Exploring the recruitment, ethical considerations, conduct and information dissemination of an audiology trial: a pretrial qualitative study (q-COACH)

INTRODUCTION

Randomised controlled trials (RCTs), while still considered the gold standard approach in medical research, can encounter impediments to their successful conduct and the dissemination of results. Pretrial qualitative research can usefully address some of these impediments, including recruitment and retention, ethical conduct, and preferred methods of dissemination. However, pretrial qualitative work is rarely undertaken in audiology. The Comparison of outcomes with hearing aids and cochlear implants in adults with moderately severe-to-profound bilateral sensorineural hearing loss (COACH) is a proposed RCT aiming to clarify when hearing aids (HAs) or cochlear implants (CIs) are the most suitable for different degrees of hearing loss and for which kinds of patients. q-COACH is a pretrial, qualitative study examining stakeholders' experiences of HAs and CIs, current clinical practices and stakeholders' perspectives of the design, conduct and dissemination plans for the proposed COACH study.

METHODS

Twenty-four participants including general practitioners, audiologists, adult HA users, and adult support networks undertook either semi-structured individual or paired interviews and completed demographic questionnaires. Data were analysed thematically.

RESULTS

Four key themes arose from this study: 1) rethinking sampling and recruitment strategies, 2) ethical considerations, 3) refining trial conduct, and 4) interconnected, appropriate and accessible methods of results dissemination.

CONCLUSIONS

This qualitative investigation identified key considerations for the proposed RCT design, conduct and dissemination to help with successful implementation of COACH, and to indicate a plan of action at all RCT stages that would be acceptable to potential participants. By drawing on the perspectives of multiple key stakeholders and including a more general discussion of their experience and opinions of hearing loss, hearing device use and service availability, the study revealed experiential and ethical paradigms in which stakeholders operate. In so doing, q-COACH has exposed the benefits of preliminary qualitative investigations that enable detailed and rich understandings of the phenomenon at stake, forestalling problems and improving the quality of trial design, conduct and dissemination, while informing future RCT development discussions.

Examination of Insert Ear Interaural Attenuation (IA)Values in Audiological Evaluations

PURPOSE

The purpose of this study was to evaluate Interaural Attenuation (IA) in frequency base in the insert earphones that are used in audiological assessments.

METHODS

Thirty healthy subjects between 18-65 years of age (14 female and 16 male) participated in our study. Otoscopic examination was performed on all participants. Audiological evaluations were performed using the Interacoustics AC40 clinical audiometer and ER-3A insert earphones. IA value was calculated by subtracting good ear bone conduction hearing thresholds of the worst airway hearing threshold.

RESULTS

In our measuring for 0.125-8.0 kHz frequency were performed in our audiometry device separately for each frequency. IA amount in the results we found in 1000 Hz and below frequencies about 75-110 dB range avarage is 89±5dB, in above 1000 Hz frequencies in 50-95 dB range and avarage it is changed to 69±5dB.

CONCLUSION

According to the obtained findings the quantity of melting in the transition between the ears are increasing with the insert earphones. The insert earphone should be beside supraaural earphone that is routinely used in clinics. Difficult masking applications due to the increase in the value of IA can be easily done with insert earphones.

Automatic quality assessment and peak identification of auditory brainstem responses with fitted parametric peaks

The recording of the auditory brainstem response (ABR) is used worldwide for hearing screening purposes. In this process, a precise estimation of the most relevant components is essential for an accurate interpretation of these signals. This evaluation is usually carried out subjectively by an audiologist. However, the use of automatic methods for this purpose is being encouraged nowadays in order to reduce human evaluation biases and ensure uniformity among test conditions, patients, and screening personnel. This article describes a new method that performs automatic quality assessment and identification of the peaks, the fitted parametric peaks (FPP). This method is based on the use of synthesized peaks that are adjusted to the ABR response. The FPP is validated, on one hand, by an analysis of amplitudes and latencies measured manually by an audiologist and automatically by the FPP method in ABR signals recorded at different stimulation rates; and on the other hand, contrasting the performance of the FPP method with the automatic evaluation techniques based on the correlation coefficient, FSP, and cross correlation with a predefined template waveform by comparing the automatic evaluations of the quality of these methods with subjective evaluations provided by five experienced evaluators on a set of ABR signals of different quality. The results of this study suggest (a) that the FPP method can be used to provide an accurate parameterization of the peaks in terms of amplitude, latency, and width, and (b) that the FPP remains as the method that best approaches the averaged subjective quality evaluation, as well as provides the best results in terms of sensitivity and specificity in ABR signals validation. The significance of these findings and the clinical value of the FPP method are highlighted on this paper.

