Speech recognition scores in bilateral and unilateral atretic ears.

OBJECTIVE: Congenital aural atresia causes severe conductive hearing loss disturbing auditory development. The differences in speech recognition were investigated between bilateral and unilateral aural atresia. DESIGN: The maximum speech recognition scores (SRSs) were compared between patients with bilateral and unilateral aural atresia. In patients with unilateral aural atresia, the maximum SRSs were compared between the atretic and unaffected ears. Furthermore, the correct response rates for test material monosyllables were compared with those of patients with sensorineural hearing loss (SNHL), which had been previously obtained. STUDY SAMPLE: Twenty-four patients with aural atresia (8 bilateral, and 16 unilateral) participated. RESULTS: The maximum SRS in unilateral atretic ears (median: 72%) was significantly lower than that in unaffected ears (median: 89%) (p < 0.05) and in bilateral atretic ears (median: 91%) (p < 0.05). Patients with aural atresia had relatively high correct response rates for monosyllables with low correct response rates by patients with SNHL. Conversely, incorrect responses were obtained for several words for which high correct-response rates were attained by patients with SNHL. CONCLUSIONS: Poor unilateral atretic-ear development may induce low speech recognition, and the mechanisms underlying speech-recognition reduction differ from those in SNHL.

Long-term (16-26 years) follow-up outcome of steroid therapy in refractory autoimmune sensorineural hearing loss.

Autoimmune sensorineural hearing loss (ASHL) is a rare disease of uncertain etiology, with no established treatment strategy. The duration of morbidity is increased in refractory cases; and therefore, the preservation of hearing and the prevention of adverse effects with steroid therapy are serious long term issues to consider. Long-term follow up of patients treated for ASHL was performed retrospectively in order to elucidate the pathogenesis of ASHL, evaluate the consequences of steroid therapy, and determine a promising treatment course. The cohort in this study consists of four female patients with refractory ASHL that were followed for 16-26 years. Three patients already had profound deafness on one side, probably due to ASHL, before the initiation of steroid treatment. ASHL was managed with steroid administration and the hearing was evaluated through regular audiometric tests (173-212 times). The relationship between pure tone threshold average and steroid dose was reviewed over a long-term follow-up period for each patient. During follow-up, hearing deficit progressed rapidly several times in all patients, as did responsiveness to steroid therapy. Long-term high-dose steroid therapy was not required for hearing maintenance. Hearing thresholds were nearly maintained in three patients during the 16- to 21- year follow-up, and gradually declined over a 26-year follow-up period in one patient. Considering the progress due to presbycusis, the maintenance of hearing was considered sufficient in all patients. No serious adverse effects were observed in any of the patients. Management of patients affected by ASHL with regular audiometry allowed for hearing maintenance without the morbidity of prolonged steroid therapy. The current observations give insight into the pathogenesis of ASHL pathogenesis and establish an efficient course of treatment.

Effect of fixation place on airborne sound in cartilage conduction.

When a transducer is placed on aural cartilage, relatively loud sound becomes audible in a conduction form termed cartilage conduction (CC). Previous studies have revealed the acoustical differences between CC and conventional air or bone conduction. This study elucidates the working principle of CC through measurements of threshold shifts by water injection into the ear canal under various fixation place conditions. Seven volunteers with normal hearing participated. A lightweight transducer was fixed for three CC conductions (on the tragus, antitragus, and intertragal incisure), and two non-CC conditions (on the pre-tragus and mastoid). Thresholds were measured at 500, 1000, and 2000 Hz in the 0%-, 40%-, and 80%-water injection conditions. Results for the three CC conditions revealed unique features different from those for the non-CC conditions. For the CC conditions, the thresholds increased by the 40%-water injection at all frequencies. However, with additional water injection (80%-water injection), the thresholds decreased at 500 and 1000 Hz; in particular, dramatically at 500 Hz. The results suggest that a direct vibration of the aural cartilage is important to obtaining the significant contribution of airborne sound to hearing above 1000 Hz. Fixation place results in no significant difference in acoustic features among CC conditions.

Sound localisation ability using cartilage conduction hearing aids in bilateral aural atresia.

