Myelitis after immunisation against tick-borne encephalitis.
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Adult↗
Biomedical subjects
G Deuschl
Publications and source records attributed to G Deuschl.
Characteristics of hand tremor time series.
Tremor is classified into physiological, essential, and parkinsonian tremor by means of clinical criteria. The aim of our work was to extract quantitative features from the measurements of the acceleration of human postural hand tremor. Different mathematical methods were adopted and modified in order to separate these three types of tremor. Best discrimination between physiological and pathological tremors has been achieved by methods distinguishing nonlinear from linear behavior. On the other hand, methods separating different forms of nonlinear behavior have been found to be superior in discriminating parkinsonian and essential tremor. By these methods physiological and pathological tremors can be separated with an error rate below 20% and essential and parkinsonian tremor with an error rate below 10%. This may help to classify tremor time series by objective mathematical criteria and may increase the understanding of the pathophysiological differences underlying these kinds of tremor.
Cybernetics↗
Source analysis of scalp-recorded movement-related electrical potentials.
We used brain electric source analysis to study the sources generating the movement-related cortical potentials during the interval from 200 msec before to 200 msec after the movement onset. Dipole solutions were obtained for the peak of the negative slope (pNS') and the frontal peak of the motor potential (fpMP) on scalp-recorded movement-related electrical potentials elicited by self-paced, repetitive unilateral finger movements in 10 normal volunteers. Two sources in homologous areas on each side of a spherical head model provided a satisfactory solution for the activity occurring at the instant of the pNS' in all subjects. The fpMP was modeled by a contralateral source and a midline source in 6 subjects and by a single contralateral source in the remaining 4 subjects. The percentage of the residual variance, or goodness-of-fit, over the interval from -200 to 200 msec, using the derived at pNS' and fpMP, was low. The results support the hypothesis that the NS' originates from the activity of bilateral generators in the sensorimotor cortex, and the motor potential arises from the combined activity of sources in the contralateral postcentral regions and the supplementary motor area.
Adult↗
Task-related changes in the effect of magnetic brain stimulation on spinal neurones in man.
1. The effect of magnetic stimulation of the human motor cortex on the excitability of soleus, tibialis anterior and flexor carpi radialis motoneurones was investigated by H reflex testing in ten healthy subjects. 2. At rest, an early facilitation of the flexor capri radialis and tibialis anterior H reflexes was always seen, whereas a similar early facilitation of the soleus H reflex was seen in only two out of seven subjects. For all three motoneuronal pools the facilitation was curtailed 1-5 ms later by an inhibition which lasted for another 3-4 ms. In five subjects an inhibition without any evidence of an earlier facilitation was seen for the soleus H reflex. 3. The intensity of the magnetic stimulation was subsequently decreased so that it had no effect on the H reflex at rest. When the subject then performed a voluntary agonist contraction a facilitatory effect with an early onset and a duration of 20-25 ms was observed for all three muscles. When the subject performed a voluntary antagonist contraction an inhibition was seen for the soleus H reflex with an onset 1-3 ms later than the facilitation. This is interpreted as resulting from the excitation by the magnetic stimulus of corticospinal neurones voluntarily activated in relation to the given motor task. 4. The initial part of the facilitation was significantly smaller during co-contraction of both agonists and antagonists than during isolated agonist contraction. 5. Whereas the early part of the facilitation always occurred during plantarflexion when the H reflex was conditioned by magnetic stimulation, this was never the case when it was conditioned by electrical stimulation of the cortex with the stimulus regimes used in these experiments. 6. It is suggested that the early part of the facilitation observed during agonist contraction is caused by activation of cortico-motoneuronal cells projecting to the agonist motoneuronal pool and that the inhibition observed during antagonist contraction is caused by activation of corticospinal cells projecting both to the antagonist motoneuronal pool and Ia inhibitory interneurones to the agonist motoneuronal pool. The smaller size of the earliest part of the facilitation observed during co-contraction in relation to agonist contraction suggests a different cortical control of the two tasks.
Adult↗
Cortical tremor. A common manifestation of cortical myoclonus.
Ten patients, three with postural tremor and seven with action myoclonus, had stereotyped involuntary rhythmic movements when attempting to execute a sustained isometric muscle contraction. The movements were characterized by rhythmic EMG bursts lasting less than 50 msec and appearing synchronously in agonist and antagonist muscles at a rate of 9 to 18 Hz. Backaveraging of the EEG activity related to the onset of the rhythmic EMG bursts identified a cortical potential preceding the EMG bursts in all patients. These symptoms and signs fit the description of "cortical tremor," a variant of cortical reflex myoclonus. Cortical tremor is common in patients with cortical myoclonus and may be a source of functional disability. In two patients in whom we studied the effects of graded levels of isometric force, force recruitment modulated the abnormal EMG bursting frequency, amplitude, and spatial distribution of the myoclonic jerks in the activated limb. Transcranial magnetic and electrical stimulation, but not peripheral nerve stimulation, influenced the abnormal EMG bursting pattern, implying a greater dependence of this rhythmic phenomenon on a central generator than on peripheral feedback loops.
