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Biomedical subjects

W Fritze

Publications and source records attributed to W Fritze.

13 recordsLinked to original sources
PubMed1992

The time course of spontaneous otoacoustic emissions.

Spontaneous otoacoustic emissions (SOAEs) are amplitude-modulated pure sinus tones. The character of the sinus tone, which is a rare phenomenon in nature, can be proven by resolving the shifts and drifts that more or less always occur. In this report amplitude modulation was studied by digital filtering. The SOAEs were composed of bursts which, in small emissions, appeared only a part of the time. This procedure is not only suited for studying SOAEs but also for demonstrating evoked emissions, even without averaging.

Audiometry, Pure-Tone↗
PubMed1992

A long-term observation of spontaneous oto-acoustic emissions (SOAEs).

In a follow-up study of 22 ears made after a mean interval of 68 months, spontaneous oto-acoustic emissions (SOAEs) showed marked changes. At follow-up visits, fewer SOAEs were recorded than at the first examination. As the set-up employed at follow-ups was much more sensitive, this observation gains even more weight, because--given identical cochlear structures--a greater number of SOAEs ought to have been recorded. In analogy to age-related high-frequency hearing loss, SOAEs recorded at the follow-up examination were found at lower frequencies. This was associated with yet another phenomenon: Precise frequency data (derived from a 4,000 line spectrum) available for 13 SOAEs (7 subjects) from the first examination showed that SOAE frequencies had dropped slightly in all subjects. In 5 of them the frequency drop was significant (p less than 1/1000 in each case).

Acoustic Stimulation↗
PubMed1979

[Audiologic diagnosis of sensorineural deafness by discriminant analysis (author's transl)].

The audiometric test-battery surely is a help to the diagnosis of a lesion of the VIIIth nerve. The discriminant analysis is the most suitable statistic procedure for reduction of the test-battery and for clearer decision in cases of ambigous constellation of findings. The persons are divided into three groups: normals, patients with presumable inner-ear disturbance, and those with lesions of the acoustic nerve. By means of the classification-coefficients (a result of the discriminant analysis) in new cases a diagnosis per conclusionem can be found on-line.

Audiometry↗
PubMed1978

[Spatial orientation with regard to short-term memory, age and cerebral dominace].

Though orientation in acoustic space frequently has been the subject of investigations, sound was offered as a rule only in one or two dimensions of the subjective polar system of coordinates. In an earlier paper a test-situation was presented in which the offering of sound is varied in all three dimensions (horizontal and vertical angle as well as distance); the mistake also is calculated in these three dimensions separately. In this paper the investigations are continued by examinating the influence of age, the cerebral dominance and the short-term memory (offering of two different noises with following indication). Our results show that 1) age has no significant influence; 2) the relation of mistakes of the right and the left side is significantly more inhomogen in all three dimensions in left-handed persons; 3) the influence of the memory does not enlarge the mistake significantly.

Adult↗
PubMed1978

[An attempt to predict the noise-induced PTS. Beginning a long-time study (author's transl)].

After the exposure to a sinus-tone of 250 cps the audiogram shows two dips: the first in the low-frequency-range, the second at about 5 kcps. In noise-resistant men (having normal hearing in spite of having worked in noise for many years) the TTS in the high-frequency-range is significantly smaller than in the average of the population. Therefore this depression is to be used for a tentative prognosis of PTS. The test is done with frequency-constant Békésy-audiometry before and after the exposure to a sinus-tone of 250 cps (120 dB HL) for 10 min. Attention is payed to TTS2 as well as to the alteration of the altitude of the spikes and also to the reconstitution of both of them. A decision on the usefullness of this test for the prognosis could be expected in about two or three years.

Audiometry↗
PubMed1977

[The comparison of binaural balance-tests (author's transl)].

14 normal-hearing persons were examined in 7 different versions of the balance-test. Thereby a severe dependence to the methods was found out, caused by psychological factors. By randomization of the side and the intensity (computer-controlled test-procedure) no case showed a significant recruitment. In 23 persons with inner-ear disturbance there was not only the randomized test performed, but also the methods of Jerger (keeping the intensity constant on the worse ear) and Hood (constant on the better ear). By using the randomized test all patients showed a significant recruitment, calculated as the deviation of the angle in relation to the diagonal of the diagram. In 7 cases the method of Jerger and in 20 of all the 23 persons the method of Hood brought a compensation of loudness.