OBJECTIVE: Patients with bilateral aural atresia often exhibit poor sound localisation due to bone conduction (BC) features. However, most patients using cartilage conduction (CC) hearing aids reported improvement of sound localisation. DESIGN: CC hearing aids were fitted binaurally. Subsequently, sound localisation was evaluated in three conditions: unaided, aided with previously used hearing aids (air conduction or BC hearing aids), and aided with CC hearing aids. Ears were evaluated with eight loudspeakers positioned in a full-circle at 45-degree interval. Loudspeakers were classified into left and right by midline and front and back by horizontal line. The abilities to distinguish left from right and front from back were compared among three conditions. STUDY SAMPLE: Thirteen patients with bilateral aural atresia participated. RESULTS: The ability to distinguish sounds originating from left or right for participants aided with CC hearing aids was significantly better than that for other conditions (p < 0.05). For distinguishing sounds originating from front or back, unaided ears were significantly better than ears aided with CC hearing aids (p < 0.05). CONCLUSIONS: CC hearing aids provide the ability to distinguish left from right in patients with bilateral aural atresia.

Association between stairs in the home and instrumental activities of daily living among community-dwelling older adults.

BACKGROUND: There is insufficient evidence regarding the relationship of home environment with functional capacity among community-dwelling older people without disabilities. We conducted a population-based longitudinal cohort study and examined whether stairs in the home were associated with capability to perform instrumental activities of daily living (IADL) in community-dwelling high-functioning older adults. METHODS: The target population was individuals aged 65 years or older living in two municipalities in Nara Prefecture in Japan. At the baseline survey, residents who were independent in IADL (n = 6722) were included as survey subjects. Subjects were divided into three groups according to their home type; one-storey residences, walk-up residences, or residences with an elevator. IADL was evaluated using the Tokyo Metropolitan Institute of Gerontology Index of Competence. Multiple logistic regression analyses stratified by gender were used to calculate the odds ratio (OR) and a 95% confidence interval (CI) for a decline in IADL, with one-storey residences as a reference. Age, studied area, marital status, working status, self-perceived economic status, body mass index, chronic diseases, smoking, drinking, eating habits, basic activities of daily living, cognitive functioning, depression, self-rated health, and social participation were used as covariates. RESULTS: During the 3-year follow-up, 11.6% of the subjects showed a decline in IADL. After adjusting for covariates, women who lived in walk-up residences had a lower risk for IADL decline (adjusted OR = 0.72, 95% CI = 0.52-0.99), while living in a home with an elevator was not associated with IADL decline (adjusted OR = 0.94, 95% CI = 0.49-1.77). In contrast, there was no association between home type and IADL decline in men (walk-up residences, adjusted OR = 0.90, 95% CI = 0.71-1.14; residences with an elevator, adjusted OR = 0.82, 95% CI = 0.39-1.72). CONCLUSIONS: The presence of stairs in the home was associated with prevention of IADL decline over a 3-year period in older women without disabilities. Although a barrier-free house is recommended for older people, our findings indicate that a home with stairs may maintain the capability to perform IADL among older adults without disabilities.

Self-rated health predicts decline in instrumental activities of daily living among high-functioning community-dwelling older people.

Background: self-rated health (SRH) is a strong predictor of mortality, but it is unclear if SRH independently predicts a decline in instrumental activities of daily living (IADL). Objective: to verify whether SRH is an independent predictor of IADL decline. Design: a population-based longitudinal cohort study. Setting: two local municipalities in Nara, Japan. Subjects: community-dwelling older adults 65 years or older (2,638 males and 3,346 females) with independent IADL at baseline. Methods: SRH was assessed using a single-item measure. IADL was assessed using the Tokyo Metropolitan Institute of Gerontology Index of Competence. Multiple logistic regressions were used to examine the association of SRH with IADL decline. Results: during the 3-year follow-up, 13.2% of males and 8.2% of females developed IADL decline. After adjusting for age, family, body mass index, economic situations, chronic diseases, alcohol, smoking, depression, cognitive functioning and ADL, poorer SHR was significantly associated with IADL decline in both genders. Compared with very good SRH, the odds ratios of good, poor and very poor were 1.69 (95% confidence interval: 1.14-2.51), 2.10 (1.25-3.55) and 3.11 (1.50-6.45) for males, and 0.88 (0.54-1.42), 2.08 (1.16-3.75) and 3.42 (1.57-7.42) for females, respectively. Significant associations were not affected by chronic diseases, cognitive functioning or ADL but observed only among subjects aged 65-74 or those without depression. Conclusions: this study confirms that SRH is an independent predictor of IADL decline among non-disabled community-dwelling older adults. Our findings suggest that SRH is an effective tool for identifying older people with future risk for IADL decline, particularly among the young-old or those without depression.

