Completely-in-the-canal Research Articles

Extended wear hearing aids: a comparative, pilot study.

The study evaluated if there were differences between three types of hearing aids, Lyric extended wear (EW), receiver-in-the-ear canal (RITE), completely-in-the-canal (CIC) hearing aids in terms of audiological and psychosocial outcomes. Fifteen patients were selected. Pure-Tone Average (PTA) air conduction range of hearing threshold at 500, 1000, and 2000Hz from 15dB HL to 75dB HL. Patients were assigned in three groups according to the hearing aid used: Extended wear, RITE, and CIC. Pure-tone audiometry, speech audiometry, free-field pure-tone and speech audiometry with hearing aids, and Matrix sentence test were performed. The Satisfaction with Amplification in Daily Life (SADL) questionnaire and the Abbreviated Profile of Hearing Aid Benefit (APHAB) questionnaire were used to assess the psychosocial and audiological benefits provided by hearing aids. No differences were demonstrated in the Matrix sentence test between the groups. A statistically significant difference was present between the "Personal image" of patients with EW and RITE with a p value of 0.01 (better outcome using EW). For the APHAB questionnaire, a significant difference was present in the "Aversiveness" of the patients with EW in comparison to CIC and RITE with a p value of 0.01 (higher aversiveness of sound using EW). In terms of audiological advantage, extended ear hearing aids are similar to RITE and CIC as demonstrated from the Matrix speech reception threshold. The result was confirmed using the APHAB questionnaire. Extended wear devices are better than daily hearing aids concerning the "personal image".

Experience of applying phoneme perception test to the process of hearing aid selection and fitting

Aim. To study the effectiveness of phoneme perception test for evaluation of different hearing aids’ types performance 
 Methods. Hearing aid was provided to 100 patients aged 45-59 years with bilateral chronic sensorineural moderate and moderate-to-severe hearing loss. 4 equal groups were formed depending on the type of a hearing aid - behind-the-ear with standard (BTE) and slim (BTEslim) tubes, receiver-in-the-canal (RIC), and completely-in-the-canal (CIC). All devices had comparable characteristics and were fitted monaurally. The efficacy was evaluated by phoneme perceprion test, which was performed before and 12 weeks after the correction (with and without the hearing aid). 
 Results. The detection test before correction revealed 38 deviations from the expected numbers, after 3-month adaptation - 28 without the device and 23 with it reflecting the significant dynamics compared to baseline parameters in CIC group (p

Comparative Analyses between Receiver in the Canal Hearing Aids and Closed Fit Hearing Aids: Preliminary Study

Received August 19, 2014 Revised October 7, 2014 Accepted October 23, 2014 Address for correspondence Jeong Hun Jang, MD Department of OtorhinolaryngologyHead and Neck Surgery, School of Medicine, Kyungpook National University, 130 Dongdeok-ro, Jung-gu, Daegu 700-721, Korea Tel +82-53-420-5781 Fax +82-53-423-4524 E-mail jangjh@knu.ac.kr Background and ObjectivesZZThe aim of this study was to compare the degree of satisfaction of the patients, hearing loss type and severity, and satisfactory and unsatisfactory factors between closed fit hearing aid (HA) and receiver in the canal (RIC) HA. Subjects and MethodZZSeventeen patients with hearing loss participated in this study. All patients had used closed fit HAs prior to the study, with the ratio of those using in the canal (ITC) types and completely in the canal (CIC) types being 4:13. After a 2-week trial period of using RIC HAs, patients were evaluated for their satisfaction of using RIC HAs by filling out the questionnaire on the Korean version International Outcome Inventory for hearing aids (K-IOI-HA). ResultsZZThe visual analogue scale (VAS) score of closed fit HA was higher in the RIC-HAdissatisfied group (≤5, n=8) than in the RIC-HA-satisfied group (>5, n=9). The K-IOI-HA score of closed fit HA was higher than that of RIC HA in the RIC-HA-dissatisfied group and similar in the RIC-HA-satisfied group. Audiologically, air conduction and bone conduction thresholds at 500 Hz were lower in the RIC-HA-satisfied group than in the RIC-HA-dissatisfied group. In addition, the VAS score of RIC HA was negatively correlated with air and bone conduction thresholds and the K-IOI-HA score of RIC HA was positively correlated with speech discrimination score, whereas the VAS and K-IOI-HA scores of closed fit HA were not. ConclusionZZAmong the patients with closed fit HA, some patients indicated RIC HA to be suitable and showed intention to change. The HA should be prescribed firstly based on audiologic criteria, which could increase the subjective satisfaction and prevent poor compliance due to incongruity. Korean J Otorhinolaryngol-Head Neck Surg 2015;58(4):249-56

