Search PubMed⌕ Search

Biomedical subjects

W Fritze

Publications and source records attributed to W Fritze.

At least 37 records · Page 2Linked to original sources
PubMed1983

Registration of spontaneous cochlear emissions by means of Fourier transformation.

Fourier transformation is a suitable procedure for the detection of spontaneous cochlear emissions. In the setup used, the microphone lies unsupported at the entrance to the external auditory canal; after amplification and optional filtering, the signal is processed digitally. The frequency distribution of the emissions is considerably narrow and shows alterations in frequency and intensity. Emissions seem to occur in slightly damaged cochleas.

Adolescent↗
PubMed1981

[A factor analysis of cochleovestibular findings. (author's transl)].

Using the variables auditory threshold, speech audiometry, SISI, ABLB, stapedius reflex, Carhart-test, Békésy audiometry and calorization three factors could be extracted: 1. The quality of peripheral speech-coding in combination with central processing; 2. the degree of damage of the inner ear (threshold, distance between hearing-threshold and reflex-threshold, SISI and calorization); 3. a retrocochlear factor. SISI and ABLB are both tests concerning the inner ear, but must be regarded separately as it is to be supposed that these two findings are caused be two different pathologic processes.

Audiometry↗
PubMed1981

[A method for prediction of permanent threshold shift (PTS) (author's transl)].

A new test for noise resistance was performed in persons at the time they started on a job with a high noise level; three years later, the initial test results were compared with the chronic damage caused to their hearing by the noise to which they had been expose. In other words, the test results were correlated with the PTS which had since been acquired. The significance was found to be 5%, proving that this professional disease can be predicted. The test is based on an effect in TTS (Temporary Threshold Shift) experiments which had been overlooked so far: Exposure to a tone of low frequency caused a second TTS in the PTS frequency range. This "dip" in the audiogram is always at the same position, independent of the exposure. The amplitude of this second "dip" does not correlate with that of the well-known large frequency-dependent first "dip", which had so far been used by many authors for prognosis. The knowledge of this fact cannot have any bearing on public health until existing legislation has been modified. At present, a small percentage only of workers employed in a job involving noise are transferred; after due modification of the law involving a meaningful prognostic examination prior to their being accepted for a job, the extent of PTS in the population will depend on the number of candidates accepted for professions involving noise in relation to the total number of persons required.

Auditory Fatigue↗
PubMed1980

The graph of loudness recruitment (ABLB-test).

The ABLB-test compares the subjective loudness in patients with unilateral sensorineural hearing loss. The graph of this comparison of loudness at different suprathreshold intensities is of interest for understanding the function of the hair cells.

Auditory Threshold↗
PubMed1980

Psychoacoustic study on the dependence of the TTS in the high-frequency range on the exposing frequency (150--500 cps).

When exposing a normal-hearing person to a low-frequency tone this results in two dips in the audiogram; the second one is of interest because it is in the range of the PTS. The amplitude of this dip is dependent on the exposing frequency: 200 cps causes significantly more TTS than 350 cps. The origin of this TTS is supposed to be in the cochlea.

Audiometry, Pure-Tone↗
PubMed1980

[The present position of the computer in audiometry (author's transl)].

Alike other fields, in the last years there was a considerable progress in the use of computers in audiology. Here the on-line-operation in the so-called subjective audiometry is dealt with. On principle we have to discriminate between different arrangements, where on the one hand the machine is merely registering and on the other hand the machine is also controlling the test. The last one has the exceeding advantage to be more flexible and also allows the use of randomization, which means a fundamental condition to statistics. In this case the machine also can check the patient's responses - according to the programmm e.g. periods of the patient's inattentiveness may be discovered and the audiometrist may be called. Further on at certain tests the computer may check the results of the investigation in respect to significance in on-line-operation; by this investigations can be shortened. Several situations of application are described; the computercontrolled automatical audiometry can be performed in accordance to Kékésy (the temporal sequence of pulses is independent on the patient's response) or - similar to conventional audiometry - the calculator will wait for patient's response after each stimulus. For scientific investigation the computer-controlled-performance has great advantages because of the machine-compatible output of the results (for further statistical evaluation). By the use of a calculator the audiometry is not at all limited by the inexactness of the patient during an investigation. In spite of this inexactness possibilities are shown to detect farmore smaller differences of the threshold. At least for the moment the use of a computer in routine audiometry seems to be of worth only at great audiometric station and means that the audiometrist has to pay special attention to the psychological state of the patient.

Audiometry↗
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↗