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Biomedical subjects

G Deuschl

Publications and source records attributed to G Deuschl.

At least 145 records · Page 8Linked to original sources
PubMed1995

Movement-related cortical potentials in writer's cramp.

Movement-related cortical potentials in response to simple, self-paced, brisk index finger abduction movements were recorded in patients with simple and complex writer's cramp and compared with those of age-matched control subjects. Analysis of the movement-related cortical potential waveforms showed that the Bereitschaftspotential, the peak of the negative slope, and the frontal peak of the motor potential did not differ in the two groups, except for the average amplitude of the early part of the negative-slope peak, which was decreased in the patient group during the interval of 300 to 200 msec prior to electromyographic onset. This finding was restricted to the electrodes overlying the contralateral and midline central electrodes. Movement-related cortical potentials from patients and control subjects could be equally accounted for by a four-dipole source model with sources located in the contralateral and ipsilateral sensorimotor regions and the supplementary motor area. There was a trend for a reduction in the strength of the sensorimotor sources active during the premotor period in the patient group, but the difference did not reach a significant level for any individual source. No differences were found between the movement-related cortical potentials elicited by movements of the affected and unaffected hand, or between those of patients with simple or complex hand cramps. This result suggests a deficiency of contralateral motor cortex activation just prior to the initiation of voluntary movements in patients with focal dystonia.

Adult↗
PubMed1995

Hand muscle reflexes following air puff stimulation.

Hand muscle reflexes following muscle stretch and electrical nerve stimulation show a typical pattern consisting of short- and long-latency reflexes. The present investigation was designed to test reflexes following pure cutaneous stimulation. Air puffs were delivered to the palmar tip and the nail bed of the first, second and fifth fingers during isotonic contraction of hand muscles. The EMGs from the thenar muscles, the first dorsal interosseous muscle and the hypothenar muscles were recorded. Reflexes were obtained in all muscles, with a typical configuration consisting of a short-latency excitatory component (cutaneous long-latency reflex I, cLLR I) and a second excitatory component (cutaneous long-latency reflex II, cLLR II), with an inhibitory component between them. The size of cLLR II differed depending on the area stimulated and the muscle recorded. We found the largest responses always in the muscle acting on the stimulated finger. The reflex size depended on the strength of air puff stimulation. Allowing small displacements of the fingers led to an additional increase in the size of the reflex. The pattern of reflexes was identical independent of whether the finger tip or the nail bed was stimulated, but the size of the reflexes was smaller following nail bed stimulation. Following blockade of the cutaneous nerve branches of the thumb with local anaesthetics, air puff stimulation of the thumb no longer elicited this reflex pattern. Hence, under our experimental conditions, cutaneous receptors were the only source of afferent input for these reflexes.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

3.1-kb deletion of mitochondrial DNA in a patient with Kearns-Sayre syndrome.

Mitochondrial DNA (mtDNA) deletions have been found in the majority of patients with chronic progressive external ophthalmoplegia and Kearns-Sayre syndrome. A large number of different mtDNA deletions have been identified. They generally spare the two origins of replication and are frequently flanked by direct or indirect repeats. We have found a 3.1-kb deletion of mtDNA in a patient with Kearns-Sayre syndrome that has some unusual features. First, it encompasses nucleotides 11259 to 14368, a localization that was not described before. Second, the deletion is not flanked by direct or indirect repeats, supporting the view that homologous recombination and slip-replication do not account for all mtDNA deletions.

Base Sequence↗
PubMed1995

Electrophysiological characteristics of lesions in facial palsies of different etiologies. A study using electrical and magnetic stimulation techniques.

