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Bone conduction speech discrimination: an indication of cochlear function in the immediate postoperative period.

We illustrate that the apparent sensorineural audiometric changes immediately following stapedectomy are not indicative of a true sensorineural type hearing loss. The cochlear changes evident by postoperative pure-tone and air conduction speech discrimination audiometric tests are not reflective of the true cochlear reserve when the procedure of bone conduction speech discrimination is used. We report 25 consecutive stapedectomy cases in which most of the one-week postoperative audiograms of stapedectomized ears revealed a mid- and high-frequency sensorineural pure-tone loss and a drop in the standard speech discrimination scores. The decrease in speech discrimination, however, was not verified when using the bone-speech discrimination test, using maximum masking in the opposite ear.

Audiometry↗

Effects of sophistication on four tests for nonorganic hearing loss.

Three groups of 15 normal-hearing subjects were asked to simulate a hearing loss in one ear. Each subject was then tested on four measurements often used in determining the presence of pseudohypacusis (a comparison of the SRT to the pure-tone average, ascending vs descending pure-tone tests, the Stenger test, and pure-tone delayed auditory feedback). Results showed that as practice and sophistication on each of the procedures increased, there tended to be more improvement in the subjects' ability to "beat" some of the tests than others.

Adult↗

Pure tone delayed auditory feedback: effect of instructions.

This study compared the effect of instructions to the subject upon key tapping performance with pure-tone delayed auditory feedback. One set of instructions stressed the importance of maintaining tapping rate whereas a second set emphasized consistency of the pattern. A third set stressed rate and pattern equality. The results lead to the recommendation that instructions stress equally both rate and pattern consistency.

Acoustic Stimulation↗

Calibration force levels for bone conduction vibrators.

Two bone conduction vibrators (Radioear B71 and B72) and a headband (Radioear P-3333) have been developed to meet specifications of both the International Electrotechnical Commission and the American National Standard Institute. Pure-tone thresholds for air conduction and bone conduction were obtained from 24 normal-hearing young adults at audiometric frequencies between 250 and 4000 Hz. Results of this study are in good agreement with the standard air conduction threshold sound pressure levels (ANSI) and with bone conduction threshold force levels reported in the literature.

Adult↗

Brain stem response audiometry at speech frequencies.

Auditory-evoked brain stem response (BSR; wave V) was studied, using tone pips at three speech frequencies (500, 1 000 and 2 000 Hz) as stimuli. The tone pips consisted of 5-ms rise-decay times without a plateau. BSR recordings were made in 10 normal subjects and in 16 subjects with impaired hearing. In the normal subjects, BSR thresholds ranged from 10 to 20 dB SL at these three frequencies. In the subjects with impaired hearing, BSR thresholds corresponded well to conventional pure-tone thresholds at each frequency in cases of low- as well as high-frequency hearing loss. In all subjects with impaired hearing, the BSR thresholds were higher by as much as 25 dB than the pure-tone thresholds. The mean differences between these two thresholds at 500, 1 000 and 2 000 Hz were 11.3 +/- 8.0, 10.9 +/- 6.2 and 10.9 +/- 7.3 dB, respectively. Thus, we conclude that the BSR is useful for objective assessment of hearing thresholds at each of these speech frequencies.

Acoustic Stimulation↗

Aided and unaided narrow band noise thresholds in listeners with sensorineural hearing impairment.

This study explored the relationship between narrow band noise thresholds obtained under aided and unaided conditions with normal listeners and with subjects demonstrating sensorineural hearing impairment. Pure-tone and narrow band noise thresholds obtained under earphone conditions were found to approximate each other within 3 dB. Mean noise thresholds obtained in sound field required less sound pressure than thresholds obtained under earphone conditions. In comparing the predicted aided noise thresholds with the observed thresholds, a 4-dB mean difference was found. The close relationship between hearing aid acoustic gain and changes in aided narrow band noise thresholds suggests the use of narrow band noise audiometry in hearing-aid selection when traditional measures cannot be used.

