Slow cortical potentials neurofeedback in children with ADHD: comorbidity, self-regulation and clinical outcomes 6 months after treatment in a multicenter randomized controlled trial.

Despite sizeable short-term effects of neurofeedback (NF) therapy on attention-deficit and hyperactivity disorder (ADHD), longer-term clinical, comorbidity and self-regulation outcomes are less systematically studied. The aim of this largest NF follow-up to date was to evaluate these outcomes 6 months after NF compared to a semi-active control to disentangle specific from unspecific sustained effects. We performed a multicenter, randomized, parallel, controlled, clinical, superiority trial in five German university outpatient departments. Participants were eligible if they fulfilled DSM-IV-TR criteria for ADHD and were aged from 7 to 9 years. Participants were randomly assigned (1:1-ratio) to 25 sessions of slow cortical potential (SCP)-NF or electromyogram biofeedback (EMG-BF). Participants were not blinded, since they received instructions according to each treatment setting. Primary outcomes were parent ratings of ADHD. The trial was registered, number ISRCTN761871859. Both groups showed improvement of ADHD symptoms compared to baseline at 6-months follow-up with large effect sizes for SCP-NF (d = 1.04) and EMG-BF (d = 0.85), but without group differences. When analyzing all assessments (pre-test, post-test-1, post-test-2 and follow-up), a group-by-time interaction emerged (p = 0.0062), with SCP-NF showing stable improvement following treatment but EMG-BF showing a relapse from post-test-1 to post-test-2, and subsequent remission at follow-up. Six months after the end of treatment, improvement after SCP-NF remained large and stable. However, the lack of group differences at follow-up suggests shared specific and unspecific effects contributing to this clinical outcome. Our correlational results indicate specificity of SCP-NF for selected subscales after training, but not at follow-up.

Modification of slow cortical potentials in patients with refractory epilepsy: a controlled outcome study.

PURPOSE: To compare self-regulation of low-frequency EEG components (slow cortical potentials, SCPs) with other methods of seizure control for patients with drug-refractory partial epilepsy and to separate the real anticonvulsive effect from placebo effects. METHODS: Results of a treatment program of SCP self-regulation (experimental group) are compared with two groups of patients, one of which learned self-control of respiratory parameters (end-tidal CO2 and respiration rate: RES group); the other received medication with new anticonvulsive drugs (AEDs) in combination with psychosocial counseling (MED group). Clinical, cognitive, behavioral, and personality measures were assessed before and after treatment. In addition, to control for placebo responses, patients repeatedly estimated their beliefs in the efficiency of the respective treatment, their satisfaction and expectations, and the quality of the relationship with their therapists. RESULTS: SCP and MED groups showed a significant decrease of seizure frequency, but the RES group did not. Clear positive changes in the sociopsychological adjustment were obtained in all three groups, with the maximal improvement being attained in the RES group. CONCLUSIONS: All kinds of therapy result in considerable improvement of patients' emotional state, which may in part be due to potential placebo effects: however, this improvement is not related to the quality of the therapeutic effect proper (i.e., seizure reduction). Traditional double-blind control group designs are inappropriate for behavioral interventions or treatments with psychoactive pharmacologic drugs. Rather, specific tests can be developed to control the placebo effect and to separate it from the genuine therapeutic effects.

Negative potential shifts and the prediction of the outcome of neurofeedback therapy in epilepsy.

About two-thirds of epilepsy patients who learn to control their slow cortical potential shifts (SCP) reduce their seizure rate, but the remaining third does not demonstrate clinical improvement. In the present study, this finding was replicated in a group of 27 patients with focal epilepsy. We found that patients who consistently produced larger negative SCP in all conditions during the first phase of treatment, showed no decrease in seizure frequency during the six-month follow-up, as compared with the three-month baseline phase. The large negative SCP explained about one-third of the variance of the clinical outcome. Age, medication, seizure history, or the localization of focus were found to be unrelated to clinical improvement.

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 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.

Behavioral psychophysiological intervention in a mentally retarded epileptic patient with brain lesion.

Behavioral psychophysiological treatment entailing Slow Cortical Potential (SCP) biofeedback training and behavioral self-control training was conducted with a 27-year-old male epileptic patient (seizures for 23 years) with Wechsler IQ 64 who underwent callosotomy. The patient had 12/week secondary generalized tonic-clonic seizures. The treatment, consisting of 43 SCP training sessions and 22 behavioral control sessions, yielded a highly significant reduction of seizure frequency to about 7.5/week; such a decrease had never been observed after administration of new anticonvulsant drugs, nor after the callosotomy. During SCP feedback training, the patient was able to produce highly-significant cortical differentiation of SCPs of about 4 microV. In addition, he developed several new behaviors indicating growing ability of self-perception and self-regulation. These findings suggest that a combination of SCP biofeedback with behavioral treatment of epilepsy can be used even in mentally retarded patients with organic brain disorders.

Stability of cortical self-regulation in epilepsy patients.

Biofeedback-supported self-regulation of slow cortical potentials (SCP) is increasingly being used for treatment of intractable epilepsy. However, it is unknown whether the acquired ability to regulate one's own cortical potentials remains stable over time. In this study, 18 patients with drug-resistant partial epilepsy performed 35 training sessions in which they learned to generate slow cortical potential shifts in either positive or negative direction. At the end of training, they differentiated significantly between required cortical positivity and required cortical negativity. Six months after this point, they still demonstrated an unchanged between-condition differentiation. The performance in the booster session was particularly good in trials without continuous SCP feedback. The ability to generate positive SCP shifts was related to decrease of seizure frequency during the 6 months follow-up period compared with the 3 month baseline period. This data indicate that the acquired ability of humans to regulate their cortical potentials did not decrease over a 6 month period but rather, tended to consolidate.

Self-regulation of slow cortical potentials in epilepsy: a retrial with analysis of influencing factors.

Twenty sessions of biofeedback training were carried out with 12 drug-resistant patients with focal epilepsy who learned to produce either negative or positive shifts of their slow cortical potentials (SCPs) at vertex. Feedback trials were interspersed with transfer trials in which only a discriminative stimulus (signalizing whether positivity or negativity was required) was presented, without feedback signal. Patients were able to differentiate significantly between the conditions of cortical positivity and cortical negativity, with larger differentiation scores being obtained in feedback trials than in transfer trials. The amplitude of positivity generated in the positivity condition increased linearly across sessions both in feedback and in transfer trials. The largest negativity was produced in the 5th session; after this, more transient negativities were generated, whose amplitude decreased towards the end of trial. The mean severity of seizures, estimated as the frequency of seizures weighted by their subjective 'strength', decreased significantly after training as compared to the pre-training phase. The data suggest that (1) patients could learn to achieve a state of cortical disfacilitation and (2) with progressed learning, they became less motivated for (or afraid of) producing considerable negative shifts, since extensive negativity may reflect cortical over-excitation and therefore be associated with early signs of seizures. The inability of producing cortical negativity is however not necessarily a bad predictor.