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Biomedical subjects

K F Eichhorn

Publications and source records attributed to K F Eichhorn.

7 recordsLinked to original sources
PubMed1993

Influence of repetitive magnetic stimuli on verbal comprehension.

The influence of repetitive magnetic transcranial stimulation over the temporo-parietal cortex on verbal comprehension was investigated in 44 healthy subjects. In right-handed subjects, trains of 50 Hz magnetic stimuli over the left hemisphere produced more errors than stimulation over the right hemisphere. The result is not very clearcut, however; thus the test cannot be used for diagnostic investigation of language dominance.

Adolescent↗
PubMed1990

Effects of long-impulse electrical stimulation on atrophy and fibre type composition of chronically denervated fast rabbit muscle.

The efficacy of electrical stimulation on a chronically denervated muscle depends on stimulus parameters, which have an important influence on the development of atrophy. Stimulus frequency and/or total activity are particularly responsible for the development of some histological, biochemical and contractile features. The present study in 18 rabbits deals with a recently developed electrical stimulus, which had proved effective in maintaining muscle force following denervation. This current has (1) unusual long bidirectional rectangular impulses (20 ms) and (2) a frequency of 25 Hz, which is between the frequencies of fast- and slow-firing motor units. Electrical stimulation began 28 (in one animal 53) days after total motor and sensory denervation of the right hindleg, and was continued until the end of the experiment, up to 205 days. To mimic a therapeutic regimen, which should be agreeable to patients, daily treatment times were kept to a minimum (2 x 6 min), and surface electrodes were used. Morphometric evaluation of the fast flexor digitorum sublimis muscle showed that such electrical stimulation was able to preserve fibre diameter at a level of 72-86% of the initial values for several months, while unstimulated fibres showed the usual atrophy with a decrease of diameters below 40% of normal. The stimulation induced a "hybrid" fibre type with properties of a slow muscle (rich in mitochondria in NADH-dependent tetrazolium reductase staining and electron microscopy) as well as of a fast-twitch muscle (fibre type IIb in myofibrillar ATPase stainings).

Animals↗
PubMed1990

[Inductive stimulation].

Electrical stimulation, which has long been known, has recently been complemented by electromagnetic stimulation. This method is based on the law of induction and employs coils in place of electrodes. The effect of this process is deduced from both the relationship between magnetic and electrical fields and the stimulating effect. A new type of stimulator has been developed from a resonant circuit, thus allowing nerves to be excited with low-frequency pulses up to fusion frequency.

Animals↗
PubMed1984

Maintenance, training and functional use of denervated muscles.

In the case of cerebral paralyses electrical stimulation can not only maintain the muscles, but may also enable their functional use. In flaccid paralyses, however, the conventional therapy using exponential currents produces rather unsatisfactory results. Only when applying bi-directional currents, were we successful in producing tetanic contractions. At present, some 20 children suffering from different diseases, such as spina bifida, Erb's palsy or a tumour of the cord, perform a daily domiciliary treatment with especially constructed home stimulators. Measurements prove distinct improvements of blood circulation, phosphoric metabolism and of the condition of the affected extremities. First investigations with computer-controlled, multi-channel devices show that by means of these devices the efficiency of training can be improved, the daily time for treatment can be shortened, and the disabled patient can perform the training almost autonomously. The existing experience on simple locomotion chains, and the achieved strengthening of the muscles will gradually enable a functional electrical stimulation of flaccid, denerved muscles and thus extend the radius of action for the disabled patient, for example by gripping, standing upright or walking.

Biomedical Engineering↗