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At least 415 records · Page 23Linked to original sources
PubMed1997

Visual reinforcement audiometry. Comparison of loudspeaker arrangements.

Two different loudspeaker arrangements are currently used when performing Visual Reinforcement Audiometry (VRA). In the one arrangement, the loudspeakers are mounted on separate movable arms and positioned 15 cm from each ear. In the other, the loudspeakers are rigidly mounted close to their respective picture monitor at a distance of 50-70 cm from the child. In the present study, these two arrangements were compared by measuring real-ear sound pressure levels and actual sound field conditions. It was shown that a predominantly monaural stimulation was best achieved by using the 15-cm position, but also that the measurements were significantly more affected by small head movements when using this close position. When assessing the acoustics as well as practical aspects, it was concluded that loudspeakers mounted beside the picture monitors at a distance of 50-70 cm from the child makes a generally appropriate arrangement for VRA.

Adult↗
PubMed1997

Extended high-frequency audiometry in traumatic tympanic membrane perforations.

Air- and bone-conduction audiometry in the frequency ranges 0.125-18 kHz and 0.25-16 kHz respectively were performed in 38 patients with unilateral traumatic tympanic membrane perforation. Sensorineural threshold elevation was found in 16 ears. In nine of these this was permanent and in four restricted to the frequency range > 8 kHz. Both sensorineural threshold elevation and tinnitus (n = 16) diminished with time. A temporary, mean 5 dB, bone-conduction threshold elevation > or = 8 kHz was seen in 26 ears before spontaneous tympanic membrane closure. Closure resulted in a 7-20 dB improvement of air-conduction thresholds in the 0.125-18 kHz range, somewhat less in the upper than in the lower frequencies. A 3 dB mean final conductive hearing loss > 8 kHz was found in these 26 ears approximately 5 months after injury, probably due to scars in the pars tensa at the site of the former perforations. Thirty-seven of 38 perforations had healed at final follow-up examination.

Adolescent↗
PubMed1999

A comparison of some clinical features of visual reinforcement audiometry and the distraction test.

The aim of this study was to compare aspects of visual reinforcement audiometry (VRA) and the distraction test (DT), the two most commonly used behavioural tests of hearing for young children. The number of assessments completed, time taken, parental opinion and levels of minimum responses were compared in a group of 20 infants (mean age 17.7 months; SD 4.7 months; range 12-25 months) who had been selected from those referred from a local second-tier community audiology service. Each infant was assessed with each test following set protocols and a balanced design on two occasions separated by one week. Parental opinion was determined by application of two questionnaires, one after each session. There was no difference in the number of minimum response levels (MRLs) measured by the two tests. However, if a VRA protocol using three MRLs was assumed then the assessment was completed successfully in a significantly greater number of subjects with VRA. VRA took, on average, two minutes less than the DT to measure six MRLs. Most of the subject sample had normal hearing as defined by both tests. However, where MRLs were >30 dB HL for at least one of the tests, the DT elicited responses at significantly higher levels than VRA, suggesting that in these subjects the DT under-estimated hearing sensitivity. Seventy per cent of parents selected VRA when asked to choose between the tests.

Attention↗
PubMed2000

A modified pure tone audiometry technique for medico-legal assessment.

A modified method of pure tone audiometry (PTA) in which the auditory threshold is approached from silence in ascending steps, with tone presentations of 1-4 seconds and interval durations of 1.5-5 seconds was assessed against the British Society of Audiology (BSA) method of PTA in terms of its ability to establish valid thresholds in cases of non-organic hearing loss, prevalent in medico-legal testing. The results reveal that the modified technique of PTA is a valid threshold measurement for honest subjects, and yields less non-organic overlay than the standard method of PTA in cases of non-organic hearing loss.

Adult↗
PubMed1980

Air-radiated sound from bone vibration transducers and its implications for bone conduction audiometry.

The effect of air-borne sound radiated from transducers used in bone conduction audiometry has been known for many years. This paper seeks to quantify this effect for the vibrator types (B70A, B71, and B72. Using three examples of each vibrator sound pressure levels were measured at the entrance to the external ear canal on four human heads. Values obtained have been related to hearing theshold levels for otologically normal young persons using two different methods: firstly using international standard values of open-ear free-field theshold with corrections for monaural listening and for diffraction, and secondly by direct measurement of the subjects' monaural open-ear thresholds. None of the vibrators tested meets international standard requirements for air-borne sound radiation at all frequencies, but in practics, provided a high quality ear plug is fitted to the test ear at 3 and 4 kHz large errors are unlikely to be recorded for any of the vibrator types tested.