Using magnetic stimulation techniques in addition to conventional electrical stimulation, the entire facial motor pathway can be assessed electrophysiologically. To study the diagnostic yield of these examinations, 174 patients with facial palsies of a variety of etiologies were examined (85 Bell's palsies, 24 Guillain-Barré syndrome (GBS), 19 Lyme borreliosis, 17 zoster oticus, 12 meningeal affections, 10 brain-stem disorders and 7 HIV-related facial palsies). The facial nerve was stimulated electrically at the stylomastoid fossa and magnetically within its canalicular portion. Additionally, the face-associated contralateral motor cortex was stimulated magnetically. Recordings were from the nasalis or mentalis muscle, or both, using surface electrodes. Bell's palsy patients showed typically a unilateral local hypoexcitability of the facial nerve to canalicular stimulation. In GBS, bilateral latency prolongations were frequent, as expected for a myelinic disorder. In contrast, in zoster, predominant axonotmesis was unilateral, and in HIV infection sometimes bilateral. The method was very sensitive to detect subclinical dysfunctions in meningo-radiculitis and malignant meningeal diseases, either prior to the onset of palsy, or on the contralateral (clinically unaffected) side. It also distinguished reliably between central and peripheral facial motor pathway lesions. In our experience, these inexpensive and non-invasive electrophysiological techniques contribute substantially to the differential diagnosis of facial palsies.

Adult↗
PubMed1995

Dystonic posture of lower extremities associated with myelomeningocele: successful treatment with botulinum A toxin in a six-month-old child.

We report on a six-month-old child with severe intermittent dystonic posture of both legs associated to a thoraco-lumbar myelomeningocele. The patient presented with a combination of progressive hypertonic knee extension and hip flexion. While the mobility of the right leg improved sufficiently after physiotherapy and splinting, satisfactory improvement of the left leg could be achieved only after local injections of botulinum A toxin, allowing for adequate functional motor development.

Botulinum Toxins↗
PubMed1994

Symptomatic and essential palatal tremor. 2. Differences of palatal movements.

Palatal tremor, a rhythmic movement disorder of the soft palate, may be described as two separate entities: symptomatic palatal tremor (SPT) and essential palatal tremor (EPT). The symptomatic form is associated with brain stem or cerebellar disease, whereas the essential form has no known etiology. A cardinal symptom of EPT is the presence of ear clicks, which do not occur in SPT. Visual observation of the movements in the two disorders suggests that the difference in symptoms is due to the activation of different palatal muscles, the levator veli palatini in SPT and the tensor veli palatini in EPT. Electromyographic recording from the levator veli palatini muscle showed abnormal bursting activity time locked to the palatal movements in patients with SPT, but not in those with EPT. Because the two palatal muscles are innervated by different cranial nerves, SPT and EPT are likely to have separate origins.

Adult↗
PubMed1994

Detection of brain activation using oxygenation sensitive functional spectroscopy.

A nonwater-suppressed localized spectroscopy experiment using the PRESS-sequence has been used to study the signal changes of the water resonance during cortical activation. Significant effects with an effect-to-noise ratio up to 50:1 for a single shot experiment have been observed upon photic stimulation. The exceedingly high signal-to-noise ratio of the experiment was used to demonstrate signal changes as low as 0.1% after electrical stimulation of the median nerve.

Cerebral Cortex↗
PubMed1994

Cortical magnetic and electric fields associated with voluntary finger movements.

Multichannel recordings of both movement-related magnetic fields (MRMFs) and movement-related cortical potentials (MRCPs) were simultaneously recorded in association with voluntary unilateral self-paced index finger abduction movement in two normal volunteers. 1) Slow magnetic field (readiness field; RF) can be detected several hundred msec before the movement onset, and its field distribution indicates the existence of the largest generator source over the contralateral primary motor area. Taken together with the vertex-maximal Bereitschaftspotential which corresponds to the earlier part of the RF, the complexity of this magnetic field suggested by relatively low correlation value in single dipole model indicates the co-activation of other underlying generators besides this largest dipole. 2) The utilization of MRMF with MRCP facilitates the separation of two distinct electrophysiological events in proximity to the movement onset, which are difficult to be determined by the technique of MRCP only. Those are the motor field (MF) and the movement evoked field I (MEFI) in MRMF, and the parietal peak motor potential (ppMP) and the frontal peak motor potential (fpMP) in MRCP, which occur approximately 20 and 100 msec after EMG onset, respectively. These two subcomponents may imply the culmination of motor cortex and sensory feedback activation, respectively. Combined study of MRMF and MRCP will provide better definition of cortical events related to voluntary movement than the study of either modality alone.

