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Biomedical subjects

H G Dieroff

Publications and source records attributed to H G Dieroff.

At least 37 records · Page 2Linked to original sources
PubMed1985

[Distorted Freiburg Speech Test].

In 107 patients with different types of hearing loss (air conduction, sensorineural and combined) we ascertained the monaural discrimination loss of monosyllables with the help of the normal and distorted Freiburg speech test. It was evident that the quotient obtained from the measured discrimination is a very good and useful measure to characterise the ability to analyse the peripheral hearing system. Compared with normal hearing individuals and patients with air conduction hearing loss or combined loss of hearing, persons with perception hearing loss show a much greater and more divergent quotient. The discrimination of distorted speech depends more on age than that of normal speech; however, it is considerably reduced from the sixth decade of life onwards. The distortion test offers the expertising the possibility of improved assessment of speech discrimination by workers in a noisy environment in case of unfavourable hearing conditions, but it is also of considerable importance in fitting hearing aids and in the diagnosis of acoustic tumours.

Adolescent↗
PubMed1980

Efficiency of subjective audiometry in children up to the third year of age.

After a discussion of possible methods for measuring the hearing of infants, we present a more appropriate method which we have developed and used over a number of years. The method applied is called "sound orientation audiometry" and is based on the readiness of infants to seek out the sources of sounds. As the infants are observed by means of a one-way mirror, no distraction is possible. In the light of our experience, the proof of intentional application is most favorable when the infants are 5-6 months or 3-4 years old. The application threshold is at 40-50 dB SPL. The results gained by this measuring method are compared wtih sound threshold audiometric results gained 4-9 years after the first examination. Judging from the evaluation, we can see a good correlation of the measuring results obtained by sound orientation audiometry during the first examination with audiometric hearing loss values determined later. The correlation coefficient of the group examined is r = 0.77. The procedure is being discussed as to its value and is considered especially valuable because the whole auditory apparatus as far as the central auditory center is under control. This method is clinically appropriate without much expenditure and may be applied at any time.

Audiometry↗
PubMed1980

[Ultrasound perception in deaf patients (author's transl)].

The acoustic evoked potentials (AEP) of 100-300 ms latency, evoked by ultrasound irritation (20-80 kHz) in normal hearing subjects cannot be derived from deaf persons. There was no reaction of 10 patients with congenital or acquired deafness during ultrasound - ERA - examination according to the absent subjective hearing perception.

Auditory Perception↗
PubMed1977

[The reliability of audiometry based on conscious orientation of the hearing impaired child (author's transl)].

The authors present the audiometric procedure for hearing impaired children, which has been developed and performed routinely for some years by the Department of Audiology in the ENT-Clinic of the Friedrich-Schiller-University Jena. Problems of children's audiometry are discussed. The procedure developed, is based on the children's conscious orientation to the source of sound which can regularly be registered especially in children of the age from 5 or 6 months to 3 or 4 years. The threshold provoking orientation is 45 to 50 dB (absolute). The results gained by the method described are compaired with those which were obtained 4 to 9 years later in 41 subjects suffering from heredodegenerative hearing loss. A coefficient of correlation r = 0.77 was found, indication a very near correlation of results for both procedures. When compaired to ERA, the test presented is simple to perform and is though to be very valuable for praxis. The orientation audiometry is more exact than the test of subjective audiometry and various procedures based on acoustical reflexes, too.

Age Factors↗
PubMed1976

Possibilities of improving the diagnosis of noise-induced hearing damage by means of directional audiometry, the dichotic speech discrimination test, and the EEG1.

Several audiometric tests were made of 85 noise workers exposed to an intensive impulse noise during pressing and punching. These tests aimed at finding out noise-induced central hearing damages (directional audiometry, dichotic speech discrimination test according to Feldmann and checking of the induction of the impedance jump). In addition, a clinical EEG was taken from each subject. Having obtained the necessary norms with series of tests in subjects with normal hearing abilities for their respective ages, the following results have been obtained: (1) directional hearing has hardly been affected by noise-induced hearing damage. It behaves like age changes in the group compared with it; (2) the dichotic speech discrimination test shows increasingly pathological values with progressive noise-induced hearing damage; this was already obvious in the age group 41-50. The impedance jump is less and less produced with progressive noise-induced hearing damage and finally disappears at a noise intensity of up to 110 dB. Because of these findings a progressive degeneration of the spiral ganglion and hearing nerve in noise-induced hearing damage is discussed as a cause of a deteriorated speech discrimination and the absence of the impedance jump. The EEG findings show changes in the alpha-rhythm in about 50% of the cases at an exposure time of 10 years onwards which may be possibly due to damage to the reticular formation, once increasing noise-induced hearing damage no longer exists.