Audiometry↗
PubMed1991

An evaluation of ABR audiometry for the screening and detection of hearing loss in ex-SCBU infants.

The study aimed to use auditory brainstem response (ABR) audiometry to test ex-SCBU infants born during 1986 in West Berkshire. Two hundred and forty-three babies were tested as out-patients, thus achieving a coverage rate of 86% of the target population. Mean post-conceptional age at test was 48 weeks. Whenever possible, full ABR threshold determination was performed on both ears and the mean ABR threshold was found to be 14 dB nHL. Of those babies attending, 85% showed ABRs at less than or equal to 30 dB nHL bilaterally and the remaining 15% were referred for further assessment. Approximately two-thirds of these were recalled successfully for repeat testing. The estimated prevalence rate for bilateral sensorineural hearing impairment was 1.4% with four confirmed cases. Two additional permanent unilateral hearing losses were also detected. On the basis of recorded ABR data, sensitivity, specificity and positive predictive values were estimated for click intensities which could be used for single-intensity ABR screens. It is concluded that delaying screening until the post-neonatal stage is a viable alternative to screening neonates prior to discharge from the SCBU.

Ambulatory Care↗
PubMed1995

Measurement of variability in sound field audiometry due to subject movement.

Sound field audiometry is used primarily for hearing assessment in young children and for functional hearing aid evaluation. It is important that measurements are accurate and reliable as they affect the management of patients. Most clinics use a substitution method for calibration and, as a result, if the subject moves from the calibrated test point, the sound pressure level (SPL) at the ears will vary as the sound field is very rarely uniform. This variation can result in inaccurate threshold estimation and increased test-retest variability. A commonly used method for evaluating the potential errors due to subject movement involves measuring the variation in SPL, with respect to the test point, at six points around the test point. This method makes assumptions about the sound field which may not be valid and could lead to an underestimation of the variation present. The aim of this investigation was to assess the accuracy of this method. Measurements of variation were taken with a microphone and repeated with a head and torso simulator (HATS) which was used to represent a test subject. The total degree of variation indicated by these two methods was compared. The microphone measurements indicated less variation than the HATS measurements. The differences were statistically significant but small in clinical terms. Assuming that the HATS is properly representative of the normal population, then this result indicates that simple microphone measurements are acceptable for normal clinical practice but that higher quality measurements are desirable for critical work.

Audiometry↗
PubMed1996

A pilot investigation of high-frequency audiometry in obscure auditory dysfunction (OAD) patients.

The diagnosis of obscure auditory dysfunction (OAD) has been an elusive one, based primarily upon reports of poor speech perception in noise by the patient. Basic audiometric testing reveals hearing within normal threshold limits and it is thought that there may, in part be some subtle psychoacoustic and/or central auditory deficits causing this phenomenon. The use of high-frequency audiometry (HFA) as a test of subclinical cochlear damage has been well documented, especially to monitor the early effects of noise exposure and ototoxic drugs. However, it has not been used in the diagnosis of OAD patients. This study examines the use of HFA as an aid to the understanding of OAD pathophysiology. HFA was conducted on nine OAD subjects, each matched to two controls. Results indicate an elevated threshold amongst all frequencies (10-20 kHz) in OAD patients with significant differences occurring at 10, 14, 16 and 20 kHz. It could be postulated that OAD in fact, is the product of an ultra-high-frequency hearing impairment and its psychoacoustic sequelae. Furthermore, HFA may be a useful inclusion in a diagnostic test battery for OAD status. However, the degree to which it can be used may be limited due to the large intersubject variability in HFA thresholds in the normal population. It is suggested that further investigations into the ultra-high-frequency hearing abilities of OAD patients should be completed in the future.

Adolescent↗
PubMed2003

Minimal response levels for visual reinforcement audiometry in infants.

