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PubMedDate not supplied

Sound field audiometry: recommended stimuli and procedures.

Comprehensive recommendations are presented for conducting sound field audiometry with frequency specific stimuli. These recommendations are primarily based on a series of investigations by the authors. The rationale for each recommendation is presented, together with a brief overview of the supporting research. The preferred stimuli are frequency modulation tones, triangularly or sinusoidally modulated at a rate of about 20 Hz, or suitably generated narrow bands of noise. The optimal bandwidths of the stimuli, expressed in percentages of the center frequency, vary with frequency. Stimuli suitable for most purposes have bandwidths ranging from about 30% at 0.25 kHz to about 10% at 4 kHz. Stimuli having narrower or broader bandwidths are desirable for some special purposes. The test room should be as nonreverberant as possible and the subject should be seated on an adjustable height chair with headrest. The control microphone method of calibration is preferred but a method is also presented for carrying out the traditional precalibration procedure. The SPL of the complex stimulus should be taken as the peak deflections on a sound level meter set to "RMS-FAST." A conversion table is presented which allows thresholds obtained in the sound field to be expressed as dB HTL. With the materials and methods described here it is possible to achieve the same reliability for sound field testing as for audiometry under earphones.

Acoustic Stimulation↗
PubMed1989

Comments on "Earphones in Audiometry" [Zwislocki et al., J. Acoust. Soc. Am. 83, 1688-1689 (1988)].

The Zwislocki et al. ["Earphones in Audiometry," J. Acoust. Soc. Am. 83, 1688-1689 (1988)] Letter to the Editor states that insert earphones have some unresolved technical problems, such as limited frequency response, limited dynamic range and power handling capability, intersubject variability, and hygiene safety. In evaluating circumaural earphones, Zwislocki et al. say that the lack of a standard coupler disqualifies them for audiometry. Since this letter carries the weight of a CHABA committee recommendation, these issues are commented on herein. Section I was written primarily by Mead Killion and Sec. II primarily by Edgar Villchur. For brevity throughout, the authors of the Zwislocki et al. letter will be referred to as "the authors."

Audiometry↗
PubMed1980

Improved contingent negative variation audiometry.

In earlier reports we described contingent negative variation audiometry (CNV-A) and explored the accuracy of the method used in clinical conditions. Amplitude was found to be the factor which determines the accuracy of CNV-A. With this study we aimed to increase the amplitude of the CNV so as to improve the accuracy of CNV-A. The amplitude of the CNV is dependent on the content of the information of the S2 stimulus in the CNV paradigm. For this purpose we used a light stimulus (red or green) for the S2. The patient had to recognize the stimulus and act accordingly. The tests were performed on 12 volunteers in whom we simultaneously registered the CNV and the slow vertex response. The amplitude of the CNV was on average higher than with the previous CNV-A methods. The mean value of the absolute difference of the results between CNV-A and subjective tonal audiometry (ADG) was 6.9 +/- 5.5 dB. The mean difference between the results of both methods, however, was only 4.3 +/- 7.8 dB. The new CNV-A method is more accurate than the previous one. Nevertheless, we believe that not all possibilities for the improvement of the method have been explored. By taking into account the psychological factors which influence the amplitude of the CNV, and with a better computer analysis of the recordings, it will probably be possible to obtain even more accurate objective data on the threshold of perception of auditory stimuli with the aid of CNV-A.

Adult↗
PubMed1980

Efficiency of subjective audiometry in children up to the third year of age.

After a discussion of possible methods for measuring the hearing of infants, we present a more appropriate method which we have developed and used over a number of years. The method applied is called "sound orientation audiometry" and is based on the readiness of infants to seek out the sources of sounds. As the infants are observed by means of a one-way mirror, no distraction is possible. In the light of our experience, the proof of intentional application is most favorable when the infants are 5-6 months or 3-4 years old. The application threshold is at 40-50 dB SPL. The results gained by this measuring method are compared wtih sound threshold audiometric results gained 4-9 years after the first examination. Judging from the evaluation, we can see a good correlation of the measuring results obtained by sound orientation audiometry during the first examination with audiometric hearing loss values determined later. The correlation coefficient of the group examined is r = 0.77. The procedure is being discussed as to its value and is considered especially valuable because the whole auditory apparatus as far as the central auditory center is under control. This method is clinically appropriate without much expenditure and may be applied at any time.

Audiometry↗
PubMed1991

Prognostic validity of brainstem electric response audiometry in infants of a neonatal intensive care unit.

This study compared the results of brainstem electric response audiometry (BERA) in infants of a neonatal intensive care unit to those obtained on the same children with pure-tone audiometry at 3 years of age. Six hundred children were initially tested in infancy, and complete follow-up information was obtained on 333. In 297 (89%) the BERA results accurately predicted the hearing status at the age of 3 years. Twenty-nine (9%) of the discrepancies were related to conductive hearing losses: 17 patients with a conductive hearing loss in the first few months of life had normal hearing at 3 years, and 12 patients normal in infancy had a conductive loss at 3 years. Two patients evaluated as a sensorineural hearing loss by BERA had normal hearing. These may have been due to a conductive loss. Six patients assessed as normal by BERA had significant hearing losses at the age of 3 years. Five of these had normal hearing at one frequency between 1,000 and 4,000 Hz. The sixth may have developed a sensorineural hearing loss after birth.

