[Neurosurgical therapy of Parkinson disease. Deep brain stimulation]. / Neurochirurgische Therapie der Parkinson-Krankheit. 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.

Acute bilateral arm paresis.

OBJECTIVE: To study pure motor bilateral arm paresis of acute onset. This syndrome is as yet a barely described clinical feature attributed to ischemia in the territory of the anterior spinal artery (ASA). CASES: We present 2 patients with acute onset of pure motor deficit in both upper extremities. RESULTS: Magnetic resonance imaging of the cervical spinal cord revealed infarcts in the territory of the ASA. In 1 case, electrophysiology further suggested discrete gray matter involvement. CONCLUSION: In patients with acute weakness of both arms without further neurological deficits, an incomplete ASA syndrome should be considered with the anterior horns predominantly being affected. Magnetic resonance imaging and electrophysiology are valuable tools to further confirm both location and extension of the spinal lesion.

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.

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.

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.

[Effect of emotional problems on the course of idiopathic spasmodic torticollis]. / Uber die Wirkung emotionaler Einflüsse auf den Verlauf des idiopathischen spasmodischen Torticollis.

Although in many cases of idiopathic spasmodic torticollis emotional problems play an important role in symptom onset their influence on the course of the disease seems little. In some cases however psychotherapy is indicated. Working through the basic neurotic problems may lead to an improvement of the torticollis.

[Effect of emotional factors on the occurrence of idiopathic spasmodic torticollis]. / Der Einfluss emotionaler Faktoren beim Auftreten des idiopathischen Torticollis spasmodicus.

Beginning with a pathophysiological and historical introduction the author gives an overview over the different forms of psychotherapy used for torticollis. A special reference is given to psychoanalytic concepts. The different etiological concepts of this disease imply corresponding heterogeneous forms of therapy.

[Electric stimulation of the human olfactory nerve--an approach to short-term memory?]. / Elektrische stimulation des menschlichen N. olfactorius-ein Zugang Zum Kurzzeitgedächtnis?

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.

[Early ischemic lesions of hippocampus neurons in experimental status epilepticus]. / Fräuhe ischämische Läsionen der Hippofampusneurone im experimentellen 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.

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.

[Electroencephalographic changes induced by baclofen]. / Elektroenzephalographische Veränderungen unter 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.

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.

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.

[Absence of the first component of the blink reflex with preservation of late components in a case of intrapontine tumor (author's transl)]. / Orbicularis-oculi-Reflex mit fehlender früher Komponents und normaler später Reaktion bei einem Patienten mit intrapontinem Tumor.

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).