Therapeutic trial with N-acetylcysteine in amyotrophic lateral sclerosis.
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Acetylcysteine↗
Biomedical subjects
A Struppler
Publications and source records attributed to A Struppler.
Transformation modes in computerized human thalamic brain mapping.
An exact transfer of data intraoperatively gathered in thalamic nuclei to an anatomical atlas requires an efficient mathematical transformation mode. Three different kinds of transformation modes were analyzed: First, the AC PC distance was used as a parameter to correlate data with the atlas coordinate system. Second, the influence of the patients 3rd ventricle widths on the transformation procedure. Third, a transformation mode was performed based on "noise"-data, registered when the electrode penetrated patient's thalamus. This method was also used to combine the atlas and CT images.
Brain Mapping↗
Computer-assisted analysis of functional anatomy of human ventrolateral thalamus.
A three-dimensional map was created by a computer-assisted analysis of functional and somatotopic organization of the target area in the human ventrolateral thalamus. Stimulation in the target area mostly elicited increased tone in skeletal muscles, with a concomitant decrease or stop of tremor. Despite averaging of all responses, no clear somatotopic organization could be demonstrated for the tonifying stimulation effects. In addition, somatosensory-evoked potentials were recorded, indicating an afferent projection to the target area.
Brain Mapping↗
An intraoperative interactive method to monitor stereotactic functional procedures.
A computer graphic technique is presented, which makes it possible to handle neurophysiological and neuroanatomical data collected during functional stereotactic procedures.
Computer Graphics↗
Somatosensory evoked potentials in the ventrolateral thalamus.
Within the target area (VL) used for the stereotactic treatment of parkinsonian tremor and spasmodic torticollis, electrical stimulation as well as recording of somatosensory evoked potential (SEP) was performed. The effects of stimulation in the target area are facilitation of muscle tone showing some degree of somatotopic distribution. The recorded SEPs indicate a projection of an afferent system (probably of muscle afferents) to the target area. We assume that the target area is a relay station involved in the control of muscle tone. The interruption of muscle afferents in combination with the correct somatotopic localization of the lesion is important for the therapeutic efficacy in parkinsonian tremor and spasmodic torticollis.
Afferent Pathways↗
Discharge pattern of single motor units in basal ganglia disorders.
We studied the discharge pattern of motor units (MUs) from the first dorsal interosseous muscle during slight stationary isometric contraction. In six controls, seven patients with parkinsonism, and five patients with choreic disorders, we analyzed 78 MUs. About one-half of the MUs in both patient groups fired irregularly as shown by interval histograms, joint interval histograms, and corresponding statistical calculations. Cross-correlation techniques revealed a characteristic type of MU synchronization in parkinsonism. Analysis of the MU discharge pattern can be useful in clinical assessment of these disorders.
Adult↗
[Differential diagnosis of pain].
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Abdomen↗
[Disorders of motor unit discharge activity in parkinsonism].
The discharge activity of single motor units (MUs) of the first dorsal interosseus muscle was recorded in slight stationary isometric contractions. Normal subjects and patients with parkinsonism of various degrees were investigated. The purpose was to study disturbances of the discharge pattern in the patients and their potential diagnostic role. Automatic signal recognition and statistical analysis of the interval distribution were used. Most MUs of the patients revealed considerable irregularities of their discharge sequences best marked by the so called "floating standard deviation". All patients, also 2 without tremor, showed a characteristic synchronization of their MU discharges ("broad-peak" type). Since the above changes were also seen in the patients with only slight symptoms, these investigations, if methodically simplified, could be of diagnostic value.
Action Potentials↗
Changes in the recruitment pattern of single motor units in the blink reflex of patients with parkinsonism and hemiplegia.