Embedding Active and Passive Devices in Medical Electronics

Efforts to increase the packaging efficiency of microelectronic systems have been extensive and continuous over the past few decades. Evidence of this can be seen even before the expansion of the space program by the United States in 1961 and the race to the moon; one of the first settings where size was truly limited and miniaturization of electronics was a necessity. In the 1950's the world saw its first major size reduction of electronic component with the phase out of the vacuum tube in favor of the transistor. The transistor saw its first major commercial use in 1952 via hybrid vacuum tube transistor technology. While many industries benefitted from the shift, in 1954 the hearing aid industry specifically experienced major improvements owing to the implementation of transistors, becoming smaller, requiring less power and having better functionality. The first 4-transistor AM radio product followed shortly thereafter. Much of today's effort since 1978 has been driven by the telecommunications industry that has succeeded in reducing cell phone size while simultaneously increasing functionality. Just as in the 1950's, hearing aid technology continues to be at the forefront when it comes to miniaturization. The hearing aid business has always had the need to use extremely small electronic packaging. The first completely in the canal (CIC) hearing aids were produced in 1993 and required all electronic components to be small enough that they fit entirely inside the ear canal. The introduction of wireless systems into hearing aids has sharply increased component count. Due to the size and shape of a multitude of types of hearing aids, flexible circuits need to be folded and bent to fit inside hearing aid cases, with essentially all available space being used. More powerful processors and more memory are enabling sophisticated algorithms that are able to greatly improve sound quality. There is also a strong market desire to add more features to hearing products while at the same time making them smaller and less visible. The latest hearing aids have succeeded in the later demand, constructed so small they are not visible and consequently are called invisible in the canal (IIC). In order to continue meeting the markets want for smaller and more features, a new packaging method needed to be developed. One such option is embedded die packaging. This paper will examine the use of embedded die packaging (or chip-in-flex) to drive significant further size reduction in custom and standard hearing instruments over what can be achieved using chip-on-flex or traditional ceramic hybrid based technologies. The historical drivers, available circuit board technologies, use of integrated passive devices, performance improvement, size reduction, device reliability, changes in supply chain, impact on wafer test, impact on device test, and challenges of working with wafers instead of die will be discussed.

Sub $\mu$W Noise Reduction for CIC Hearing Aids

This paper presents a sub noise reduction design to enhance speech for completely-in-the-canal (CIC) type hearing aids by optimizing its algorithm and associated architecture. In algorithm optimization, a low-complexity mixed perceptual-discrete wavelet packet transform (P-DWPT) and fast Hartley transform (FHT) are adopted for spectral decomposition and reconstruction. A simple yet efficient denoise method with 4-zone-voice activity detection (VAD) supports a consonant protection to improve speech quality and a skip scheme to reduce power consumption. In the designed architecture, mixed P-DWPT and FHT are folded into one 8-by-8 configurable butterfly computation unit with on-time scheduling for low power operation. The circuit is implemented with 0.18 μm CMOS process and consumes only 0.65 μW power at 1.0 V with a speech quality that is comparable to that achieved using other high-complexity algorithms.

