Franz Benninger
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Forschung - Publikationsliste

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Computing: 

EEG EMG Z Elektroenzephalogr Elektromyogr Verwandte Geb  1989 Jun;20(2):67-75

Strategies of data reduction in computer-assisted EEG analysis in the time

domain--measurement of theoretical aspects and redundancy relations within and

between various strategies of data reduction

Spiel G, Spiel C, Benninger F.

The enormous amount of data after performing computer assisted EEG-analysis

makes necessary reduction methods. Different strategies have been proposed.

Traditionally the distribution of frequencies is shown by using frequency bands.

The aim of this paper is to compare different strategies of data reduction

regarding frequency distribution and to discuss results concerning validity.

Three data reduction methods and their mutual relations will be discussed. The

classification with regard to frequency bands, the computation of quartils of

the frequency spectrum and the search for prominent frequencies. It will be

shown wether or not calculated values are redundant and reflect identical

information (latent dimensions).

EEG EMG Z Elektroenzephalogr Elektromyogr Verwandte Geb  1986 Mar;17(1):7-10 

Demonstration of an interpolation method for determining approximate maximum

and minimum points as a prerequisite for EEG analysis in the time domain using

computers with limited memory capacity

Spiel G, Kundi M, Benninger F.

The EEG analysis in the time domain provides several advantages compared to the

power spectra analysis, based on a FFT. There is the possibility to

differentiate frequency, amplitude and other elementary characteristics of the

wave form. This technique of EEG analysis is based on the definition of distinct

characteristics of the wave form. Problems for calculating the frequency

distribution arise--according to Harner, 1977--due to the fact, that the

digitalization rate has to be very fast to reach an adequate resolution. On the

other hand a high digitalization rate of 5 ms or below produces problems

concerning the limited memory capacity of laboratory computers, especially if

more than one derivation should be analysed simultaneously, to make further

topological analyses possible. Three procedures of EEG analysis to calculate

frequency distributions are shown, two of them are based on an interpolation

technique to calculate adjusted minima-maxima. The results of these procedures

using two different digitalization rates, were compared and discussed to respect

similarity of resulting frequency distributions.

EEG EMG Z Elektroenzephalogr Elektromyogr Verwandte Geb  1986 Mar;17(1):2-6 

Data display and reduction in computer-assisted EEG analysis in the time

domain

Spiel G, Kundi M, Benninger F.

Analysis of EEG frequency spectra leads in two fields to problems demanding

optimal data reduction methods: especially if topological aspects have to be

considered, it is likely that the rather limited memory capacity of laboratory

computer systems will be exceeded; furthermore severe methodological problems

arise in statistical analysis of combined data sets, including frequency

spectra, other physiological, and non-physiological data. Three data reduction

methods are discussed: the classification with respect to frequency bands, the

search for prominent frequencies, and the computation of quartiles of the

frequency spectra. There is some evidence in favour of the method of prominent

frequencies. This method seems to preserve much of the differential information

of the frequency spectra.

Padiatr Padol  1986;21(3):221-31 

Automatic EEG analysis in the time domain and its possible clinical

significance--presentation of a flexible software package

Spiel G, Benninger F.

The intention of the automatic EEG analysis is to take several EEG

characteristics into account and therefore be usable for different applications

to quantify events in the EEG. This procedure of analysis is based on the

estimation of maxima and minima points within the measured data and the

calculation of the wavelength of the half-waves. This is done by correction of

the actually measured maxima-minima-points along the t-axis by means of an

interpolation technique, and the frequency of half waves are calculated from

this solution with an accuracy of half a Hertz. This method was necessary

because our equipment allows only a digitalisation rate of 8 ms (Harner, 1977).

Using this procedure it is possible to record the frequency distribution, the

distribution of amplitudes, and the distribution of steepness as distributions

of elementary EEG characteristics. To characterize specified EEG patterns, the

EEG data can be classified according to categories of combinations of quantified

characteristics. If we consider topological aspects as well there are the

following possibilities: 1 element. characteristic--1 EEG channel; 1 element.

characteristic--2 or more EEG channels; several element. characteristics--1 EEG

channel; several element. characteristics--2 or more channels. There are

possibilities of data reduction, exemplified on the distribution of frequencies

without taking into account the topological aspects. The above mentioned methods

of data reduction are useful for one EEG channel. On the other hand a comparison

of the EEG activity in different channels can be done.