Comparison of the hearing threshold measured by manual pure-tone and by self-recording (Békésy) audiometry.

The hearing threshold of 115 subjects aged 25--63 years and working on a shipyard were determined both by Békésy sweep audiometry and by conventional manual octave pure-tone audiometry at fixed audiometric frequencies. The attenuation rate was 2.5 dB s-1 with pulsed-tone presentation and the sweep time from 0.25 to 10 kHz was 400 s for the Békésy audiometer. Manual pure-tone audiometry was performed in 5-dB steps. The Békésy method gave the lowest values for the hearing thresholds. It has been possible to find a useful linear relation between pure-tone and Békésy hearing thresholds. With the help of a retest experiment, it has been established, that the standard deviations of hearing thresholds obtained under similar conditions in a pure-tone investigation are about twice as large as those obtained in a Békésy investigation.     

Reliability of Békésy threshold tracing in identification of carriers of genes for an X-linked disease with deafness

Seven identified carriers and 20 potential carriers of Norris's disease have been examined by pure tone octave audiometry and Békésy audiometry. The investigation supports earlier results of Békésy threshold tracings performed in heterozygote carriers of genes for recessive hearing impairment. The sensitivity of the method is poor. The specificity of the Békésy threshold tracing is high, meaning that an absent dip cannot exclude the possibility of a subject being a carrier, whereas a present dip can be regarded as an indication of carrier. When comparing conventional octave audiometry and Békésy threshold tracing, the latter method is found to be more subtle in finding carriers of genes for recessive deafness. Therefore, Békésy threshold tracing may be of help in the genetic counselling of potential carriers of genes for recessive deafness.     

Auditory adaptation and auditory fatigue

Twenty subjects without otological disease were examined for auditory thresholds by Békésy audiometry and by the Feldmann Test (Adaptogramm), before and after noise exposure to one ear of 90 db SPL at 3 kHz for 15 minutes. The exposed ear was also tested for hearing fatigue (TTS). There was no significant correlation between Békésy audiometry and Feldmann test curves or between these adaptation tests and the hearing fatigue test (TTS) after noise exposure. Our results suggest that these methods of measuring adaptation do not correspond, and that adaptation measurements, prior to noise exposure, have no predictive value for hearing fatigue test results following noise exposure. After noise exposure changes were found in the non-exposed ear which were manifested as variability of the Békésy audiometry curves and flattened Feldmann curves. We thought that these results might indicate a central adaptation following noise exposure. There was interference of this so called "central adaptation" with peripheral fatigue in the exposed ear.     

On the interpretation of Békésy audiograms (author's transl)]

A group of 112 subjects with sensorineural hearing loss was checked by an audiological test battery consisting of: pure tone audiometry, SISI Test, tone decay test and fixed frequency Békésy audiometry. Classification of Békésy tracings by two audiologists showes good agreement when introducing a hybrid type I/II, which completes Jerger's classification system of types I--IV. The results of our investigation exhibit no significant differences of manual pure tone threshold and automatic tracing contrary to some other authors. Finally the correlation of diagnosis and type of Békésy audiogram is discussed.     

High-frequency Békésy audiometry. V. Excursion width

26 normally hearing young adults produced Békésy-type tracings for pure tones ranging from 7 to 19 kHz. Tones were pulsed (2.5/s) and delivered in the fixed-frequency mode. Chart rate (1 octave/min) and rate of attenuation (2.5 dB/s) were analogous to that typically used in clinical Békésy audiometry. Results indicated that subjects typically produced median excursion widths ranging from 5 to 15 dB. No systematic change in excursion width for conventional-frequency Békésy audiometry. The results of the present study were discussed regarding their utility in validation of responses to Békésy audiometry.     

High-frequency audiometry using precision earphones: reliability under laboratory and field conditions

New circumaural earphones were tested in the frequency range from 100 Hz to 20 kHz and compared to commonly used supra-aural earphones. The circumaural earphone HD 230 (Sennheiser) generates test stimuli at up to 20 kHz with almost constant sound pressure levels when its pos ed on an artificial ear. The reproducibility of hearing threshold mea ed with a new microprocessor-controlled Békésy audiometer using the ne was nearly as good as under free-field conditions. The practicabil diagnostic value of high-frequency audiometry have been demonstrated er field conditions. For this application, the good sound attenuation these earphones (30 dB above 1 kHz) are important. High-frequency he ds of healthy pupils and of pupils with a history of otitis media are kHz, the hearing threshold level difference between both groups reached 20 dB.     

