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Biomedical subjects

U Reker

Publications and source records attributed to U Reker.

At least 19 recordsLinked to original sources
PubMed1991

[Welding spark injuries of the ear. Observations of personal case material].

25 cases of tympanic welding spark injuries of the years 1959-1989 are reported. Early results and late sequelae after conservative therapy, immediate and interval operation are described and discussed. Regarding the tendency of tympanic defects to enlarge after thermal injuries despite conservative and early operative therapy, secondary seal by tympanoplasty is recommended. Even then, however, the rate of residual and recurring perforations must be reckoned as being higher than after tympanoplasty in comparable defects of other origin, due to the inferior nutritive supply owing to the extended scar caused by burning. On the other hand, the rate of inner ear traumatisation with 12% directly after welding injury and with 4% remaining impairment of hearing, is low.

Burns↗
PubMed1990

[Measuring the voice field in general ENT practice. How, when, why?].

The phonetogram depends on measurement of the intensity of sound in dB(A) at 30 cm from the microphone of tones over the whole individual range of frequency sung as soft or loud as possible. The recording of other parameters such as degree of hoarseness, type of vocal attack, and breathing technique might be desirable for a complete description of individual voice characteristics. However, the phonetogram in combination with measurement of maximum phonation time and mean fundamental speaking frequency yields an objective and quantitative record of the fundamental parameters of an abnormal voice. The phonetogram is thus a prerequisite for phoniatric scientific studies, for medicolegal work and for a decision about fitness for work in certain professions. A phonetogram is recommended before and after microlaryngoscopic phonosurgery for benign lesions of the vocal cords, as it is of considerable documentary importance if the expected improvement of voice is not achieved. Furthermore, the phonetogram is valuable both to the physician and the patient to illustrate the individual abnormal characteristics.

Humans↗
PubMed1989

Time constants of the vestibular thermal reaction.

For the thermal test, adaptation time constants of about 100 s are described in the literature. By automatically alternating hot-cold irrigation, as designed by us, precision of stimulus application of different temperatures was considerably improved. Furthermore, temperature was registered with a thermocouple device. The actually effective thermal stimulus on the horizontal canal was calculated by a mathematical model. Nystagmus analysis was carried out automatically with the Kiel-program. With 15 radical cavities (where stimulus intensity is very strong) non-linearities were especially distinct. After switching to the 44 degrees C stimulus, there was an extremely steep rise in the reaction in the form of a so-called "on-effect" or "post-inhibitory overshoot". After reaching maxima of up to 150 degrees/s, the reaction decreased quickly with time constants of 22-45 s.

Adaptation, Physiological↗
PubMed1988

[Indications for electronystagmography. When should the ENT physician indicate electronystagmography?].

With the increasing application of technology in medicine, clinical vestibular examination using Frenzel's spectacles is often thought to be out of date, and an electronystagmogram (ENG) is ordered. However, some important facets of the clinical behaviour cannot be determined by ENG alone, especially nystagmus after head-shaking, and the rotatory nystagmus of paroxysmal positional vertigo. Thus, in most cases routine vestibular examination is sufficient, and ENG is only indicated in certain cases. The ENG is then of considerable advantage for determining qualitative characteristics and for quantitative analysis of the nystagmus. The various methods of stimulation and of recording, the limitations and the advantages of the ENG are described in detail. An examiner fully familiar with the advantages and disadvantages of the various methods will profit from the use of ENG. However, the classical examination, including a thorough vertigo analysis, remains indispensable.

Electronystagmography↗
PubMed1986

[Significance of the Bárány convection hypothesis for thermal nystagmus. Quantitative comparison of the intensity of thermal nystagmus in supine and prone position].