Adolescent↗
Clinical and polymyographic investigation of spasmodic torticollis.
Polymyographic recordings were used to identify the most dystonic muscles suitable for local injection with botulinum toxin in 100 patients with spasmodic torticollis (TS). Rotating TS (72% of the patients) was due to dystonic activity of the splenius muscle ipsilateral to and/or the sternocleidomastoid muscle contralateral to the side of chin deviation. One-third of these patients had also dystonic activation of the contralateral splenius muscle and, rarely, the contralateral trapezius muscle. Ten patients had laterocollis due to dystonic activation of all recorded muscles on one side of the neck. Nine patients had retrocollis due to activity of both splenius muscles and rarely additional activity in both trapezius muscles. The type of dystonic muscle activity was found to be tonic, phasic or tremulous. Besides the evaluation of spontaneous dystonic EMG activity further examination during the "geste antagoniste" or the muscle activity during rotating head movements can provide additional information. It is concluded that polymyography may provide a rationale for identifying the dystonic muscles underlying the different forms of TS. It may prove to be helpful for the successful therapy with botulinum toxin and may be useful in differentiating tremulous torticollis from other types of head tremor.
Adolescent↗
Treatment of spasmodic torticollis with local injections of botulinum toxin. One-year follow-up in 37 patients.
Thirty-seven patients with spasmodic torticollis (cervical dystonia) who received repeated local injections of botulinum toxin have been followed up for a mean period of 12.3 (10-29) months, during which time 138 treatment sessions were performed. Mean doses per muscle averaged 320 mouse units (mu; range 160-1000 mu botulinum toxin A prepared by CAMR, Porton Down, UK). Eighty-six per cent of patients experienced significant improvement of posture and 84% of those with pain had relief following the first injection. Muscular patterns of recurrent torticollis were relatively constant and in most patients efficacy was maintained with subsequent injections, while 15% of all follow-up sessions failed. Only 2 of 37 patients were consistent nonresponders; 22% and 10% of all sessions were complicated by transient dysphagia and weakness of neck muscles, respectively. It is concluded that local botulinum toxin injections can be a safe and efficaceous long-term treatment of spasmodic torticollis and that optimal doses should be between 200 and 400 mu/muscle.
Botulinum Toxins↗
Reciprocal inhibition of forearm flexor muscles in spasmodic torticollis.
Reciprocal inhibition between forearm extensor and flexor muscles was tested by means of an H-reflex technique in patients with spasmodic torticollis and normal controls. In both, patients and controls three different phases of reciprocal inhibition could be demonstrated with maximal inhibition at conditioning test intervals of 0 ms, 15 ms and 100 ms, respectively. However, the quantitative amount of this inhibition was different for the patients and the controls. Significantly less inhibition was found for the second and the third phase of reciprocal inhibition in the patient group. Discriminant analysis showed a clear separation between normal subjects and patients if the amount of reciprocal inhibition of the second and third phase were taken into account. We were not able to detect any side differences neither for the patients nor for the controls. The findings demonstrate a functional disturbance of motor control mechanisms of a clinically unaffected extremity in spasmodic torticollis. This is believed to reflect a bilateral disturbance most likely within the basal ganglia or their outflow. Therefore, our data support the idea, that spasmodic torticollis is associated with or even due to a generalized rather than a focal disturbance of motor control mechanisms.
Analysis of Variance↗
Tremor in reflex sympathetic dystrophy.
Postural hand tremor was quantitatively investigated on both sides in 21 patients suffering from unilateral reflex sympathetic dystrophy of the upper extremity. On the affected side, enhanced tremor amplitude, with a mean tremor frequency of 7.2 Hz, was found in 57% of the patients. The appearance of tremor did not correlate to the occurrence of a single clinical symptom of reflex sympathetic dystrophy. On loading with increasing weight, the frequency of this pathological tremor shifted toward lower values, as it is found in physiological tremor. However, the peak frequencies of the electromyogram remained more or less stable. On recovery from this condition, the reflex sympathetic dystrophy tremor disappeared. Acute sympatholytic intervention could normalize reflex sympathetic dystrophy tremor. This would suggest that the sympathetic supply of the affected extremity contributes to the tremor in reflex sympathetic dystrophy. In conclusion, it is suggested that reflex sympathetic dystrophy should be included among the causes of tremor. According to our findings, tremor in reflex sympathetic dystrophy should be regarded as an enhanced physiological tremor.
