholds estimated by the auditory steady-state response (ASSR) using the multiple simultaneous stimulation technique was investigated. ASSR thresholds at four frequencies in both ears were assessed in 11 normal hearing adults and 12 hearing-impaired children at rest. The difference scores between ASSR and the behavioral hearing thresholds were compared for ASSR recordings of 16, 24 and 32 sweeps, corresponding to 5, 7.5 and 10minutes of recording time. The mean difference scores were 19.5±11.2, 17.4±10.4, 15.6±10.3dB in adults and 13.1±14.4, 12.2±14.3, 11.7±15.2dB in children after recordings for 5, 7.5 and 10minutes respectively. In adults, increase of the test duration decreased the noise level and reduced the difference score significantly, while a longer test duration led to a reduced noise level, but did not contribute to higher precision of the hearing threshold estimates by ASSR in children. In the recording of ASSR in sleeping children, it is considered that a test duration of 16 sweeps would be sufficiently long to yield the precise thresholds.