[Isolation and characterization of caffeic acid-3-beta-D-glucoside].
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Chromatography↗
Biomedical subjects
R Benecke
Publications and source records attributed to R Benecke.
Somatosensory evoked potentials (SEPs) elicited by magnetic nerve stimulation.
Magnetic stimulation of peripheral nerves at distal and proximal sites of the upper and lower extremities and at the midlumbar level were used to elicit cortical somatosensory evoked potentials. Evidence is provided that peripheral nerve trunks, rather than distal receptor afferents, are the anatomical structures stimulated by the electromagnetic fields. Magnetic stimulation of peripheral nerves is considered to be useful for an evaluation of the integrity of proximal nerves, nerve roots and central conduction along sensory pathways. In contrast to electrical nerve stimulation, magnetic stimulation is painless and can be applied to proximal nerves and plexus. By means of proximal nerve stimulation central sensory conduction can be tested even in patients with peripheral nerve lesions or polyneuropathy.
Adult↗
Technical approaches to hemisphere-selective transcranial magnetic brain stimulation.
Clinical application of transcranial magnetic brain stimulation is mainly used to determine central motor conduction times. With the stimulation coil (Magstim 200, Novametrix) centered conventionally over the midline of the skull convexity and using high stimulus intensities, which are often required in pathological states, the motor cortices of both hemispheres are usually activated simultaneously. Under this condition it is not possible to determine from which hemisphere the descending excitatory volleys to a particular motoneurone pool originate and how the input to the lower motoneurons is organized (uni-/bilateral, ipsi-/contralateral). This limitation can be overcome by two different techniques for selective stimulation of the motor cortex of one hemisphere without coactivation of the other even when using maximal stimulus intensities: 1. A large 12 cm (outer diameter) stimulation coil could be used for selective stimulation when a) the magnetic field radiated over the non-stimulated hemisphere is modified by using a prototype coil shield covering the half of the coil over the nonstimulated hemisphere in combination with b) placing the coil away from the midline towards the preferentially excited hemisphere. The coil shield consists of a sheet of a nickel iron alloy which alters the time course of the induced currents by reducing the initial rate of current intensity change (dI/dt). 2. The use of a smaller 6.5 cm (outer diameter) coil also provided a useful tool for selective stimulation of one hemisphere but was restricted to subjects with low excitation thresholds. In subjects with high excitation thresholds the described use of the large stimulation coil is advisable.
Adult↗