Tracking of Complex Binaural Images

Subjects were presented with an initially stationary binaural image formed by the fusion of two identical pulses, without interaural time difference (ITD), at the two ears. The image was then made to traverse the subject's auditory perceptual space by introducing ITD, varying linearly with time, under computer control. The direction of movement, i.e. towards the right or left ear, could be reversed by the listener, by pressing a button. Subjects were requested to keep the image central, by pressing the button when they judged that deviation from subjective centre had occurred.

Experiments of this type can be considered as analogous to Békésy audiometry, where the subject automatically traces his threshold of hearing, in that here the listener traces out his auditory perceptual centre as it varies with time. Hence, equivalent analyses to those employed for Békésy audiometry are possible.

Subsequent to the initial part of the experiment, an additional pulse was added to one channel, preceding the original pulse, to form a pulse pair. The monaural masking of the original pulse by this additional pulse thus acts to shift the pre-existing binaural image. The effect of varying the amplitude and onset time of the masking pulse, relative to the original pulse, on the Békésy-type trace was examined.     

Audiometric tests in gene carriers of Norrie's disease.

The purpose of the present study was to validate the reliability of audiometric testing procedures in the identification of carriers of Norrie's disease by using DNA analysis. Potential female carriers of Norrie's disease were investigated by means of Békésy tracing audiometry and stapedial reflex thresholds previously found to reveal carriers of recessively inherited hearing impairment by means of peculiar 'dips' and elevation in the thresholds. Relating the audiometric test results to the outcome of the DNA analysis the previous findings could not be confirmed. In addition no concordance between the two audiometric test procedures was demonstrated, and Békésy threshold tracing exhibited poor repeatability and sensitivity. It is concluded that none of these audiometric test procedures are feasible for detection of carriers of an X-linked hearing disorder, such as Norrie's disease.     

Audiologic Diagnosis of Central versus Eighth Nerve and Cochlear Auditory Impairment

122 subjects divided into four groups according to the site of lesion (cochlea, eighth nerve, brainstem and temporal lobe) were subjected to an audiometric test battery, including pure-tone sensitivity measures, recruitment testing, tone decay, Békésy audiometry, speech audiometry, stapedius reflex measures and auditory brainstem response (ABR) audiometry. The results were contrasted among the four groups by calculating several measures of test performance, including sensitivity, specificity, efficiency, A' (test performance) and plots on the receiver operating characteristic (ROC) space of pure positives versus false alarms. In the differential diagnosis between eighth nerve and cochlear site, the various measures did not rank the tests in the same order: (a) for efficiency: ABR, Békésy audiometry; (b) for A' (similarly to the analysis into the ROC space): ABR, recruitment, Békésy, stapedius reflex, speech audiometry, tone decay. In distinguishing an eighth nerve from a brainstem site, it is important to consider amount of hearing loss, presence of tinnitus, abnormal tone decay and Békésy audiometry patterns. ABR adds significant diagnostic efficiency only when waves II, III and V are detectable: a prolonged I–II interpeak interval (IPI) and a normal III-V IPI are characteristic of the eighth nerve site. ABR gives good diagnostic support in the intrinsic brainstem lesions by suggesting changes in the generator sites of the component waves. The audiometric diagnosis of temporal lobe lesions involving the auditory cortex still relies upon speech audiometry: tests specifically designed for this purpose by Bocca and Calearo and by Jerger - i.e. the 'sensitized sentences' and the identification of synthetic sentences under ipsi- or contralateral competing message - are commendable for their sensitivity and efficiency in distinguishing brainstem from temporal lobe sites. In brainstem sites, the most affected ear is ipsilateral to the lesion for ABR, but contralateral for speech audiometry.     

Genetic disposition to deafness in maternal rubella: fact or myth?

Eleven parental pairs, each having a child deaf from maternal rubella, were evaluated with a battery of specialized audiologic tests. The tests which included measurement of Békésy hearing threshold and the stapedial reflex threshold at 0.5, 1.0, and 2.0 kHz were used to test the theory that these parents have a predisposition to elevated reflex thresholds, Békésy hearing threshold dips, and a history of familial deafness. The present study failed to find any history of familial deafness or Békésy dips. Elevated reflex thresholds were noted in seven couples. This proportion was shown to be significant (p less than 0.03). The relevance of these findings in light of current clinical practice is discussed. A comparison of pure tone hearing levels of the children of parents with and without elevated reflex thresholds, failed to show a significant difference.     