Audiometry, Evoked Response↗
PubMed1980

On the combination of otometry with brainstem-evoked response audiometry.

Compound action potentials (AP) are measured in guinea pigs during stimulation with damped waves or with tone bursts. Results are compared in order to investigate whether damped waves are suitable stimuli for brainstem-evoked response audiometry. This investigation was done because a combination of brainstem-evoked response audiometry with otometry was recently proposed. Otometry is a hearing aid fitting method using damped waves as acoustic stimuli.

Acoustic Stimulation↗
PubMed1983

Comparison of manual and computer-controlled audiometry using identical procedures.

Ten normal-hearing subjects were evaluated with both manual and computer controlled audiometry using the ascending threshold determination method as proposed by ISO. The study shows that the thresholds obtained with the two different techniques correlate well and that standard deviations for the test--retest difference are significantly lower in the computer-controlled situation. The results also indicate that computer-controlled audiometry may be of importance in general clinical applications giving rapid and reliable threshold determination.

Adult↗
PubMed1985

High-frequency audiometry. Normative studies and preliminary experiences.

A new, commercial high-frequency audiometer, Demlar 20K, for measuring hearing thresholds between 8 and 20 kHz has been used routinely in different patient groups and in a control population over the past 3 years. Test-retest studies have shown that this instrument can be used in the clinic with approximately the same degree of reproducibility as in conventional audiometry. While inter-subject variation is comparatively large, repeated evaluations can be performed in individual cases with an acceptable degree of reliability. This techniques can be helpful in differentiating between noise damage and presbycusis. Pre- and post-operative high-frequency audiometry may prove to be of value in the assessment of middle ear surgical techniques.

Adult↗
PubMed1993

High-frequency air conduction audiometry. Testing of a new low impedance circumaural transducer system in normal young persons.

A new circumaural transducer was tested in the frequency range 125 Hz to 20 kHz. The new transducer has a low acoustic impedance and loads the ear closely to free-field conditions, thus ensuring that sensitivity to different positions of the transducer around the ear is reduced compared to conventional audiometric headphones. The transducer was tested on 57 individuals (114 ears) in the age range 10 to 20 (median age 17.0 years). The results, showing a fairly good accordance with the ISO standard free-field thresholds values, seem to confirm that the new transducer system loads the ears similarly to free-field conditions. The results were also compared with the threshold values from other high-frequency investigations using different transducer systems. In order to verify the reliability of the system, a test-retest was carried out on 12 inexperienced normal individuals (24 ears) (median age 26.5 years; range values from 22 to 44 years). The standard deviations of the test-retest ranged from 2.8dB to 6.6dB. A comparison of these values with the results from other high-frequency test-retests is of dubious value, as such retests have often been performed and estimated in different ways. International standards for high-frequency audiometry threshold and international standards for test-retest procedure are needed. The increasing administration of cytotoxic drugs in the treatment of malignant diseases will increase the need for reliable high-frequency audiometry equipment.

Adult↗
PubMed1983

Audiometric zero for air conduction using manual audiometry.

Thresholds of hearing of 76 subjects in the age range 18-24 years were measured using manual audiometers. Particular attention was paid to the otological selection of subjects. In spite of precautions the testers introduce some variation in results, and it is suggested that tester variation might account for differences between various manual audiometry studies and automatic audiometry studies. When tester variation is included there is no significant difference between results of this manual study and that undertaken with automatic audiometers by Robinson, Shipton, and Hinchcliffe, except that our average threshold is higher at 0.5 kHz. We support their main recommendation for adjustment of standards at 0.5 and 6 kHz.

Adolescent↗
PubMed2000

Pure tone audiogram and speech audiometry in patients with hereditary motor and sensory neuropathy.

The goal of our work was to determine hearing thresholds in patients with hearing impairment due to hereditary motor and sensory neuropathy (HMSN I). In assessment of auditory function we used two methods: pure tone and speech audiometry. Pure tone audiometry was performed using air and bone conducted signals. Speech comprehension was defined with a test battery of monosyllabic words unknown to the patient. By comparing the results of these methods we were able to differentiate whether the hearing loss was of cochlear or retrocochlear origin. We tested 5 patients with HMSN I associated with difficulty in speech understanding. The tests showed mild to severe elevation of pure tone thresholds but no speech perception in any of tested patients. We suggest that this type of hearing impairment be due to the disorder of the auditory nerve function--a neuropathy of the auditory nerve as part of HMSN.

Adolescent↗
PubMed1999

Clinical interpretation of brainstem evoked response audiometry abnormalities in cochlear pathology.

