Speech audiometry has been a fundamental tool in the assessment of hearing loss. It provides information concerning both hearing sensitivity to speech stimuli and hearing acuity to understand various speech materials at suprathreshold levels. In everyday clinical practice, the pure-tone threshold test is preferred for hearing loss patients because of its simplicity. However, speech sound recognition tests at suprathreshold level are indispensable in the evaluation of hearing acuity. Speech test materials for use in speech audiometry should be chosen with careful consideration of the linguistic characteristics of the patients' mother tongue. The speech recognition threshold is measured by the use of Spondaic word lists in the US, whereas lists of single digit numerals are used in Japan. Suprathreshold speech-sound recognition testing is performed using phonetically balanced monosyllabic word lists in the US, whereas meaningless monosyllables are used in Japan, which allows a simple dictation method to be used for response testing. Speech audiometry is performed using the mother tongue of the patient. Even though linguistic difference may influence the establishment of a fundamental test method, the principle of the test would not be affected. Speech audiometry can help validate the impact of intervention using hearing aids. The results of cochlear implants can be evaluated directly by speech-sound recognition testing. Also, speech audiometry facilitates audiological rehabilitation in postoperative cases with cochlear implants.
There are significant individual differences in age-related changes in the hearing acuity. Theses individual differences are caused by genotypes as the internal factor, and various environmental and lifestyle factors as the external factors. It would be important to clarify these factors to minimize the development of hearing disturbances in the elderly. We confirmed the age-related changes in the hearing acuity among the 120, 000 men and women followed up for 18 years in Nagoya city. We also analyzed the factors that might influence individual differences in the hearing acuity based on detailed 10-year longitudinal data in 2, 400 community-living men and women. Age-related hearing disturbance was more prominent for high-pitched sounds than for low-pitched sounds, and disturbances in the hearing acuity were more significant in men than in women. Hearing acuity decreased in any generation both the sexes? during the 18-year follow-up from 1989. There were significant genetic influences in the age-related hearing disturbance. Presence of underlying chronic diseases such as diabetes, ischemic heart disease and renal diseases was also related to the hearing acuity. Significant association of the hearing acuity was also found with the presence of arteriosclerosis as determined by carotid artery ultrasonic tomography and examination of the ocular fundus. As for lifestyle factors, the effects of noise exposure and smoking were found to be significant in the age-related changes in hearing acuity.
We present the current status of the fitting and evaluation processes for the hearing aids prescribed at the hearing aids clinic of Kitasato University Hospital. The indications for a hearing aid were considered following general otological examination and hearing tests. During the fitting process, evaluation of the hearing aids, hearing tests and subjective evaluation were performed. Evaluation of the hearing aids was performed by adjusting the maximum output level and insertion gain of the tested hearing aid. Input and output function was recorded for the nonlinear hearing aids. Real ear insertion gain was evaluated as an objective and practical parameter. Pure-tone audiometry, speech discrimination test, and audiological tests for recruitment phenomenon are essential. The uncomfortable loudness test was also useful. Evaluation of hearing was done by comparing the aided and non-aided hearing levels. Fitting was considered to be ideal when the mechanical evaluation and hearing test results were balanced. Subjective evaluation of hearing was done using the hearing questionnaire 2002. This questionnaire has been found to be useful for detecting and solving fitting problems at the outpatient clinic and also for analyzing the effectiveness of hearing aids as well.
The hearing threshold test, speech discrimination test, questionnaires, etc., are used for evaluation of the effects of aided hearing and it is necessary to judge the compliance with the use of a hearing aid from an overall investigation perspective. However, it is difficult to judge compliance with the use of a hearing aid in practice and the selection and adjustment of hearing aids are left to the person with the hearing disorder. Therefore, it is important to establish a method for accurate assessment of the effects of hearing aids and the criteria for the assessment of compliance. In the hearing aid outpatient clinic of our hospital, the effects of a hearing aid are measured using a combination of several test methods. These tests not only confirm compliance with the use of the hearing aid but also clarify adjustment points by comparing the test results in the context of the complaints the patients with impaired hearing. This procedure has been very useful. We hope to actively perform hearing aid compatibility tests to deepen our understanding of the problems faced by the patients and their families about the effects and limitations of hearing aids and to help patients accept their disorders. The current status of the outpatient clinic is reported and future prospects are outlined.
