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Biomedical subjects

K F Hamann

Publications and source records attributed to K F Hamann.

At least 19 recordsLinked to original sources
PubMed1998

Long-term deficits in otolith, canal and optokinetic ocular reflexes of pigmented rats after unilateral vestibular nerve section.

Static and dynamic otolith, horizontal vestibular and optokinetic ocular reflexes were investigated in pigmented rats 1-6 and more months after unilateral vestibular nerve (UVN) section. Evoked responses were compared with published data from control rats studied under identical conditions. Static lateral tilt of UVN rats in the light evoked a vertical deviation in static eye position that was as large as in controls. In darkness, the evoked responses in UVN rats 6 months after the lesion were consistently smaller than in controls. Linear horizontal acceleration in darkness evoked vertical and torsional response components in UVN rats that were parallel-shifted towards lower gains and larger phase lags. Off-vertical axis rotation on a platform provoked responses that differed markedly from those recorded in intact rats with respect to the bias velocity component. These results suggest a permanent deficiency in the static and dynamic otolith-ocular reflex performance of UVN rats. Ocular responses to horizontal table velocity steps in darkness exhibited a direction-specific asymmetry in UVN rats. Step responses evoked by acceleration towards the intact side were larger in gain and longer in duration than responses evoked by acceleration towards the operated side. When compared with control data, responses to either side were reduced in UVN rats and the velocity store mechanism was barely activated by velocity steps towards the operated side. Responses evoked by horizontal optokinetic stimulation with constant pattern velocities were below control values in either direction. Slow-phase eye velocity saturated at much lower values than in intact rats, particularly during pattern motion towards the intact side. The duration of the optokinetic afternystagmus was asymmetrically reduced with respect to control data. Practically identical reductions in duration were found for vestibulo-ocular responses in the opposite directions. Behaving animals exhibited no obvious impairment in their spontaneous locomotory or exploratory activities. However, each UVN rat was impaired, even 2 years after the lesion, in its postural reaction to being lifted by the tail in the air. This observation suggests the presence of a permanent deficit in static and dynamic otolith-spinal reflexes that may be substituted on the ground by proprioceptive inputs.

Animals↗
PubMed1994

[Therapy of isolated acute laryngitis with fusafungin. A phase IV study].

Four-hundred and eighty-four patients with acute laryngitis were examined before and after treatment with fusafungin under phase IV conditions. After one week of therapy such complaints as hoarseness, sore throat and difficulties in swallowing were improved in about 90% of the patients, while the leading complaint of "hoarseness" had disappeared in 60%. Inflammatory findings, documented by a physician, showed comparable results. An analysis of subgroups (ineffectively treated patients and patients with long-lasting symptoms and complaints) shows that fusafungin was effective therapeutically for treating for acute laryngitis. This study also shows that the generally accepted high rate of spontaneous recovery does not exist.

Acute Disease↗
PubMed1993

[Therapy of vestibular vertigo].

The non-surgical treatment of vestibular disorders must be based on current knowledge of vestibular pathophysiology. It is generally accepted that after vestibular lesions a self-repair mechanism exists that allows a more or less complete recovery. In cases of persisting vestibular complaints the physician's duty consists in stimulation of these pre-existing mechanisms. This can be done by physical exercises, as has been recommended since the work of Cawthorne and Cooksey in 1946. This concept is meanwhile supported by modern neurophysiological research. This article describes a short training program consisting of exercises for fixation during rotations, smooth pursuit, optokinetic nystagmus and motor learning mechanisms. Physical exercises can be reinforced by nootropic drugs.

Dominance, Cerebral↗
PubMed1989

[Ultrasonics in the diagnosis and follow-up of tumors of the inner nose and paranasal sinuses].

Ultrasound diagnosis is not applicable in diagnostics and monitoring of tumors of the inner nose; the B-mode can be used only if the lumen of the nose is completely filled out by the tumor. In case of the paranasal sinuses the A-mode imaging furnishes a pattern containing back wall echoes and intermediate echoes which necessitates further diagnostic measures. Thanks to the B-mode imaging it is possible to determine the tumor extent and an eventual infiltration into the surrounding tissues. The pre- and posttherapeutic diagnosis of tumors of the inner nose and the paranasal sinuses contains also an investigation of the neck in order to detect possible metastases.

Follow-Up Studies↗
PubMed1988

[Rehabilitation of patients with vestibular disorders].

The connections between the two vestibular nuclei permit vestibular compensation after unilateral lesions. The interactions between the vestibular and the visual and proprioceptive system can support vestibular compensation. Our physical training program for the treatment of vertigo is based on these mechanisms. The training consists of fixation exercises, smooth pursuit and motor learning by proprioceptive cognition. The results are very convincing.

Humans↗
PubMed1988

[Neurinoma of the vocal cord. A case report].

Neurilemmoma is an extremely rare tumour of the larynx. A case of a 75-year-old woman who complained of increasing hoarseness for several months is reported. Clinically the tumour looks like a polyp of the left vocal cord. The tumour was completely removed endoscopically. Histological examination, however, revealed a neurilemmoma. To the present day only two cases of neurilemmoma of the vocal cord have been reported in the literature.

