Conventional Hearing Research Articles

Comparative study of efficiency and characteristics of FMT and DRT installed in human cadavers for round-window stimulation

Acoustic hearing aids generate amplified sound in the ear canal, and they are the standard of care for patients with mild to moderate sensorineural hearing loss. However, because of their limited frequency bandwidth, gain, and feedback, there is substantial room for improvement. Active middle ear implants, which directly vibrate the middle ear and cochlea, are an alternative approach to conventional acoustic hearing aids. They provide an opportunity to improve sound quality and speech understanding with amplification rehabilitation. For floating-mass type and direct-rod type (DRT) middle ear transducers, a differential floating-mass transducer (DFMT) and a tri-coil bellows transducer (TCBT), respectively, were fabricated to measure the output characteristics in four human temporal bones. Both were fabricated to have similar output forces per unit input and were placed in four human temporal bones to measure their output performances. The TCBT resulted in higher output than did the DFMT throughout the audible frequency range, and the output was more prominent at lower frequency ranges. In this study, we showed that DRT was a more effective method for round window stimulation. Because of its frequency characteristics and vibration efficiency, this implantation method can be utilized as a driving solution for middle ear implants.

Patient safety and the annulment of medical clearance exams for hearing aids: Are we “closing the book” too soon?

To determine the utility of medical clearance exams by otolaryngologists prior to the distribution of hearing aids to patients with hearing loss. Medical records of 313 consecutive hearing-impaired individuals seeking financial assistance for hearing aids from the Lions Hearing Center of Michigan and who presented for medical clearance exams between January 2014 and May 2017 were retrospectively analyzed. Separate determinations were made for each patient about (1) benefit from the exam and (2) avoidance of significant harm. Majority (64.2%; n=201) of patients benefited from medical clearance exams. Furthermore, 5.4% of patients (n=17) were found to have avoided significant harm due to administration of the medical clearance exam. Finally, 14.4% (n=45) were offered alternative interventions over conventional hearing aids. Medical clearance exams are beneficial to a majority of patients with hearing loss prior to receiving hearing aids. With the impending arrival of over-the-counter hearing aids in the United States, special consideration should be placed on educating the general public about the importance of the medical evaluation prior to purchasing any type of hearing aid.

Establishment of a Gene Detection System for Hotspot Mutations of Hearing Loss

Hearing loss is an etiologically heterogeneous trait with a high incidence in China. Though conventional newborn hearing screening program has been widely adopted, gene detection can significantly improve the means of early discovering genetic risk factors. Thus, simple and efficient methods with higher sensitivity and lower cost for detecting hotspot mutations of hearing loss are urgently requested. Here we established a mutation detection system based on multiple fluorescent probe technique, which can detect and genotype nine hotspot mutations of four prominent hearing loss-related genes in two reactions on a four-channel real-time PCR instrument, including GJB2 (rs750188782, rs80338943, rs1110333204, and rs80338939), GJB3 (rs74315319), SLC26A4 (rs111033313 and rs121908362), and mtDNA 12S rRNA (rs267606617 and rs267606619). This system is with high sensitivity that enables detecting as low as 10 DNA copies samples per reaction. A comparison study in 268 clinical samples showed that the detection system had 100% concordance to Sanger sequencing. Besides, blood and saliva samples can be directly detected without DNA extraction process, which greatly simplifies the manipulation. The new system with high sensitivity, accuracy, and specimen type compatibility can be expectedly a reliable tool in clinical application.

Neural representation of speech in pediatric cochlear implant recipients

ObjectiveCochlear implantation (CI) is an established treatment for selected individuals with bilateral severe-to-profound sensorineural hearing loss who derive limited benefits from conventional hearing aids.This work was designed to assess speech processing at the brainstem and the cortical level in children fitted with CIs after a variable duration of implantation and speech therapy compared with language acquisition.Patients and methodsThirty-one children between 4 and 5 years of age fitted with unilateral CIs of variable duration ranging from 1 to 3 years were assessed at 1 year (n=10), 2 years (n=12), and 3 years (n=9) after device activation. They underwent aided sound–field audiological evaluation, speech-evoked auditory brainstem response, and speech-evoked mismatch negativity test. The results were compared among the study groups and then correlated with language assessment and speech perception tests.ResultsBoth speech-evoked auditory brainstem response and mismatch negativity test responses were significantly different among the three groups. Moreover, language development showed a significant difference among the three groups.ConclusionChildren fitted with CI showed cortical and brainstem activation from the first year and these activity changes continue with CI use and both are highly correlated with receptive and expressive language. Thus, both electrophysiologic tests could be early and critical objective indicators of optimal speech encoding after programming of the CI device.