Adult↗
PubMed1977

[On the testing of the difference limen of intensity (author's transl)].

To extinct to a great extent the methodic faults (rhythm) at the common way of the measurement of the difference-limen of intensity, the original parameter (the intensity) is randomized. The patient himself has to find out the minimal hearable modulation at this intensity. The testing-signal is interrupted in a rhythm of 0.8 cps, so that the effects of adaptation are reduced to a great extent. This test was carried out on 20 normal-hearing persons; 13 of them also were examined with a continuous tone; by this continuous tone the difference-limen of intensity was significantly reduced (p less than 1%).

Acoustic Stimulation↗
PubMed1977

[A comparison of tympanometric with audiometric and otoscopic findings (author's transl)].

An analysis is reported of the assessment of 233 ears by otoscopy from which the tympanic membrane appearances were classed into five groups, audiometry, tympanometry and in 57 cases middle-ear-puncture. Although observer errors must be acknowledged the findings were that the type B tympanogram does not conform to a specific pathology and may occur with different degrees of conductive hearing loss. Furthermore in the diagnosis of middle ear effusion the tympanogram does not supercede careful otoscopy and pure tone audiometry.

Acoustic Impedance Tests↗
PubMed1976

[On the practice of audiological balance-tests (author's transl)].

The psychological factors influencing the common test-situation of the ABLB are still unknown. The fact that always on the same ear the intensity is remaining constant and that this intensity is increased in equal steps is no longer due to modern psychological principles of testing. Both--the side and the intensity--should be randomized within the given range (both sides and all possible intensities). Therefore the test-procedure is controlled by a computer, which also calculates the significance of the relative recruitment. When the test is finished a diagram is plotted containing the values and the regressionline. Also the monaural test (comparison of two frequencies) is well practicable using the same program, because the incertainty (being greater if the test is more difficult) is included in the statistic calculation.

Audiometry↗
PubMed1975

[The prognosis of the noise-induced permanent hearing-loss (author's transl)].

Basing on a microscopic study the question was explored whether a TTS is found in the high-frequency range after exposure to a low-frequency tone or not. Such a depression is demonstrable after several registrations with automatic audiometry. This depression is significantly higher in the average of normal-hearing persons than in noise-resistant men (having a normal threshold after working in noise for many years). Also after the exposure the spikes of the Békésy-audiogram are significantly smaller in the noise-resistant men than in the control-group. Paying attention to both parameters the significance is 1%. Therefore the investigation of the high-frequency-range after exposure to a low-frequency tone seems to be a method of prediction of PTS.

Audiometry↗
PubMedDate not supplied

[A testing arrangement for spatial hearing].

A test-situation which concerns the spatial character of hearing is demonstrated. The subject indicates the estimated location of the stimulus. The WN is presented at a short distance from the head and thus discrepancies in distance can also be discriminated. The subjective space of man (polar system of coordinates) consists of three dimensions (horizontal, vertical and distance equals radius); for each of these three dimensions the average shift of the centre and the standard deviation (representing the error) are calculated. When testing lateral (45 degrees right or left) the average error is a little smaller for the horizontal scale than for the vertical. As far as the distance is concerned the results of the 21 subjects varied considerably; while some of the persons showed surprisingly good location ability, others supposed the noise to come from even outside the camera silens. The investigation has been carried out to contribute to the exploration of subjective acoustic space. It is also planned to apply the test as a diagnostic procedure in various neurological disturbances.

Acoustic Stimulation↗
PubMedDate not supplied

A computer-controlled binaural balance test.

The commonly used ABLB procedure (Alternate Binaural Loudness Balance) is strongly influenced by two psychological factors: the consistency of the referred side and the increase in intensity in equal stages on this side. To avoid this influence, side and intensity have to be randomized. The test has therefore been subjected to computer control and the results are continuously checked as to their significance. 26 patients with suspected inner-ear disturbance showed a significant relative recruitment; by contrast, in not one of 14 normal-hearing persons was the result positive. This test takes no longer than the conventional procedure.

Computers↗