Adult↗
PubMed1994

Event-related desynchronization and movement-related cortical potentials on the ECoG and EEG.

Event-related desynchronization (ERD) 2.0 sec before and 1.0 sec after movement in the frequency bands of 8-10, 10-12, 12-20 and 20-30 Hz and movement-related cortical potentials (MRCPs) to self-paced movements were studied from subdural recordings over the central region in 3 patients, and from scalp-recorded EEGs in 20 normal volunteers. In direct cortical recordings, the peak ERD response and peak MRCP amplitude to self-paced finger movements were maximal over recording sites in the contralateral hand motor representations. The topography and time of onset of the ERD response to finger and foot movements suggest that the ERD responses in the 8-10 Hz and 10-12 Hz bands are more somatotopically restricted than the responses in the higher frequency bands. The power recovery and subsequent overshoot in the different frequency bands occurred in an orderly fashion with the faster frequencies recovering earlier. The ERD responses on the scalp-recorded EEGs were of lower magnitude and more widely distributed than those occurring on the subdural recordings. Across the population, there was no relation between the magnitude of the ERD response in any of the frequency bands studied and the peak amplitude of the negative slope (pNS') and the frontal peak of the motor potential (fpMP) of the MRCPs. MRCPs and ERD responses originate in similar cortical regions and share some common timing features, but the magnitude and spatial distribution of the two responses appear to be independent of each other, which suggests that the physiological mechanisms governing these two events are different and may represent different aspects of motor cortex activation. Differences in the timing and topographical features of the ERD responses in the various frequency bands also suggest a distinct functional significance for the various spectral components of the electrical activity in the motor cortex.

Adult↗
PubMed1994

[Functional spectroscopy: the limits and potentials of a new method for the study of brain activation with MR tomography].

The possibility of examining brain activity by means of localised spectroscopy was studied in relation to its neurological basis. Measurements on 18 normals during optical stimulation showed an improvement in signal to noise ratio compared with functional imaging of almost one order of magnitude. Time dependent measurements during stimulation by a 500 ms light impulse showed definite delay of increased blood flow when compared with oxygen utilisation. The excellent signal to noise ratio and the inherent stability of the method permits reliable detection of weak effects such as are caused by finger tapping or electrical stimulation.

Artifacts↗
PubMed1994

Symptomatic and essential palatal tremor. 1. Clinical, physiological and MRI analysis.

Palatal tremor (brief, rhythmic involuntary movements of the soft palate) apparently comprises two different nosological entities: essential palatal tremor (EPT) and symptomatic palatal tremor (SPT). The site of the abnormality in EPT is unknown, whereas SPT is believed to arise from a lesion of the brainstem or cerebellum (within the Guillain-Mollaret triangle). The clinical and physiological properties of these conditions were studied in four patients with EPT and six patients with SPT. Patients with EPT had normal cerebellar function, but those with SPT had clinical signs of cerebellar dysfunction. The palatal movements were consistent with activation of the tensor veli palatini muscle in EPT and of the levator veli palatini muscle in SPT. During sleep, EPT stopped, whereas SPT continued with only slight variations in the tremor rate. The cycle of palatal tremor could not be reset by stimulation of trigeminal afferents in either EPT or SPT patients, and Valsalva's manoeuvre did not consistently affect the rhythm of the tremor in either group. The palatal tremor cycle exerted remote effects on the tonic electromyographic activity of the upper and lower extremities only in patients with SPT. These effects were present only on the side of the cerebellar signs (opposite the side with the enlarged inferior olive) in patients with a unilateral syndrome. Essential palatal tremor patients had only polysynaptic brainstem reflex abnormalities, whereas SPT patients had abnormalities of monosynaptic, oligosynaptic and polysynaptic brainstem reflexes. Magnetic resonance imaging showed no evidence of structural abnormalities in EPT patients, but SPT patients had a hyperdense signal of the ventral upper medulla (the region of the inferior olive) on T2-weighted images. These observations support the hypothesis that EPT and SPT are two different diseases. In SPT, cerebellar dysfunction ipsilateral to the palatal tremor may be due, in part, to abnormal function of the contralateral hypertrophic inferior olive. The proposed basis of SPT is a disturbance of electrotonic coupling between the cells of the inferior olive induced by a lesion of the dentato-olivary pathway. Similar mechanisms could be responsible for postural tremors in general. The pathophysiological basis of EPT remains unknown.

