Pauline A. Smith

Comparison of manual and computer-controlled self-recorded audiometric methods for serial monitoring of hearing.

Manual and self-recorded audiograms obtained from 240 ears on two occasions 2-3 years apart were compared, with the objective of establishing the preferred method for serial monitoring of hearing thresholds. The self-recording method incorporates an objective scoring algorithm which is compared with subjective scoring carried out independently by two experienced audiology staff members. The objective scoring method agreed well with the subjective method but gives substantial advantages in terms of cost and freedom from scorer bias. The variability associated with manual audiometry was somewhat lower than that associated with self-recording audiometry when used for serial monitoring.

Transient-Evoked Otoacoustic Emissions in a Representative Population Sample Aged 18 to 25 Years: Emisiones otoacüAsticas evocadas por transitorios en una muestra representativa de población con edades entre 18 y 25 años

Transient-evoked otoacoustic emissions (TEOAEs) were obtained from 688 ears of a group of 345 young adults aged 18 to 25 years, using the Otodynamics ILO88 in the standard, non-linear mode. Normative data for TEOAEs obtained from 186 otologically normal (ON) ears are presented. In 5 ON ears, there was no recordable response, despite hearing threshold levels better than 20 dB. The main factors affecting the TEOAE level were (1) gender, where females had larger responses on average than males; (2) tym-panometric measures, where ears with entirely normal tympanometric measures had larger responses than those with minor tympanometric abnormalities; (3) click stimulus intensity measured in the ear canal, which correlated positively with TEOAE level; and (4) hearing threshold level at 0.5 kHz, which correlated negatively with amplitude. There was also a small effect of social noise exposure in the 2-kHz region of the TEOAE, where the response was lower in those subjects exposed to significant social noise.

Efficiency of tests used to screen for cerebello-pontine angle tumours: A prospective study

With increasing use of imaging in the investigation of cerebello-pontine angle (CPA) tumours, the role of audio-vestibular and electrophysiological testing has changed. Field performance data on the efficiencies of these tests to screen for CPA tumours are lacking, but must be known to choose an appropriate testing strategy. A prospective observational study of 237 patients attending a neuro-otology clinic for audio-vestibular investigation was carried out. The aim was to provide field performance data on which to base an effective protocol to screen for CPA tumours. All patients presenting at the ENT department and meeting any of the following criteria were referred to the neuro-otology clinic and included in the study: (1) asymmetrical sensorineural hearing loss, (2) unexplained asymmetrical tinnitus with normal bearing thresholds, (3) unilateral bearing difficulties with normal hearing thresholds and (4) other neurological indications. In addition to audio-vestibular and auditory brainstem response (ABR) investigation, every patient underwent computed tomography (CT), with magnetic resonance imaging (MRI) in cases having marginal results on CT, to exclude or confirm the presence of a tumour. Pass or fail on each test was based on a priori criteria from other studies. Eighteen patients were found to have CPA tumours. ABR testing was the only effective procedure for screening, but had some limitations. A contingent protocol using ABR in all cases except those with asymmetrical tinnitus and normal bearing thresholds, those with severe hearing loss, and those with neurological signs, was retrospectively defined: the exceptions would go straight to CT. This protocol would have missed two of the 18 tumour patients. CT scanning alone would have missed one small intra-canalicular tumour, which was picked up on MRI triggered by abnormal ABR. Based on the results from the present study we conclude there is no effective screening protocol for detecting CPA tumours, as MRI scanning with gadolinium enhancement will identify virtually all tumours. Where MRI is available but waiting lists are long, the described strategy using ABR to select priority referrals for MRI scanning is recommended.

Comparative study of four noise spectra as potential tinnitus maskers

Ten experienced tinnitus-masker uses compared four widely different noise bands as potential maskers in a laboratory environment. No reliable individual preferences could be found, and most of the noises were acceptable to most of the subjects. A wide-band noise was marginally most frequently preferred. In this sample, there was no indication that individual tailoring of the frequency spectra of tinnitus maskers is required to achieve acceptable masking. Subjects also underwent tests of hearing, tinnitus matching and tinnitus masking. Most subjects chose noise levels for therapeutic masking that only partially masked their tinnitus. This suggests prescription or trial of tinnitus maskers even for patients who have high minimal masking levels.