Adult↗

[Basis and clinical application of the "contingent negative variation" in "evoked response audiometry" (author's transl)].

After repeated stimulation with an indicative stimulus and a second imperative stimulus, a slow negative potential shife, the "Contingent Negative Variation" (CNV), can be recorded in the EEG before the second stimulus. On account of the main features of CNV two qualitative tests can be used in audiometry. "Tone-CNV" is an objective test of perception of a pure-tone. The indicative pure-tone is followed regularly by a second imperative stimulus, a flash of light or a slide. The appearance of CNV is the positive sign of perception, even if the "acoustically evoked potential" (AEP) is difficult to define. Adults and children (5 to 12 years) with normal hearing or suffering from several forms of hearing loss developed a CNV, except those patients with severe brain damage. The advantage of this method is the short testing time and accentuation of AEPs. The test can be also done under sedation. In "Objective Speech Audiometry", a proof of concept discrimination, only words of one concept are combined with a second imperative stimulus. The other group of words of the second concept remains "unreinforced". After correct discrimination all normal subjects developed a CNV before the second stimulus and after the "unreinforced" concept a "Discriminative Positive Variation" (DPV). Thus, this method can be used for clinical purposes. Loss of discrimination, perseveration phenomena and hemispheric differences were observed in aphasic patients.

Acoustic Stimulation↗

Evaluation of a clinical method for measuring comfortable loudness for speech.

The reliability of a clinical method for measuring most comfortable loudness for speech was evaluated on 100 subjects with sensorineural hearing loss. The method uses spondaic words as the test stimuli. The test-retest reliability was determined for an ascending and descending approach mode for all 100 subjects as well as for subgroups categorized on the basis of severity of hearing loss and pure-tone configuration. Results indicated that reliability was not affected by approach mode, hearing loss severity, or pure-tone configuration. Test-retest differences were not significant and test-retest correlations were high (r = 0.73 to 0.93) across all subgroup categories. Clinical reliability was demonstrated by the high percentages (85 to 92%) of subjects who had test-retest differences no greater +/-5 dB. The procedure is rapid, uses no special equipment, is easily performed, and is reliable. Thus, it is recommended as the preferred clinical procedure.

Adult↗

[Tympanometry in chronic otitis media].

We present an analysis of the otological and audiological findings in 63 patients (113 ears) in which a myringotomy for suspected serous otitis media has been performed. In 98 ears (87%) the impedance data correlated with otoscopy. Tympanograms did not give further information than otoscopy alone in 49 patients with reliable pure-tone audiometrical results, whereas tympanograms would have missed 6 out of 78 ears containing fluid and 6 out of 49 ears who improved in hearing following myringotomy and transtympanic tube therapy. We feel, however, that, in patients who are too young or too retarded to be tested audiometrically, tympanometry in combination with otoscopy could eventually be helpful in settling the indication for a myringotomy, since 3 out of 83 ears with middle ear fluid and hearing improvement following transtympanic tube therapy had pathological tympanograms in spite of normal-seeming ear drums.

Audiometry↗

Age effect in hearing - a comparative analysis of published threshold data.

Numerical data from the literature on presbyacusis, in the form of pure-tone hearing threshold levels as a function of age, are subjected to critical evaluation and analysis. A formula is derived for predicting the age effect for otologically screened groups of males and females. Further, the complete distribution of hearing levels for each audiometric frequency in the range 0.125-12 kHz and at any age can be estimated with the aid of tabulated coefficients and some simple rules. The study was undertaken in connection with the work of ISO on standardization of normative audiometric data.

Adult↗

Audiotympanometric findings in myasthenia gravis.

Myasthenia gravis can be a difficult diagnostic and therapeutic problem. Our study on six patients consisted of pure-tone audiograms, tympanometry, and acoustic reflex tests. Positive findings in the myasthenia gravis patients prior to medication included hyperacusis and increase in the intensity of sound required to elicit an acoustic reflex. Following medication, the hyperacusis lessened and the intensity of sound required to elicit the acoustic reflex decreased. During follow-up of two of the patients we encountered cholinergic (overdosage) crisis in one patient and myasthenic (underdosage) crisis in the other patient. Muscle weakness can be a common factor in both conditions. The acoustic reflex test can differentiate between the two types of crises. We believe audiotympanometric tests can aid in diagnosis and treatment of myasthenia gravis patients.