The recruitment pattern of single motor units (SMUs) was studied in the early (R1) and late (R2) blink reflex components in normal subjects (15), patients with parkinsonism (10) and with hemiplegia due to hemispheral lesions (5). Reflexes were evoked by constant current stimuli applied to the supraorbital nerve. SMU discharges were recorded in the preseptal part of the lower eyelid using a bipolar needle electrode. Thresholds of R1 and R2, latencies at the thresholds and the number of discharges in R2 were determined. In parkinsonism, the recruitment of SMUs in R1 was impaired, suggesting that the malfunction of the basal ganglia in this disorder is associated with a reduced excitability of neurons in the pontine brain-stem. In hemiplegia, the recruitment in both R1 and R2 could be impaired. The orderly function of neurones in the pontine and medullary pathways of these components appears to require facilitatory hemispheral influences. Signs of disinhibition occasionally found in R1 may point to an imbalance between facilitatory and inhibitory hemispheral influences upon the pontine pathway.
Adult↗
Synchronous discharges in pairs of steadily firing motor units tend to form clusters.
Discharges of several motor units (MU) were simultaneously recorded during slight isometric contractions of the first dorsal interosseus muscle using bipolar needle electrodes. Correlograms constructed by counting the relative discharge intervals (1-ms binwidth) between two MU frequently showed narrow central peaks reflecting the occurrence of more synchronies than expected by chance. Diagrams of the temporal distribution of these synchronies revealed that they tend to form clusters consisting of several subsequent events associated with an adjustment of the firing pattern of the two MU. The synchronization described here may be explained by similar mechanisms as the so-called 'short-term synchronization'.
Adult↗
Effect of stereoencephalotomy on long-latency EMG responses and motor control of arm movements in Parkinson's syndrome.
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Diencephalon↗
Blink reflexes in hemi-Parkinson syndrome--reduction of the responses on the affected side.
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Blinking↗
Reinnervation of mechanoreceptors in the human glabrous skin following peripheral nerve repair.
The technique of percutaneous microneurography was used to record single unit activity from 65 reinnervated and 24 normally innervated mechanoreceptors in the glabrous skin of the human hand. The results were obtained from 20 patients and 5 control subjects. The patients had suffered complete traumatic transsection, with subsequent repair, of the median or ulnar nerves. Three types of mechanoreceptors (RA, SAI, SAII) and many unidentified units located in deep tissues were found to become reinnervated. No reinnervated PC units could be identified. Response thresholds, discharge characteristics and receptive field properties of reinnervated receptors were comparable to normal, with the exception that reinnervated SA I units had slower static discharge rates and smaller receptive fields. No evidence was found for multiple peripheral innervation by a single afferent fiber. The reinnervated mechanoreceptors were predominantly located in the palm and the proximal fingers with few in the finger tips, contrary to normal. The locations and frequency of occurrence of the different types of receptors could be correlated with the goodness of sensory recovery. It is suggested that these differences result from misguidance of regenerating fibers and from poor reinnervation, and that they account for reduced sensitivity and poor tactile discrimination in patients with peripheral nerve injuries.
Adolescent↗
Spindle activity and monosynaptic reflex excitability during foreperiod.
Healthy volunteers were instructed to perform an isometric plantar foot flexion as quickly as possible after a foreperiod (FP) of 1000 msec defined by two clicks (warning signal (WS) and response signal (RS). In 6 volunteers the H reflex was evoked in triceps surae muscle and recorded by surface electrodes (stimulus intensity 30% of maximum). The H reflex was elicited at WS and RS as well as during FP at intervals of 100 msec. H reflex amplitudes were taken as a sign of monosynaptic reflex excitability (MSRE). Amplitudes during FP were compared with the average control values at rest. Relaxation of lower limb muscles before and during FP was controlled by EMG. MSRE was increased in the first part of FP with a maximum at 300 msec after WS and decreased in the second part, with a minimum at 800 msec after WS. In a second series of experiments, in 10 volunteers, single fiber activity from primary muscle spindle afferents was recorded with tungsten electrodes from deep peroneal nerve (6 records) and from tibial nerve (3 records). The activity of primary spindle afferents before and during the FP was calculated by instantaneous discharge frequency and histograms of spike distribution. The EMG was taken from sural triceps and anterior tibial muscles with needle electrodes; a mechanogram of tendon deflection was taken by an appropriate strain gauge. In 5 primary afferents without spontaneous activity at rest and during FP, discharge started with a delay of 10-15 msec after the onset of EMG activity during the motor reaction.(ABSTRACT TRUNCATED AT 250 WORDS)
Electromyography↗
The effect of epidural application of opioids on spasticity of spinal origin.
