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Biomedical subjects

V Diekmann

Publications and source records attributed to V Diekmann.

26 records · Page 2Linked to original sources
PubMed1986

The influence of concentration and relaxation on the EEG power spectra during a CNV paradigm.

EEG segments of 1 sec duration, beginning 1 sec before the imperative stimulus were analysed by Fast Fourier Transformation in a CNV paradigm with interstimulus intervals (ISI) of different durations (1, 3, 5 sec) and with constant (K1, K3, K5) and randomized (R1, R3, R5) ISI presentation. In the alpha band, there were found differences in the power spectra between the constant and the longer randomized (R3, R5) ISI conditions, the latter having a slower center frequency, a smaller radius of gyration and a higher kurtosis. This describes a sharper alpha line of slower frequency in the R3 and the R5 ISI condition, due to pronounced synchronisation of alpha activity. It is discussed as an expression of increased relaxation and reduced concentration. In the theta band, differences appeared between the short ISI conditions (K1, R1) and the longer ones.

Adult↗
PubMed1982

Disturbed smooth pursuit and saccadic eye movements in schizophrenia.

Smooth pursuit and saccadic eye movements of schizophrenic patients were examined. In a pendulum (0.5 Hz) tracking task schizophrenic inpatients had a slightly lower smooth pursuit gain than outpatients and controls, who showed no significant differences. The number of saccades, counter-saccades and velocity arrests occurring in a 20 s tracking epoque was the same in patients and controls, but patients made larger saccades. When tracking a stepping target by saccadic eye movements, schizophrenic inpatients, and to a lesser extent outpatients, exhibited longer reaction times than controls and had a higher incidence of "non-fixation" (saccades away from the target while the target is stationary). Schizophrenic patients also showed a significantly larger proportion of dysmetric saccades (undershooting the target). While similar changes of reaction time and non-fixation score were observed in manic-depressives and alcoholics, dysmetria was more often found in schizophrenics and possibly constitutes the expression of a specific impairment of attention.

Adolescent↗