Acoustic Stimulation↗

Two experiments on subtle mid-frequency hearing loss and its influence on word discrimination in noise-exposed listeners.

The present study consisted of two experiments. Experiment I was directed toward the detection of subtle mid-frequency cochlear dysfunction and the determination of word discrimination in noise for persons with noise-induced hearing loss. The presence of significantly elevated aural-overload thresholds, consistent with the presence of cochlear pathology in regions of normal pure-tone sensitivity, confirmed previous findings obtained with this subject population by other investigators. In addition, a marked reduction in word discrimination was observed in the presence of a background of competing noise. For experiment II, normal hearers listened to consonant-nucleus-consonant monosyllables filtered to match the mean audiometric configuration of the noise-exposed subjects in experiment I. Results showed significantly better performance with these filtered words by the normally hearing subjects than that by the noise-exposed group for unfiltered materials. The results of the second experiment were interpreted as providing further support for the presence of subtle auditory dysfunction in the mid-frequencies despite normal threshold sensitivity in this same frequency region.

Acoustic Stimulation↗

Using circumaural enclosures with children.

Pure-tone thresholds were obtained from 24 children between the ages of eight and 13 years using a standard, supraaural cushion (MX-41/AR), and one of four circumaural cushions. Testing was performed in quiet and in the presence of wideband noise presented at 60 dB SPL fro three conditions: Condition 1 (test) used a TDH 39 driver mounted in the MX-41/AR cushion; Condition 2 (experimental) used the same TDH 39 driver mounted in one of the circumaural cushions under investigation; and Condition 3 (retest) which was the same as Condition 1. Statistically significant differences were found between thresholds with the MX-41/AR cushion and thresholds with one of the circumaural enclosures in quiet. In noise, thresholds with three of the circumaural enclosures were significantly lower than those with the MX-41/AR cushion. A significant test/retest difference was observed for the MX-41/AR cushion at 6000 Hz in quiet only.

Adolescent↗

Masking level difference: another tool for the evaluation of peripheral and cortical defects.

Masking level difference (MLD) due to binaural unmasking was measured for speech signals (5-word meaningful sentences) masked by broad-band noise. Tests were carried out in a group of patients with unilateral cerebral lesions of vascular origin and apparently normal pure-tone audiograms (CNS patients), in a control group (normally hearing young adults) and in 5 other groups of patients (conductive symmetrical hearing loss, conductive asymmetrical hearing loss, bilateral presbyacusis, unilateral sudden deafness, Menière's disease). Testing pattern implied three or more S/N ratios in the listening conditions, of SmNm, Sdelta tNo and SmNu (noise correlated), and the speech signal intensity was 70 dB SPL re 20 muPa for the control group, whilst for the pathological cases, speech level intensities were established by means of alternate binaural loudness balance and simultaneous balancing median-plane localization procedures to assess subjective suprathreshold sound image localization at the midline. The results obtained in the control group and in the patients are discussed. With specific reference to the CNS patients, a statistically significant tendency was evident for the binaural condition to produce more MLD when the ear leading in time was ipsilateral to the normal hemisphere. The importance of this and of sensitized speech testing methods in CNS disorders is discussed on the basis of the results obtained in the CNS patients.

Acoustic Stimulation↗

Auditory test results in 500 cases of acoustic neuroma.