Age and gender differences in the association between social participation and instrumental activities of daily living among community-dwelling elderly.

BACKGROUND: Although many studies have suggested social participation (SP) has beneficial effects on elderly people's health, most of them failed to deal with paid work. Additionally, few studies have focused on the age effect between SP and older people's health. To investigate whether the association between SP, including paid work, and instrumental activities of daily living (IADL), exhibits not only in gender, but also in age among community-dwelling older adults. METHODS: In 2014, we distributed self-administered questionnaires to all community-dwelling elderly aged ≥65 in two medium-sized cities in Nara Prefecture, Japan (n = 32,825). 22,845 residents submitted the questionnaire (response rate, 69.6%). Analyzed subjects were limited to 17,680 persons who had neither dependency in basic ADL nor missing data for required items. SP was assessed based on participation frequency in seven types of social activities: volunteer groups, sports groups, hobby groups, cultural groups, senior citizens' clubs, neighborhood community associations, and paid work. Using Poisson regression models, prevalence ratio for poor IADL was calculated. To examine age and gender differences in the association between SP and IADL, we performed stratified analyses by age and gender group; male young-old (aged 65-74), male old-old (aged ≥75), female young-old, and female old-old. RESULTS: Prevalence of those with poor IADL was 17.1% in males and 4.5% in females, showing a significant gender difference. After adjustment for relevant covariates, volunteer groups were inversely associated with poor IADL only in males and the relationship was stronger in the old-old group than in the young-old group. Conversely, only females had a significant inverse association between paid work and poor IADL, and the association was not reliant on their ages but only those who participated infrequently had a favorable effect. Influence of age in the beneficial association between SP and IADL was generally larger in the old-old group than in the young-old group, but hobby groups were inversely associated with poor IADL, regardless of age, gender, and frequency. CONCLUSIONS: Our results suggest that SP in older age is positively associated with IADL, however, the association seems to differ depending on the type of activities participated in, the participants' gender, and their age.

Positive and negative influences of social participation on physical and mental health among community-dwelling elderly aged 65-70 years: a cross-sectional study in Japan.

BACKGROUND: Although numerous investigations have indicated that social participation (SP) has positive effects on the health of older adults, there have been few studies on its negative health consequences. We examined the cross-sectional associations of the type, frequency, and autonomy for SP with physical and mental health. METHODS: The analytical subjects were 5126 males and 7006 females who were functionally independent, born between 1945 and 1949, and covered by A City's medical insurance system. Physical and mental health were measured using the SF-8 Health Survey. SP was measured through six types of social groups. These social groups included volunteer groups, sports groups, hobby clubs, senior citizens' clubs, neighborhood community associations, and cultural groups. Analysis of covariance was conducted to compare adjusted physical health component summary scores (PCS) and mental health component summary scores (MCS) by the frequency and autonomy of SP. Age, family size, body mass index, chronic conditions, smoking, alcohol intake, depression and cognitive functioning were included as covariates. To examine whether the associations between SP and PCS/MCS are different between genders, we performed analyses stratified by gender. RESULTS: Overall, positive associations of the frequency and autonomy of SP with PCS and MCS were stronger in females than males. As to frequency, frequent participation in sports groups and hobby clubs had significantly better PCS among both genders and better MCS among females than non-participation. None of the groups differed significantly in the MCS among males. As to autonomy, among both genders, voluntary participation in sports groups and hobby clubs had significantly better PCS than non-participation, and better MCS than not only non-participation, but also obligatory participation. Among females, obligatory participation in all groups had significantly poorer MCS than voluntary participation, and obligatory participation in sports groups had significantly poorer MCS than non-participation. CONCLUSIONS: Obligatory SP had significantly poorer MCS than voluntary participation, occasionally than non-participation; there is a possibility that obligatory SP has harmful influences on mental health of community-dwelling elderly. Measures to promote SP with consideration for individuals' autonomy may be effective in the public health approach to maintaining mental health.