Aged↗
PubMed1988

[Possibilities for quantifying vestibular vertigo].

The problem of the quantification of vertigo is still unsolved. In this article, two methods in the field of visual orientation in which the vestibular system is involved, are proposed. The visual subjective vertical allows to determine the degree of deviations, which is augmented in acute vestibular lesions. - The degree of deviation correlates well with the subjective intensity of vertigo. Both methods seem to be useful in the quantification of subjective vestibular complaints.

Humans↗
PubMed1987

Dynamic characteristics of vestibular nuclear neurons responses to vestibular and optokinetic stimulation during vestibular compensation in the rat.

In albino rats and pigmented rats, neurons were recorded extracellularly in the vestibular nuclei during the first 2 weeks after unilateral labyrinthectomy in order to study the neuronal events occurring during vestibular compensation and the effect of unilateral vestibular lesion on the optokinetic responses of neurons in the vestibular nuclei. It was found in albino rats that a re-equilibration took place in the gains of type I neurons between both lesioned and intact sides. The gain of the rare type I neurons on the deafferented side, which was low just after the lesion (t less than 48 h) subsequently increased (48 h less than t less than 14 d) while on the intact side the gain was greater just after the lesion, and then decreased. This re-equilibration of the gains of type I neurons is considered to be the neuronal equivalent of behavioural effects which occur after hemilabyrinthectomy. In pigmented rats, most type I and II VN neurons recorded on both sides 24 to 96 h after the lesion did not respond to pure horizontal OKS, while in controls almost all of them responded. It seems evident that the tonic activation of VN neurons by vestibular afferences is necessary for their responsiveness to pure OKS. However, when comparing the gain/phase of their responses to pure, vestibular and combined optokinetic-vestibular stimulations, it was found that optokinetic inputs improved the performance of type I and II VN neurons on both lesioned and intact sides. Finally, the time course of vestibular compensation is shorter in pigmented rats than in albino rats, since the re-equilibration in gains between the two sides was already reached 4 days after the lesion in the former.

Animals↗
PubMed1987

[Diagnosis of malignancies in the head and neck area: impasse or progress? From the viewpoint of the otorhinolaryngologist].

The article describes the role of sonography in the diagnostic of head and neck tumors, comparing the advantages and disadvantages in regard to other methods. The suprasonic procedure permits the detection of the dimension, type, borderlines and relations of tumors to neighbour tissues. The method has a special value for preoperative staging and surgical planning strategy. But also in long time controls sonographic diagnostic takes a definitive place. The ultrasound controlled biopsy is regarded as an important progress.

Diagnosis, Differential↗
PubMed1987

[Effects of visual field stabilization on the behavior of automobile drivers: visuo-vestibular model trials].

Postural changes of body equilibrium on a moving force plate were examined for sinusoidal movements, saccades and frequency whilst different stimuli were applied under various visual conditions. If a dynamic stimulus was used, the stabilization of vision shows a distinct visual-vestibular conflict which provokes postural disequilibrium. This is the cause of motion sickness during car driving. This disequilibrium is also the cause of the motor insecurity experienced during walking and reading at the same time.

Adult↗
PubMed1987

[New aspects of differential vertigo diagnosis in childhood].

Eight cases of vertigo in childhood are reported. Four of them suffered from benign paroxysmal vertigo, and the other four from atypical migraine. History of a head injury and attacks of vertigo lasting only a few seconds are typical of benign paroxysmal vertigo. These children are older than 4 years and the vertigo is of peripheral origin. Vertigo due to atypical migraine is frequent in young children up to 4 years of age, shows a longer duration of vertigo (more than 1 min) and is of central origin.

Adolescent↗
PubMed1986

[Effect of stabilization of the visual field on rotatory testing].

The nystagmus of 20 normal subjects was compared by means of the rotatory test in the dark, in respect of visual fixation, and with stabilization of vision. Visual fixation was tested by means of a small lamp placed at a distance of 40 cm in front of the eyes of the subject. This point of fixation was attached to the rotating chair. Stabilization of vision was attained through a box placed above the head of the test person. This box - covering the whole visual field - moved synchronously with the rotating chair. Contrary to the test with fixation, the eye received no information about the real movement. The question was whether there would be any differences between the fixation test and the stabilization of vision. In both test conditions, fixation overrides the vestibular stimulus and results in suppressing both per- and postrotational nystagmus. This proves that the foveal vision and not peripheral vision is responsible for the suppression of fixation.

Adolescent↗
PubMed1985

[Critical remarks on so-called cervicogenic vertigo].

A critical review of neurophysiological literature is given about the part played by the neck proprioceptors in the regulation of vestibular functions. In comparison with vestibular and optokinetic influences the neck proprioceptors are of secondary importance. A critical review of the publications by the supporters of a cervical genesis of vertigo leads to the conclusion that "cervical nystagmus" must be proven before the concept of neck-triggered vertigo can be accepted. In relation to all forms of vertigo, vertigo induced by cervical disorder represents a very low percentage only.

Afferent Pathways↗