The hypothesis of Bárány explaining thermic nystagmus has been shaken. We must accept a non-convective triggering of nystagmus in extraterrestrial space. Under terrestrial conditions, however, the reversibility of the thermic nystagmus by changing from supine to prone position continues to support the convection hypothesis. We examined the nystagmus intensity in the supine and prone position with 22 healthy ears. The thermic stimulus was monitored via computer-controlled alternating irrigation system. The sequence of examinations was randomised and the evaluation of the nystagmus effected by automatic analysis. Our data allow to assess the importance of the non-convective nystagmus. With clinical test conditions about 85% of the maximal thermal reaction can be explained by the convection hypothesis of Bárány. However, interindividual variance is considerable, and one exceptional case with predominantly non-convectively released nystagmus is presented.

Adult↗
PubMed1985

[Function of proprioceptors of the cervical spine in the cervico-ocular reflex].

Disease of the cervical spine may cause vestibular vertigo. The anatomical basis for this type of cervical vertigo are the proprioceptive stretch receptors of the upper cervical joints. These are connected to the vestibular nuclei, and, thus, to ocular reactions (nystagmus). Quantitative data about this cervico-ocular reflex are still scarce since the reflex is strongly suppressed in healthy persons. However, suppression ceases in bilateral complete vestibular deficiency. We measured the cervico-ocular reflex in 6 patients with complete bilateral labyrinthine deficiency. One patient showed a complete absence of the reflex, which might be explained by degeneration of the vestibular nuclei. 5 patients showed a strong cervico-ocular reflex with a gain (relation of eye amplitude to head amplitude) of 0.35-1.0. This gain was present with stimulus frequencies of 0.15-0.65 Hz. Data on the proprioceptive sensory organ of the cervical column could be the basis for evaluation of the widely-discussed importance of diseases of the cervical spine in vertigo.

Adult↗
PubMed1984

The high frequency limit of the fundamental vestibulo-ocular reflex.

The high frequency limit of the image-stabilizing trineuronal vestibulo-ocular reflex is very difficult to assess experimentally, as the necessary accelerations are extremely high. We chose to examine fistulae of the bony horizontal semicircular canal. Oscillating pressures of between 3 and 40 Hz were applied to the fistula, and the fast pendular eye movements were registered by electronystagmography. Above 15 Hz there was no regular reaction. Up to 15 Hz the eye movements corresponded to the alternating pressure stimulus upon the fistula. Up to 11 Hz the ocular reaction was very strong, with calculated acceleration values near the dynamic limit of the bulbus and eye muscles. The capacity of the vestibular organ has often been underrated. In view of previous investigations and our own experiments it seems justified to set the frequency limit of the fundamental vestibulo-ocular reflex at at least 10 Hz.

Electrooculography↗
PubMed1984

[Development of audiologic symptoms in Ménière disease].

A flat or low-frequency hearing loss is generally accepted as being characteristic of Menière's disease. However, the transition between different types of pure tone audiograms during the course of the disease, and their relation to vestibular damage, have so far been investigated only rarely. We investigated the correlation between the vestibular deficiency and changes in the pure tone threshold on 50 patients with confirmed Menière's disease. We also analyzed the correlation between duration of the disease and vestibulo-cochlear impairment. The 0.25-kHz-tone and the frequency range of 2 kHz showed a highly significant correlation to vestibular impairment, but the higher frequencies of 4 and 6 kHz correlated poorly with vestibulo-cochlear deficiency. Thus conclusions may be drawn about the extent of the permanent vestibular damage and the stage of the disease from the pure tone audiogram.

Audiometry, Pure-Tone↗
PubMed1983

[Monosymptomatic onset of Menière's disease].

The occurrence of monosymptomatic courses of Menière's disease is not generally accepted, although cochlear forms are described in literature. Retrospectively, we evaluated the case histories of 108 patients with Menière disease, who developed the typical trias in the further course of the disease. Among these 108 patients, we found 39 with a true monosymptomatic course, i.e., in each case we could exclude the participation of either the cochlea, or the labyrinth by exact clinical investigations. Two-thirds of the patients first noticed the impairment of hearing, one-third the vertigo. Basing on a time interval of more than one year, there were still 18 patients with a monosymptomatic course. The average duration of the monosymptomatic courses is distinctly shorter than the duration of the typical trias and, consequently, we defined them as equivalents to early forms of the disease. At this early stage a diagnosis is possible by the fluctuating cochlear signs with their typical audiogram configurations, and the attack character of the vestibular symptoms.