The aim of this study was to determine normative values for minimal response levels (MRLs) for normal-hearing young infants using insert earphone visual reinforcement audiometry (VRA). The subjects were 46 normally developing infants aged between 33 and 50 weeks who had hearing sensitivity assumed to be within normal limits and no evidence of middle ear dysfunction. VRA was carried out using insert earphones with warble tone stimuli, generated from an AC33 audiometer and calibrated to ISO 389-2 for insert earphones in adults. The frequencies assessed were 500 Hz, 1 kHz, 2 kHz and 4 kHz. In total, 102 MRLs were obtained, with an approximately equal number of MRLs per frequency. Mean MRLs for 500 Hz, 1 kHz, 2 kHz and 4kHz were 16 dB HL, 13 dB HL, 7 dB HL and 6 dB HL, respectively. Standard deviations were close to 6 dB for all frequencies. Mean MRLs at the lower frequencies were significantly greater than MRLs at the two higher frequencies. MRLs did not vary significantly with age. The results obtained from this study suggest significant infant adult differences when testing hearing using VRA with insert earphones, particularly at lower frequencies. Possible reasons for this and the clinical use of these normative values are discussed.

Acoustic Stimulation↗
PubMed1990

Time-intensity relations in Békésy audiometry.

Threshold and amplitude measurements were made for fixed frequency Bekesy pure tones on subjects with normal hearing, sensorineural hearing impairment, and functional hearing loss. Following conventional Bekesy audiometry (intensity change 4 dB/sec), -20 dB was added to a signal at the threshold of audibility (bottom of the spike). When sensation was lost at the threshold of inaudibility (top of the spike), +20 dB was added. Adding +/- 20 dB in subjects with normal hearing reduced the amplitude of the spike about 4 dB, corresponding to 1 second, for both pulsed and continuous tones. Adding +/- 40 dB produced essentially similar findings. Adding +/- 20 dB in subjects with sensorineural loss with reduced amplitude of continuous tone tracings also reduced the amplitude approximately 4 dB for pulsed tones, but 3 dB, corresponding to 0.75 seconds, for continuous tones. Abnormal rapid adaptation may account for this reduced amplitude of the spikes. A subject with multiple sclerosis producing excessive abnormal adaptation showed spectacular increased amplitude for continuous tone only when -20 dB was added at bottoms and +20 dB at tops of spikes. An explanation based on slow adaptation is offered. Subjects with functional hearing loss may emphasize either time or intensity in their inappropriate responses when +/- 20 dB is added at tops and/or bottoms of spikes.

Audiometry, Pure-Tone↗
PubMed1993

[Computerized database system for pure tone audiometry].

The management and storage of pure tone audiometry data creates a major problem for otolaryngological clinics. We have devised a new computerized database system to overcome this problem. The hardware involved includes multiple audiometers and computers interfaced with a glassfiber local area network (Pi-Net). The software used is database 3 plus, a popular database language and utility software package. Programs were written for data entry, data transfer, reference, entry of patient ID, and evaluation of tympanoplasty. The following benefits of the system are noted. 1) Data entry is possible at every terminal (audiometer and computer). 2) Storage capacity is sufficient for more than 10 years of operation. 3) All data can be retrieved rapidly at any terminal. Evaluations of pre- and post-tympanoplasty hearing loss are facilitated by this system. This system is very effective for follow up of hearing disorders.

Audiometry, Pure-Tone↗
PubMedDate not supplied

[Assessment of acuteness of hearing using white noise. A comparison with classical audiometry in 357 cases of deafness].

From statistics of 357 cases of deafness it would appear that figures for white noise threshold are practically identical with those for global auditory loss of hearing calculated by means of tonal audiograms according to the usual 5 criteria. Measurement of white noise threshold is a quick and simple method of assessing acuteness of hearing. By bringing into play the whole of the auditory field, it is the equivalent of a real functional investigation of the ear. Furthermore, it is comparable to tonal audiometry in its use of complex sounds but without the disadvantage of relying on intelligibility. In conclusion, the authors suggest a mathematical interpretation to confirm these results.

Adolescent↗
PubMedDate not supplied

[High-frequency audiometry: variations in auditory thresholds in the premenstrual period].

The hormonal changes that occur during the premenstrual period have been implicated as a causative factor for many psychological and physical symptoms. The present work was undertaken to determine the effect of these hormonal changes on audition. We studied 60 ears from 30 women (20-30 years old) with regular menstrual cycles and no middle/inner ear pathology. We performed audiometries one week before menstruation and one week after it, testing the range of frequencies from 250 to 16,000 Hz. After calculating the mean pre and postmenstrual threshold the results were compared using the paired < >-Student test. We found statistical significant differences in the frequencies 9,000, 10,000 and 11,200 Hz.

