Intractable epilepsy
Research Papers
Changes in EEG measurements in intractable epilepsy patients with neurofeedback training
To assess the effects of neurofeedback on brain electrophysiology and to determine how biofeedback works, power spectral density (PSD) and approximate entropy (ApEn) analyses are applied to the EEGs of six patients with intractable epilepsy who received neurofeedback training. After sessions of treatment, the EEG sensorimotor rhythm to theta PSD ratio calculated from the C4 electrode site becomes larger than that before the treatment, which is consistent with the biofeedback protocol. The ApEn over 16-channel EEG recordings all increase to different degrees. Larger increases occur in channels located near the training position (C4). All these results suggest that these EEG measurements are new criteria that can be used to evaluate the effect of neurofeedback.
View Full Paper →Power Spectral Frequency and Coherence Abnormalities in Patients with Intractable Epilepsy and Their Usefulness in Long-Term Remediation of Seizures Using Neurofeedback
Medically intractable seizures appear to be highly correlated with focal slow activity (delta or theta). They also correlate highly with decreases in the coherence of theta. Normalization of focal slowing and of decreased theta coherence will probably be the neurofeedback approaches most likely to decrease or eliminate seizures in future cases. Neurofeedback has been used for over 35 years to reduce the incidence and severity of seizures. With power training to decrease theta and increase the sensorimotor rhythm (12–15 Hz), an average of 82% of patients experienced a significant reduction in seizure frequency, and occasional remissions were seen. Recent improvements using QEEG to guide neurofeedback training have made it possible to eliminate seizures in most patients, even those with intractable seizures. Following our previous study in 2005, we report an additional 25 patients so treated. We also report an analysis of the frequency of QEEG abnormalities in this patient group. All of the intractable epileptic patients had one or more slow foci (excessive theta or delta compared with the normal database). One third had a relative deficiency of beta power. One fourth had a deficiency of absolute delta. Eighteen percent had excessive absolute alpha power, 18% had deficient absolute alpha power, 18% percent had excessive absolute beta power, and 18% percent had deficient absolute beta power. Hypocoherence of theta was found in 75%, and decreases in alpha coherence were noted in 42%. Hypocoherence of beta was found in 50%, and hypocoherence of delta was found in 25%. Increases in alpha coherence were noted in 33%. Seventeen percent had no coherence abnormalities. When most of the power and coherence abnormalities were normalized with neurofeedback training, all the patients became seizure-free; 76% no longer required an anticonvulsant for seizure control.
View Full Paper →Nonlinear analysis in treatment of intractable epilepsy with EEG biofeedback
About 25% epilepsy patients are suffering from medically intractable epileptic seizure. Many studies have shown that electroencephalogram (EEG) biofeedback therapy has the exciting potential for seizure control. In this paper, five patients with intractable epilepsy were trained to increase the production of sensorimotor (12 15 Hz) activity and decrease the production of slow theta (4 7 Hz) activity. Nonlinear analysis are proposed to evaluate the effect of biofeedback training. In all the five patients, the complexity and approximate entropy of EEG increased significantly (P<0.05) after (about 1-month) the biofeedback treatment
View Full Paper →Neurofeedback and epilepsy
Over the past three decades, researchers have examined various behavioral approaches to the treatment of epilepsy. One prominent line of inquiry concerns the effectiveness of neurofeedback, which entails the entrainment of specific electroencephalographic frequencies for the purpose of decreasing seizure frequencies in patients with epilepsy. This article reviews the current literature on the efficacy of neurofeedback in reducing seizure frequency. While it is clear that neurofeedback had a positive effect in most of the studies reviewed, these findings are limited due to multiple confounding factors. In the absence of any rigorously controlled studies, the relationship between neurofeedback and seizure frequency cannot be firmly established. Despite these limitations, the promising role of neurofeedback as a treatment for epilepsy is illustrated.
View Full Paper →Changes in EEG Power Spectra During Biofeedback of Slow Cortical Potentials in Epilepsy
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 θ2 power (6.0–7.9 Hz) and the relative power decrement in all other frequency bands (particularly δ1, α2, and β2) 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 δ, θ, and α 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.
View Full Paper →Behavioural treatment of slow cortical potentials in intractable epilepsy: neuropsychological predictors of outcome.
The study aimed to explore the predictive value of neuropsychological tests within the context of acquisition of slow cortical potential (SCP) self-control, a technique which has beneficial effects on seizure frequency in epilepsy. Patients with epilepsy who successfully achieved SCP control had longer digit or block-tapping spans than less successful patients. Patients who showed a better learning rate across training also displayed better verbal memory and learning abilities. Seizure reduction was related to block-tapping spans only. The results indicate that measures of attention, as indicated by digit spans or block-tapping spans, offer some predictive value for acquisition of SCP control and treatment outcome, whilst measures of visuospatial or frontal lobe function are unrelated to SCP acquisition and seizure reduction.
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