The Acute Profound Deafness Research Committee of the Ministry of Health, Labour and Welfare of Japan conducted a follow-up study of patients with acute low-tone sensorineural hearing loss. We investigated the clinical findings in 2007 of 195 cases registered in fiscal 2000 and 2001 based on the medical records. An 80% cure or improvement rate was found in the 52 cases (26.7%) who were followed up for one year after enrollment. The incidence of Ménière's disease in these cases was 7.7%, being diagnosed at an average interval of two years and ten months after enrolment. Seven cases (3.6%) developed progressive hearing loss up to middle and/or high tones. These cases showed significantly worse hearing level at the initial visit, such as the sum of low frequencies and the threshold at 1kHz. Therefore, careful follow-up is required for these patients. In all, 49 cases (25.1%) developed recurrence. Among the cases with recurrent disease, more than half of the cases developed recurrence within half a year. On the other hand, 30.6% of cases developed recurrence more than one year after symptoms first appeared.
Exaggeration of the hearing loss was detected in 28 ears of 14 cases (24%) among 58 cases who were referred to our department between 2003 and 2006 for compensation of noise-induced hearing loss as a workers' accident an occupational hazard. Exaggeration of hearing loss was noticed by discrepancies in the results among several hearing tests or behavior, for example, between bilateral pure-tone audiometry test thresholds and the conversation status (93%), tinnitus masking tone thresholds (64%), auditory brainstem response thresholds (57%), stapedial reflex thresholds (50%), and speech audiogram thresholds (21%). Unexplained pure-tone audiogram threshold fluctuations were observed in 57% of the cases with hearing thresholds aggravation loss exaggeration. Eight of the 14 cases of exaggeration showed better and reliable pure-tone audiometry test thresholds after being requested to desist from exaggeration. Comparison of the results of pure-tone audiometry between cases with and without exaggeration revealed the functional exaggerative overlay mainly in the low and mid frequencies. Additionally, 2 cases revealed to deceive the cause of hearing loss by showing in 2 cases, an attempt at deception as to the cause of the hearing loss was detected by an evident air-bone gap caused by middle ear disease.
We report two cases of sudden sensorineural hearing loss, presumably due to inner ear hemorrhage. The first case was a 78-year-old man on anticoagulant therapy (ticlopidine hydrochloride), and the other was a 61-year-old woman with Helicobacter pylori-positive idiopathic thrombocytopenic purpura. In both cases, T1-weighted MR images showed a high signal intensity without gadolinium enhancement in the labyrinth, suggesting inner ear hemorrhage. Despite steroid therapy in the early stage after the onset, no hearing improvement was obtained in either case. MRI examination is essential to diagnose inner ear hemorrhage, and this imaging modality plays an important role in evaluating the pathologic conditions underlying sudden sensorineural hearing loss.
We followed and investigated the abilities of language and intelligence in each case of a deaf-only child, deaf-child with low-birth-weight anamnesis, and deaf-child with newborn-asphyxia anamnesis. We had these children wear a H. A. or C. I. and administered preschool language-training, basically by the ‘auditory-verbal method’ for 6 years and 8 months, from the age of 2 years and 8 months to the age of 9 years and 9 months, on average. The results were as follows; 1. In the case of the deaf-only child who started wearing a C. I. at the age of 3 years and 6 months, the child was able to catch up with and exceed the language and intelligence abilities of children of similar calendar age. 2. In the case of the deaf-child with low-birth-weight anamnesis who started wearing a C. I. at the age of 3 years and 6 months, the child was able to catch up in the abilities of language and intelligence with children of the same calendar age by 8 years of age, and his developmental progress was the same as that of a normal child with low-birth-weight anamnesis. 3. In the case of the deaf-child with newborn-asphyxia anamnesis who started wearing a C. I. at the age of 8 years and 2 months, the abilities of language and intelligence remained retarded even when the child reached llyears of age, that is, 2 years and 10 months after he started wearing the C. I. 4. Therefore, we should eliminate the effects of profound severe hearing loss by prescribing C. I. early in life; furthermore, it is also important to ensure adequate total developmental training. Our results suggest that if these measures could be implemented effectively the long-lasting adverse effects of low-birth-weight and newborn asphyxia on development may be avoided.
Making a hearing-impaired infant wear a hearing aid serves two purposes: one is to enable the infant to learn the language, and the other is to enable him/her to learn to eventually speak as a result of hearing spoken language. When considering the type of hearing aid that a hearing-impaired infant should wear and his/her adjustment to it, it is necessary to consider these two purposes. In this research, we examined the voices exchanged between a mother and her baby. We recorded and analyzed the voices of both the baby and the mother when they were separated by a natural distance. Based on the results, the behind-ear hearing aid was selected from among the behind-ear, pocket, and baby hearing aids, because it can detect even a small sound pressure difference between another's voice and one's own voice. Further, when the hearing aid had been adjusted, we focused on the non-linear I/O characteristic that have started as a knee-point equals as another's voice and sets compression characteristics over one's own voice.