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Cortical habituation in episodic migraine patients without medication overuse headache (MOH), recorded by contingent negative variation (CNV), is often reduced compared with healthy controls. There is evidence that with longer duration of migraine disease (DOD) amplitudes and habituation of CNV become progressively abnormal. The aim of the study was to examine habituation characteristics of contingent negative variation in episodic migraine patients suffering from short- and long-lasting migraine compared to matched healthy controls. 32 migraine patients without aura and without MOH diagnosed according to the revised ICHD-II criteria and 16 age- and sex-matched healthy controls were included. According to DOD, the total sample of migraine patients was divided into two groups (group a: DOD <121 months, n = 17 subjects, group b: DOD >120 months, n = 15 subjects). Both migraine groups did not differ in the number of days of migraine and the duration of attacks. Overall CNV and initial CNV differed significantly between migraine patients and controls, whereas the former produced more negative amplitudes. In the migraine group lack of or deficient habituation occurred, whilst controls showed habituation. There were middle range correlations between the DOD and overall CNV, initial CNV, and y-intercept. Patients suffering from long-lasting migraine produced higher CNV amplitudes with a higher y-intercept. The results are interpreted as 'maladaptive plasticity' with a risen intercept in long-lasting migraine. [ABSTRACT FROM AUTHOR]

Clinically subtle executive dysfunctions have recently been described in essential tremor (ET), though the presence of attentional deficits is still unclear. We investigated the psychophysiological aspects of attention in ET, using event-related potentials (ERPs). Twenty-one non-demented patients with ET and 21 age- and sex-matched healthy controls underwent a psychophysiological evaluation. P300 components and the Contingent Negative Variation (CNV) were recorded. The latencies and amplitudes of the P3a and P3b subcomponents and CNV areas were evaluated. Possible correlations between clinical parameters and ERP data were investigated. P3a latency was significantly longer in the ET group ( p < 0.05), while no differences emerged between patients and controls in P3b latency. No differences were observed between the two groups in the CNV parameters. ET patients display a difficulty in the response to novelty and in the recruitment of prefrontal attentive circuits, while the memory context-updating process appears to be spared. This selective cognitive dysfunction does not appear to interfere with the attentional set linked to the expectancy evaluated during a complex choice-reaction time task, which is preserved in ET. This multitask psychophysiological approach reveals the presence of a peculiar attentional deficit in patients with ET, thus expanding the clinical features of this disease. [ABSTRACT FROM AUTHOR]

According to the Seligman theory of learned helplessness, depression is caused by a repetitive experience of loss of control resulting in internal, stable and global attributional styles for negative events. In depressed patients and healthy controls experiencing such events, an increased amplitude of the post-imperative negative variation (PINV) has been described. The aim of the study was to investigate a possible correlation between migraine, depression, learned helplessness and PINV. 24 patients suffering from migraine without aura and 24 healthy controls were exposed to a situation of loss of control whilst the contingent negative variation (CNV) from C3, C4 and Cz were recorded. Before conducting the experiment, the subjects were asked to answer the Beck Depression Inventory (BDI) and the German attributional style questionnaire (GASQ). Amplitudes of total CNV, early and late component and PINV were calculated in eight blocks of four recordings each. The results confirm findings of a pronounced PINV in situations of loss of control, though high amplitudes were not correlated with low values in the GASQ and therefore with learned helplessness. High PINV in migraine patients correlated with high scores in the BDI and the list of the complaints questionnaire. However, this was not the case in healthy controls. In this experimental situation, PINV in migraine patients can be interpreted as an expectancy potential in order to avoid failure and helplessness. [ABSTRACT FROM AUTHOR]

This study compared changes in quantitative EEG (QEEG) and CNV (contingent negative variation) of children suffering from ADHD treated by SCP (slow cortical potential) neurofeedback (NF) with the effects of group therapy (GT) to separate specific from non-specific neurophysiological effects of NF. Twenty-six children (age: 11.1 ± 1.15 years) diagnosed as having ADHD were assigned to NF ( N = 14) or GT ( N = 12) training groups. QEEG measures at rest, CNV and behavioral ratings were acquired before and after the trainings and statistically analyzed. For children with ADHD-combined type in the NF group, treatment effects indicated a tendency toward improvement of selected QEEG markers. We could not find the expected improvement of CNV, but CNV reduction was less pronounced in good NF performers. QEEG changes were associated with some behavioral scales. Analyses of subgroups suggested specific influences of SCP training on brain functions. To conclude, SCP neurofeedback improves only selected attentional brain functions as measurable with QEEG at rest or CNV mapping. Effects of neurofeedback including the advantage of NF over GT seem mediated by both specific and non-specific factors. [ABSTRACT FROM AUTHOR]

In the present study gender differences related to the contingent negative variation (CNV) were investigated. A series of two acoustic stimuli was presented to participants across a wide age range. The first stimulus was consistent throughout the experiment whereas the second one was either a high frequency or a low frequency tone. One of them had to be answered by a button press (go condition) the other did not require any response (nogo condition). Between the first and the second tone there was a time period of two seconds in which the CNV appeared as a slow negative potential shift. Within this episode data were analysed with respect to gender differences. Statistical analysis revealed topographical differences between men and women in go conditions for both left and right index finger movements. Differences were found over frontal regions where women showed higher brain activity than men and over temporo-parietal regions where men produced higher brain activity than women. In order to explain the fact that only in “go” conditions significant gender differences occurred we introduce the phenomenon of implicit learning. Due to implicit learning assumed predictions related to S2 might have occurred from time to time. This is so, because a 50% chance for one of two different stimuli to occur leads to reasonable assumed predictions after two or more stimuli of a kind occurring in a series. The present data now provide evidence that if such assumed prediction or expectancy is directed towards an upcoming demand to act then brain activity is subject to gender differences. Further studies providing controlled sequences of “go” conditions versus “nogo” conditions have to be done to prove this idea true. [ABSTRACT FROM AUTHOR]