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Biomedical subjects

M Sobieszczańska

Publications and source records attributed to M Sobieszczańska.

9 recordsLinked to original sources
PubMed1998

[The effect of the gender of the examined subjects on the course of the visual potentials evoked by the checker board pattern stimulation].

A goal of the present work was to analyze the correlation between a course of visual potentials elicited with the pattern stimulation and gender of the examined subjects. VEPs (Visual Evoked Potentials) recordings were performed using STELLA system in a group of 65 healthy adult subjects, with the age ranging from 18 to 70 years, consisting of the age-matched subgroups of 37 females and 28 males, applying a checkerboard as the pattern-reversal stimulation. In result of the analysis of the individual VEPs parameters, no effect of gender on the P100 latency was found. The discrepancies in the course of VEPs concerned P100 amplitudes, likewise a difference of the maximum and minimum amplitude, which proved to be significantly greater in the recordings collected from the left hemisphere in women than in men. Moreover, there was the appreciably greater symmetry between the responses registered over the both cerebral hemispheres, reflected by the higher correlation coefficients, in the male subgroup compared to the female subjects. The herein reported differences in the VEPs characteristics recorded in the male and female subjects can be elucidated on the ground of the documented discrepancies regarding the structural and functional cerebral organisation in women and men with regards to visual perception.

Adult↗
PubMedDate not supplied

[Exercise test in the neurotic patients].

While testing neurotic patients it was noted that almost all of their complaints concerned physical weakness, easy tiredness, chest pain, heart beating and palpitation. In order to evaluate objectively their physical efficiency, the patients were subjected to exercise test on a treadmill, their ECG, HR and blood pressure being monitored. The exercise test was carried out twice, i.e. before and after 3-month psychotherapy. The average physical efficiency coefficient before treatment was significantly lower than after the treatment, but repolarization disorders were significantly higher before the treatment. ECG analysis proved non-specific repolarization changes induced by excitability of sympathetic system. 8 patients showed changes in ST-T before the treatment and 4 persons after it. Another kind of changes (that appeared in 14 cases before the treatment) were extrasystoles mainly supraventricular. After psychotherapy they were noted only in 1 case. The analysis of HR and blood pressure proved a significantly higher HR and lower blood pressure before the treatment. The obtained results may become an argument supporting the functional character of the changes mentioned.

Adult↗
PubMedDate not supplied

[The evaluation of central visual fatigue in computer terminal users by visual evoked potentials].

Visual evoked potentials (VEPs) were recorded in a group of 20 operators aged 25-45 years during two sessions, before and after a 5-hour work at computer terminals, in order to assess visual system fatigue. The outcomes were referred to the norms established for the age-matched population of 30 subjects not exposed to professional contact with computers. Most of the examined operators suffered various complaints concerning not only the organ of vision but the central nervous system as well. VEPs were elicited by means of monocular stimulation using the reversal checkerboard pattern and recorded simultaneously from the scalp electrodes placed over the right and the left cerebral hemisphere. Only recording acquired after finishing of a working day demonstrated significant statistically abnormalities of the VEPs waveforms, which suggests their transient character. The changes mentioned above included prolongation of peaks P100 and N2 latency with concomitant attenuation of their amplitudes and a decrease of the correlation coefficient values for the recordings from the hemispheres. The preliminary findings presented in this paper seem to justify a conclusion that the non-invasive VEPs method can be considered as the objective indicator of the central visual fatigue induced by the workload at computer terminals.

Accommodation, Ocular↗
PubMedDate not supplied

[Visual system in the light of the study of evoked potentials after stimulation by pattern stimuli in healthy subjects].

In 65 healthy subjects aged 18-70 the characteristics of VEPs elicited with two kind of "pattern reversal" stimulus, checkerboard and gratings, in 13 various configurations were tested. In the recordings the latency and amplitude of peaks P1, N1, P100 and N2, and the difference between maximum and minimum amplitude and correlation coefficient for the cerebral hemispheres were analysed. It was found that checkerboard and gratings elicited in the both hemispheres the responses of comparable latencies and their amplitudes were consequently greater over the left hemisphere. Analyses of the correlation between VEPs and gender showed no influence on latencies and the occurrence of greater amplitudes in females and lower correlation coefficients in males. Differences were noted between potentials evoked by monocular and binocular stimulation, and for the responses elicited with the patterns of checkerboard and gratings, which reflects the activation of two separate channels of the visual system. It was also shown that the characteristics of VEPs obtained using for stimulation the fractionated visual field (checkerboard in the individual hemi-fields and quadrants) was consistent with the topography of visual pathways and retinotopic organisation of the striate cortex, which would suggest a location of the main generator of VEPs in Brodmann's area 17.

Adolescent↗