Audiologic diagnosis of central versus eighth nerve and cochlear auditory impairment

122 subjects divided into four groups according to the site of lesion (cochlea, eighth nerve, brainstem and temporal lobe) were subjected to an audiometric test battery, including pure-tone sensitivity measures, recruitment testing, tone decay, Békésy audiometry, speech audiometry, stapedius reflex measures and auditory brainstem response (ABR) audiometry. The results were contrasted among the four groups by calculating several measures of test performance, including sensitivity, specificity, efficiency, A' (test performance) and plots on the receiver operating characteristic (ROC) space of pure positives versus false alarms. In the differential diagnosis between eighth nerve and cochlear site, the various measures did not rank the tests in the same order: (a) for efficiency: ABR, Békésy audiometry; (b) for A' (similarly to the analysis into the ROC space): ABR, recruitment, Békésy, stapedius reflex, speech audiometry, tone decay. In distinguishing an eighth nerve from a brainstem site, it is important to consider amount of hearing loss, presence of tinnitus, abnormal tone decay and Békésy audiometry patterns. ABR adds significant diagnostic efficiency only when waves II, III and V are detectable: a prolonged I-II interpeak interval (IPI) and a normal III-V IPI are characteristic of the eighth nerve site. ABR gives good diagnostic support in the intrinsic brainstem lesions by suggesting changes in the generator sites of the component waves. The audiometric diagnosis of temporal lobe lesions involving the auditory cortex still relies upon speech audiometry: tests specifically designed for this purpose by Bocca and Calearo and by Jerger - i.e. the 'sensitized sentences' and the identification of synthetic sentences under ipsi- or contralateral competing message - are commendable for their sensitivity and efficiency in distinguishing brainstem from temporal lobe sites. In brainstem sites, the most affected ear is ipsilateral to the lesion for ABR, but contralateral for speech audiometry.     

Long-term measurements using home audiometry with Békésy’s technique

Objective: To examine the efficacy of fixed-frequency Békésy’s home audiometry to assess hearing fluctuation and treatment outcomes in patients with subjectively fluctuating hearing loss. Design: SMAPH, a software audiometry program for Windows, was installed and calibrated on laptop computers. Békésy’s audiometry was carried out daily in the patients’ homes, using sound-attenuating earphones. Study sample: Seventeen patients with previously or currently subjectively fluctuating hearing loss. Five patients received of treatment for their conditions during the measurement period. Results: Measurement periods ranged from 6 to 60 days. Varying degrees of compliance were seen, some patients measuring less than 50% of the days, others measuring every day. Based on their long-term measurements the patients were classified into three groups: patients with stable recordings, with fluctuating low-frequency hearing loss, or with fluctuating high-frequency hearing loss. In the patients with stable recordings, significant test–retest differences were seen below 10?dB at frequencies 0.125–8?kHz. Conclusions: Home audiometry with Békésy’s technique can be used to evaluate disease activity and to monitor hearing results after therapy.     

Sensorineural hearing loss associated with hypoparathyroidism

The hearing loss of 21 patients with hypoparathyroidism was investigated by pure tone audiometry, short increment sensitivity index (SISI) test, Békésy audiometry, speech audiometry, and auditory brain stem response. Sensorineural hearing loss was found in 7 of 21 patients (13 of 42 ears) receiving no treatment for hypoparathyroidism or having chronic hypocalcemia. The high SISI score, presence of recruitment, and prolongation of the wave I (N1) latency suggested that the inner ear is responsible for hearing loss in these cases. Inner ear dysfunction was probably due to the low calcium level in inner ear fluid and/or the direct effect of vitamin D deficiency on the inner ear.     

The question of the term "presbyacusis" (author's transl)]

Tone threshold, SISI-test, Langenbeck test, Békésy audiometry, tympanometry, acoustico-facial reflex, speech audiometry and dichotic discrimination test were performed in a selected group of 252 patients. Statistical analysis demonstrated that those forms of hearing which are generally considered to be presbyacusis are sensory hearing impairments and not neural ones (as previously considered). These peripheral functional disorders, particularly those which occur in older individuals, derive from preceding injury as well as intercurrent or chronic diseases of the inner ear which may be coincidentally associated with age. The real aging process of the hearing system is presumed to occur predominantly in central pathways and their interconnections; this appears as a hearing disorder only if there is additionally present a peripheral hearing impairment which is not dependent on age. As this differs greatly among individuals, it would seem that the term "prebyacusis" should not be considered a hearing norm of aging.     

