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Biomedical subjects

C Pantew

Publications and source records attributed to C Pantew.

4 recordsLinked to original sources

Brainstem auditory evoked magnetic fields in response to stimulation with brief tone pulses.

Brainstem auditory evoked magnetic fields evoked by monaural stimulation with Gaussian-modulated tone pulses were recorded in the parieto-occipital region of two normally hearing human subjects. Very small signals with an amplitude of 5-10 fT were detectable only under optimal (with respect to selection of subjects, technique of stimulation, minimization of ambient and instrumental noise level, signal processing, etc.) experimental conditions. The most important findings are that: (a) different components of the magnetic signal show maxima at different recording positions over the scalp, and (b) the magnetic equivalent of the electric wave V exhibits a polarity reversal at symmetrical positions in both hemispheres.

Acoustic Stimulation↗

[Acoustically evoked potentials (aep) in children (author's transl)].

The differences between amplitudes and latencies of acoustically evoked potentials (AEP) in children, aged between 3 and 7 years, were tested using random distributed stimuli with mean interstimulus intervals (ISI) of 1.45 sec, 2.1 sec, and 4.1 sec and periodic stimuli with the same ISI. We applied three different intensities, 30, 50, and 70 dB SPL and a frequency of 1000 c/s. We determined the peak to peak amplitudes P2N2 and N2P3 and the latencies of P2, N2, and P3 for our calculation because of the typical AEP pattern in children. There were no significant differences between the mean amplitudes and mean latencies, using an error probability of 1% comparing the AEP determined by the two different ways of stimulation. The increase of the ISI from 1.45 to 4.1 sec didn't yield to a significant improvement of the AEP in both stimulation patterns. In the tested group of children the used stimulation pattern, as we already stated in adults, is without greater importance.

Acoustic Stimulation↗

ERA-stimulation with free-programable frequency and intensity sequence--a method to reduce the examination time.

A new method for ERA-stimulation with free-programable sequence of intensity and frequency will described. We developed to realize this method a Free-Programable ERA-Stimulator, FPERAS/74. The expectation has been confirmed that this way of stimulation which includes a regular change of frequency and intensity of the auditory stimuli decreases effective the development of habituation in its amount and velocity. In our experiment (K- and P-experiment) it will be clarified the efficiency of this method both with regard to the time-saving during the recordings of the AEP and its quality comparee with the conventionally determined AEP. It can be stated a triple shortening of the examination time with a simultaneous improvement of the quality and the reproductibility of the AEP.

Audiometry↗