The effect of comprehensive intervention on anxiety, depression and quality of life of patients with sudden sensorineural hearing loss

Objective To analyze the effect of comprehensive intervention on anxiety, depression and quality of life of patients with sudden sensorineural hearing loss. Methods A total of 90 cases of sudden sensorineural hearing loss patients were randomly divided into intervention group(n=45)and control group(n=45). All the patients were given the standard conventional sudden sensorineural hearing loss treatments.The patients of control group were given the regular deafness nursing and health direction, while beyond that the patients of intervention group were given the combined comprehensive intervention treatment of cognition, behaving and family social support, etc..Zung Self-rating Anxiety Scale(SAS), Self-rating Depression Scale(SDS)and Quality of Life Index(QOL)were taken to evaluate the psychological state of patients respectively within 3 days after the admission to hospital and before their discharge from the hospital. Results The comparison and differences of the SAS, SDS and QOL data of the two groups conducted within 3 days after their admission were not statistically significant(P>0.05). The SAS score of intervention group(42.58±8.06)was decreased obviously compared with that of control group(54.28±11.06)before their discharge from hospital(t=-4.26, P<0.01). The SDS score of intervention group(44.13±6.75)was also decreased compared with that of control group(52.25±11.26), (t= -3.74, P<0.01). The scores based on different dimensions of QOL of intervention group were obviously higher than those of control group(P<0.01). Conclusions SAS and SDS could be used by the nursing staff to evaluate the patients with sudden sensorineural hearing loss.And comprehensive interventions could be carried out to improve the psychological state of the patients' depression and anxiety, and to promote their rehabilitation and to enhance the overall quality of life of the patients. Key words: Sudden sensorineural hearing loss; Anxiety; Depression; Quality of life; Comprehensive intervention

Tri-axial telecoil hearing aid for improved connection to public induction loops.

Telecoils in hearing aids serve a dual purpose: to enhance telephone conversation and enable hearing aids to serve as a wireless interface for public audio broadcasts. When broadcasting audio signals, the signal is transmitted to the telecoil sensor (a magnetic field sensor located in the hearing aid) via magnetic energy from an induction wire loop located near the listener. This induction loop can be a small assembly located in the handset of the telephone or a large wire loop within a public venue like a theatre. Current hearing aids detect the magnetic signal using a single telecoil. If the telecoil is not aligned with the magnetic field, the strength of the detected signal is diminished. Unfortunately, public induction loops and telephone handsets seldom share a common alignment to the hearing aid, leading to sub-optimal performance by one or both in hearing aids available today. In this research, a prototype behind-the-ear (BTE) hearing aid with tri-axial telecoils was developed and DSP algorithms to process and combine the three signals were developed. The resulting hearing aid was evaluated in a human trial and provided better performance than a similar quality conventional telecoil hearing aid.

Quality standards for bone conduction implants

Conclusion: Bone conduction implants are useful in patients with conductive and mixed hearing loss for whom conventional surgery or hearing aids are no longer an option. They may also be used in patients affected by single-sided deafness. Objectives: To establish a consensus on the quality standards required for centers willing to create a bone conduction implant program. Method: To ensure a consistently high level of service and to provide patients with the best possible solution the members of the HEARRING network have established a set of quality standards for bone conduction implants. These standards constitute a realistic minimum attainable by all implant clinics and should be employed alongside current best practice guidelines. Results: Fifteen items are thoroughly analyzed. They include team structure, accommodation and clinical facilities, selection criteria, evaluation process, complete preoperative and surgical information, postoperative fitting and assessment, follow-up, device failure, clinical management, transfer of care and patient complaints.

A Practical Tablet-Based Hearing Aid Configuration as an Exemplar Project for Students of Instrumentation.