Electromyography↗
Effects of electric and magnetic transcranial stimulation on long latency reflexes.
The interaction of transcranial electric and magnetic brain stimulation with electrically elicited short- and long latency reflexes (LLR) of hand and forearm flexor muscles has been investigated in normal subjects. In the first paradigm, the motor potential evoked in thenar muscles by transcranial stimulation was conditioned by median nerve stimulation at various conditioning-test intervals. At short intervals (electric: 5-12.5 ms, magnetic: 0-7.5 ms) facilitation occurred that corresponded to the H-reflex and at longer intervals (electric: 25-40 ms, magnetic: 22.5-35 ms) there was a facilitation corresponding to the LLR. Electric and magnetic stimulation resulted in a similar degree of facilitation. A second paradigm investigated the facilitation of the forearm flexor H-reflex by a cutaneo-muscular LLR elicited by radial superficial nerve stimulation and transcranial stimulation used separately or together. When electric and magnetic brain stimulation were compared, magnetic brain stimulation was followed by significant extrafacilitation but electric stimulation was not. This result favours an interaction between the afferent volley eliciting the LLR and transcranial magnetic stimulation most likely at supraspinal level.
Adult↗
Ear click in palatal tremor: its origin and treatment with botulinum toxin.
We report the successful treatment of a rhythmic, continuing ear click in a patient with palatal tremor with local injections of botulinum toxin into the tensor veli palatini muscle. We could demonstrate that the ear click occurred during contraction of the tensor veli palatini, which opens the eustachian tube. Therefore, we believe that the clicking noise is due to the sudden breakdown of the surface tension within the eustachian tube. Our observations suggest that the ear click is due to rhythmic discharges of the trigeminal nucleus rather than the ambiguous nucleus.
Auditory Perception↗
Parkinson's disease patient's behaviour in a covered maze learning task.
A computerized maze task was constructed that allowed only partial vision of the maze structure and produced measurements for separate analysis of cognitive processes described as impaired in Parkinson's disease. Eighteen patients suffering from mild Parkinson's disease and 18 individually matched normal controls were investigated. Baseline task response times were found to be identical for both groups. Differences between patients' and controls' performance could be related to (a) a response bias in Parkinson patients that favoured repetition of the previous action and slowed down shifting and (b) an impairment of multistep plan generation. It is speculated that the response bias reflects the disinhibition of cortico-thalamo-cortical reverberation loops which results from striatal dopamine depletion.
Aged↗
Physiology and clinical applications of hand muscle reflexes.
Hand muscle reflexes to stretch or electric stimulation of mixed nerves consist of two main components, the short latency reflex (SLR, M1) or Hoffmann reflex (HR) and the long latency reflex (LLR, M2). The SLR is most likely a spinal, monosynaptic reflex and all the evidence presently available supports a transcortical pathway of the LLR. Investigations in normal subjects demonstrate that the LLR is a reflex mediated by fast conducting muscle and cutaneous afferents. Group II muscle afferents do not significantly contribute to this reflex and it cannot be explained by repetitive excitation of spinal oligosynaptic pathways. These findings should not be uncritically generalized to other muscle groups, because the central and peripheral mechanisms apparently differ according to the body region and mode of stimulation. The LLR of hand muscles is most likely involved in skillful movements of the fingers. It is believed to assist rapid compensatory responses to unexpected disturbances. In addition to the main component of the LLR, which is called LLR II, the study of electrically elicited thenar reflexes following stimulation of the median nerve disclosed further LLR components, the LLR I and the LLR III. The latter reflexes are rarely seen in normal subjects but have a significance in several diseases. Several abnormalities could be demonstrated in different diseases. Enhanced HR and reduced LLR are found in spasticity of various origin. Enhanced LLR I are frequently seen in Parkinson's disease, essential tremor and reflex myoclonus. Absent or reduced LLR II is found in Huntington's disease and in different focal brain lesions but not in symptomatic choreatic syndromes of other origin. Delayed latencies of the LLR II or absent LLR II have been described in multiple sclerosis. Enhanced LLR III may occur in cerebellar diseases. The method to elicit LLR of thenar muscles by electric stimulation may prove to be useful for clinical neurophysiology.
Electric Stimulation↗
Symptomatic and essential rhythmic palatal myoclonus.