Adult↗
PubMed1976

[A proposal for a method of precalculation of hearing losses (author's transl)].

Three well-known procedures for the determination of auditory noxiousness from noise level and time of exposure are discussed and the theoretically expected 4 kHz hearing losses in selected textile and metal workers exposed to noise are compared with the measured PTS values. The method after Kraak showed the best correlation between noise load and hearing loss. On the basis of these results a noise level table with intervals of 2-3 dB between 85 and 110 dB(A) was developped, from which the noise load after 1 to 40 working years can be read off in figures. After evaluation of 256 noise opinions a method for determination of maximum noise doses is proposed. The table presented may be used in the determination of characteristic coefficients.

Adult↗
PubMed1976

[Experiences in high frequency audiometry and possible applications (author's transl)].

Observations on the ultrasonic perception of noise-impaired persons gave rise to use the high frequency audiometry described by Fletcher for the early recognition of noise-induced damages. Using commercial equipment we found that the earpiece was not adapted to high frequency conditions. The adaptation problem and ways of modification are described in detail. After having improved the coupling features reproducible hearing curves were obtained. Examinations were carried out on workers, whose noise exposure exceeded the critical intensity by only a few dB. The following 3 categories of impairment were found: 1. Normal hearing between 125 and 8,000 Hz as well as in the high frequency region. 2. Unsignificant noise-induced impairments between 125 and 8,000 Hz; no high frequency hearing. 3. Acoustic hearing; no high frequency hearing. The results are discussed. It is supposed that high frequency hearing losses due to noise and chemical noxious exposure (streptomycin) are valuable in diagnostics and prognostics. Accordingly persons are to be assessed as noise sensitive, when there is no more high frequency hearing before practising noise work.

Audiometry↗
PubMed1975

[Limit of measurement of middle ear impedance (author's transl)].

The air volume enclosed in the acoustic duct is considered to be one of the causes of the bad reproductibility and the great scattering of measurement results of middle ear impedance. Therefore this volume was measured with ten subjects (20 ears) and the measured values of impedance were corrected. A procedure for determining the volume between the occlusion of the external canal and the ear-drum is described. The difficulties of carrying out this procedure are pointed out. Because of the volume determination for series examinations the measurement of the value of the impedance change as a criterion for individual resistance to noise of persons exposed to pulse noise involves great efforts and is therefore considered to be an inappropriate method as long as the indicated difficulties with measuring techniques continue to exist.

Air↗
PubMed1975

Some thoughts on the perception of ultrasonics by man.

After a short specification of the ultrasonic transmitter device by which the test frequencies of 20,40,60 and 100 kHz could be emitted by means of a transmitter fixed to the forehead of the subject with constant pressure, the mean perception threshold for ultrasonics is described, which had been recorded by using the wide-band noise of the audiometer MA 30. Both curves do not differ considerably so that ultrasonic investigations can be carried out in the presence of working noise without producing wrong measurement results. A comparison of perception between ultrasonic frequencies and audio frequencies in the hearing range showed that ultrasonics produce, independent of the stimulation frequency, the same sensory impression as a sound at a frequency of about 12 or 13 kHz. Applying this method to hard of hearing subjects with noise induced hearing damages and deaf subjects had the following results: 1. Subjects with noise induced hearing damages very early have a raised perception threshold for ultrasonics. There was no correlation between the extent of the auditory threshold (the shift of the threshold) and the perception threshold of ultrasonics. 2. Deaf people almost without exception are not able to perceive ultrasonics. 3. With hard of hearing of the inner ear of different genesis ultrasonic perception is varying. There was no particular raise of the ultrasonic perception threshold with hereditary hard of hearing of the inner ear. 4. On the basis of the results the question is discussed in which section of the auditory system ultrasonic perception occurs. In the opinion of the authors the origin of perception might be in the organ of Corti itself. An unambiguous proof, however, could not be found so far. At present the procedure of investigation does not yet allow an application in practical diagnostics of ear specialists.

Adolescent↗
PubMed1975

[The behaviour of the post-stimulatory acoustic response trigger threshold during experiments and with noise workers (author's transl)].

The findings on impedance jump responses after experimental and professional exposure to noise are presented and discussed. It can be shown that the trigger threshold of the impedance jump is raised only slightly by the development of a temporary shift of the threshold of audibility (TTS). By sealing the acoustic duct with ear-plugs (made of cotton and wax) however, the trigger threshold shifts by the same amount in decibel which originated through the sound attenuation itself. Furthermore, the impedance jump can be triggered more and more rarely with increasing exposure to noise during the working years under noise of noise workers. This can be explained by the additional increasing degeneration of the ganglion cells and the auditory nerve.

Acoustic Stimulation↗