Auditory test results in the first 53 causes of this series of 500 acoustic neuromas were reported in 1964. Subsequent studies involving larger numbers of patients detailed new results based on these additional cases. Five hundred cases of surgically confirmed acoustic neuromas were analyzed. Pure-tone loss configurations, speech discrimination, auditory adaptation as measured by the modified tone decay test, Bekesy audiometry, short increment sensitivity index test, and alternate binaural loudness balance test data were evaluated. The results of this investigation in general confirm previous studies, although percentage figures for positive tests differed in the large series. Acoustic reflex results were reported for those patients evaluated more recently. Slightly more than half of the cases had inconsistent audiometric results in one or more aspects. Inconsistencies to the tests were examined in detail. Consistent responses to the tests appear to be related to the size of the lesion. The full battery of audiologic tests is of importance in the differential diagnosis of acoustic neuromas.

Adolescent↗

Cochlear initiation site of the frequency-following response: a study of patients with sensorineural hearing loss.

The cochlear initiation of the frequency-following response (FFR) was assessed by comparing the FFR thresholds to the pure-tone thresholds in four groups of patients suffering from different forms of sensorineural hearing loss. The groups consisted of patients suffering from (1) pure high-frequency hearing losses; (2) high-frequency hearing losses mixed with moderate low-frequency losses; (3) flat hearing losses, and (4)low-frequency hearing losses. Across groups, the pattern of thresholds of the FFR evoked by 500-Hz tome bursts paralleled the pattern of pure-tone thresholds only for the low frequencies- not the high frequencies. In order to clarify the interpretation of this result, a high-pass masking experiment was performed on patients with low-frequency hearing losses. High-pass masking noise did not affect the FFR thresholds to 500-Hz tone burst, but it produced a phase shift of the FFR at stronger intensity levels. The data are interpreted as strongly supporting the view that the FFR at low levels is initiated primarily by activity in the apical portion of the cochlea.

Acoustic Stimulation↗

Auditory nerve and brain stem volume-conducted potentials evoked by pure-tone pips in the CBA/J laboratory mouse.

The short latency (less then 10 ms) auditory nerve and brain stem evoked potentials of Jewett were examined in the inbred CBA/J laboratory mouse. Tone pips, at nine frequencies from 4 to 64 kHz, were used to determine auditory nerve evoked potential (P1) thresholds. Maximum sensitivity occurred at 32 kHz, and a second sensitive area was seen at 56 kHz. With the exception of 32 kHz, as stimulus frequencies were increased in octave intervals, the 90 dB P1 amplitude also increased. P1 latency decreased as the stimulus frequency was increased up to 32 kHz, but this trend reversed with further increases of frequency. However, the P1 amplitude-latency function produced a better agreement of latency and frequency with the travelling wave theory for amplitudes less than 1 micro V, while amplitudes from 2 to 8 micro V were independent of frequency. Latency and amplitude input-output functions for responses from the four auditory brain stem loci suggest that auditory information is differentially processed as a function of frequency at each level, This is especially true for the inferior colliculus, which is most sensitive to 8-KHz stimuli.

Acoustic Stimulation↗

Changes in auditory perception in the menstrual cycle.

In a attempt to specify the critical functional components involved in the menstrual fluctuation of the upper frequency limit of the binaural beat we have obtained evidence of better performance in a variety of tasks at period and mid-cycle than at other times. These tasks include detection of physical beating, low-frequency octave matching, and lateralisation of clicks having interaural time delays in the 100 musec region. Continuous pure-tone frequency discrimination did not show a significant cyclical pattern overall but there was a tendency for low-frequency discrimination to show the described pattern. An attempt is made to reconcile some of these results with those of Wynn (1973) on absolute pitch, in terms of possible physiological and biochemical correlates. Three conclusions can be drawn: (1) The representations both of low-frequency tones and of the interaural time differences involved in some localisation tasks are particularly susceptible to alteration by the biochemical changes of the menstrual cycle: (2) The changes underlying perceptual variations are multiple, and inevitably confounded in any single task. (3) The distinction between the sensitivity and bias parameters of performance appears to be valuable in specifying menstrual effects. Several further lines of enquiry are suggested, but methodological difficulties in cycle research make it likely that more progress will come from better understanding of the physiological bases of psychoacoustic tasks using other methods, rather than from investigating natural menstrual effects.

Adult↗