PubMed Health⌕ Search

Biomedical subjects

C R Pfaltz

Publications and source records attributed to C R Pfaltz.

120 records · Page 7Linked to original sources
PubMedDate not supplied

The influence of optokinetic training upon vestibular habituation. Ok-induced modification of vestibular responses elicited by sinusoidal stimuli.

Unidirectional optokinetic training modifies the response pattern of bidirectional sinusoidal vestibular stimuli (pendular rotation), resulting in an initial response decline. The latter affects only slow phase velocity, whereas the former shows a frequency increase. Optokinetic training obviously has a facilitating effect upon vestibular habituation which cannot be induced by repeated sinusoidal vestibular stimuli alone. Peak frequency increase as well as slow phase velocity decrease of vestibular nystagmus, induced by optokinetic stimuli, are interpreted as a typical transfer mechanism across two sensory systems.

Eye Movements↗
PubMedDate not supplied

Studies on the anatomy of the facial nerve.

The present study on the anatomy of the human facial nerve is based on the results of a series of gross dissections, and histological and electro-diagnostic examinations. From our findings it follows that there is a definite spatial orientation of the peripheral branches in the facial nerve trunk. The results of the morphologic studies are in agreement with those obtained by electric stimulation combined with electromyography.

Axons↗
PubMedDate not supplied

Vestibular compensation. Physiological and clinical aspects.

Vestibular compensation is achieved by means of a multisensory substitution process. Experimental and clinical observations indicate that patients, suffering from a sudden loss of vestibular function, should get an early multisensory training in order to induce adaptive changes as soon as possible.

Humans↗
PubMedDate not supplied

Long-term modifications of vertical and horizontal vestibulo-ocular reflex dynamics in man. I. After acute unilateral peripheral vestibular paralysis.

Horizontal (HOR) and vertical (VERT) vestibulo-ocular reflex (VOR) responses to whole-body triangular velocity profiles with constant accelerations of 10, 15 and 20 deg/s2 were studied in two populations: normals, and patients with acute unilateral peripheral vestibular paralysis. The effect of this type of unilateral deficit on VOR gain and long time constant were determined as well as the time course of the compensation processes for HOR and VERT VOR dynamics. In the patient population, HOR VOR gain was asymmetric post deficit, being, on average, 50% and 75% of normal for rotations toward and away from the deficit, respectively. For the VERT VOR, on average, a symmetric 66% reduction occurred. The VERT VOR time constant was marginally affected by the deficit. HOR time constants were reduced for both directions of rotation. HOR and VERT VOR gain was within normal limits 1-3 months following an acute paralysis; time constants required a longer recovery period. Our results indicate that a unilateral deficit causes a markedly different alteration for HOR VOR dynamics compared to the effect on VERT VOR.

Adolescent↗
PubMedDate not supplied

Indicators of the influence a peripheral vestibular deficit has on vestibulo-spinal reflex responses controlling postural stability.

For a controlled sway stabilization task, the areas underlying EMG responses in ankle and neck muscles, as well as amplitudes of ankle torque responses, were shown to be significantly correlated with the clinically defined extent of a patient's peripheral vestibular deficit. The responses, elicited by ankle dorsiflexion of the support surface on which the subject stood, were statistically examined in order to select those measurements which would best indicate differences between a normal, a patient with a unilateral deficit, or one with a bilateral deficit. For this purpose, a stepwise discriminant analysis was performed on measurements of head and trunk angular accelerations in addition to muscle EMG and ankle torque signals. The primary measurements selected to optimally assign a subject to a population were the periods of ankle torque and neck extensor activity associated with correcting for the imposed body displacement backwards and maintaining upright head position respectively. The resulting division into populations was 100% correct. However, within the population of unilateral deficit patients, the technique failed to correctly identify those with acute from those with compensated deficit. This technique of investigating vestibulo-spinal reflex responses is more specific and sensitive than Romberg tests, because it will quantify and specify the underlying cause of the patient's balance and ambulatory disorder.

Adult↗
PubMedDate not supplied

Critical evaluation of the immunofluorescence microscopic test for identification of serum antibodies against human inner ear tissue.

One hundred and nineteen serum samples from patients with bilateral sensorineural hearing loss of unknown etiology were investigated for the presence of antibodies against homologous inner ear tissue. 54% of all investigations revealed a binding of serum immunoglobulins even after repeated checks, whereas the investigation of 25 control sera of healthy subjects revealed a false-positive result in only one single case: in this control subject, a manifest rheumatism could be diagnosed later. A correlation between the positive result of the immunofluorescence test and clinical parameters which might indicate a pathoimmune mechanism could not be detected. The question arose as to whether immunologically induced alterations in the region of the human inner ear can be demonstrated at all with the methods of investigation in clinical use today to detect a systemic pathoimmune mechanism.

Autoantibodies↗