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Biomedical subjects

C R Pfaltz

Publications and source records attributed to C R Pfaltz.

At least 73 records · Page 4Linked to original sources
PubMed1977

The influence of optokinetic training upon vestibular responses induced by repetitive sinusoidal stimuli.

Optokinetic and vestibular training alternatively applied during two cycles, using sinusoidal pendular rotation and a stationary projection optokinetic stimulator, resulted in a progressive vestibular response decline. This response decrement was only revealed by the parameter of the slow-phase velocity. Combined optokinetic and vestibular training shows a facilitating effect upon vestibular habituation which cannot be induced by repetitive pendular rotation alone. Both a response decline, expressed by the parameter of the slow-phase velocity and a response increment, expressed by the number of nystagmus beats, were observed during one cycle of the pendular rotation. Both phenomena could be induced by alternative optokinetic and vestibular training and were interpreted as typical visual-vestibular interaction mechanisms.

Eye Movements↗
PubMed1977

Optokinetic training and vestribular habituation.

The present study deals with the interaction of the visual and vestibular system with special reference to habituation. The results indicate that vestibular responses are modified by repeated uni- and bidirectional optokinetic stimulation. This transfer mechanism is more evident in test subjects after wide angle (foveo-peripheral) than after narrow angle (foveal) optokinetic stimulation. The modification of vestibular responses by means of repetitive optokinetic stimuli is characterized by an enhancement on the one side and a decline of the responses on the other, depending entirely on the nature of the optokinetic stimulus (uni- or bidirectional, foveal or foveo-peripheral). There is some evidence to suggest that these phenonomena are habituation transfer mechanisms. They seem to subserve the improvement of the gain of the vestibulo-ocular reflex. They help the vestibular system to improve the assessment of self-rotation within the environment and to impede the development of visual-vestibular conflicts.

Adolescent↗
PubMed1977

[Pathophysiological aspects of therapeutic procedures in Menière's disease (author's transl)].

Meniére's disease is a nosologic entity. Its underlying pathophysiological mechanism is based on a disturbance of the quantitative correlation between peri- and endolymph volume on the one side and on a qualitative disorder of sodium and potassium concentration in the inner ear fluids on the other, resulting in a disregulation of osmotic pressure within the labyrinth. However, a critical review of the current literature as well as personal observations confirm that at the present time the scientific basis of a causal therapy is still lacking. Hence, both conservative and surgical treatment of Menière's disease does not allow to cure the cause but only some of the symptoms.

Humans↗
PubMed1976

Vestibular diagnosis in Menière's disease.

Vestibular diagnosis of Menière's disease must be based on the results of an elaborate test battery. The latter should include a complete caloric test (stimulation with cold and warm water), carried out under nystagmographic control. Statistical analysis of caloric responses recorded in 100 normal test subjects by D.C. nystagmography show clearly that culmination frequency and culmination eye velocity are the most reliable parameters indicating an unilateral loss of function. With respect to the differential diagnosis - endorgan or neuronal lesion - only the galvanic test allows an unequivocal localisation of the site of the lesion. An analysis of 50 cases of Menière's disease reveals normal liminal and supraliminal galvanic responses without exception, thus indicating that the concomitant reduced caloric response is due to a lesion strictly confined to the vestibular endorgan. Hence the galvanic test may serve the same diagnostic purposes as supraliminal tests in pure tone audiometry.

Caloric Tests↗
PubMed1976

[Diagnostic importance of electrophysiologic tests in Bell's palsy: report on a longterm follow-up study in 100 cases (author's transl)].

The present study is based upon the results of repeated electrodiagnostic tests carried out in a series of 100 cases of Bell's palsy (Determination of Rheobase and Chronaxy). The first symptoms of denervation can be observed during the second week after the onset of the paralysis. This seems to be the critical period in which the ultimate consequences of the lesion are determined: partial or total recovery or complete irreversible denervation. In cases showing a rapid increase of chronaxy during the 2nd week, prognosis is rather poor because a difference of 240% between the affected and the normal side indicates a progressive denervation. Cases in which the difference of chronaxy values during the 2nd week is increased upto 240% (i.e. partial denervation) recover incompletely in 15% of the cases. Estimation of prognosis in Bell's palsy and timing of a facial nerve decompression must be based on reliable facts, such as the results of repeated electrodiagnostic tests (modified measurement of Rheobase and Chronaxy) carried out at least every secont but preferably every day during the first 3 weeks after the onset of the paresis.

Chronaxy↗
PubMed1975

[The acute vestibular paralysis (author's transl)].

Acute vestibular paralysis may not be considered as a nosologic entity but as a syndrome. Symptomatology (vertigo, spontaneous and provoked vestibular nystagmus, absence of cochlear signs) shows an uniform picture. The results of the caloric test as well as the nystagmic responses induced by galvanic stimulation and the development of central vestibular compensation however indicate that the site of the lesion is not only confined to the labyrinth but may also occur at the level of the peripheral neuron or even the vestibular nuclei. Etiology and pathology are still vague. Our own clinical observations as well as the scarce data in literature about morphological and experimental studies suggest in a way that vascular and infectious disorders are of importance as primary releasing factors. Hypothetically, vestibular loss of function may either be caused by a disturbance of labyrinthine microcirculation, initiated in a great majority of cases by infection, or by a direct lesion of the peripheral neuron as well as the vestibular nuclei. Retrolabyrinthine lesions may be due to menigoencephalitis, caused by a neurotropic virus or other infectious agents such as Toxoplasma gondii. Acute vestibular paralysis should be strictly distinguished from vestibular neuronitis. While vestibular paralysis is a syndrome, vestibular neuronitis must be considered as a nosologic entity, including a lesion of the peripheral neuron as well as evidence of an infectious event.

Adolescent↗
PubMed1975

Reconstructive surgery in chronic otitis media. Statistical analysis of long-term results.

Success or failure of tympanoplasty depends on the following factors: (1) the anatomic and functional state of the tympanic membrane and the ossicles; (2) type, extension and activity of chronic otitis media at the time of surgery; (3) permanent restoration and drainage of the middle ear, and (4) surgical technique. In the present long-term study 440 cases of tympanoplasty have been followed up for 2-10 years. The anatomic and functional results were evaluated statistically by a computerized data processing procedure. Thus, multiple correlations between the factors influencing the anatomic and functional results could be investigated.

Cholesteatoma↗