Anatomic Dimensions of the Bony External Auditory Canal

INTRODUCTION: With increasing numbers of the new generation regularly using high-powered sound technologies but without adequate auditory protection, it is projected that hearing loss will reach record levels in the near future. As such, the hearing aid industry has been, in the past few decades, offering gradually more miniature and lightweight hearing aid technologies. The goal is to meet the current and future demand for patients seeking treatment while preserving a dimension of portability and, if possible, aesthetics. Among the varieties of hearing aids available to patients today, in-the-canal (ITC) and completely-in-the-canal (CIC) devices have received significant attention for their cosmetic appeal.1 In addition to providing a cosmetic effect, these devices also generally provide good auditory function.2-4 Of note, the newest innovation in hearing aid devices, the invisible extended-wear deep-canal device (Lyric®, InSound Medical, Newark, CA), depends entirely on fitting and securing the device in the patient’s external auditory canal (EAC) by an exterior mold.5 Currently, to overcome anatomical variation among different patients, a number of different EAC molds are available for in-clinic test fitting. The human EAC is comprised of two parts – the cartilaginous portion, which is more lateral, and the bony portion, which is more medial. The contours of the bony EAC are reliably visualized using a temporal bone computed tomography (CT) scan.6, 7 To our knowledge, no systematic measurement of anatomic dimensions of the bony and cartilaginous EAC, let alone standardized dimensions for auditory devices that fit into the EAC, has been reported in the literature. In this study, we report a novel method for performing standardized measurements of the bony EAC, as well as average EAC dimensions for 68 patients with special attention to dimensional differences among different age groups. Knowledge of these dimensions may be helpful in guiding surgical procedures or in the design of novel in-the-ear devices (i.e., hearing aids).

Cerumen management requires skill, knowledge, and a cautious approach

Cerumen management requires skill, knowledge, and a cautious approach

Hearing Aid Outcomes for Listeners With High-Frequency Hearing Loss

To determine whether listeners with primarily high-frequency sensorineural hearing loss (HF SNHL) perceived benefit from amplification provided by completely-in-the-canal (CIC) hearing aids. The Hearing Handicap for the Elderly-Screening version, the Abbreviated Profile of Hearing Aid Benefit, and the Satisfaction With Amplification in Daily Life questionnaires were mailed to 2 groups of listeners (n = 79) who matched preset criteria, including threshold at 2000 Hz and use of CIC amplification. Sixty-seven percent (n = 53) of the questionnaires were returned and were divided into 2 groups. Group I (n = 26) consisted of listeners with normal hearing through 2000 Hz, and Group II (n = 27) consisted of listeners with normal hearing only through 1000 Hz. Results revealed that both groups perceived significant hearing handicap, hearing aid benefit, and hearing aid satisfaction. Differences between the 2 groups on the 3 measures, however, were not statistically significant. Listeners with HF SNHL perceived benefit and satisfaction from amplification with CIC hearing aids. Individuals with SNHL limited to the high frequencies should be considered candidates for amplification.

Hearing aid outcomes with open- and closed-canal fittings

Hearing aid outcomes with open- and closed-canal fittings

Noise-management algorithm may improve speech intelligibility in noise

A likely consequence of sensorineural hearing loss is a diminished ability to understand speech in noisy backgrounds. Indeed, the inability to hear in noise is one of the main reasons for dissatisfaction with hearing aid use.1 Although hearing aids with a directional microphone provide substantial improvement in the ability of wearers to understand speech in noisy environments,2 space requirements and the uncertainty of directional characteristics when a directional hearing aid is inserted deeply into the ear canal prevent the implementation of such technology in the smallest completely-in-the-canal (CIC) hearing aids. A patient who insists on wearing CIC hearing aids will have to rely solely on the efficacy of single-mic noise-management strategies. Currently, most commercial “noise reduction” schemes use the modulation rates of the input signal as a basis for estimating the “speech” and “noise” nature of the input. “Speech” sounds are amplified with input-dependent gain, while “noise” sounds are typically amplified at a reduced gain level beyond input-dependent levels (see Chung, 20043). The exact amount of gain reduction and its time course vary greatly among manufacturers. Despite such differences, most studies have reported only an improvement in listening comfort by use of such a scheme.4 The improvement in listening comfort is noteworthy. It suggests that hearing-impaired persons whose hearing aids have noise reduction may be less affected by high-output sound pressure levels, less stressed, and less distracted in noisy situations, and may be more likely to attend to the sound sources and wear their hearing aids longer than if they lacked this feature. Wearers may also improve their participation in daily activities and their quality of life. It is possible that the reduction in stress level (or distractions) may improve the user’s speech understanding in some noisy environments.