This paper presents the configuration and digital signal processing details of a tablet-based hearing aid transmitting wirelessly to standard earphones, whereby the tablet performs full sound processing rather than solely providing a means of setting adjustment by streaming to conventional digital hearing aids. The presented device confirms the recognized advantages of this tablet-based approach (e.g., in relation to cost, frequency domain processing, amplification range, versatility of functionality, component battery rechargeability), and flags the future wider-spread availability of such hearing solutions within mainstream healthcare. The use of a relatively high sampling frequency was found to be beneficial for device performance, while the use of optional off-the-shelf add-on components (e.g., data acquisition device, high fidelity microphone, compact wireless transmitter/receiver, wired headphones) are also discussed in relation to performance optimization. The easy-to-follow configuration utilized is well suited to student learning/research instrumentation projects within the health and biomedical sciences. In this latter regard, the presented device was pedagogically integrated into a flipped classroom approach for the teaching of bioinstrumentation within an Allied Health Sciences School, with the subsequent establishment of positive student engagement outcomes.

The Effect of a High Upper Input Limiting Level on Word Recognition in Noise, Sound Quality Preferences, and Subjective Ratings of Real-World Performance.

One important factor that plays a role in front-end processing is the analog-to-digital converter within current hearing aids. The average input dynamic range of hearing aids is 96 dB SPL with an upper input limiting level (UILL) of 95-105 dB SPL. The UILL of standard hearing aids could distort loud signals, such as loud speech or music, which have root-mean-square values of 90 and 105 dB SPL with crest factors of 12 dB SPL to 14-20 dB SPL, respectively. This indicates that these loud sounds could create a distorted signal for patients when the input limiting level is reached. To examine if significant differences in word recognition in noise, sound quality preferences, and subjective ratings of real-world performance exist between conventional and high UILL hearing aids. Words in noise and sound quality preferences were assessed using recordings on a Knowles Electronic Manikin for Acoustic Research with conventional and high UILL hearing aids, different microphone modes, and listening conditions. Participants wore the hearing aids for 2 mo and completed questionnaires on subjective performance. Ten adults with bilateral slight to moderately severe sensorineural hearing loss were recruited. A four-factor repeated-measures analysis of variance (ANOVA) revealed significant differences between the conventional and high UILL across microphone modes and listening conditions for words in noise [F(2, 18) = 6.0; p < 0.05]. A three-factor repeated-measures ANOVA for sound quality preferences revealed a significant difference only for presentation level [F(1, 9) = 81.0; p < 0.001]. A one-factor ANOVA did not reveal significant differences between the conventional and high UILL on subjective ratings of real-world performance. Word recognition and sound quality preferences revealed significant differences between the conventional and high UILL; however, there were no differences in subjective ratings of real-world performance. One participant preferred the conventional UILL, two the high UILL, and seven thought performance was equal, which may be due to the listening environments participants encountered, as evidenced by datalogging.

Osseointegration and its role in management of hearing loss

Osseointegration is a biological process by which a structural connection is created between living bone and the surface of a load-carrying implant. This phenomenon has been used in a range of medical interventions. In 1977, Tjellstrom reported on osseointegrated bone-anchored hearing device as an alternative to conventional bone-conducting hearing aids, which were required to be worn on a headband or a pair of glasses. Since that time, there has been significant development in surgical technique and device technology for bone-anchored hearing devices. A review of the current literature was conducted to describe these advancements and provide an up-to-date summary of the usage of osseointegrated bone-anchored hearing device in the management of hearing loss.

Influence of Loudness Compression on Hearing with Bone Anchored Hearing Implants

Bone Anchored Hearing Implants (BAHI) are routinely used in patients with conductive or mixed hearing loss, e.g. if conventional air conduction hearing aids cannot be used. New sound processors and new fitting software now allow the adjustment of parameters such as loudness compression ratios or maximum power output separately. Today it is unclear, how the choice of these parameters influences aided speech understanding in BAHI users. In this prospective experimental study, the effect of varying the compression ratio and lowering the maximum power output in a BAHI were investigated. Twelve experienced adult subjects with a mixed hearing loss participated in this study. Four different compression ratios (1.0; 1.3; 1.6; 2.0) were tested along with two different maximum power output settings, resulting in a total of eight different programs. Each participant tested each program during two weeks. A blinded Latin square design was used to minimize bias. For each of the eight programs, speech understanding in quiet and in noise was assessed. For speech in quiet, the Freiburg number test and the Freiburg monosyllabic word test at 50, 65, and 80 dB SPL were used. For speech in noise, the Oldenburg sentence test was administered. Speech understanding in quiet and in noise was improved significantly in the aided condition in any program, when compared to the unaided condition. However, no significant differences were found between any of the eight programs. In contrast, on a subjective level there was a significant preference for medium compression ratios of 1.3 to 1.6 and higher maximum power output.