This investigation involved 45 patients with sensorineural hearing loss (SNHL): 24 with Meniere's disease, 18 with acoustic trauma, and 3 with SNHL due to ototoxic drugs. They all underwent pure tone audiometry and standard brainstem evoked response audiometry (BERA). In patients without wave I in auditory brainstem response, electrocochelography (ECochG) was performed. The findings are presented showing that cochlear lesions (beside threshold elevation) cause latency prolongation of wave I, III and V relative to normal latencies at the actual click hearing level. At high stimulation levels, this effect is almost completely compensated for by the fact that cochlear recruiting ears exhibit steeper latency-intensity curves than do normal ears. But, at the same time this pathology does not cause latency prolongation of central conduction time (CCT). Beside this, cochlear lesions will cause, in some cases, deterioration of replicability (poor waveform resolution) of waves preceding wave V. In such cases, the authors strongly recommend electrocochleography (ECochG) to make wave I visible, because they think that it is the best way to verify the diagnosis of cochlear lesion using BERA.

Adolescent↗
PubMed1988

Pure tone audiometry: comparison of general practice and hospital services.

Pure tone audiometry was obtained for both ears of 32 children by a general practitioner using a simple audiometer in his surgery, and by audiometricians in a hospital department on the same day. Comparing the worst hearing threshold at any of the three tested frequencies, the general practitioner did not find any ears to hear more than 10 dB better than the hospital (no false negatives). However, there were six false positives (9%) where the general practitioner identified an apparent hearing loss of greater than 15 dB. It is concluded that pure tone audiometry could be carried out accurately in the practice.

Audiometry↗
PubMed1986

[Suitability of speech audiometry study procedures for current demands in clinical and general practice].

The quality of the recorded audiometric test material (the "Freiburg" and "Marburg" language test) meets the High Fidelity standards of the 1960's. In the light of current technology (digital technique, compact disc, etc.), the question arises whether speech-audiometry can still contribute to diagnosis, medico-legal assessment and fitting of hearing aids. Results of the "Freiburg" language test are presented, which analyse the comparability of the individual groups in quiet and in noisy surroundings, the technical and technological aspects of the sound systems, orthophonic reproduction and the practical performance of audiometric speech tests. Finally, recommendations of the commission for speech-audiometry and hearing aids of the ADANO are presented and discussed. These may explain present and future demands and possibilities of a broad-band audiometric investigation spectrum in hospital and practice.

Audiometry, Pure-Tone↗
PubMed1985

[The audioanalysator. A bridge between audiometry and psychoacoustics].

An analyser with a system of continous sweeping frequencies and a spectrum of strongly different control signals is described here. Including the active participation of the patient and his impaired hearing a much more accurate finding of symptoms is possible than with the standard methods of audiometry. The major factors mentioned include the continuous fine testing of the sounds heard in an unlimitated choice of frequencies ranging between 20 Hz. and 20 000 Hz. with an automated search unit as well as a test for the highest tones. After brief instruction the tests are determined by the patient himself according to choice monaurally and/or binaurally depending on comparisons and corrections right/left. This leads to highly differentiated statements on the sounds heard and to comparable qualities of tone which until today have been unknown in this wide extent of variety to audiometry and audiology and which presents totally new aspects. One of the main purposes of the audioanalyser is to detect the role played by the transients in discrimination. Obviously also the highest tones influence the character of the transients. They are apt to be easily lost e.g. by infections any kind. A vigilant patient will become aware of this loss.

Adolescent↗
PubMed1983

[Problems of electric response audiometry in practice].

In recent years Electric Response Audiometry (ERA) has become a valuable method in the clinical audiology. However, there are two specific problems that make Electric Response Audiometry more complicated than other hearing tests. First, the evaluation of the averaged signals is subjective, and in some cases the distinction between response signals and remaining electrical background noise or artifacts may be rather difficult. The second problem concerns the interpretation of response signals. As there is no simple but only an ambiguous relation between response parameters and the different types of hearing disorders, again, it depends on clinical experience and knowledge to avoid misinterpretations and to arrive at a reliable diagnosis.

Audiometry↗
PubMed1983

Abnormal brainstem response audiometry in normal patients.

Brainstem response audiometry is a technique which is objective, reliable, and non-invasive. Analysis of tracings performed on 200 subjects with no detectable clinical abnormalities inexplicably revealed an 8.5% of major anomalies. In order to avoid false interpretation, it is important to remember that brainstem response audiometry should serve only as an adjunct to other clinical techniques.

Adolescent↗
PubMed1980

Clinical considerations in the interpretation of auditory brainstem response audiometry.

Auditory brainstem response (ABR) audiometry which monitors the electrical activity of the auditory nerve and brainstem nuclei, has provided a new technique in the diagnosis of neurological dysfunction and peripheral hearing deficits. Brainstem potentials consist of seven waves, each separated in latency by approximately one millisecond and each representing successively higher order neuron activity of the auditory pathway. The criteria used for ABR interpretation are based primarily on the latency of individual were peaks and their interpeak latencies. Due to its consistency and stability, the fifth wave has been considered prominent in the interpretation of auditory threshold sensitivity. Unfortunately, Wave V latency-intensity function may be affected by extrinsic and intrinsic variables. Consequently, in order to establish diagnostic criteria that are comparable, the elimination and/or control of these variables must be examined. Therefore, the purpose of this paper is to report the effects of various pathological and nonpathological conditions which contribute to difference in ABR audiometry interpretation.

Acoustic Stimulation↗