Effects of noise exposure on neonatal auditory brainstem response thresholds in pregnant guinea pigs at different gestational periods.

AIM: Noise exposure during pregnancy has been reported to cause fetal hearing impairment. However, little is known about the effects of noise exposure during various gestational stages on postnatal hearing. In the present study, we investigated the effects of noise exposure on auditory brainstem response (ABR) at the early, mid-, and late gestational periods in newborn guinea pigs. METHODS: Pregnant guinea pigs were exposed to 4-kHz pure tone at a 120-dB sound pressure level for 4 h. We divided the animals into four groups as follows: the control, early gestational exposure, mid-gestational exposure, and late gestational exposure groups. ABR thresholds and latencies in newborns were recorded using 1-, 2-, and 4-kHz tone burst on postnatal days 1, 7, 14, and 28. Changes in ABR thresholds and latencies were measured between the 4 × 4 and 4 × 3 factorial groups mentioned above (gestational periods × postnatal days, gestational periods × frequencies). RESULTS: The thresholds were low in the order of control group < early gestational exposure group < mid-gestational exposure group and late gestational exposure group. Noise exposure during pregnancy influenced ABR thresholds in neonatal guinea pigs. CONCLUSION: This is the first study to show that noise exposure during the early, mid-, and late gestational periods significantly elevated ABR thresholds in neonatal guinea pigs.

Autocorrelation factors and intelligibility of Japanese monosyllables in individuals with sensorineural hearing loss.

Some Japanese monosyllables contain consonants that are not easily discernible for individuals with sensorineural hearing loss. However, the acoustic features that make these monosyllables difficult to discern have not been clearly identified. Here, this study used the autocorrelation function (ACF), which can capture temporal features of signals, to clarify the factors influencing speech intelligibility. For each monosyllable, five factors extracted from the ACF [Φ(0): total energy; τ1 and ϕ1: delay time and amplitude of the maximum peak; τe: effective duration; Wϕ(0): spectral centroid], voice onset time, speech intelligibility index, and loudness level were compared with the percentage of correctly perceived articulations (144 ears) obtained by 50 Japanese vowel and consonant-vowel monosyllables produced by one female speaker. Results showed that median effective duration [(τe)med] was strongly correlated with the percentage of correctly perceived articulations of the consonants (r = 0.87, p < 0.01). (τe)med values were computed by running ACFs with the time lag at which the magnitude of the logarithmic-ACF envelope had decayed to -10 dB. Effective duration is a measure of temporal pattern persistence, i.e., the duration over which the waveform maintains a stable pattern. The authors postulate that low recognition ability is related to degraded perception of temporal fluctuation patterns.

Cross-sectional association between medical expenses and intellectual activity in community-dwelling older adults.

BACKGROUND: Little is known concerning the lifestyle habits and health conditions in community-dwelling elderly who do not get medical care. We investigated the cross-sectional association between medical expenses (ME) and intellectual activity (IA) in community-dwelling older Japanese. METHODS: Self-administered questionnaires were mailed to all residents born between 1945 and 1949 and covered by A City's medical insurance system (n = 19,354). Independent variables including health behaviors, oral health, social capital, neighborhood environment, and physical and mental functioning were included in the questionnaires. Medical fee receipts were used to evaluate ME for fiscal 2014, and respondents were classified into no, low, medium, and high ME groups. Higher-level functional capacity was evaluated using the Tokyo Metropolitan Institute of Gerontology Index of Competence, which is comprised of three subscales: instrumental activities of daily living, IA, and social role. Poisson regression models were used to examine the association of ME with IA, with the low ME group as reference. RESULTS: Questionnaires were returned by 12,747 individuals (response rate 65.9%). The no ME group had the lowest response rate, the worst lifestyle behaviors, and the lowest social capital, but no problems with neighborhood environment. Higher-level functional capacity, especially IA, was reduced in both the high ME and no ME groups. After adjustments for age, gender, health insurance, accessibility to public facilities in their residential area, family size, body mass index, and physical and mental functioning, the prevalence ratio (PR) for impaired IA lost its significance in the high ME group (PR 0.97, 95% confidence interval 0.90-1.05), but remained significant in the no ME group (1.19, 1.08-1.31). After additional adjustments for health behaviors (i.e., health checks, smoking, fitness, and dietary variety), the PR of the no ME group was attenuated towards the null (1.08, 0.98-1.20). CONCLUSIONS: Community-dwelling elderly who did not seek medical treatment were indifferent to health surveys and health-promoting behaviors, and undesirable health behaviors were a possible determinant of their impaired IA. Further longitudinal research is needed to confirm the causal associations.