The "Hearing Aid Effect" 2005

The visibility of open ear (OE) styles of hearing instruments was rigorously investigated for their potential to reduce the stigma of wearing hearing aids. Three groups of 50 young adults (150 total) rated the visibility of 6 hearing aid styles-OE, invisible completely-in-the-canal (CIC), mini in-the-canal (m-ITC), half- and full-shell in-the-ear (ITE), and behind-the-ear (BTE)-worn by a peer model with revealing hairstyle, photographed from 2 ft and at 3 different angles (45 degrees, 90 degrees, and 135 degrees). CIC was rated significantly most "invisible" at 45 degrees and 90 degrees, OE and m-ITC were next at those angles, and OE and BTE were least invisible at 135 degrees. The findings have implications for counseling potential users who are reluctant to try hearing aids for cosmetic reasons.

Stick It in Your Ear: A Systematic Approach to Earmold Selection

Stick It in Your Ear: A Systematic Approach to Earmold Selection

Vent Configurations on Subjective and Objective Occlusion Effect

The current study reexamined the effect of vent diameters on objective and subjective occlusion effect (OE) while minimizing two possible sources of variability. Nine hearing-impaired participants with primarily a high-frequency hearing loss were evaluated. Laser shell-making technology was used to make ear inserts of completely-in-the-canal (CIC) hearing aids for the study. This was to minimize any potential slit leakage from the inserts. The vent dimensions were systematically altered during the study. Participants sustained /i/ for 5 sec, and the real-ear occluded response was measured with a custom-made program that performed frequency averaging to reduce response variability. Participants also repeated the phrase "Baby Jeannie is teeny tiny" and rated their own voice. The results showed a systematic change in the objective OE and subjective ratings of OE as the vent diameter was modified. Furthermore, a significant correlation was seen between subjective rating and objective occlusion effect.

Real-World Performance of a Reverse-Horn Vent

The present study compared differences in subjective and objective performance in completely-in-the-canal (CIC) hearing aids with conventional uniform 1.5 mm parallel vents and another with a reverse horn vent where the diameter increased from 1.5 mm on the lateral faceplate to 3 mm on the medial opening of the hearing aid. Nine hearing-impaired persons with a high-frequency hearing loss participated. The test battery included unaided in situ thresholds, amount of available gain before feedback, speech in quiet, speech in noise (HINT), subjective ratings of hollowness and tolerance, objective measures of the occlusion effect, and real-ear aided response. Results showed less available gain before feedback but less occlusion effect for subjective ratings and objective measures with the reverse horn vent. This type of vent design may be useful to increase the effective vent diameter of custom (including CIC) hearing aids.

Predicted gain and functional gain with transcranial routing of signal completely-in-the-canal hearing aids.

Transcranial routing of signal (TCROS) was accomplished using completely-in-the-canal (CIC) hearing aids in 5 profoundly unilaterally hearing-impaired individuals. The functional gain realized by the participants far exceeded the gain predicted by measuring the acoustic output and real ear aided response of the hearing aids. The difference between predicted and functional gain increased with signal frequency and was attributed at least in part to mechanical vibration of the hearing aid in the external canal. Implications for fitting unilateral hearing loss using TCROS amplifying systems are discussed.

The effects of completely-in-the-canal hearing aids, active noise reduction headsets, and ambient noise on speech intelligibility

Many people with hearing loss need to communicate and work in high noise environments. Hearing aids and headsets are often worn to protect the ear from further damage and facilitate communication. The purpose of this study was to determine the effects of the active noise reduction (ANR) headsets and Completely-in-the-Canal (CIC) hearing aids on speech intelligibility in ambient noise. Six male listeners with noise-induced hearing loss were each fitted with two digital CIC hearing aids. The listeners wore the hearing aids successfully for one year. The speech stimuli were presented over the ANR headphones in quiet and in 95 dB and 105 dB SPL of ambient pink noise. The independent variables were the active noise reduction, hearing aids, and noise level. All MRT stimuli were presented at the most comfortable loudness level. The dependent variable was speech intelligibility as measured with the Modified Rhyme Test (MRT). A main effect was discovered for noise, however no effect was found for active noise reduction or hearing aids. Although no overall effect was found with ANR or hearing aids on speech intelligibility there were differences across phoneme identifications and initial and final consonants.

Effects of CIC hearing aids on auditory localization by listeners with normal hearing.