An overview of wideband immittance measurements techniques and terminology: you say absorbance, I say reflectance

This article reviews the relationships among different acoustic measurements of the mobility of the tympanic membrane, including impedance, admittance, reflectance, and absorbance, which the authors group under the rubric of immittance measures. Each of these quantities is defined and related to the others. The relationship is most easily grasped in terms of a straight rigid ear canal of uniform area terminated by a uniform middle ear immittance placed perpendicular to the long axis of the ear canal. Complications due to variations from this geometry are discussed. Different methods for measuring these quantities are described, and the assumptions inherent within each method are made explicit. The benefits of wideband measurements of these quantities are described, as are the benefits and limitations of different components of immittance and reflectance/absorbance. While power reflectance (the square of the magnitude of pressure reflectance) is relatively invariant along the length of the ear canal, it has the disadvantage that it ignores phase information that may be useful in assessing the presence of acoustic leaks in ear-canal measurements and identifying other potential error sources. A combination of reflectance and impedance magnitude and angle give a more complete description of the middle ear from measurements in the ear canal.

Curtis's cephaloscope: deafness and the making of surgical authority in London, 1816-1845

Aural surgery is a branch of nineteenth-century medicine and surgery providing specialized treatment for ear diseases. During the 1830s, faced with a "popular prejudice" against the curability of deafness as well as intraprofessional rivalries and continuous accusations of quackery, aurists found their surgical authority questioned and their field's value threatened. In an attempt to bolster aural surgery's reputation, in 1841, the aurist John Harrison Curtis (1778-1856) introduced his new diagnostic instrument, the cephaloscope, which could not only improve diagnosis but also provide approaches for regulating aural knowledge, thus strengthening aural surgery's authority. This article examines the motives underlying Curtis's introduction of the cephaloscope and the meanings it held for the occupational group at large.

Instrumentation for studies of cochlear mechanics: from von Békésy forward

Georg von Békésy designed the instruments needed for his research. He also created physical models of the cochlea allowing him to manipulate the parameters (such as volume elasticity) that could be involved in controlling traveling waves. This review is about the specific devices that he used to study the motion of the basilar membrane thus allowing the analysis that lead to his Nobel Prize Award. The review moves forward in time mentioning the subsequent use of von Békésy's methods and later technologies important for motion studies of the organ of Corti. Some of the seminal findings and the controversies of cochlear mechanics are mentioned in relation to the technical developments.

A model of the VU (volume-unit) meter, with speech applications

The Volume- Unit (VU) meter, used in speech research prior to the advent of computers and modern signal processing methods, is described in signal processing terms. There are no known software implementations of this meter, which meet the 1954 ASA standard and provide the instantaneous needle level. Important speech applications will be explored, such as making comparisons of speech levels to earlier classic works, and measuring speech levels using traditional methods on modern computers. It is our intention to make this venerable method of measuring speech levels available once again. The VU meter is simulated and its properties are studied. A 1950s vintage and a recent vintage VU meter are studied by comparing the transient responses to tones and measurement of speech levels. Based on these measurements, a software VU meter (henceforth referred to as VUSOFT) is simulated, and verified. The method for reading the meter is explained, and simulated in software. The VU level for speech is shown to depend on the reading duration. The relationship between the root-mean-squared (rms) level of a signal and the VU level of a signal is determined, as a function of the meter-reading time.

Internet application to tele-audiology--"nothin' but net"

The Telehealth program at East Carolina University has developed a system for real-time assessment of auditory thresholds using computer driven control of a remote audiometer via the Internet. The present study used 45 adult participants in a double-blind study of 2 different systems: a conventional audiometer and an audiometer operated remotely via the Internet. The audiometric thresholds assessed by these 2 systems varied by no more than 1.3 dB for air conduction and 1.2 dB for bone conduction. The results demonstrated the feasibility of this new "telehearing" audiometric system. With the rapid development of Internet-based applications, telehealth has the potential to provide important healthcare coverage for rural areas where specialized audiological services are lacking.