Adult↗
PubMed1983

[Cervical nystagmus caused by proprioceptors of the neck].

A pathological nystagmus, occurring during turning of the trunk in relation to the head, which is held stationary in space, clearly points towards a cervical origin of vestibular vertigo. Such a cervical nystagmus may have a vascular origin by the compression of the arteriae vertebrales, or a proprioreceptive origin via the upper neck joints, or it may possibly be due to functional disturbances of the upper cervical spine. The dynamic characteristics of the so-called cervico-ocular reflex can be examined only in patients with non-functioning labyrinths, since in a healthy person the reflex is so strongly suppressed that it cannot be analyzed any more. In five patients with isolated bilateral complete vestibular deficiencies, we found a strong cervico-ocular reflex. Detailed examinations showed that nystagmus occurred during turning of the body in relation to the head ("phasic neck reflex"). On the other hand, when remaining in the extreme positions, the proprioreceptive nystagmus does not persist. Contrary to this, a cervical nystagmus due to vascular causes shows a latency period after torsion of the neck and increases if the head remains in the extreme position. Before assuming a cervical origin of a vestibular vertigo, an examination for cervical nystagmus should be carried out. Such a cervical nystagmus is the only definite pointer towards a relation between an upper cervical spine syndrome and vertigo, which is sometimes assumed rather uncritically.

Adult↗
PubMed1982

[Enhanced variability of the thermal test with patients with vestibular disease (author's transl)].

The reproducibility of nystagmus-intensity was measured with patients with peripheral vestibular disease, and with healthy persons, by a fivefold repetition of the same thermal stimulus. Variability of the data of the patients was considerably higher than of the healthy persons. Thus, the "normal" data have only a restricted value. Therefore, interpretation of thermal tests is more difficult for patients with an eventual vestibular disease. The origin of the enhanced variability seems to be the weakness of the reaction per se, because strong stimuli and hence strong reactions with healthy persons, have a lower relative standard deviation. Furthermore, tonic fluctuation in the diseased vestibular system is probable, as healthy ears of patients with unilateral vestibular disease show increased variability. An improvement of the method of the test is necessary. This can, for instance be achieved by an examination with eyes open under Frenzel's glasses and by repeated, by short and by strong stimuli.

Ear Diseases↗
PubMed1981

[The effect of non-coplanarity of the horizontal semicircular canals on experimental vestibular testing (author's transl)].

It is generally accepted that the horizontal semicircular canals are coplanar. One hundred three elliptic tomograms of human temporal bones have been evaluated for their planar relationship. The median was 180 degrees. However, the values varied between 160 degrees and 223 degrees. Differences of more than +/- 10 degrees were found in 31% of all cases. These anatomic variations are important for experimental vestibular testing, if, e.g., vestibulo-spin al effects result in a deviation or a torsion. With rotatory testing, stimulus intensity is a function of head inclination in relation to the stimulus plane. Non-coplanarity associated with head inclination results in asymmetric stimulus strength. With thermic testing, the effective stimulus is a function of the angle between temperature gradient across the canal and gravitation. Besides deviations from the perpendicular plane, rotations within this plane, according to Brünings "Schiefoptimumstellung", additionally cause asymmetrical errors.

Ear, Inner↗
PubMed1981

[Impedance measurement for the diagnosis of middle ear effusions (author's transl)].

Impedance measurement is especially important for the diagnosis of middle ear effusions with pre-school-children. Instead of simply classifying into different tympanogram types, a descriptive analysis of each parameter is preferable. The presence of the stapedius reflex, middle ear pressure, form of peak, compliance and gradient of the tympanogram are discussed separately as to their sensitivity and specificity regarding diagnosis of effusion. The diagnostic certainty of the tympanogram is thereby considerably increased.

Acoustic Impedance Tests↗