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H C Hopf

Publications and source records attributed to H C Hopf.

226 records · Page 13Linked to original sources
PubMedDate not supplied

A computerized re-evaluation of the collision technique.

A computer program is described for the collision technique by which data acquisition and data interpretation is possible. Paired stimuli with varying interstimulus times evoke a muscle action potential. The amplitude or the rectified area integral as a function of interstimulus times was used to define the scatter of conduction velocities within the ulnar nerve. In normal and slightly distorted EMG signals the amplitude and area produces the same scatter. In distorted potentials the integrated area is more sensitive. The technique was furthermore used to separate two different age groups of normal persons. Significant differences were seen as well as in an age matched group of patients with myotonic dystrophy. The collision technique and the computer program proved to be sensitive and applicable in routine examinations.

Action Potentials↗
PubMedDate not supplied

Cerebral potentials are not evoked by activation of Golgi tendon organ afferents in human abductor hallucis muscle.

The earliest components of the somatosensory evoked potentials (SSEP) are generated by excitation of the fastest low-threshold, thick myelinated group I afferents. Ib afferents belonging to this group innervate Golgi tendon organs and are excited almost selectively by a muscle twitch. Contraction of the abductor hallucis muscle was evoked by intramuscularly placed teflon insulated needle electrodes in ten healthy volunteers. We failed to demonstrate any cortical activity (over Cz' vs. Fz) following isolated muscle contractions. Our results do not point to a significant projection of group Ib afferents to the human somatosensory cortex at least with the small numbers of fibers activated by intramuscular stimulation of abductor hallucis muscle.

Adult↗