[Hearing evaluation on young children (less than five years old) in an under-equipped center. An adaptation of the Delaroche protocol]

The authors report their experience of audiometric test in childhood (less than fifty years old). It's an adaptation of Delaroche protocol which was first described by the Bordeaux's team. This prospective study has been realized in their works conditions in Abidjan (Ivory Coast) on 75 children under five years of age (average 2,64 years). This protocol is essentially based on: at first, hearing evaluation with acoustic toys; secondly, bone conduction on the vibrator; at the end, air conduction on the head set. The analysis of the results on 75 children shows that there were 35 normal examinations, 5 conductive deafness, 32 sensorineural hearing loss among which 9 partial failures (hearing threshold non evaluated), 3 complete failures (refuse the test). The authors insist on the utility of audiometric tests in early management of hearing loss in young children.

Growth of evoked otoacoustic emissions during the first days postpartum. A preliminary report

Evoked otoacoustic emissions (EOAEs) were recorded twice in 20 ears of 15 newborns. The recordings were performed in a room of the well baby ward, using the ILO88 in its default setting, i.e. with click stimulation. On the first test occasion, the infants were between 3 and 51 h of age, and EOAEs were identified in 10 ears. On the second test occasion, while the infants were at least 1 day older (range 42-107 h), EOAEs were present in all ears. The second EOAE was stronger, so the EOAE appeared to grow in the first days postpartum. This might be due to middle ear clearance of amniotic fluid, shortly after birth. The results of the EOAEs of the second examination were compared with 10 EOAEs in adult ears. The response levels of the newborns were significantly higher than in the adults. The (cross)-correlation peak value of the two tests' waveforms is over 0.75, however sometimes only after filtering around the most pronounced emission frequencies. The study proves that newborns failing the EOAE screen in the first 24 h after birth can pass if retested 1 day later, simply because of growth of EOAE strength.

Evaluation and assessment of FM systems

In the past, frequency modulated (FM) systems were recommended for use only in educational settings for children with severe or profound hearing losses. Recent studies, however, have suggested that FM systems may be appropriate in nonacademic settings and also may benefit children with minimal hearing loss. In addition to the more widespread application of FM use, advances in amplification technology have provided audiologists with a variety of devices and coupling options, resulting in more variables to evaluate in the fitting process. There are three commonly used methods of evaluating FM systems: functional gain measures, probe tube microphone measures, and coupler measures. This paper is intended to provide the audiologist working with FM systems with an overview of the complexities involved in selecting and setting FM systems and the benefits and limitations of each evaluation method. Each evaluation method is examined in view of how well it answers three basic questions related to frequency response, maximum output, and distortion in FM systems. Finally, other issues which may impact on the selection of an FM system for a given individual are discussed.

A comparison of commercial auditory evoked potential units: the midpriced and luxury units

This report represents the second of two providing a consumer-oriented comparison of commercially available auditory evoked potential units. The units compared here were those whose basic price was between $10,000-$30,000 ("midpriced"), and greater than $30,000 ("luxury"). The midpriced group included the Amplaid MK15, Bio-Logic Navigator and Traveler LT, Cadwell 5200A and Quantum 84, GSI-50, Nicolet CA-2000 and Compact Auditory, Nihon-Kohden Neuropak IV Mini, Madsen ERA2250, Siegen (Dantec) Neuroscope, and Tracor Nomad. The luxury units comprised the Bio-Logic Brain Atlas, Cadwell Spectrum 32 and Nicolet Pathfinder. Descriptive information and the names and addresses of users were solicited from the manufacturers for each of the above units. Questionnaires were sent to the users asking them for information on how their unit was used and to rate some of its features. The midpriced and luxury units offer more flexibility and options than less expensive (i.e., "economy") units. However, the basis for a given unit's price versus another's was not always apparent by a comparison of features or options. In general, users of the midpriced and luxury units rated the majority of their instruments' features highly. The lowest ratings were received for some aspect of the printer or print-out, and portability.

HyperShell: an expert system shell in a hypermedia environment--application in medical audiology

HyperShell is an expert system shell developed in a hypermedia environment. Several artificial intelligence techniques such as frames and semantic networks are used in an original interpretation to enhance the interaction between the user and the program. The typical navigation tools of hypermedia such as clickable buttons and text search are extended to the semantic structure of HyperShell, creating a set of new tools. Examples from a medical expert system (Audex HM) developed in HyperShell are described.

