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J M Mol

Publications and source records attributed to J M Mol.

14 recordsLinked to original sources
PubMed1990

The imaging quality of angiodynography in the ilio-femoral tract.

The imaging quality of angiodynography (Quantum; Philips) in the ilio-femoral tract was compared with uniplanar angiography. One hundred ilio-femoral tracts were investigated with both translumbar conventional angiography and angiodynography. The ilio-femoral tract was divided into five parts; proximal and distal common iliac, proximal and distal external iliac and common femoral. Stenosis was scored from 0-24, 25-49, 50-74, 75-99 and 100% and the lengths of those of 25% or more were measured in centimeters. Because the thickness of the subcutaneous fat layer decreases the depth range (normally 11.5 cm) of the 5.0 MHz transducer it was also measured in centimetres. The results showed that a significantly larger number of vessels were not seen (especially the common iliac) with an increasing thickness of the subcutaneous fat. The results based on the real-time imaging quality alone of angiodynography showed a reasonable accuracy of 83.9% when detecting stenoses graded from 0-24, 25-49, 50-74, 75-99 up to 100%. The clinically more important discrimination between a haemodynamically important stenosis of more than 50% showed a sensitivity of 88% and specificity of 98% on visual information alone. By integrating the peak velocity measurements to the results, this sensitivity rose to 95% and the specificity became 99%. The correlation in length was within a range of 1 cm in 94% and within 1-2 cm in 6% of the stenoses. In conclusion, angiodynography is a reliable technique for investigating the ilio-femoral tract.

Angiography↗
PubMed1988

Slow potential correlates of frontal function, psychosis, and negative symptoms.

The contingent negative variation (CNV) was used to study cortical activation in frontal and central areas in psychotic and nonpsychotic patients. Psychotic patients showed a higher frontal relative to central CNV amplitude than nonpsychotic patients, a finding that was correlated with performance on a test of frontal function. Negative symptom ratings (physical anhedonia and social closeness) were correlated with relatively low frontal versus central CNV amplitude, but only in psychotic patients.

Adult↗
PubMed1984

Dynamic imaging frequency analysis in clinical electroencephalography.

A new way of processing and presenting multichannel EEG recordings is introduced, called dynamic imaging frequency analysis (DIFA). Firstly power spectral analysis is applied to 14 EEG signals simultaneously. The cross-power spectra or transfer functions of 13 EEG signals are calculated in relation to the 14th EEG signal, thus obtaining not only the average amplitude but also the relative phase of diffusely occurring frequencies. The information per electrode obtained in this way can be presented in a numerical form, for quantification and statistical evaluation. Also, the information from 14 electrodes per significant frequency can be presented as a dynamic image display (frequency animation) yielding immediate information on the average amplitude and relative phase of the average activity per frequency of the EEG record. Application of the DIFA technique to several dozen patients demonstrates the value of phase information in EEG analysis.

Adult↗
PubMed1982

An application of mathematical models in posturography.

The measurement of the horizontal displacements (HD) of the centre of mass of the human body when standing still, is often performed by means of a platform. The resulting measured HD as a function of time, both in the left-right or sinister-dexter and the posterior-anterior direction, are known as stabilograms. Such stabilograms are being more widely used to obtain the so called measured statokinesigram, similar to a Lissajous-figure, by eliminating time from the sinister-dexter stabilogram and the posterior-anterior stabilogram. It is shown that in using mathematical models of the standing person to obtained the stabilograms, the resulting statokinesigram is very different from the measured statokinesigram. It is also shown that the quantity line-integral calculated from a statokinesigram is much smaller when determined from a statokinesigram corrected by means of the mathematical models.

Humans↗
PubMed1981

Human cerebral potentials evoked by moving dynamic random dot stereograms.

In 11 normal healthy human subjects an evoked potential was elicited by moving dynamic random dot stereograms. The random dots were generated by a minicomputer. An average of each of 8 EEG channels of the subjects tested was made. The maximum of the cerebral evoked potentials thus found was localized in the central and parietal region. No response earlier than 130--150 msec after the stimulus could be proved. The influence of fixation, the number of dots provided, an interocular interstimulus interval in the presentation of the dots, and lense accommodation movements on the evoked stereoptic potentials was investigated and discussed. An interocular interstimulus interval (left eye leading) in the presentation of the dots caused an increase in latency of the response much longer than the imposed interstimulus interval itself. It was shown that no accommodation was needed to perceive the depth impression, and to evoke the cerebral response with random dot stereograms. There are indications of an asymmetry between the two hemispheres in the handling of depth perception after 250 msec. The potential distribution of the evoked potentials strongly suggests that they are not generated in the occipital region.

Adult↗
PubMed1981

Spectral analysis in clinical electro-encephalography.

In the past two years the above computerisations have been applied as a routine in over 2500 EEG recordings in our department. From the experience gained with this type of registration, processing and presentation of the EEG signals it appears that the scope of electro-encephalographic examination has been considerably extended. This is evident from the following examples 1. Communication between EEG specialists and non-EEG specialists over electro-encephalographic examination is improved considerably by means of this way of data reduction and topographical presentation. 2. As far as the discriminating power is concerned, it appears that, for example, small differences in frequency of cerebral activities in for example slight unilateral or local disorders of the circulation in the brain can be indicated by the computer analysis, even if it is invisible to the naked eye [10]. 3. Further statistical analysis of various parameters has become possible by distinguishing between normal and abnormal importance in distinguishing between normal and abnormal EEG's of one and the same patient, the difference can be indicated both objectively and quantitatively. 4. By means of electrical filing of EEG signals simultaneous with the usual paper filing, there is the possibility of applying newly developed statistical and mathematical computer programs to the stored EEG data of patients whose brain disorders have been definitively diagnosed.

Electroencephalography↗