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Biomedical subjects

G Dumermuth

Publications and source records attributed to G Dumermuth.

At least 19 recordsLinked to original sources
PubMed1987

Differential diagnosis of syndromes with abnormal respiration (tachypnea-apnea).

Abnormal respiration with episodic tachypnea-apnea can occur in several syndromes (particularly, the Rett, Joubert, Mohr and Dandy-Walker syndromes). These syndromes are briefly reviewed. In the Rett syndrome, in contrast to in most other genetically determined syndromes, the onset of breathing abnormalities does not occur in the neonatal period.

Abnormalities, Multiple↗
PubMed1987

Spectral analysis of the EEG. Some fundamentals revisited and some open problems.

This tutorial was presented during the 1986 training course of the International Pharmaco-EEG Group (IPEG) in Santa Margherita Ligure, Italy. During recent years spectral analysis has been increasingly used in experimental EEG. However, to avoid misinterpretations of results, its limitations must still be carefully considered. The tutorial starts with revisiting the fundamentals of the technique, emphasizes the practical estimation of auto- and cross-spectra, discusses the assumptions underlying the spectral analysis of stochastic processes, and ends with a brief discussion concerning the postprocessing of spectral data.

Computers↗
PubMed1986

Robust spectral analysis of the EEG.

Robust methods for the spectral analysis of time series are briefly reviewed and seen to have applications in the field of EEG. After presenting two simple schemes for outliers (artifacts) generation and discussing their implications for estimation of the spectral density, the robust filtering algorithm of Kleiner et al. [J.R. Statist. Soc. Ser. B, 41: 313-351, 1979] is introduced and shown to work well for simulated data and for true EEG data containing artifacts. A new use of the robust methods for the detection of artifacts and possibly other transients in long-time EEG recordings is suggested and a preliminary implementation illustrated.

Electroencephalography↗
PubMed1979

EEG data acquisition and preprocessing by microcomputer satellite system.

Recent development in computer technology allows already medium scale EEG data processing to be performed within the clinical neurophysiology department, if a fast minicomputer with adequate mass storage and graphical output facilities is used. Data acquisition, however, should be delegated to a microcomputer which also should take over as much preprocessing as possible. A system is presented, where one or several microcomputer-based satellite units perform analog-digital conversion, Fourier transformation (FFT), calculation of power spectra and crossproducts, as well as event related averaging or other preprocessing procedures. The units are connected to a fast central minicomputer, where a supervisor program loads the microprocessors with their programs, supervises their activity, receives preprocessed data and activates appropriate postprocessing programs to produce the final results.

Analog-Digital Conversion↗
PubMed1978

The computation of EEG bispectra.

This paper presents a FORTRAN program for computation of bispectra of multichannel EEG on a PDP-11/55 computer. Input data are already digitized and file-structured. Output of power spectra, bicoherence and biphases is produced in synoptic form on a line printer.

Computers↗
PubMed1978

Nonketotic hyperglycinemia treated with strychnine, a glycine receptor antagonist.

A 6 1/2-month-old boy suffering from nonketotic hyperglycinemia has been treated for at least 12 months with oral strychnine. The drug caused improvement of muscle tone, motoricity, vigilance and social behavior. Glycine is one of the putative neurotransmitters of postsynaptic inhibition, particularly at the spinal and reticular levels, strychnine its antagonist at the postsynaptic membrane. Strychnine improved the patient's motoricity presumably by blocking the excessive glycine-mediated inhibition of motoneurons. The beneficial effect of strychnine on vigilance and social behavior is more difficult to explain but may have been related to its antagonism of glycine inhibition of brainstem reticular neurons.

Amino Acid Metabolism, Inborn Errors↗
PubMed1977

Studies on EEG activities in the beta band.

A report on first findings of quantitative investigations of beta activity in the frequency domain is presented. Spectral analysis techniques were applied in three parallel still ongoing clinical studies, i.e. (1) an exploration of beta activities in a broad clinical material, (2) a study of the possible use of quantitative beta assessment in antiepileptic drug therapy, and (3) an investigation of special patterns with harmonic components in the beta band. Several clearly distinguishable types of spectral shapes, different coherence characteristics, significant alterations by changes of drug composition and a rich variation of harmonic patterns indicate a large and fascinating new field for clinical EEG research.

Adolescent↗
PubMed1974

[Quantification and analysis of the EEG].

Quantification and analysis are of major interest in modern electroencephalography. During recent years developments in mathematical-statistical analysis of time series and in electronics and computer technology have brought significant advances. A common feature of almost all procedures proposed so far is that they treat the EEG as a random variable. Various statistical descriptors are estimated either in the time or in the frequency domain, for one or several simultaneous EEG channels. This paper reviews the various methods available today to quantize and analyze the main categories of EEG activities, i.e. (1) spontaneous non-paroxysmal activities, (2) spontaneous paroxysmal activities and (3) activities evoked by external sensory stimulation. Due to personal preferences of the author, emphasis is put on analysis methods in the frequency domain. The main problem today lies much less in the technical installation of the one or the other analytical method than in the treatment of artifacts and in postprocessing the large amount of analyzer output. Therefore, applications must be restricted to carefully selected special questions. Clinical electroencephalography is still far from automatization.

Cerebral Cortex↗