Relationship of Having Hobbies and a Purpose in Life With Mortality, Activities of Daily Living, and Instrumental Activities of Daily Living Among Community-Dwelling Elderly Adults.

BACKGROUND: This study's aim was to clarify the relationship of having hobbies and a purpose in life (PIL; in Japanese, ikigai) with mortality and a decline in the activities of daily living (ADL) and instrumental ADL (IADL) among the community-dwelling elderly. METHODS: Prospective observational data from residents aged ≥65 years who were at increased risk for death (n = 1853) and developing a decline in ADL (n = 1254) and IADL (n = 1162) were analyzed. Cox proportional hazard models were used for mortality analysis of data from February 2011 to November 2014. ADL and IADL were evaluated using the Barthel Index and the Tokyo Metropolitan Institute of Gerontology Index of Competence, respectively. ADL and IADL were assessed at baseline and follow-up and were evaluated using logistic regression models. Fully adjusted models included terms for age, gender, BMI, income, alcohol intake, smoking history, number of chronic diseases, cognitive function, and depression. RESULTS: During the follow-up of eligible participants, 248 had died, 119 saw a decline in ADL, and 178 saw a decline in IADL. In fully adjusted models, having neither hobbies nor PIL was significantly associated with an increased risk of mortality (hazard ratio 2.08; 95% confidence interval [CI], 1.47-2.94), decline in ADL (odds ratio 2.74; 95% CI, 1.44-5.21), and decline in IADL (odds ratio 1.89; 95% CI, 1.01-3.55) compared to having both hobbies and PIL. CONCLUSIONS: Although effect modifications by cognitive functioning and depression cannot be ruled out, our findings suggest that having hobbies and PIL may extend not only longevity, but also healthy life expectancy among community-dwelling older adults.

Association Between Social Participation and Instrumental Activities of Daily Living Among Community-Dwelling Older Adults.

BACKGROUND: Population-based data examining the relationship between social participation (SP) and instrumental activities of daily living (IADL) are scarce. This study examined the cross-sectional relationship between SP and IADL in community-dwelling elderly persons. METHODS: Self-administered questionnaires were mailed to 23 710 residents aged ≥65 years in Nara, Japan (response rate: 74.2%). Data from 14 956 respondents (6935 males and 8021 females) without dependency in basic activities of daily living (ADL) were analyzed. The number, type, and frequency of participation in social groups (SGs) were used to measure SP. SGs included volunteer groups, sports groups, hobby groups, senior citizens' clubs, neighborhood community associations, and cultural groups. IADL was evaluated using the Tokyo Metropolitan Institute of Gerontology Index of Competence. Logistic regression models stratified by gender were used. RESULTS: After adjustment for putative confounding factors, including demographics, health status, life-style habits, ADL, depression, cognitive function, social networks, social support, and social roles, participation in various SGs among both genders was inversely associated with poor IADL, showing a significant dose-response relationship between an increasing number of SGs and a lower proportion of those with poor IADL (P for trend <0.001). A significant inverse association between frequent participation and poor IADL was observed for all types of SGs among females, whereas the association was limited to sports groups and senior citizens' clubs among males. CONCLUSIONS: Our results show that participation in a variety of SGs is associated with independent IADL among the community-dwelling elderly, regardless of gender. However, the beneficial effects of frequent participation on IADL may be stronger for females than for males.