An experiment was conducted to determine the effects of completely-in-the-canal (CIC) hearing aids on auditory localization performance. Six normal-hearing listeners localized a 750-ms broadband noise from loudspeakers ranging in azimuth from -180 degrees to +180 degrees and in elevation from -75 degrees to +90 degrees. Independent variables included the presence or absence of the hearing aid and the elevation of the source. Dependent measures included azimuth error, elevation error, and the percentage of trials resulting in a front-back confusion. The findings indicate a statistically significant decrement in localization acuity, both in azimuth and elevation, occasioned by the wearing of CIC hearing aids. However, the magnitude of this decrement was small compared to those typically caused by other ear-canal occlusions, such as earplugs, and would probably not engender mislocalization of real-world sounds.

Digital Hearing Aids: Current “State-of-the-Art”

Digital Hearing Aids: Current “State-of-the-Art”

Current trends in implantable hearing AIDS.

When the research is examined historically, there appear to be three rationales for developing and fitting implantable hearing aids (IHA). These include improved (a) sound reception, (b) cosmetics, and (c) fitting of patients who could not derive optimal benefit from conventional amplification. With the introduction of modern completely-in-the-canal (CIC) hearing aids, the cosmetic concern is no longer a major motivation. (Johnson and Danhauer, 1997). Dumon et al (1995) clearly stated the ultimate goal of IHA research is the creation of a “… totally implantable middle ear implant (MEI), for severe and average [moderate] sensorineural deafness.” Until the technology is available to provide a totally IHA, Goode et al (1995) defined an implantable hearing aid as a class of electronic devices that are “wholly or partially implanted through surgery and … [are] designed to ameliorate hearing loss.” This definition not only covers the various middle ear implants, but also the temporal bone implants. This latter group is generally referred to as bone anchored hearing aids. Both of these types of IHAs will be discussed in great detail in this issue of Trends. Like any dynamic area of research, spin-offs of this technology are already available in related areas, such as a middle ear pump system designed to release small amounts of antibiotics for chronic otitis media (Maassen et al, 1996), and as a “transparent link [to the temporal bone] in the study of tinnitus…” (Downing, 1996). Goode et al (1995) and Ko et al (1995) delineated some of the parameters that an IHA should possess. As a general set of requirements these researchers suggested that IHAs should: provide sufficient gain and output for the patient's needs, not reduce residual hearing by having minimal loading or contact with middle ear structures, not limit daily activities such as swimming, not predispose the patient to recurrent ear infections, have proven long-term stability and tolerance to anatomical changes, have a demonstrated biocompatibility of the implanted materials and package, have minimal movement of the implanted parts in order to minimize wear and tear, be adjusted/programmed and removed easily with an external battery, have safety of the surgical procedure demonstrated, and allow the patient the ability to wear a conventional hearing aid if for some reason the IHA breaks or does not provide sufficient benefit. Given the definition of IHAs, there is no reason to assume that the various devices should be restricted to only one type of hearing loss. Indeed, many of the various IHA projects that are underway around the world can be applied to sensorineural, conductive, and mixed hearing loss, despite the original intent of the researchers. The discussion of IHAs in this manuscript is divided into two main sections; (a) bone anchored hearing aids and (b) middle ear implants (MEI). As the names suggest, a portion of a bone anchored hearing aid is surgically implanted in the temporal bone, whereas the middle ear implants are to be found partially implanted in the middle ear cavity.

The effect of completely-in-the-canal hearing aids on localization performance: Normal hearing listeners

The Completely-In-The-Canal (CIC) hearing aid, due to its placement in the ear canal, has acoustic advantages that are not offered by traditional amplification. Among these advantages are increased high-frequency gain, reduction of the occlusion effect, and subjective reports of improved localization ability over other types of aids. Quantitative data are readily available to verify the frequency response and occlusion effect; however, data on localization ability have been primarily anecdotal. A series of experiments has been designed to document the effect of CIC hearing aid use on auditory localization performance. A normal-hearing subject group, fit with low-gain CICs, was used in this phase; later studies will utilize hearing-impaired listeners and a variety of devices. The use of normal hearing subjects allowed an assessment of localization ability independent of the effects of hearing loss. Localization accuracy was measured using the God’s eye localization pointing (GELP) technique [Gilkey et al., Behav. Res. Methods, Instrum. Comput. 27(1), 1–11 (1995)]. Results showed that subjects wearing the CICs were able to localize over the entire spatial presentation range of the stimulus (±180° azimuth, −74° to +90° elevation). Localization accuracy data will be presented.