Treatment of Age-Related Hearing Loss in Dogs with the Vibrant Soundbridge Middle Ear Implant: Short-Term Results in 3 Dogs

Age-related hearing loss (ARHL), or presbycusis, is the most common form of acquired hearing loss in dogs. Middle ear implants have been used successfully in people with ARHL who cannot benefit from conventional hearing aids. Audibility improves in dogs with ARHL after implantation of the Vibrant Soundbridge (VSB) middle ear implant. Three Beagle dogs with ARHL, mean age 11.1 years. The dogs were assessed pre- and postoperatively by brainstem-evoked response audiometry (BERA), otoscopy, and computed tomography scans of the ears. A VSB middle ear implant was implanted unilaterally. Three months later the functionality of the implants was assessed by auditory steady-state responses (ASSRs), after which the dogs were euthanized for histopathological examination. The VSB was implanted successfully in all dogs. Recovery from surgery was uneventful, except for transient facial nerve paralysis in 2 dogs. ASSRs showed that hearing improved after activation of the implants with a mean of 20.7, 13, and 16.3 dB at 1, 2, and 4 kHz, respectively. The implantation procedure did not affect residual hearing (with inactive implants) as measured by BERA. Implantation of the VSB resulted in lower ASSR thresholds, but only at the higher gain settings of the audioprocessor. As in humans, a more powerful audioprocessor is required to treat sensorineural hearing loss exceeding 20 dB in dogs. A substantial improvement in patient-owner communication will have to be demonstrated in future studies before the procedure can be recommended in clinical practice.

Hearing Rehabilitation with Bone Anchored Hearing Aid: Experience in 14 Patients

Background and Objectives : Bone anchored hearing aid (BAHA) is an alternative method applicable to patients with chronic draining ear, congenital aural atresia and single sided deafness, who cannot benefit from conventional air conduction hearing aids. The objective of this study was to evaluate the experience of 14 patients who underwent BAHA surgery. Subjects and Method : We retrospectively reviewed the medical records of 14 patients who underwent BAHA surgery. Preoperative pure tone air and bone conduction thresholds and air-bone gap, postoperative BAHA-aided thresholds were measured. Hearing improvement as a result of implantation and complications related to implant were evaluated. Results : The most common indication for BAHA was congenital aural atresia (8 patients) and the rest consisted of chronic otitis media (3 patients) and unilateral sensorineural hearing loss (3 patients). The average threshold improvement with BAHA was 40 dB and 34 dB in patients with congenital aural atresia and chronic otitis media, respectively. Patients with unilateral hearing loss had a postoperative aided threshold of 25 dB. Complications were limited to the periabutment skin problem in two patients. One patient received revision surgery replacing the diseased skin with split-thickness skin graft from a thigh and the other patient received surgery to remove the abutment and the wound was closed with rotation flap, leaving the fixture underneath the skin. Conclusion : BAHA could be one of the safe and reliable treatment options available for auditory rehabilitation. Systematic evaluation for candidate selection might be needed to increase hearing gain and decrease co-morbidity.

Baha solutions for patients with severe mixed hearing loss

Patients with a mixed hearing loss present special challenges. The amplification demands of mixed hearing loss can drive powerful digital hearing aids to their limits and introduce distortion through saturation. Conversely, the Baha® System effectively bypasses the conductive component and focuses on compensating for the sensorineural component of the hearing loss. Ten patients with a mixed hearing loss participated in the present study. Results indicate that Baha provided significant benefits (p < 0.01) over conventional air conduction hearing instruments across the dimensions of audibility, speech understanding and sound quality. Given the increased output force of the latest Baha instruments, once the conductive component of a severe mixed hearing loss becomes greater than 30 dB, a Baha should be considered and evaluated on audiological grounds alone to provide optimal amplification. Copyright © 2009 John Wiley & Sons, Ltd.

