Sound source localization in daily life is one of the important functions of binaural hearing. In the past, bone-conduction hearing aids were often worn unilaterally for conductive hearing loss, such as bilateral microtia and atresia of the ears. Directional hearing is also achieved when a person with bilateral conductive hearing loss wears bone-conduction hearing aids in both ears, however, it does not reach the accuracy of directional hearing of a person with normal hearing. Binaural bone-conduction hearing aids may promote the development of the auditory system in infants with bilateral microtia and atresia of the ears, and may reduce the inconvenience of daily life in persons with conductive hearing loss.
The Rapidly Alternating Speech Perception test (RASP) was conducted to 31elderly people in dichotic condition to investigate factors in relate to binaural fusion using processed short sentence materials. The original sentences were also presented monaurally on the better ear in comparison with RASP. The results showed that RASP scores were lower than the monaural listening condition in all subjects. Findings also demonstrated significant correlation between RASP and speech perception, hearing levels, and ages.
This experiment indicated difficulties of binaural fusion in elderly people, but the relationship between aging and binaural integration ability in total requires further investigation.
We investigated the gap detection threshold for infants with hearing loss. A total of 32 (6-76 months) infants with hearing loss were administered the gap detection task using infant audiometry procedures, with the responses assessed based on turning of the infants' heads or push of the button.
The results showed that infants with hearing loss could detect silent gaps in noise. However, it took a long time to assess their gap detection thresholds. Younger infants with hearing aids showed a tendency towards higher thresholds, and infants using cochlear implants showed individual differences in their ability to detect silent gaps. There was a significant correlation between the gap detection thresholds and the degree of concentration or age, but no correlation between the gap detection thresholds and the hearing level or threshold. The response procedure for around three-year old infants was switched from turning the head to pushing the button. Therefore, closer attention to infants' responses should be paid for a precise assessment of the threshold. These findings indicate that there is a possibility of early application on temporal resolution task to infants with hearing loss.
We investigated the degree of disability associated with hearing difficulties and consciousness of hearing impairment using a semi-structured interview in 4 people with moderate hearing loss. Thirty concepts related to the disorder of hearing in people with moderate hearing loss were generated from the interview, and the individual circumstances about the difficulty of hearing, coping, method, and change in the sense of hearing impairment. Even though listening to speech was good, they found it difficult to listen to conversations. However they acknowledged the commonality in dealing with the use of conversational strategies and their own information gathering. In addition, although the consciousness about hearing impairment varied depending on the individual growth history and environment, however, in general, there are more negative awareness than the acceptance of hearing impairment. It was shown that hearing impairment and negative awareness were always mixed at any life stage. We suggest that it is necessary to provide information and long-term support depending on the stage of development of the affected person.
Alport syndrome is primarily characterized by nephritis, but is also accompanied by eye problems and gradual progressive bilateral sensorineural hearing loss. Unfortunately, few reports are available in the literature on the treatment and long-term progression of hearing loss in individual cases of Alport syndrome. We therefore examined the decrease in hearing levels, medical history, and the use of hearing aids in three male Alport syndrome patients who have been regularly monitored at our ENT department over an extended period. The monitoring periods for the three patients were 8 years (from the ages of 3 to 11 years), 13 years (from the ages of 4 to 17 years), and 7 years (from the ages of 11 to 18 years). The first two patients had developed hearing loss at a relatively young age, and their progressive hearing loss was observed relatively early. The third patient was not diagnosed as suffering from Alport syndrome until he was older, and by that time, he had already been diagnosed as having hearing loss. All three patients have continued to experience a gradual decrease in the hearing levels, but none has reached the point of needing a hearing aid(s).
The aim of this study was to compare the efficacy of frequency lowering (FL) among 3 different hearing aids with built-in FL functions, under the“off”/“on” condition. The evaluation was performed by determining the monosyllable intelligibility under speech-like noise and the impression of sentences. Frequency lowering techniques in hearing aids are often used for patients with high-frequency hearing loss. There are various FL techniques available in hearing aids, such as linear frequency transposition (LFT), non-linear frequency compression (NLFC), frequency translation (FTl), high-frequency speech feature replication, and so on. The subjects of this study were 14 persons with normal hearing and 4 patients with high-frequency hearing loss.
In the 14 persons with normal hearing (simulated high-frequency hearing loss), the intelligibility scores obtained with LFT and NLFC under the“on” condition were significantly lower than those in the“off” condition. The impression of FL under the“on” condition was relatively poor as compared to that without hearing aids. While the scores of FL (LFT, NLFC and FTl) under the“on” condition were higher than those under the“off” condition in the 4 patients, the results of impression of FL varied among the FL techniques, regardless of whether FL was in the“off”/“on” condition.
FL techniques are considered to improve speech perception of patients with high-frequency hearing loss.
Musical hallucinations refer to the phenomenon whereby subjects hear music or melody in the absence of any external sound source. We report the clinical features of musical hallucinations and the effectiveness of therapy using hearing aids. Among patients with tinnitus who visited our clinic from January 2011 to October 2018, 23 patients complained of musical hallucinations. Out of the 23 patients, 11 patients desired to receive sound therapy using hearing aids. Musical hallucinations were most common among elderly women. Out of the 23 patients, 22 had sensorineural hearing loss and none of the patients had psychiatric disease. After treatment, significant improvement was observed in the total scores on the Tinnitus Handicap Inventory (THI) and Visual Analogue Scale (VAS: loudness and discomfort of tinnitus). Our study suggested that sound therapy using hearing aids is an effective treatment for musical hallucinations caused by hearing loss. Furthermore, it is desirable for musical hallucinations with hearing loss to be treated mainly by otolaryngologists.
This research was aimed at clarifying the speech rate characteristics and adjustment strategies of those with profound hearing impairment in whom spoken language is the primary means of communication and who attended special education needs schools. Acoustic analysis was used to compare the speech duration for three speech rate types between people with profound hearing impairment and people with normal hearing. The results showed that those with profound hearing impairment showed lower speech rates than those with normal hearing, although there was no difference in the pause time, indicating that those with profound hearing impairment spent more time on articulation. However, there was much variation among individuals; while some participants with profound hearing impairment exhibited speech similar to those with normal hearing, others experienced difficulty in speaking quickly. The study found that across different speech rates, comparison of speech time and pause time revealed that both those with normal hearing and those with profound hearing impairment used increases and decreases in intra-sentence and inter-sentence pause times as a strategy to adjust the speed of their speech.