Adult↗
PubMed1994

Prolonged MRI T2 times of the lentiform nucleus in idiopathic spasmodic torticollis.

Using high-field MRI, we investigated possible morphologic changes in the basal ganglia of 22 patients with clinically diagnosed idiopathic spasmodic torticollis (iTs) compared with 28 age-matched normal controls. Two patients were found to have distinct basal ganglia lesions and were excluded from further analysis. The frequency of gross morphologic changes (atrophy, enlarged Virchow-Robin spaces) in patients was not significantly higher than in controls. However, T2 values calculated for the putamen and pallidum on both sides were significantly higher in the lentiform nucleus of the patients compared with the controls. In contrast, other well-defined subcortical regions did not exhibit a similar abnormality, nor did the optical or quantified signal analysis of various regions of interest show any differences. This finding suggests a morphologic abnormality in iTs that is not associated with a gross structural lesion. It could reflect focal gliosis and might correspond to earlier sporadic pathoanatomic descriptions of gliosis in idiopathic dystonia.

Adult↗
PubMed1994

[Corticobasal degeneration. The significance of clinical criteria for establishing the diagnosis].

Neuropathological studies show that about 20% of all patients suffering from an acinetic-rigid syndrome can not be given the diagnosis of idiopathic Parkinson's disease. Among these non-idiopathic Parkinson-syndromes the corticobasal degeneration (CBD) can be regarded as a separate disease entity. The pathological findings of moderate predominantly frontal and parietal cerebral atrophy, cortical Pick-cells and specific corticobasal inclusion bodies are considered valuable features which support the diagnosis. The clinical Characteristics of CBD are demonstrated in 3 patients including an acinetic-rigid syndrome, limb apraxia and "alien limb"-syndrome, as well as reflex myoclonus. Eye movement disorders, dementia and other rare symptoms may also be present. Electrophysiological reflex-testing helps to corroborate diagnosis. These findings and a summary which includes the previously published cases of CBD show that CBD in most cases can be diagnosed intra vitam.

Aged↗
PubMed1994

[Craniocervical dystonia. Pragmatic general concept or nosologic entity?].

The focal dystonias of cranial-nerve innervated muscles are described. They include the ocular dystonia, blepharospasmus and other facial dystonias, mandibular dystonia, pharyngeal dystonia, spasmodic dysphonia, external laryngeal dystonia, spasmodic torticollis and lingual dystonia. They share similar clinical aspects such as the inadequate co-contraction of antagonistic muscles, dystonic overflow of muscle activity to muscles not normally involved, similar facilitating and inhibitory activities and various "antagonistic gestures". Genetic, imaging, neuroanatomic, physiologic and pharmacologic findings suggest common pathogenetic mechanisms for these diseases. Similar therapeutic approaches are established. The frequent and variable combinations of these focal dystonias and their similar pathogenetic background favour their common classification as craniocervial dystonias.

Cranial Nerve Diseases↗
PubMed1994

Tremors in Parkinson's disease: symptom analysis and rating.

The object of the present study was to evaluate the hand tremor occurring under various conditions in 81 patients with Parkinson's disease (PD) and to statistically analyze their relation to clinical rating items. We found that resting and action tremor have to be separated, whereas postural tremor can be related to either one of them. Resting tremor does not correlate with disability items or performance items except for an item rating social handicaps. Action tremor shows some influence on performance items. Current rating scales of PD represent a valid measure of resting tremor but are less valid for the measurement of action tremor.

Adult↗