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Biomedical subjects

F Podivinský

Publications and source records attributed to F Podivinský.

At least 19 recordsLinked to original sources
PubMed1993

[Muscle reflex responses to paired electrical stimulation of peripheral nerves].

Double-shock bifocal peripheral nerve stimulation with varying interstimulus intervals (ISI) was applied to healthy human subjects. Short (SLR) and long latency reflexes (LLR) from the slightly active first dorsalis interosseous muscle of the hand were recorded after an electrical conditioning stimulation of the index finger and test stimulation of the median nerve. It was found with intervals from 1 to 5 ms the size of the SLR and LLRs was smaller and unstable, possibly due to transmitter depletion at these short ISIs. With intervals of 10 ms and longer, the test responses progressively increased and were far larger than the control responses, probably due to some temporal summation with double-shock stimulation and some release of the transmitter substance after the conditioning cutaneous stimulus. (Fig. 3, Ref. 18.).

Adult↗
PubMed1992

[The role of short and long latency reflexes in the small muscles of the hand in the diagnosis of movement disorders--an electrophysiology study].

EMG changes of short (SLR) and long latency reflex (LLR) responses to electric stimulation of digital nerves of the index finger were recorded from the interosseous dorsal muscle I during its slight isometric contraction. Abnormalities of SLR and LLR were found at least on one hand in 9 of 11 patients with nosologically different dysfunctions of the nervous system. SLR latency can yield information on lesions of the peripheral motoneuron. LLR latency proved to be a sensitive indicator of spinal and supraspinal lesions, and since it has also an efferent branch and, unlike SEP, it can detect also lesions of the descending corticospinal pathway. Prolonged SLR latency occurred frequently in s. m. Assessment of muscle reflexes is a valuable auxiliary method in identifying lesions of the peripheral and particularly of the central nervous system.

Adolescent↗
PubMed1992

[Computer analysis of muscle reflex responses to electric stimulation of peripheral nerves].

A computer program is described which allows analysis of reflex muscle responses to electric stimulation of peripheral nerves. Basically, the program is derived from an older methodic approach, yet the process of evaluating the obtained means of reflex muscle responses is in this computer assisted procedure simpler and of a higher quality. The proposed improvement of the original methodic approach provides an important advantage for clinical practice in significantly speeding up the investigation and evaluation of reflex muscle responses on using financially accessible computer technique of Czechoslovak make. The paper points out the possibility of using the program also for analysis of other biological signals and of adjusting it for more efficient types of personal computers.

Electric Stimulation↗
PubMed1990

[Long-loop muscle reflexes with a transcortical loop--mechanisms and practical applications].

The study of long latency muscle reflexes evoked by electrical stimulation of the digital nerves of the index finger and recorded from the first dorsal interosseous muscle with a mean latency of 50 ms provided some evidence on the potential existence of a transcortical loop. The method of long latency relexes can be used to advantage in electrophysiological diagnosis of disorders of the central nervous system, in stimulatory therapeutic rehabilitation and in motor reeducation. The study of supraspinal modulation of the H-reflex excitability curve by dermal and light stimuli inducing long loop reflexes yielded physiological characteristics of its course in healthy subjects and in patients with disorders of the central nervous system. The most striking abnormality of the curves was recorded in the different degree of their facilitation and in the absence of late inhibition in individual nosological units. The method served as the basis of the diagnostic test for the detection of cerebral dysfunction in arterial hypertension, focal cerebral lesions, and neurasthenias.

Adolescent↗
PubMed1989

[Does a "transcortical" loop of the long-latency muscle reflex exist?].

EMG responses were produced by electric stimulation of the dermal branches of the nn. digilates of the index finger of the right hand and recorded from the m. interosseus dorsalis I. during its slight isometric contraction. The mean initial latency of a long-latency muscular reflex was 50.68 ms in men and 49.13 in women. The author mentions some arguments indicating the probable existence of a transcortical loop: The latency of long-latency reflexes increases gradually from proximal to distal muscles. The short-latency component of the somatosensory evoked potential N20 appears mid-time between the time of the stimulus and the onset of the long-latency reflex and thus the time interval in the long-latency reflex is sufficient for a transcortical loop. The author found a facilitation of the muscular reflex response as well as of the preparatory cortical potential during the preparatory period of voluntary flexion of the fingers during concurrent electric stimulation of the peripheral nerve. The late reflex component increases considerably and is better synchronized during the movement of the thumb instead of isometric contraction, because during kinetic innervation afferent impulses reach the precentral cortex at a higher facilitated level. These results document well the modifiable, plastic behaviour of transcortical reflexes. The method of long-latency reflexes can be used in electrophysiological diagnosis of disorders of the CNS and it is promising also in therapeutic stimulation rehabilitation and in locomotor reeducation.

Adult↗
PubMed1985

Relation between changes in the preparatory brain potential and excitability of the H-reflex, and localization of a focal ischaemic brain lesion.

In the sample of 15 hemiparetics, ischaemic focus was localized cortically 8 times, deep subcortically 7 times. Use was made of a method that permits simultaneously to record both the cortical potential changes associated with preparation for voluntary movement, and excitability changes of the H-reflex. A slightly depressed amplitude of the preparatory brain potential and a relatively satisfactory facilitation of the H-reflex was observed in the light cortical focal brain ischaemia. A striking deformation up to disorganization of the preparatory brain potential and the absence of facilitation of the H-reflex in subjects with deeper subcortical ischaemic foci may be related to an impairment of the generator of the slow preparatory potential (thalamus, mesencephalon) and to a discruption of cooperation in the complex cerebral cortex - middle thalamus.

Adult↗
PubMed1983

Effect of vestibular electrical stimulation on the H-reflex.

A study was made of changes of exitability of the H-reflex m. solei under electrical stimulation of the labyrinth in hemiparetic patients with focal ischaemic lesion of the brain. In contrast to healthy persons, the potentiating effect of electrical stimulation of the labyrinth has a longer latency, a clearly lower amplitude and is protracted in time (we may say that the facilitating or potentiating effects are not well synchronized). The results are being interpreted on the basis of our research material and literary data obtained for the most part on experimental animals.

Adult↗