Earmoulds: some benefits from horn fitting.

The narrow bore of conventional hearing aid earmoulds restricts the transmission of higher auditory frequencies. For subjects with moderate to severe high-frequency hearing loss this is likely to have an adverse effect on the perception and recognition of phonemes with high-frequency components. Twenty-two subjects with predominantly high-frequency hearing loss underwent a series of tests to compare the performance of earmoulds having conventional 1.9 mm through-tubing with earmoulds fitted with a smooth horn with a final internal diameter of 4 mm. The test battery comprised free-field Békésy audiometry, in-the-ear pressure measurement, speech audiometry using AB word lists and semantic differential rating of the relative sound quality of the two systems. Subjectively the horn fitting was rated as clearer, more natural, undistorted and acoustically comfortable. Objectively, by both Békésy audiometry and in-the-ear pressure measurement, the horn gave more gain in the higher auditory frequencies. With the horn there was improved recognition of phonemes, especially fricatives and affricatives.     

Quantitative interpretation of audiological test battery. I. A comparison with ABR in 97 cases of unilateral sensorineural hearing loss

A retrospective study was made of 97 patients with unilateral sensorineural hearing loss who underwent an audiological test battery and ABR during a 2 1/2-year period. The test battery included tone- and speech audiometry, Békésy audiometry, loudness balance test, tone decay test and impedance measurements (reflex thresholds and reflex decay). A quantitative interpretation of each audiological test was tried out and a mean value of included tests (audiological test score ATS), was compared with results of ABR. The audiological test score showed the same predictive value as ABR for detection of acoustic neurinomas. Among the auditory tests, Békésy audiometry had the lowest sensitivity. Eight patients with neurinomas were found in the series. Retrocochlear test results prevailed in another 23 ears, most often in combined hearing loss and vestibular dysfunction and in insidious or longstanding hearing loss. Quantitative interpretation of the audiological test battery is valuable for uniformity in classification of sensorineural hearing loss, and will facilitate extended studies on aetiology and course in auditory dysfunction.     

Audiological investigation of chronic alcoholics

Pure tone audiometry performed on 67 alcoholics showed a sensorineural hearing loss in 70% of the ears examined. The prevalence of the hearing loss was related to the duration of heavy drinking. Twenty-two subjects with hearing loss were evaluated using impedance audiometry, SISI test, tone decay test and fixed frequency Békésy recording. The results of these tests are suggestive of a retrocochlear lesion in chronic alcoholics.     

Correspondence amongst microstructure patterns observed in otoacoustic emissions and Békésy audiometry.

Similar patterns of microstructure have been reported in normal ears for Békésy threshold recordings and various forms of otoacoustic emissions (OAE). It has been suggested that they have a common origin associated with the amplifying function of the outer hair cell system and wave interactions occurring within cochlear mechanics. Fine-frequency Békésy audiometry was conducted in ten normal ears and its microstructure was compared with that recorded using two OAq techniques: stimulus frequency (SFOAE) and distortion product (DPOAE). All sweeps encompassed the frequency range from 992 to 2000 Hz in 16-Hz steps. The same probe was used for all Békésy and OAE recordings to eliminate transducer effects. SFOAEs were obtained with stimulus intensities of 0, 3, 6 and 9 dB. DPOAEs were obtained for 2F1-F2 with primary levels (L1/L2) of 40/30, 45/35, 50/40 and 55/45 dB. Reliable microstructure was recorded in all ears. Mean values of microstructure peak spacing ranged from 5.6 to 9.3 per cent amongst methods, consistent with published data. Microstructure was similar within each OAE method for different stimulus intensities for each subject. However, comparisons between Békésy and OAEs, or between OAE methods, did not show the strong correspondence that would be expected if there were a simple common origin to the microstructure. There was weak support for the expected correspondence between Békésy and SFOAE, but no support for any correspondence between Békésy and DPOAE. It is concluded that the various forms of microstructure cannot be explained by a simple common origin.     

Electrodermal response, delayed auditory feedback, and lengthened off-time procedures. Comparison of use for medical-legal audiological assessment.

Results of conventional audiological procedures, lengthened off-time Békésy, and electrodermal response audiometry are compared with pure-tone delayed auditory feedback procedures for 100 subjects referred for medical-legal audiological evaluation. Specific attention is given to a new economical prototype unit for pure-tone delayed auditory feedback, to the comparison of results of special test procedures, and to the nonorganic hearing loss population.