Noise reduction strategies for elderly, hearing-impaired listeners

A variety of technical features are available in hearing aids in order to reduce the negative effects of background noise. In this investigation, 16 elderly sensorineurally hearing-impaired hearing aid candidates provided word recognition responses while listening through simple linear amplification and through a hearing aid featuring one of the following: (1) high-frequency emphasis amplification, (2) a directional microphone, (3) automatic signal processing (ASP) circuitry, and (4) ZETA noise reduction circuitry. The subjects provided responses to monosyllabic words presented in a background of cafeteria noise. Results indicated that all four noise reduction techniques provided a similar magnitude of benefit over linear amplification. In a follow-up investigation, five of the original 16 subjects were recalled in order to listen through either simple linear amplification or through the ZETA circuitry with and without the benefit of visual and contextual cues. The subjects repeated sentences presented in a background of cafeteria noise. Without the benefit of the supplemental cues, the ZETA aid allowed for superior performance when compared to the linear aid. When the visual and contextual cues were available, the ZETA aid continued to provide a performance advantage over linear amplification.

The computerized audiology clinic

Computer-assisted audiologic testing is undergoing a transition from laboratory settings to audiology clinics, resulting in increased accuracy, efficiency, and sophistication in the evaluation and treatment of patients. The computerized clinic also offers superior information storage and analysis capabilities and increasingly significant economic advantages. Implementation of new test techniques with software modification, rather than expensive new electronic instrumentation, is an advantage unique to the computer-based audiologic system. Decisions regarding the selection from a variety of system architecture designs and human interface schemes are critically important and unique to this new technology. The replacement of traditional audiometric instruments with computer-controlled systems will accelerate as system sophistication increases and cost continues to decrease.

Insertion gain measured with three probe tube systems

The study consisted of two experiments on the insertion gain measured with probe tube microphones. In experiment I, the insertion gain of the same mild gain hearing aid was measured twice on 12 subjects using three commercially available probe tube systems. Test-retest measurements were made by two different examiners. Mean test-retest differences were all less than 4 dB with 95% critical differences for these measures varying from approximately 3 to 8 dB depending upon the test system used. In experiment II, the three sets of probe tube measures of insertion gain were compared to behaviorally measured functional gain in 7 hearing-impaired subjects at several frequencies. There were no significant differences among the probe tube measures of insertion gain or between these measures and functional gain. Functional gain was significantly correlated with probe tube insertion gain for each device at frequencies from 500 through 4000 Hz.

Changes in bone conduction thresholds with vibrator contact area

An experimental bone conduction vibrator was used to measure force and acceleration directly at the point of contact, the subject's forehead. Force and acceleration at threshold were measured for six subjects over a frequency range of 250 to 6000 Hz and over a contact area range of five to one. These measurements suggest that for any test subject, the variation in force of threshold with contact area is much smaller than the corresponding variation in acceleration at threshold.

A new clinical technique for verification of hearing aid response

A new miniature wide-range electret microphone with a flat frequency response is available to the audiology clinic to measure sound pressure in the patient's ear canal. This article describes the clinical application of this new microphone for the selection and monitoring of hearing aid response. Preliminary results of the relationship between ear canal measurements and functional gain are also provided. This new clinical technique can provide the audiologist with quick objective data on the response of a hearing aid while it is being worn by the patient.

Acoustic radiation from bone vibrators

Our purpose was to investigate the influence of acoustic radiation produced by bone vibrators at 4000 Hz on bone conduction (BC) testing. In one study, BC thresholds were obtained with a Radioear B-70A, B-71, and B-72 vibrator when the subject's ear canal was unoccluded and occluded. In another study, probe-tube microphone measurements were made just inside the entrance to the ear canal for each vibrator and for an air conduction source at comparable sensation levels. Results of both studies were interpreted to indicate that the B-70A and B-71 produced minimal acoustic radiation. However, the B-72 was found to have excessive acoustic radiation which would be sufficient to influence BC thresholds and produce an invalid high-frequency air-bone gap.

The SPL hearing meter

An instrument, the SPL Hearing Meter, was devised for the measurement of hearing threshold with a hearing aid earphone in order to make a direct comparison between the hearing threshold and the output sound pressure level of a hearing aid. The author found this a handy tool for selection and adjustment of hearing aids.