Adult↗
PubMedDate not supplied

[Medium and large acoustic neurinomas with normal tonal audiometry at the moment of diagnosis].

INTRODUCTION: Early diagnosis of an acoustic neurinoma for any possible treatment is important, especially in view of the relationship between surgical morbidity and the size of the tumour. The commonest presenting symptom of these tumors is unilateral perceptive deafness. However, between 4 and 12% are diagnosed before deafness occurs, although they may be large in size. Therefore one should remember other symptoms which lead to suspicion of these tumors, and have diagnostic guidelines available to allow the earliest possible detection. PATIENTS AND METHODS: We report four cases of acoustic neurinoma or vestibular schwannoma of medium or large size in which audiological studies did not at first give rise to suspicion of the presence of this tumour, since audition was considered to be normal at conversation frequencies (500 to 3,000 Hertz) for the age of the patient or who had an audiometry curve with symmetrical deafness in both ears. CONCLUSION: We evaluated the diagnostic importance of the tests done and compared the results with data published in the literature.

Adult↗
PubMedDate not supplied

Noise-excluding enclosure for audiometry.

Excessive ambient noise adversely effects the efficiency of hearing conservation programs. Noise-excluding enclosures generally reduce the masking effects of such noise more effectively than standard earphones only. Research has shown, however, that pure-tone thresholds obtained with some enclosures may not be valid. The present study examines one particular type of enclosure, the Audiocup. The results revealed (1) that pure-tone thresholds obtained with Audiocups are almost identical to those measured with standard earphones only and (2) Audiocups more effectively reduce the masking influence of white noise. It is concluded that Audiocups may be used for screening and for threshold audiometry in less than ideal testing environments without fear of invalidating the results.

Adult↗
PubMed1975

Audiometry in fluctuant hearing loss.

Fluctuant hearing loss is a very complex matter, which involves not only neurological and physiological concepts but considerable acoustic factors as well. Fluctuant hearing loss is perhaps more visible with the use of pure tone audiometry because of the nature of its effect, the variation in the compliance properties of cochlear tissues. This visibility is due to impedance factors that bear on the inner ear as well as on the middle and external ear regions. It is suggested that changes in compliance of the cochlear tissues play a significant role in the existence of reduced sensitivity to low frequency pure tones. This indicates that sensorineural conditions with loss of hearing in the low frequency region may be a composite of conditions: sensory cell damage, which is only seen by high frequency response, and disturbance in the cochlear tissues, increasing their stiffness and resulting in loss of sensitivity for low frequency tones. When hearing damage is found in the inner ear exclusively because of permanent destruction of sensory cells, this theoretical model predicts that the fluctuating nature of certain types of hearing impairment ceases.

Aged↗
PubMed1975

Improving evoked response audiometry. Results of normative studies for machine scoring.

Normative studies were carried out with 8 adult subjects whose averaged evoked responses to auditory stimuli were scored visually and by a number of differently defined quantitative methods (machine scoring). In order to compare different scoring methods a common signal-to-noise ratio measure was introduced based on a model where noise is distributed normally and signal is additive. Visual and machine scoring proved to be approximately equally sensitive, but the latter lends itself to a superior testing procedure which takes only one-third as long for equivalent results and is not contaminated by subjective error. The authors believe that the greatest promise for improving evoked response audiometry lies in the exploration of the new techniques proposed earlier. Progress in proving out one of these techniques, fast periodic stimulation, is reported.

Acoustic Stimulation↗
PubMed1975

[Evoked response audiometry of the guinea pig before and after drop in hearing induced by furosemid (author's transl)].

Using particular surface electrodes evoked response audiometry (ERA) can be applied to small laboratory animals without any sedation or anaesthesia. In addition to other methods we have studied in this way the influence of extreme doses of Furosemid on the guinea pig inner ear. 6-20 mg Furosemid per 100 g of bodyweight (about 100 times the human therapy dose) were applicated i.v. within 5 min resulting in a drop of hearing immediately. For the anaesthesized animal the cochlear microphonic potentials (CM) decrease simultaneously, indicating Furosemid to act at the inner ear itself. By both methods recovery of inner ear function is seen to start about 10 min later according to the little biological half life of Furosemid. As being restricted in respect of time for the CM-measurements we are sure about reversibility only by the ERA-method.

Animals↗