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At least 397 records · Page 22Linked to original sources
PubMedDate not supplied

Reliability and validity of late vertex-evoked response audiometry.

In order to evaluate the current visual scoring technique in the late vertex-evoked response audiometry (ERA), the detectability of the response, errors in judgment, consistency between scorers and test-retest reliability were studied in adults and young children in waking and sleeping states. In waking adults, ERA proved to be a quite reliable and valid method for testing hearing objectively. On the contrary, a marked inconsistency was found in the appearance of the response in children during sleep. From a clinical standpoint, ERA in waking adults and sleeping children should be regarded as two substantially different methods.

Acoustic Stimulation↗
PubMedDate not supplied

Intensity and frequency discrimination monitored by evoked response audiometry: clinical application.

Delta 1 and delta f repetitive stimuli superimposed on continuous 0.5-, 1- and 4-kHz carrier tones were administered to 20 normally hearing persons, 8 adults with sensorineural hearing loss, 10 adults with conductive hearing loss and 22 children subjected to evoked response audiometry (ERA) for assessment of hearing acuity. The intensity modulation depth ranged from + 1 to 10 dB. In the subjects with normal hearing and in the adult patients, three carrier tone levels were used whenever possible: 20, 40, and 60 dB SL. The frequency modulation depth ranged from -1 to -10% of the carrier tone frequency. The same levels for the carrier tone were used: 20, 40, and 60 dB SL. With a carrier tone level of 20 dB SL, a clear-cut vertex response was noted in 80% of the tests carried out in the normal adults with 5-dB delta i stimuli and with delta f stimuli of -3 to -5% in magnitude; the same figures are valid for the patients with sensorineural and conductive hearing loss. The patients with sensorineural hearing loss showed a tendency to give vertex responses with lower delta i stimuli than subjects with normal hearing. However, this difference was not statistically significant. According to our results, the children tested can be roughly divided into two groups, the first including subjects with responses to delta i stimuli of +5 and +10 dB and delta f stimuli of -5% and -10%; the second group including subjects with no clear-cut responses to these stimuli.

Acoustic Stimulation↗
PubMedDate not supplied

Simultaneous four-channel electric-response audiometry results in 8 years of hearing evaluation among small children.

The results of 8 years' experience with slow cortical-evoked responses obtained by a four-channel method are reported. The conclusion is that, even in this form, ERA is not a reliable tool for diagnosing hearing defects in children. The time course of the mean ERA threshold of 138 children examined in Turku University for periods ranging from 6 months to over 3 years is presented. The results are discussed. Electrocochleography or brain stem audiometry is recommended for clinical use.

Age Factors↗
PubMed1983

Lateralization, impedance, auditory brain stem response and synthetic sentence audiometry in brain stem disorders.

Applied individually, the conventional audiometric tests are unsatisfactory in the diagnosis of retrocochlear disorders. An accurate identification of a retrocochlear lesion, however, is not always possible using a single test, and only an appropriate test battery provides the basis for correct prediction of a retrocochlear lesion. Because of this observation, lateralization tests, impedance studies, auditory brain stem responses and speech audiometry with synthetic sentences have been applied to patients affected with retrocochlear disorders (acute nucleoreticular vestibular syndrome, multiple sclerosis and focal lesions). Analysis of the results has demonstrated the value of the tests employed, but the various tests were not strongly correlated and are therefore complementary.

Acoustic Impedance Tests↗
PubMed1985

High-frequency audiometry above 8 kHz. Comparative results of normative thresholds obtained with a headphone system and a quasi-free-field system.

Since a standard method for high-frequency audiometry does not yet exist, the authors, using 20 young subjects, compare the results obtained with a quasi-free-field system devised by Osterhammel et al. [Scand. Audiol. 6:91-95, 1977] and those obtained by a headphone system. The headphone system is considered to be better, because it offers many practical advantages.

Adult↗
PubMed1985

Problems in interpretation of brainstem-evoked response audiometry results.

This report describes 6 cases - 3 adults and 3 children - in which no response could be obtained during the brainstem-evoked response audiometry (ABR) examination. This, in spite of the fact that maximal click intensity was used during the test, and despite the patients' nearly normal hearing sensitivity. All of the cases presented a slight degree of neurological deficiency, which could explain the faulty synchronization of the biological response to clicks. Attention is drawn to the fact that lack of response in ABR in cases with central nervous system involvement is not necessarily proof of severe hearing loss, and could supply important diagnostic cues.

Adult↗
PubMed1987

Brainstem electric-response audiometry in infants of a neonatal intensive care unit.