Diagnosing Patients with Age-Related Hearing Loss and Tinnitus: Supporting GP Clinical Engagement through Innovation and Pathway Redesign in Audiology Services

The public health challenge of hearing impairment is growing, as age is the major determinant of hearing loss. Almost one in four (22.6%) over 75-year olds reports moderate or severe worry because of hearing problems. There is a 40% comorbidity of tinnitus and balance disorders. Good outcomes depend on early presentation and appropriate referral. This paper describes how the NHS Improvement Programme in England used service improvement methodologies to identify referral pathways and tools which were most likely to make significant improvements in diagnosing hearing loss, effective referrals and better patient outcomes. An audiometric screening device was used in GP surgeries to enable thresholds for effective referrals to be measured in the surgery. Revised referral criteria, the use of this device, new “assess and fit” technology in the audiology clinic, and direct access pathways can transform audiology service delivery so that patient outcomes are measurably better. This, in turn, changes the experience of GPs, so they are more likely to refer patients who can benefit from treatment. At the end of 2011, 51 GP practices in one of the audiology pilot areas had bought HearCheck screeners, a substantial development from the 4 practices who first engaged with the pilot.

A Multicenter Trial of an Assess-and-Fit Hearing Aid Service Using Open Canal Fittings and Comply Ear Tips

Large potential benefits have been suggested for an assess-and-fit approach to hearing health care, particularly using open canal fittings. However, the clinical effectiveness has not previously been evaluated, nor has the efficiency of this approach in a National Health Service setting. These two outcomes were measured in a variety of clinical settings in the United Kingdom. Twelve services in England and Wales participated, and 540 people with hearing problems, not previously referred for assessment, were included. Of these, 68% (n = 369) were suitable and had hearing aids fitted to NAL NL1 during the assess-and-fit visit using either open ear tips, or Comply ear tips. The Glasgow Hearing Aid Benefit Profile was used to compare patients fitted with open ear tips with a group of patients from the English Modernization of Hearing Aid Services evaluation, who used custom earmolds. This showed a significant improvement in outcome for those with open ear tips after allowing for age and hearing loss in the analysis. In particular, the benefits of using bilateral open ear tips were significantly larger than bilateral custom earmolds. This assess-and-fit model showed a mean service efficiency gain of about 5% to 10%. The actual gain will depend on current practice, in particular on the separate appointments used, the numbers of patients failing to attend appointments, and the numbers not accepting a hearing aid solution for their problem. There are potentially further efficiency and quality gains to be made if patients are appropriately triaged before referral.

Real-world preferences for linked bilateral processing

Decades of research have substantiated that binaural hearing is superior to monaural hearing. This research has focused on areas such as sound detection, localization, speech intelligibility, and sound quality (see Blauert for review1). Considerable research on the advantages of bilateral hearing instrument fittings also has been conducted. In laboratory studies, advantages for bilateral hearing aids have been similar to the findings observed for binaural hearing.2-6 As discussed by Dillon, the three major factors contributing to the benefit of bilateral hearing instruments are: elimination of the head shadow effect, binaural squelch, and binaural redundancy.7 In recent years there has been an emphasis on using realworld data rather than laboratory studies to substantiate hearing aid benefit. Keeping with this trend, Noble recently reviewed the field evidence related to the benefits of bilateral amplification.8 Although the results of the studies he reviewed are not consistent, he concludes that for most people with a moderate-to-severe hearing loss, or whose lives include critical listening in dynamic listening tasks, bilateral hearing aids will be preferred. He adds that for people with milder hearing loss, or those who typically face less complex listening tasks, the preference for bilateral amplification may not be as great. One factor that could have impacted the outcome of these earlier field studies, however, is the type of signal processing employed. That is, more recently linked bilateral hearing processing has become available, and reports have suggested this feature may enhance bilateral benefits.9

Audiometer Calibration: Two Neglected Areas

British and International Standards for pure tone audiometry require that the static force exerted by the earphone/bone vibrator headband is within certain limits. However, no recommended procedure is given for making force measurements. In addition, standards for audiometers require that linearity of output level is within certain limits. Only a brief outline of a procedure is available for measuring linearity at low intensity levels. Both these areas of audiometer calibration tend to be neglected according to our survey of organizations offering calibration services. Equipment and protocols for measuring both have been developed at the MRC Institute of Hearing Research, and are described. A convenience sample of audiometers gave a wide range of headband forces, many of which do not comply with the relevant standard. Linearity of output at low levels did comply with the relevant standard for all audiometers measured. We recommend the use of simple devices, such as those described, for routine calibration. They are quick and easy to use, give reliable results, and are inexpensive.