TORP-Vibroplasty

Surgery can often eradicate chronic middle ear disease in patients with recurrent cholesteatoma, tubal dysfunction, and others; however, in many cases, social hearing cannot be restored even after multiple revision tympanoplasties. A hearing aid is then recommended. Placement of an implantable hearing aid with its advantage of an unoccluded ear canal, irrespective of middle ear function, seems to be a promising alternative. After establishing the biomechanics of the ear in our temporal bone laboratory, various locations and attachments of a Vibrant transducer were investigated. These experiments resulted in the development of a new titanium clip holder for a Vibrant integrated total ossicular replacement prosthesis assembly with placement on the footplate. Four patients with permanent severe combined hearing loss were implanted with this device after multiple revision tympanoplasties. The first case is described in detail. Placing a transducer directly on the footplate via a rod transmission gave a better gain for the high frequencies than in the round window location. The acoustic results of the patients showed an improved gain in speech understanding, unobtainable by a conventional hearing aid. The concept of a total ossicular replacement prosthesis-vibroplasty establishes a straightforward procedure in the tympanic cavity similar to a normal tympanoplasty. The open ear canal and its superior acoustic performance offer a promising perspective for revision operations in cases of incurable middle ear dysfunction.

A comparative study of the audiological outcomes with Retro-X (semi-implantable hearing aid system) and conventional open fitting hearing aids

The objective of this study was to compare the results of hearing augmentation with the Retro-X semi-implantable hearing aid to a conventional non-implantable open canal hearing aid using the same software technology (Titan-X, auric Hearing Systems, HiKaNo.:13.20.03.0047). Nineteen subjects (20 ears) with mild to moderate high-frequency sensory-neural hearing loss were included in this clinical study. All the subjects were first fitted with a conventional open canal hearing aid (Titan-X). After a period of 4-6 weeks audiological evaluations were performed using standardized speech tests in quiet and noise. Subjective evaluation was performed with the help of standardized questionnaires. After this phase the patients received the semi-implantable Retro-X device under local anaesthesia and 4 weeks later were fitted with a hearing module with the same software technology as the conventional Titan-X hearing aid. Four weeks following the first fitting the same audiological evaluations were performed under similar conditions and the patients were evaluated again using the same questionnaires in order to compare the results of the Retro-X semi-implantable system with the conventional open canal hearing aid. Audiological evaluations revealed better results with the semi-implantable Retro-X in the adaptive speech in noise test; however, the results of the monosyllabic word test in quiet were similar for the Retro-X and conventional open canal hearing aid. The patients subjectively preferred the improved wearing comfort of the semi-implantable device. The Retro-X semi-implantable hearing aid provides better speech perception in noise and higher wearing comfort in comparison to the conventional open canal hearing aids. Considering the simple implantation procedure under local anaesthesia with low complication rate, Retro-X is an alternative to the conventional open canal hearing aids in patients with mild to moderate high frequency sensory-neural hearing loss.

The Bone-Anchored Hearing Aid for children: Recent developments

In 1984 the Bone-Anchored Hearing Aid, or BAHA, system was introduced. Its transducer is coupled directly to the skull percutaneously to form a highly effective bone-conduction hearing device. Clinical studies on adults with conductive hearing loss have shown that the BAHA system outperforms conventional bone-conduction hearing aids. Therefore, the next step was to apply the BAHA system in children with congenital or acquired conductive hearing loss. Reviewed data showed that, on average, such children benefited significantly more from the BAHA than from reconstructive surgery. Thus, BAHA application appears to be the best option to achieve normal communication and speech and language development in children with bilateral conductive hearing loss. However, in children under the age of three to four years, a conventional solution must be applied, e.g. a bone conductor with a transcutaneous coupling, because they are too young to undergo BAHA implant surgery. In the case of unilateral congenital conductive hearing loss, there is no convincing evidence in the clinical literature for early intervention.In summary, the BAHA system can be considered a new, indispensable tool for children with bilateral conductive hearing loss.

Development of an Active Noise Cancellation Hearing Protector: How Can Passive Attenuation Be Retained?