The effect of prostaglandin E1 on brainstem blood flow disturbance in an animal model of vertebrobasilar insufficiency.

Using an animal model of vertebrobasilar insufficiency (VBI), in which brainstem circulatory disturbance was induced in rats, we examined how prostaglandin E1 (PG-E1) affects brainstem blood flow (BBF) to clarify whether it is effective against VBI. Fifteen healthy male Wister rats that displayed positive responses to Preyer's reflex were used. Their BBF was continuously measured on the left side of the midline of the brainstem using laser Doppler flowmetry. A rat model of VBI, a pathological condition that presents with decreased BBF, was prepared by applying a vertebral artery clamp ipsilateral to the BBF measuring site and inducing hypotension of 60-70 mmHg by blood withdrawal. Saline as a control (n = 5), 5 ng/kg/min (n = 5) or 10 ng/kg/min (n = 5) PG-E1 at a dose was continuously administered to the rats using a motor-driven syringe pump. The effects of the drugs on the rats' BBF were evaluated. BBF, which was decreased by the unilateral vertebral artery clamping combined with blood withdrawal-induced hypotension, recovered in a dose-dependent manner after the administration of 5 or 10 ng/kg/min PG-E1, and complete recovery to the baseline level was achieved by 60 min treatment; however, no such effect was observed for intravenous saline. These results suggest that PG-E1 acts on local vessels and improves blood flow insufficiency in the brainstem in our animal model of VBI. PG-E1 might be useful as a cerebral vasodilator for VBI.

New treatment strategy for cupulolithiasis associated with benign paroxysmal positional vertigo of the lateral canal: the head-tilt hopping exercise.

This study was performed to determine whether a novel treatment was effective against cupulolithiasis associated with benign paroxysmal positional vertigo (BPPV) of the lateral semicircular canal, which is characterized by apogeotropic direction-changing nystagmus. We herein describe our head-tilt hopping (HtH) exercise, which is designed to release otoconial debris strongly adhered to the cupula. The subjects were trained to hop while tilting their heads laterally. They completed 3 to 5 exercise sessions per day over a 4-week period. Each session ended with a 20-hop trial. The HtH exercises were performed by 27 patients with intractable lateral canal BPPV who exhibited positional vertigo and persistent nystagmus beating toward the uppermost ear for more than 4 weeks, despite performing therapeutic head shaking in the horizontal plane maneuver. All the patients were subjected to the supine roll test before and immediately after the first trial as well as after 1 and 4 weeks of the program to evaluate the effect of the treatment on their apogeotropic nystagmus. Nystagmus of 9 (33.3 %) patients disappeared immediately after the first training session. After 1 and 4 weeks of the training, the number of patients that had experienced either of these improvements had increased to 15 (55.6 %) and 19 (70.4 %) subjects, respectively. These results suggest that HtH exercises aimed at releasing otoconial debris from the cupula are feasible as a new therapy for cupulolithiasis associated with intractable lateral canal BPPV. However, further studies for comparison with control are required to confirm these preliminary results.

Cartilage conduction hearing.

Sound information is known to travel to the cochlea via either air or bone conduction. However, a vibration signal, delivered to the aural cartilage via a transducer, can also produce a clearly audible sound. This type of conduction has been termed "cartilage conduction." The aural cartilage forms the outer ear and is distributed around the exterior half of the external auditory canal. In cartilage conduction, the cartilage and transducer play the roles of a diaphragm and voice coil of a loudspeaker, respectively. There is a large gap between the impedances of cartilage and skull bone, such that cartilage vibrations are not easily transmitted through bone. Thus, these methods of conduction are distinct. In this study, force was used to apply a transducer to aural cartilage, and it was found that the sound in the auditory canal was amplified, especially for frequencies below 2 kHz. This effect was most pronounced at an application force of 1 N, which is low enough to ensure comfort in the design of hearing aids. The possibility of using force adjustments to vary amplification may also have applications for cell phone design.

Frailty of the.