The Beltone 5b artificial mastoid: theoretical characteristics and performance measurements

Early versions of the Beltone artificial mastoid system were designated as model 5A. Later versions were designated as model 5B due to design modifications which changed the mechanical impedance parameters. The theoretical impedance characteristics of the 5B were considerably lower than for a comparison 5A. Compared with a B & K model 4930 (new pad) artificial mastoid, the 5B had a lower impedance (closer to ANSI values) from 500 to 2000 Hz and a slightly higher impedance at 250, 3000, and 4000 Hz. Discrete and continuous output voltage measurements with a constant input revealed that the performance of the 5B was also different compared with a 5A and the B & K model 4930 for different vibrator types. Bone conduction thresholds for a Radioear B-70A, B-71, and B-72 vibrator were obtained on 30 trained normal-hearing listeners. Adjusted threshold force levels needed to achieve normal-hearing bone conduction thresholds are presented for calibrating bone vibrators in clinical use with a Beltone 5B artificial mastoid.

The use of a miniature microphone in the ear canal for the verification of hearing aid performance

An individual head, auricle, and ear canal can alter signals from a hearing aid other sources of acoustic stimulation compared to artificial couplers. The most realistic method for quantifying or verifying certain parameters of acoustic simulation delivered to the ear by a hearing aid is to measure the sound pressure level of a signal in the ear canal of an individual while wearing an aid. Probe microphone measurements have been conducted and reported for the past 33 years. Until now, such microphone measurements have used a hollow tube inserted into the ear canal which leads to a transducer outside the canal. This paper describes our preliminary clinical application of a new wide range, flat response, miniature electret microphone, measuring 4 x 5 x 2 mm for measurement of insertion gain in a patient's ear canal. We believe the information from these recordings can be useful in developing objective clinical procedures for the selection and monitoring of wearable amplification for hearing-impaired patients.

Hearing aid measurements using the revised standard: reducing variability and determining test system accuracy

Unlike previous standards, the revised hearing aid standard, (ANSI S3.22-1976), specifies tolerance requirements for the electroacoustic characteristics of hearing aids. It is essential, therefore, that measurements of performance be made as accurately as possible. To assess the precision with which these measures can be made in a clinical environment, five hearing aids of the same model were each tested five times using Bruel and Kjaer instrumentation. When possible, data were recorded directly from the meter of the measuring amplifier as well as from the chart paper. The variability of the results was always less when data were obtained from the meter than from the chart. The ratio of the variability(meter:chart) differed depending on the test being made. The accuracy of the test system was derived (as required by the standard) both theoretically and empirically. When its estimated tolerances wee added to the tolerances permitted for the aids, all hearing aids were found to perform well within the limits of the standard except for one measurement on one aid.

Clinical experience with tinnitus maskers

Results from tinnitus evaluations and follow-up questionnaires were used in an effort to assess the efficacy of tinnitus masking units as a means of providing active and/or passive relief for patients experiencing problematical tinnitus. Nine of 34 patients (26%) who were felt to be candidates for masking units reported that they were receiving some form of relief from their tinnitus.

Tinnitus maskers: a follow-up

A follow-up study was conducted on the 31 individuals who rented tinnitus maskers after otologic and audiologic examination and consultation. Ten of 31 purchased instruments after a 30-day rental period. Eight of 10 who purchased instruments have been contacted either by letter or by phone. Two of eight are presently using their instruments on a regular basis. One is using his masker sporadically and is not positive about the help received.

Evaluation of a tinnitus masking program: a follow-up study of 598 patients

A follow-up study of two groups of tinnitus patients was conducted in an attempt to evaluate the tinnitus masking program. Results are discussed separately for a group of patients seen during the first three years of the program (1976 through 1978) and during the last year (1979). These results suggest an improvement in the management of the tinnitus patient and support this procedure as a viable technique in providing relief for selected tinnitus patients.

Cochlear action potential threshold and single unit thresholds

There is a close correlation between the sound pressure of tone burst required to affect a primary auditory neuron at its characteristic frequency and that which will produce a detectable N1 response at the same frequency. Units with thresholds from 80--0 db SPL (recorded from damaged and undamaged cochleas) were 0--20 dB , respectively, more sensitive than the action potential response.

Clinical rationale for using an overhead speaker in evaluation of hearing aids

A variable that has received little attention in the psychoacoustic evaluation of the hearing aid is the position of loudspeakers with respect to the listener, particularly the azimuth of the loudspeaker, which is used for presenting the competing message. In the past, a variety of locations have been used, some of which can bias the outcome of the evaluation. For this reason, this article suggests the use of an overhead speaker to deliver the competing signal. The overhead placement provides a neutral location that is highly desirable for making reliable repeated speech performance comparisons. In addition, the overhead speaker can be easily adapted to the testing environment while it produces the effect of surrounding the listener with the competing signal.