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Biomedical subjects

M Straschill

Publications and source records attributed to M Straschill.

At least 19 recordsLinked to original sources
PubMed2001

[Neurosurgical therapy of Parkinson disease. Deep brain stimulation].

The introduction of continuous high frequency stimulation (deep brain stimulation) into functional neurosurgery has opened up new avenues in the treatment of Parkinson's disease. This new technique expands the therapeutic possibilities available to those patients in whom, over the years, the effectiveness of drug treatment has deteriorated, or severe side effects developed. In the individual case, the decision as to whether to operate is taken on the basis of interdisciplinary cooperation between the care-providing neurologist and the neurosurgeon specialized in this particular field.

Basal Ganglia↗
PubMed1992

Effect of the cholinesterase inhibiting substance galanthamine on human EEG and visual evoked potentials.

The action of galanthamine (GAL), a cholinesterase inhibiting substance, on resting EEG and on flash visual evoked potentials (VEPs) was tested in 9 healthy subjects. Alpha power was increased significantly in 4 of 8 subjects after the infusion of 10 mg, which provided a median inhibition of 47% of acetylcholinesterase in erythrocytes. Mean alpha frequency and peak alpha frequency decreased significantly in 5 of the 8 subjects by 0.22-0.98 Hz. Alpha power increase and alpha frequency decrease were not accompanied by changes in theta power. The amplitudes of the late components of the flash VEP were increased in 8 of 9 subjects receiving doses of 10-35 mg of GAL, while the early components remained unaffected. Increase of late VEP components was significantly correlated with the strength of cholinesterase inhibition. The synchronizing effect of GAL in these healthy volunteers obviously contrasts with the known desynchronizing effect of physostigmine in animal experiments.

Adult↗
PubMed1990

A technique for eliciting muscular reflex responses using position controlled dc motors.

A method for generating fast ramp movements is described. A direct current (dc) motor serves as a drive in position feedback mode. In addition to a regulator and a power amplifier, basically only two relatively simple analog circuits are required. One is a ramp function generator with continuously adjustable parameters. The ramp function can be adjusted to the electromechanic transfer function of the motor. A second circuit comprises an analog position storage and allows the ramp to be started from any resting position.

Electric Stimulation↗
PubMed1990

A method for separation of superimposed electromyographic responses in man.

Superposition of electromyographic potentials occurs when motor nerves are excited at intervals that are shorter than the duration of one single muscular signal. The method introduced here allows the separation of compound responses into their constituents in experiments with two closely spaced stimuli (conditioning stimulus and test stimulus), each of them eliciting a defined electromyographic response. Stimulus generation is controlled by a small laboratory computer which produces paired stimuli or the conditioning stimulus alone in random order. All responses are classified according to the size of the initial part of the response to the conditioning stimulus and averaged. The response to the test stimulus is obtained by a subtraction procedure. The method takes into account the considerable variability of reflex responses in man. It was tested in the analysis of recovery curves of spinal reflexes elicited by short vibratory pulses onto the tendons of relaxed human arm muscles.

Animals↗
PubMed1985

[Electric stimulation of the human olfactory nerve--an approach to short-term memory?].

Electrical stimulation of the human olfactory mucosa was performed by means of an electrode, which was attached to a rhinoscope. Stimulations of the nasal mucosa did not evoke the sensation of smell, but suppressed smell sensations of presented odorants. When electrical stimulation followed the exposure to an odorant within a certain interval, the stimulus recalled the faded sensation of the preceding odorant. Electrical stimulation without prior natural stimulation produced unpleasant sensations in three patients with a history of temporal lobe seizures and olfactory auras, but not in patients with primary generalized or focal epilepsy.

Electric Stimulation↗
PubMed1984

[Early ischemic lesions of hippocampus neurons in experimental status epilepticus].

The ischaemic changes in the hippocampus reported here were observed during a series of experiments in which the effect of ionized and non-ionized intracortically injected contrast media were investigated. Only the group with ionized contrast medium showed early ischaemic lesions in the hippocampal neurons. Our model is comparable with the final status epilepticus. Generalized spike activity of more than 2 1/2 hours, without a recovery phase, is involved. Our findings thus indicate that under certain conditions, i.e. in this case, generalized activity lasting for a long time, ischaemic lesions can occur. However, in view of the ultrastructural features, the changes can still be considered reversible.