Vestibular frailty and presbyvestibulopathy, including benign paroxysmal positional vertigo (BPPV), can cause dizziness among elderly patients. Vestibular frailty and presbyvestibulopathy may contribute to the onset of the vicious circle of falling-bone fracture-prolonged bedridden status-senile dementia. Treatment interventions for vestibular frailty and presbyvestibulopathy should be based on vestibular rehabilitation rather than vestibular implantation or regeneration. In acute BPPV, the otolith repositioning maneuver can be used to return otolithic debris to the utricle. At the chronic remission stage, there are nutritional guidelines for improving bone density in otolith organs and rehabilitation guidelines for activating otolith organs to prevent exfoliation. Moreover, sleeping in the head-up position can prevent free-floating debris from entering the semicircular canal. Throughout their old age, the psychiatric care/support is also indispensable to keep their initiative against vestibular frailty.

Cartilage Conduction Sounds in Cases of Wearing Different Transducers on a Head and Torso Simulator with a Manipulated Ear Pinna Simulator.

Cartilage conduction is known widely as a third hearing transmission mechanism after the air and bone conduction methods, and transducers dedicated to the production of cartilage conduction sounds have been developed by several Japanese companies. To estimate the acoustic performance of the five cartilage conduction transducers selected for this study, both airborne sounds and cartilage conduction sounds were measured. Airborne sounds can be measured using a commercial condenser microphone; however, cartilage conduction sounds are impossible to measure using a conventional head and torso simulator (HATS), because the standard-issue ear pinna simulator cannot reproduce cartilage conduction sounds with the same spectral characteristics as the corresponding sounds measured in humans. Therefore, this study replaced the standard-issue simulator with a developed pinna simulator that can produce similar spectral characteristics to those of humans. The HATS manipulated in this manner realized results demonstrating that transducers that fitted the entrance to the external auditory canal more densely could produce greater cartilage conduction sounds. Among the five transducers under test, the ring-shaped device, which was not much larger than the entrance to the canal, satisfied the spectral requirements.

Cartilage Conduction Hearing Aids in Clinical Practice.

A relatively loud sound is audible when a vibrator is attached to the aural cartilage. This form of conduction is referred to as cartilage conduction (CC). In Japan, a new type of hearing aid has been developed using CC and has been available in clinical practice since 2017. A clinical study conducted prior to its launch demonstrated its benefits, particularly in patients with aural atresia who were unable to use air conduction hearing aids. Several studies have been published on the benefits of CC hearing aids since their introduction into clinical practice. Most of the patients included in these studies had canal stenosis or aural atresia, and the purchase rates of CC hearing aids in these patients were relatively high. However, the number of patients with canal-open ears was small, with overall poor results in the trials, with the exception of patients with continuous otorrhea. CC hearing aids are considered a good option for compensating for hearing loss in ears with canal stenosis or atresia in both bilateral and unilateral cases. However, CC hearing aids are not currently considered the first choice for patients with a canal-open ear.

Evaluation of the Recovery of Idiopathic Sudden Sensorineural Hearing Loss Based on Estimated Hearing Disorders.

Various prognostic factors for idiopathic sudden sensorineural hearing loss (SSNHL) have been reported. Hearing loss directly derived from idiopathic SSNHL is important for understanding underlying pathogenesis and outcomes. We assessed the usefulness of evaluating hearing loss and recovery of idiopathic SSNHL on the basis of estimated hearing loss. The study included 115 patients whose characteristics and outcomes of hearing loss were investigated. The effects of vertigo/dizziness and age on hearing thresholds before/after treatment, nonaffected ear threshold, estimated hearing loss, improvement of hearing loss, and estimated remaining hearing loss were investigated. Vertigo/dizziness was a significant prognostic factor for hearing. In vertigo/dizziness patients, significantly more severe hearing loss and poorer improvement of hearing loss were observed above 500 Hz and below 1000 Hz, respectively. Severe hearing disorder remained at all frequencies. Conversely, post-treatment thresholds were significantly higher in the older population (≥65 years), although no differences in pretreatment thresholds were observed between the younger (≤64 years) and older populations. However, on the basis of nonaffected ear thresholds, previously existing hearing loss could have influenced the outcome. Thus, comparison of hearing outcomes between affected and nonaffected ears is essential for understanding hearing loss and outcomes in idiopathic SSNHL cases with existing hearing disorder.