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F Veringa

Publications and source records attributed to F Veringa.

8 recordsLinked to original sources

Neural conduction time and steady-state evoked potentials.

Signal processing in neural networks will inevitably include delays due to the finite conduction velocity of the neurones and their interconnections. Diamond proposed a method for finding these delays in the case of (visual) steady-state responses. Alignment of response features, when represented in a time domain plot, would, allegedly, yield the delay. We show that filter action, by introducing frequency-dependent phase shifts, is bound to distort the time domain plot considerably, thereby aligning the response features in such a way that a wrong value for the delay is found. This makes that analysis method of doubtful significance.

Evoked Potentials, Visual↗

Relation between meteorological factors and pain in rheumatoid arthritis in a marine climate.

Reports indicate that weather conditions may affect some symptoms of rheumatoid arthritis (RA) but not the disease itself. Eighty-eight patients living in the marine climate of the Dutch coastal provinces scored their pain symptoms daily during a full year. Correlation analyses of monthly patient averaged pain scores against each of 6 weather factors indicated that RA pain associates positively and quite significantly (p less than 0.01) with temperature and with vapour pressure, negatively and significantly (p less than 0.02) with relative humidity and not with any of the other factors. The fact that the relation between the temperature/vapour pressure complex and RA pain is stronger in summer than in winter is discussed.

Adult↗

Recording the visual electrically evoked potential (VEEP).

A system for recording cortical responses to electrical stimulation of the visual system (electrical phosphene) is described. The system included a rotatable electrode pair for stimulation, with which artifacts caused by the relatively large stimulating currents could be reduced to suitable levels. Optical isolation on both the stimulating and recording sides of the equipment provided safety for the subject and made precise application of the stimulating current possible.

Electric Stimulation↗