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Biomedical subjects

N Roth

Publications and source records attributed to N Roth.

At least 19 recordsLinked to original sources

[Localization of rhythmic activity around 4/s].

The results of the studies carried out in four carriers of characteristics are presented under localistic aspects proceeding from the different local distribution of rhythmized activity around 4/s with unipopular and bipolar lead technique. A hypothesis of the origin of the activity is presented which would be in agreement with its distribution characteristics and reactivity.

Brain Mapping

[So-called slow posterior activity in the EEG and the sensori-motor reaction time. Results of re-examinations made after 5 years].

Six persons showing what is called slow posterior activity (4/s rhythm) in the electroencephalogram were reexamined after a period of five years. Sensorimotor reaction times were recorded in addition to the electroencephalogram which was analyzed for the frequency of LPA and for the degree of stability of time dependence. The frequency and distinctness of LPA were found to be stable after five years (r = 0.09 and 0.82, respectively; p less than 0.001), whereas the alpha rhythmus of the subjects had undergone considerable changes (r = 0.34; p greater than 0.05). The extension of reaction times to be observed under the influence of LPA was also seen to remain constant (r = 0.79; p less than 0.05). Accordingly, LPA proved an extremely stable characteristic which did not show any substantial variations in the course of five years.

Adult

Effects of ethosuximide upon psychomotor responses and electromyographic parameters of healthy individuals.

The purpose of this paper was to investigate the effects of anticonvulsant ethosuximide upon physiological parameters, psychomotor reactions and electromyographic criteria. Ethosuximide increased the reaction times to flashes and the choice reaction time in most subjects, often provoked a greater amount of errors during choice reactions and decreased the average heart frequency. The functional activation during the tasks was diminished. The EEG showed no marked qualitative or quantitative changes. Ethosuximide reduced the maximum conduction velocity of the motor nerve and changed the action potential duration but not the action potential shape. There is no exact parallelism between the increase in reaction time and decrease of nerve conduction velocity. The drug effect upon psychomotor reactions seems to be caused by reduction of vigilance and an inhibitory effect upon the individual's motor responsiveness. Like other anticonvulsants, ethosuximide may alter the electrical properties of all excitable membranes and, by this ubiquitous site of action, exerts the described effects.

Action Potentials

Pseudoaccommodation and progressive addition lenses.

The limitations of traditional multifocal lenses to replace normal ocular accommodation are well known. The recent development of progressive addition lenses circumvent many of those problems, furnishing smoothly varying power in desired amounts for various distances and allowing freedom from distracting lines. Optical characteristics, screening considerations, prescribing and fitting requirements, and the advantages and limitations of progressive addition lenses are discussed.

Accommodation, Ocular

Four physicists.

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Electronics, Medical