The modest low-frequency attenuation of the conventional passive hearing protector can be improved electronically by active noise cancellation techniques. This paper presents the theory and some of the actual limitations of an active noise cancellation hearing protector. Three prototypes with similar types of controller, but with different mechanical construction were made and their performance was measured. The electronics of the system were implemented using analog electronics and feedback construction. The measurement results were compared with the results of an equivalent passive hearing protector with no internal electronics and with an intact earcup. The results show that the integration of the controller inside the earcups degrades the passive attenuation of the hearing protector at frequencies below 200 Hz. With proper design, an active noise cancellation hearing protector can still have 15 dB more noise attenuation at 100 - 200 Hz range than an equivalent passive hearing protector.

頭部外傷後耳小骨離断の２例

Two cases of the ossicular disruption due to head injury were surgically treated in our department. These two cases also showed conductive hearing loss after the injury. An exploratory tympanotomy was carried out in these two cases.In the first case, there was a fracture in the left external ear canal, and the fracture led to the middle ear with a fracture of the long process of incus.In the second case, there was ossific change and adhesion between the malleus and scutum. Almost normal hearing was obtained after tympanoplasty modified 3 types in both cases.It is difficult to confirm the presence of lesion by conventional hearing and imaging tests. Preoperative approaches to this disease are mentioned from these cases and literature.

Otoacoustic Emissions in the General Adult Population of Nord-Trondelag, Norway: II. Effects of Noise, Head Injuries, and Ear Infections: Emisiones Otoacústicas En La Poblacian Adulta General De Nord-Trøndelag, Noruega: II. Efectos Del Ruido, Traumatismos CefÁlicos E Infecciones De oído

Otoacoustic emissions (OAEs) have been suggested as a sensitive measure of cochlear function with the potential for preclinical detection of damage. The present work assesses the risk for decreased OAEs associated with occupational and leisure noise, head injuries and recurrent ear infections. The predictive power of the environmental factors on different OAE values is compared with the prediction of conventional pure-tone hearing thresholds (PTTs). The analyses are based on data from 5072 adult subjects comprising a subsample of the 51975 subjects from the Nord-Trondelag Hearing Loss Study. The subjects participated in a general health screening, including an examination of pure-tone audiometry, transient OAEs and distortion-product OAEs, and completed a questionnaire regarding history of noise exposure and ear disease. The predictions of OAEs and PTTs were analysed using regression analysis for various sex and age groups (20 44 years, 45–64 years, ±65 years). The fraction of the variance explained by exposure was generally moderate (0–4%, varying with age, sex, and type of measurement). Males showed moderate effects of work noise, impulse noise and ear infection, while ear infection was the only significant predictor in females. There were no effects of music noise and head injuries. The effect of exposure on OAEs that remained after controlling for PTTs was small and similar to the effect of exposure on PTTs that remained after controlling for OAEs.SumarioSe ha sugerido que las emisiones otoacústicas (EOAs) son una medida sensible para para medir la funciócute;n coclear y que tienen potencial para la detectiócute;n preclínica de daño. Este trabajo evalúa el riesgo de EOAs decrecientes, asociadas con ruido ocupacional o recreativo, lesiones craneoencefálicas e infecciones recurrentes del oído. El valor predictivo de los factores ambientales en los diferentes valores de las EOAs sc compara con la predicciócute;n hecha con umbrales auditivos por tonos puros (PTTs). El análisis se basa en datos de 5,072 adultos de una submuestra de 51,975 sujetos del Estudio Nord-Trøndelag de Pérdidas Auditivas. Los sujetos participaron en un estudio de salud general, incluyendo un examen de audiometría por tonos puros, TEOAEs y DPOAEs y completaron un cuestionario relacionado con historia de expositiócute;n al ruido o enfermedades otolócute;gicas. Las predicciones de las EOAs y de los PPTs se estudiaron usando análisis de regresiócute;n por grupos etáreos (20–44 años, 45–64 años y >65 anos) y de génera La fractiócute;n de la variancia explicada por la expositiócute;n fue generalmente moderada (0–4%, variando con la edad, sexo y tipo de mediciócute;n). Los hombres mostraron efectos modcrados del ruido laboral, ruido impulsivo e infection de oídos, mientras que éste último fue el único factor predictivo en las mujeres. No se vieron efectos de ruido por música o por lesiones cefálicas. El efecto de la expositiócute;n en las EOAs que permaneciócute; después del control con los PTTs fue pequeño, y similar al efecto de la expositiócute;n en los PPTs, que permaneciócute; después del control con las EOAs.