Article

Changes in EEG power spectra during biofeedback of slow cortical potentials in epilepsy.

Institute of Medical Psychology and Behavioral Neurobiology, University of Tübingen, Germany.
Applied Psychophysiology and Biofeedback (Impact Factor: 1.13). 01/2000; 24(4):213-33. DOI: 10.1023/A:1022226412991
Source: PubMed

ABSTRACT The goal of the study was to explore parallel changes in EEG spectral frequencies during biofeedback of slow cortical potentials (SCPs) in epilepsy patients. Thirty-four patients with intractable focal epilepsy participated in 35 sessions of SCP self-regulation training. The spectral analysis was carried out for the EEG recorded at the same electrode site (Cz) that was used for SCP feedback. The most prominent effect was the increase in the theta 2 power (6.0-7.9 Hz) and the relative power decrement in all other frequency bands (particularly delta 1, alpha 2 and beta 2) in transfer trials (i.e., where patients controlled their SCPs without continuous feedback) compared with feedback trials. In the second half of the training course (i.e., sessions 21-35) larger power values in the delta, theta, and alpha bands were found when patients were required to produce positive versus negative SCP shifts. Both across-subject and across-session (within-subject) correlations between spectral EEG parameters, on the one hand, and SCP data, on the other hand, were low and inconsistent, contrary to high and stable correlations between different spectral variables. This fact, as well as the lack of considerable task-dependent effects during the first part of training, indicates that learned SCP shifts did not directly lead to the specific dynamics of the EEG power spectra. Rather, these dynamics were related to nonspecific changes in patients' brain state.

0 Bookmarks
 · 
51 Views
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Despite considerable research on EEG-feedback of slow cortical potentials (SCPs) for seizure control in epilepsy, the underlying mechanisms and the direct effects on intracerebral pathological activity within the focal area remain unclear. Intrahippocampal EEG recordings from four patients with temporal lobe epilepsy and implanted electrodes were analyzed with regard to spike activity and power in 10 frequency bands (0.5-148Hz) during SCP feedback based on surface recordings (position Cz). Trials with positive, negative and indifferent SCPs were contrasted. Three of the four patients showed changes in spike activity during SCPs, but these were inconsistent between patients, and resulted in increased and decreased activity in both positive and negative SCPs. Spectral analysis revealed that in all patients, positive surface shifts showed a bi-hemispheric higher power in the high-frequency activity above 40Hz. Two patients showed a higher power also during negative shifts, both in high-frequency activity and one in most other frequency bands. Feedback-related power effects did not differ between focal and non-focal side. The inconsistent change in spiking activity and the lack of decrease of power in pathology associated frequency bands during SCPs show that these SCPs do not decrease pathological activity within the epileptic focus. A possible relation of higher power in high-frequency activity during positive SCPs to cognitive processes, such as memory functions, is discussed.
    Epilepsy research 06/2011; 95(1-2):136-43. · 2.48 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Neurofeedback training procedures designed to alter a person's brain activity have been in use for nearly four decades now and represent one of the earliest applications of brain computer interfaces (BCI). The majority of studies using neurofeedback technology relies on recordings of the electroencephalogram (EEG) and applies neurofeedback in clinical contexts, exploring its potential as treatment for psychopathological syndromes. This clinical focus significantly affects the technology behind neurofeedback BCIs. For example, in contrast to other BCI applications, neurofeedback BCIs usually rely on EEG-derived features with only a minimum of additional processing steps being employed. Here, we highlight the peculiarities of EEG-based neurofeedback BCIs and consider their relevance for software implementations. Having reviewed already existing packages for the implementation of BCIs, we introduce our own solution which specifically considers the relevance of multi-subject handling for experimental and clinical trials, for example by implementing ready-to-use solutions for pseudo-/sham-neurofeedback.
    International journal of psychophysiology: official journal of the International Organization of Psychophysiology 09/2013; · 3.05 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: While the field of brain computer interfaces (BCIs) has produced impressive results regarding movement and communication restoration in patients with disability, among its less known clinical applications lie the array of treatment-resistant epileptic conditions. The control of BCI systems relies on brain activity control and regulation and it was to be expected that such systems would be tested for the regulation of abnormal brain activation in epilepsy. A few electroencephalographic (EEG) features have been used as BCI modalities for that cause. Such features are the slow cortical potentials (SCPs) and sensorimotor rhythm (SMR) regulation, and have been tested on epileptic patients with promising results. These methods – especially when used as supplementary to classic treatment - have produced superior results and appear to benefit long-term seizure suppression, seizure prevention and improvement of life quality. In certain cases an increase in cognitive functioning and IQ score has been observed.
    7th European Symposium on Biomedical Engineering, Halkidiki, Greece; 05/2010

Full-text

View
0 Downloads