The effect of epidural opioids on spinal spasticity is demonstrated in a patient suffering from multiple sclerosis. Flexor reflex spasms are abolished and muscle tone is markedly reduced by the epidural administration of morphine 3 mg or fentanyl 0.1 mg. In contrast, the oligosynaptic motor responses and voluntary movements were unaffected. This is documented by EMG-recordings. Sensory perception thresholds were elevated for pain, but unchanged for touch and vibration sense. Effects on enkephalinergic interneurons on the spinal level are discussed.
Epidural Space↗
The control of isometric contractions in patients suffering from different types of hypotonia.
Different forms of hypotonia, resulting from various lesions in the somatosensory system, are discussed. In order to investigate the causes of hypotonia the forearm flexors of patients were stretched and the segmental EMG responses studied. Special attention was given to parkinsonian patients who were stereotaxically operated for the relief of tremor. These patients were studied before and after their operation and their reflex responses were compared to those of normal subjects. It was found that the M2 component was always significantly larger before operation when compared to normal subjects. This could be due to high-frequency firing of single motor units during the M2 interval, as shown with single unit analysis. After operation the M2 component was significantly reduced; clinically hypotonia was observed. It is thus suggested that hypotonia observable in parkinsonians following subthalamotomy and/or thalamotomy could be the result of the decreased M2-component. Pathways which may be interrupted by the lesion are discussed and possible mechanisms mediating unusually high M2-components are mentioned. The hypothesis is forwarded that the stereotaxic lesion may selectively interfere with the static gamma drive to muscle spindles.
Diencephalon↗
[Function of early and late components of the blink reflex--study of discharge behavior of single motor units].
The discharge pattern of single motor units in the early (R1) and late (R2) component of the electrically evoked trigemino-facial blink reflex was investigated by means of selective EMG-recording techniques. At low rate stimulation (0,1 Hz) the stimulus threshold of motor unit discharges in R1 was clearly above that in R2. Higher stimulation rates (1 Hz) were associated with an attenuation of motor unit discharges in R2 according to the well known habituation. The same motor units, however, revealed stable discharges in R1 or even signs of facilitation. These differences of motor unit recruitment in the two components indicate that R1 cannot be simply interpreted as a protective reflex like R2. At higher stimulus intensities, the characteristical firing pattern consisted of single discharges in R1 followed by high frequency multi-discharges of the same motor units in R2. This means that the motor unit discharges in R1 do not only evoke a single twitch of the eyelids but initiate a vigorous tetanic contraction with short latency. Thus, R1 yet reveals a protective function shortening the latency of the reflex blink upon stronger stimuli on the side of the affected eye.
Adult↗
Quantitative analysis of the glabellar reflex in patients with hemiplegic disorders.
The glabellar reflex (GR) was investigated in 15 patients with hemiplegia and in 10 control subjects. The reflex was elicited mechanically by a light tap on the glabella. The EMG-responses were recorded bilaterally from the orbicularis oculi muscles by pairs of surface electrodes. The EMG activities were averaged and integrated off-line. In addition, the latencies of the early and late components were determined. Two major types of the GR alterations could be distinguished. These two patterns probably indicate a lowered excitability of the brainstem trigeminal systems or brainstem facial systems respectively. A loss of facilitatory influences associated with the hemispheral lesion seems probable. The alterations of the early component showed essential linkage to those of the late component. The latencies of GR responses on both sides were frequently prolonged. This fact and the decrease of the GR responses on the unaffected side as well as on the affected side indicates that the glabellar reflex can be altered bilaterally in hemiplegic patients.
Adult↗