Brainstem electric-response audiometry was used to assess the auditory function of 600 infants from a neonatal intensive care unit. Two groups of children were tested, one group as inpatients prior to discharge with a mean age at test of 39.4 weeks and one group as outpatients with a mean age at test of 55.4 weeks. Our results indicate that testing infants when they are older will reduce the incidence of failure on the initial evaluation and will reduce the identification of transient hearing losses which resolve spontaneously. Our results also indicate that a threshold of 30 dB nHL or less is probably normal and that some infants with a threshold of 40 dB nHL at first test require otological or audiological management.

Audiometry, Evoked Response↗
PubMedDate not supplied

Extended high frequency audiometry in pre-school children.

Since adequate and reliable earphones are now available and standards have been established, clinical audiometry can be performed at extended high frequencies (EHFs). In the present study, 47 preschool children (aged 4-7 years) were examined with EHFs (8-16 kHz) using the new Sennheiser HDA 200 earphone. The hearing thresholds correspond to those of other studies; the median thresholds and range increase with increasing frequency. The medians and quartiles were: 10 kHz: 25 (5-35) dB(SPL), 11.2 kHz: 35 (20-40) dB(SPL), 14 kHz 40 (30-50) dB(SPL) and 16 kHz: 50 (40-60) dB(SPL). The hearing thresholds could be more reliably determined in the older children (> 5 years) and were 5 dB better than in the younger ones (< 5 years). Thresholds in the 10-12.5 kHz range correspond to those of adults but are more sensitive by 5-12 dB in the 14-16 kHz range.

Adolescent↗
PubMedDate not supplied

Dual response audiometry: a time-saving technique for enhanced objective auditory assessment.

The effectiveness of objective audiometric assessment can be improved by simultaneously recording transient evoked otoacoustic emissions (TEOAE) and auditory brainstem responses (ABR). Using a stimulation paradigm based on sequences of linearly balanced click stimuli (as described by Kemp et al.) acoustical and electrical responses of the auditory system can be obtained in one single run (dual response audiometry, DRA). The click stimuli are presented via an ear canal probe containing a speaker and a miniature microphone. EEG activity is recorded from surface electrodes fixed at the vertex and the mastoid ipsilateral to stimulus presentation. Microphone output and voltage difference between electrodes are fed into a dual-channel data acquisition system, where they are separately amplified and filtered into appropriate frequency ranges. After each stimulus, sweeps of 256 samples within a time window of 17 ms are taken of both signals. They are subject to artefact rejection and averaging of amplitude and polarity. The electrical responses to low and high level clicks within one stimulus sequence are processed separately, whereas the acoustical responses are summated across levels in order to eliminate stimulus-related contamination. As the result of one single run, ABR at two levels and non-linear TEOAEs are obtained within approximately 1 min. The signal quality is estimated by correlation analysis and binomial statistics. Among various features of DRA, the most important advantage is the improvement of the success rate. The influence of perturbations is limited since muscle artefacts due to motor activity affect only the ABR, whereas noise contamination affects only the TEOAE. The accuracy of threshold determination is better than with conventional ABR since the stimulus level is measured in situ. One DRA examination provides complete information about the functional integrity of the cochlea and neural pathways without additional time. It appears ideal for the application as a second stage infant screen.

Acoustic Stimulation↗
PubMedDate not supplied

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.

Adult↗
PubMed1979

High-frequency audiometry and noise-induced hearing loss.

A group of noise-exposed male subjects with an audiogram that is characteristic for noise trauma were submitted to high-frequency audiometry (HFA) up to 20 000 HZ. The results were compared with those obtained in a group of normally hearing persons with no history of noise exposure. Conserved high frequency hearing was found. Very strict selection criteria were applied in both groups in order to avoid hereditary diseases and to ensure normal middle ear function. The findings are in good overall agreement with histological findings in noise-exposed animals and also with high-frequency studies in the older literature. Two illustrative case stories from patients with severe 4--6 kHz dips are reported, one with preserved high-frequency hearing in spite of a considerable acoustic trauma and one with extreme sensitivity towards noise and with no hearing at all in the high frequencies. It is concluded that 1) HFA cannot be used as an early indicator of the traumatic effect of high intensity noise; 2) presbycusis and noise damage may be additive elements in the older age groups (above 50 years); 3) persons with abnormal high-frequency hearing are possibly hypersensitive towards excessive noise and HFA might be useful in the routine audiological evaluation of workers before these are exposed to noise.

