According to recent findings activation of anterior cingulate co
rtex (ACC) is related to detecting cognitive conflict. This
conflict related activation elicits autonomic responses which can be assessed by psychophysiological measures such as
heart rate variability calculated as beat to beat R-R interv
als (RRI). Recent findings in neuroscience also suggest that
cognitive conflict is related to specific nonlinear chaotic changes of the signal generated by neural systems. The present
study used Stroop word-color test as an experimental approach to psychophysiological study of cognitive conflict in
connection with RRI measurement, psychometric measurement of limbic irritability (LSCL-33), depression (BDI-II)
and calculation of largest Lyapunov exponents in nonlinear data analysis of RRI time series. Significant correlation 0.61
between largest Lyapunov exponents and LSCL-33 found in this study indicate that a defect of neural inhibition during
conflicting Stroop task is closely related to
limbic irritability. Because limbic irritability is probably closely related to
epileptiform abnormalities in the temporolimbic structures, this result might represent useful instrument for indication
of anticonvulsant treatment in depressive patients who are resistant to antidepressant medication.
T wave morphology (TWM) descriptors derived from Holter electrocardiograms during hemodialysis (HD) are of potential value for cardiac risk assessment in HD patients. Our knowledge on autonomic regulation of TWM descriptors is limited. The purpose of this study was to investigate the association between TWM parameters and heart rate variability (HRV) during intradialytic monitoring. In each of 81 patients on maintenance HD, continuous electrocardiograms were recorded 5 times during HD on alternate weeks. TWM descriptors were calculated every 5 s in overlapping 10-s ECG segments and Low Frequency (LF) (0.04 Hz to 0.15 Hz), High Frequency (HF) (0.15 Hz to 0.40 Hz) powers of the spectrum of HRV were calculated every five min. The calculated values of TWM and HRV were averaged during the first hour of the recordings and subsequently over all recordings in each subject. Analyzable data for HRV and TWM were available in 71 HD patients (aged 61±15, 36 % diabetics, 32 % females). LF in normalized units correlated positively with Total Cosine R to T (r=0.374, p=0.001) and negatively with T wave morphology dispersion (r=-0.253, p=0.033) after adjusting for heart rate. A heart rate independent association between repolarisation descriptors and HRV exists in HD patients. Autonomic modulation needs to be considered when using TWM characteristics for risk profiling of HD patients., D. Poulikakos, D. Banerjee, M. Malik., and Obsahuje bibliografii