Animals↗
PubMed1983

Effects of electrical stimulation of the human olfactory mucosa.

Electrical stimulation of the human olfactory mucosa was performed by means of an electrode attached to a rhinoscope . Stimulation of the nasal mucosa did not evoke smell sensations, but suppressed smell sensations of presented odorants. When electrical stimulation followed the exposure to an odorant within a certain interval, the stimulus recalled the already faded sensation of the preceding odorant. Electrical stimulation without prior natural stimulation produced unpleasant sensations in 3 patients with a history of temporal lobe seizures and olfactory auras , but not in patients with primary, generalized or focal epilepsy.

Electric Stimulation↗
PubMed1982

[Electroencephalographic changes induced by baclofen].

Electroencephalographic and clinical effects of baclofen were investigated in 46 neurological patients and 7 healthy volunteers. 27 cases showed an increase of slow EEG activity. Patients with spinal disease, brain-stem disease, disturbed vibratory sensation and also with renal insufficiency showed pronounced EEG-slowing. Baclofen depresses the activity in primary afferents and reticulocortical afferents. These effects can lead to EEG slowing. One patient developed a reversible organic brain syndrome and myoclonias with marked EEG-slowing and bilateral synchronous sharp and slow waves. This was interpreted as an epileptic stupor induced by Baclofen. The patient had renal insufficiency and accumulated Baclofen. Both conditions may have contributed to the epileptic manifestation.

Adult↗
PubMed1981

The effects of focal epileptic activity on the somatosensory evoked potentials in the rat.

The cortical somatosensory evoked potential (SEP) of the rat, evoked by contralateral forepaw stimulation, consisted of early (P 1 and N 1) and the late components (P 2 and N 2). Microelectrode recording yielded evoked unitary responses of short latencies in the range of the early components and responses of longer latencies in the range of P 2. During the development of focal epilepsy after topical application of penicillin, the late components of SEP were enhanced and the enhanced late negativity corresponded to a surface negative cortical spike. The prominent enlargement of later components was associated with prolonged, often recurrent discharges of long latency unitary responses and with enlarged local field potentials. Early components of SEP remained relatively unaffected and so did unitary responses with short latencies. Epileptic spike-conditioned SEPs in the cuneate nucleus, thalamic sensory relay nucleus and sensory cortex were depressed from 100 ns (cuneate nucleus) to about 300 ms (thalamus and cortex) subsequent to spike discharge. Transmission in the cuneate nucleus was least affected. Thalamic and cortical early components of SEP had similar time courses of recovery, which differed markedly from hat of cortical late components. Our findings suggest that two different neuronal activities generate different components of SEP and are differentially involved in the epileptic activities, which results in the different amplitude recovery following spontaneous epileptic spike discharges.

Animals↗
PubMed1981

Slow potentials in the human subthalamus associated with rapid arm movements.

During stereotactic operations brain potentials were recorded from the zona incerta of Parkinsonian patients. When the patient performed a rapid contralateral elbow flexion in response to a light signal, a slow positive or positive-negative EEG potential preceded the EMG activation by 30-130 ms (average 60 ms) and extended into the biceps activation phase. It was not evoked by the light flash alone or by rapid passive flexion. The potential may be interpreted as a correlate of movement-related activity of cerebellothalamic pathways mediating command signals for rapid arm movements. In support of this assumption, a marked delay of contralateral biceps activation followed coagulation of the recording site.

Arm↗
PubMed1980

[Absence of the first component of the blink reflex with preservation of late components in a case of intrapontine tumor (author's transl)].

In a patient with an infiltrating intrapontine tumor the first component of the blink reflex on the lesion side was abolished, while all other components during ipsi- and contralateral stimulation were intact (fig. 1). Such a response pattern suggests a lesion, which selectively interupts the intrapontine afferent are of the mono- or disynaptic pathway underlying the early response (fig. 2).

Blinking↗