Study finds compliant eartips can be used instead of custom earmolds

In recent years, NHS (National Health Service) Hearing Aid Services in England have undergone a major modernization. This has led to an increase in the amount of audiology staff time spent per patient. Meanwhile, patient demand has also increased. The resulting shortages in staffing have led to unacceptably long waiting times in some parts of England. Accordingly, alternative approaches are needed that will permit NHS Hearing Aid Services to reduce waiting times without any loss in the quality of care. One way of achieving this is to reduce the number of appointments by including the assessment and fitting in one appointment. There are a number of products on the market designed to enable audiologists to “assess and fit” in one session. Of particular interest are the universal openear tips, e.g., Siemens Life products and Life tubes and Oticon Corda. While these sorts of solutions show great promise for patients with relatively acute hearing in the low frequencies, the disposable compliant eartip (CET) manufactured by Hearing Components, Inc., is suitable for use with patients who have a wider range of hearing thresholds. CETs make it possible at the patient’s initial appointment to provide either behind-the-ear (BTE) hearing aids (by means of a ComplyTM Snap Tip device) or in-the-ear (ITE) hearing aids (by means of the universal hearing aid manufactured by Siemens Hearing Instruments, Ltd.). The compliant eartips from Hearing Components are available in three diameters (10, 14, and 16 mm), with or without venting, and are suitable for hearing losses up to 65 dB HL (6-mm depth) and 95 dB HL (9-mm depth) at 500 and 1000 Hz. The manufacturer recommends that CETs be replaced every 10 to 14 days. The eartips are made of slow-recovery foam, which is temperature-activated and becomes three times softer and more pliable at body temperature. Since ear canals are active and change size with simple, everyday changes in jaw position,1,2 the use of CETs may mitigate a number of hearing aid problems, including discomfort, feedback, poor retention, and the occlusion effect. There are no reports on the use of CETs with ITE hearing aids. A major problem associated with ITE hearing aids is the build-up of cerumen inside the hearing aid, which affects reliability. Additionally, when an ITE instrument is returned to the manufacturer for repair or remake, the patient usually has no replacement. CETs have the potential to address both these problems for ITE users. * While both these products are now discontinued, the principles remain. PURPOSE OF STUDY The study reported in this article was designed to assess the feasibility of using CETs with digital signal processing hearing aids (both BTE—Oticon DigiFocus II, and ITE— Siemens Selectra).* Outcome measures included patient reports of hearing, comfort, feedback, and preference, as well as real-ear insertion gain measurements, speech-in-noise testing, and cost.

Comparison of measures of frequency resolution and recruitment in patients undergoing neuro-otological investigation

Loudness recruitment and reduced frequency resolution both occur in cochlear types of hearing loss. One theory of loudness recruitment suggests that, as intensity is coded partly by spread of excitation across the nerve fibre array, recruitment is a direct consequence of the broad spread of excitation associated with poor frequency resolution. The present study investigated the relationship between these two quantities. The study involved a simple measure of frequency resolution (three-point psychoacoustical tuning curve, PTC) and conventional measures of recruitment obtained from patients undergoing neuro-otological investigation. Results from 376 ears of 226 patients without any material conductive impairment are presented. Measures of recruitment included the alternate binaural loudness balance test (ABLB) and estimates of dynamic range given by the sensation levels of the uncomfortable loudness level and the acoustic reflex threshold. Once covariation with hearing threshold level had been accounted for, no clear relationship emerged between frequency resolution and any of the measures of recruitment. This finding does not support the notion that frequency resolution and recruitment are specifically related. Rather, PTCs provide information complementary to measures of recruitment.