Adult↗
PubMed1980

Quiet and masked brief-tone audiometry in subjects with normal hearing and with noise-induced hearing loss.

Twenty subjects with normal hearing and 20 with noise-induced hearing loss (NIHL) were tested with brief-tone audiometry at 500 and 4000 Hz in both quiet and masked conditions. The two tone durations used were 20 and 500 msec. The masker was a continuous white noise at 90 dB SPL. Results are consistent with other studies in that subjects with NIHL showed less temporal integration than normals. The frequency effect was found both in normals and in the hearing-impaired. The discrepancy of results on frequency effect found in the literature was discussed. Also, results suggest that suprathreshold measurement of temporal integration with the masking technique deserves further study.

Adult↗
PubMed1988

High-frequency audiometry in children.

On the grounds of recent literature and of their own previous studies, the authors have examined a group of 25 normal-hearing children, ranging from 7 to 10 years of age, with high-frequency audiometry. The results were compared with those obtained in a group of young adults. On the basis of these findings, average threshold values were derived for this age group; such data have not yet been published for this simple headset technique. Furthermore, the comparison between the two age groups enabled the authors to determine a deterioration of the high-frequency hearing threshold which takes place at a fairly early age. Reliability of the equipment, in which headphones were used as transducers, was checked and the reproducibility for this test was shown to be adequate, as seen from the low test-retest variability.

Adolescent↗
PubMed1990

Reproducibility of hearing threshold measurements. Supplementary data on bone-conduction and speech audiometry.

The reproducibility of bone-conduction pure-tone audiometry and speech recognition thresholds has been tested in groups of normal-hearing subjects. Each person was tested twice during the same day, and the test-retest difference was calculated. The reproducibility is presented as the standard deviation of this difference. Bone-conduction threshold measurements have a high degree of test-retest precision, whereas air-bone gaps show a large range of distribution in these normal-hearing subjects. This makes the interpretation of such gaps spurious when values are below 20-30 dB. Speech recognition threshold has the highest degree of test-retest precision of all audiometric tests, and this is probably due to the steep slope of the psychometric function at 50% intelligibility. A more detailed graphic presentation of the 50% point of intersection will bring the reproducibility down to less than 2.5 dB.

Adult↗
PubMed1991

Recognition of telegraphy disturbed by noise at different S/N-ratios and different telegraphy speeds. A comparison to short-tone audiometry.

The ability to recognize telegraphy at different S/N ratios and telegraphy speeds was compared for 10 normal-hearing men trained in detecting telegraphy. The ability to recognize telegraphy disturbed by noise decreased with increasing telegraphy speed and reduced S/N ratio. The recognition of telegraphy disturbed by noise seems to follow the relations known from experiments with short-tone audiometry.

Adult↗
PubMed1992

Quantization error in clinical pure-tone audiometry.

The current clinical procedure for pure-tone audiometry was analysed for statistical measurement errors. Theoretically, the root-mean-square (RMS) error in a single threshold measurement is always greater than the standard deviation (SD) of measured intra-individual test-retest differences, divided by the square root of two. The RMS error includes an additional quantization component, caused by the finite step size between presented signal levels. In Monte-Carlo simulations with 2-dB and 5-dB steps the quantization error was negligible compared with other errors. Therefore, the single-test RMS error can be estimated with sufficient accuracy from the test-retest SD. The simulated single-test RMS error decreased from about 2.7 dB about 2.3 dB when the audiometric step size was reduced from 5 dB to 2 dB. Hearing thresholds appeared to be about 1.7 dB better with 2-dB steps than with 5-dB steps.

Acoustic Stimulation↗
PubMed1993

Microcomputer with a sound card. Low-cost flexibility for audiometry.

An ordinary Personal Computer equipped with a sound card for entertainment electronics can significantly improve the flexibility of speech and pediatric audiometry. New programming tools have made it possible for the layman to construct his own user-interface.

Audiometry, Speech↗
PubMed1996

Evaluation of the list of numerals in the Danish speech audiometry material. Dantale.

The psychometric function for the list of numerals in the Danish 'Dantale' speech audiometry material was obtained by presenting the lists to 30 normally hearing subjects at eight different sound pressure levels. Six of the subjects participated in a test of a possible learning effect. The psychometric function is presented, showing that 50% speech recognition is reached at a mean of 15 dB SPL, and the slope of the function around the 50% value is 8.3% per dB. It was found that in no more than 7% of the cases was each numeral on the list confused with another numeral. A strong correlation between the recorded RMS value and the SRT for the individual numeral was found. The short-term learning effect was found to be negligible.

Adolescent↗