Rhythmic palatal myoclonus (RPM) is a rare movement disorder consisting of continuous synchronous jerks of the soft palate, muscles innervated by other cranial nerves and, rarely, trunk and limb muscles. It usually develops secondary to brainstem or cerebellar disease (symptomatic RPM). Some patients, however, fail to show evidence of a structural lesion (essential RPM). A total of 287 cases with RPM from the literature including 210 cases with symptomatic and 77 cases with essential RPM have been reviewed and analysed statistically to look for criteria separating the two conditions. Patients with essential RPM usually have objective earclicks as their typical complaint which is rare in the symptomatic form. Eye and extremity muscles are never involved. The jerk frequency is lower in essential than in symptomatic RPM. Patients with essential RPM are younger and have a balanced sex distribution as compared with a male preponderance in the symptomatic form. The rhythmicity of RPM seems to be more profoundly influenced by sleep, coma and general anaesthesia in essential than in symptomatic RPM. We conclude from these results that essential RPM should be separated as a distinct clinical entity. Symptomatic RPM is a rhythmic movement disorder whose pathogenesis is quite well established. The cells of the hypertrophied inferior olives are believed to represent the oscillator. Among other possibilities, essential RPM may represent its functional analogue, based on transmitter changes only. Such a relationship could be of theoretical interest for the understanding of rhythmic hyperkinesias in general.
Age Factors↗
New mutation to Huntington's disease.
We report a large family with an isolated case of Huntington's disease (HD), which is probably the result of a new mutation. The patient developed clinical signs typical of HD at the age of 36. The clinical course of the patient's disease is documented by several clinical admissions over a period of 14 years at present. The family history is strikingly negative with the parents having been clearly unaffected into their 80s and with 13 older and two younger, living, healthy sibs. Extensive testing of polymorphic markers (blood groups, red cell and serum proteins, HLA antigens) showed no indication of non-paternity, but rather gave strong support to the hypothesis that the proband is a full sib. In addition, DNA typing for several RFLPs known to be closely linked to the HD gene locus indicated that several clearly unaffected sibs share one or the other or both of the patient's haplotypes. This is further evidence in favour of the hypothesis of a new mutation at the HD locus. The posterior probability of a new mutation to HD in the patient exceeds 99%, even if an a priori probability of non-paternity of 10% and a mutation rate of HD of 10(-7) is assumed.
DNA↗
Hand muscle reflexes following electrical stimulation in choreatic movement disorders.
Thenar reflexes following electrical stimulation of the median nerve (containing proprioceptive and cutaneous afferents) and the radial superficial nerve (cutaneous afferents only) were investigated in 23 patients with manifest Huntington's disease (HD) at an early stage, in 17 clinically healthy descendants of HD-patients and in 18 patients with choreatic hyperkinesia due to various aetiologies other than HD. In 61% of the patients with early HD the long-latency reflexes (LLR) were uni- or bilaterally absent in response to both median nerve and radial superficial nerve stimulation. The remaining patients had a diminished mean amplitude and mean duration of their LLR. In contrast, offspring and patients with symptomatic chorea had preserved LLR which did not differ in amplitude or duration from normal controls. Additionally, the mean amplitude and mean duration of the Hoffmaan-reflex (HR) was found to be increased in patients with HD and their offspring but not in patients with other aetiologies. It is concluded (1) that the loss of LLR is not related to the choreatic hyperkinesia itself but to the degeneration of a hitherto poorly defined neuronal circuit in HD; (2) that among a variety of diseases presenting with chorea, the loss of LLR seems to be specific for HD; (3) that the testing of hand muscle reflexes in choreatic movement disorders is helpful for the differential diagnosis of early HD but not for the detection of gene carriers among offspring of patients with HD.
Afferent Pathways↗
[Idiopathic spasmodic torticollis: a focal dystonia].
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Animals↗
The diagnostic significance of long-latency reflexes in multiple sclerosis.
Reflexes of thenar muscles after median or radial superficial nerve stimulation have been investigated in both hands of 47 patients with probable or definite multiple sclerosis (MS) and compared with somatosensory evoked potentials (SEPs) to median nerve stimulation. A delay or absence of long-latency reflexes (LLRs) was found as pathological patterns. The results after median or radial superficial nerve stimulation were usually both pathologic or both normal except in cases with latencies at the upper limit of normal values. Pathological results of reflex testing were obtained in 61% of the patients with probable MS and in 79% of those with definite MS. Abnormal SEPs were found in 44% of the patients with probable MS compared to 62% with definite MS. All cases which had pathologic SEPs also had pathologic LLR. Hence, LLR testing detected more abnormalities than the routine median nerve SEP testing that has been used.
Adolescent↗