continuous performance task
Research Papers
Neurofeedback of slow cortical potentials: neural mechanisms and feasibility of a placebo-controlled design in healthy adults
To elucidate basic mechanisms underlying neurofeedback we investigated neural mechanisms of training of slow cortical potentials (SCPs) by considering EEG- and fMRI. Additionally, we analyzed the feasibility of a double-blind, placebo-controlled design in NF research based on regulation performance during treatment sessions and self-assessment of the participants. Twenty healthy adults participated in 16 sessions of SCPs training: 9 participants received regular SCP training, 11 participants received sham feedback. At three time points (pre, intermediate, post) fMRI and EEG/ERP-measurements were conducted during a continuous performance test (CPT). Performance-data during the sessions (regulation performance) in the treatment group and the placebo group were analyzed. Analysis of EEG-activity revealed in the SCP group a strong enhancement of the CNV (electrode Cz) at the intermediate assessment, followed by a decrease back to baseline at the post-treatment assessment. In contrast, in the placebo group a continuous but smaller increase of the CNV could be obtained from pre to post assessment. The increase of the CNV in the SCP group at intermediate testing was superior to the enhancement in the placebo group. The changes of the CNV were accompanied by a continuous improvement in the test performance of the CPT from pre to intermediate to post assessment comparable in both groups. The change of the CNV in the SCP group is interpreted as an indicator of neural plasticity and efficiency while an increase of the CNV in the placebo group might reflect learning and improved timing due to the frequent task repetition. In the fMRI analysis evidence was obtained for neuronal plasticity. After regular SCP neurofeedback activation in the posterior parietal cortex decreased from the pre- to the intermediate measurement and increased again in the post measurement, inversely following the U-shaped increase and decrease of the tCNV EEG amplitude in the SCP-trained group. Furthermore, we found a localized increase of activity in the anterior cingulate cortex (ACC). Analyses of the estimation of treatment assignment by the participants indicate feasibility of blinding. Participants could not assess treatment assignment confidently. Participants of the SCP-group improved regulation capability during treatment sessions (in contrast to the participants of the placebo-group), although regulation capability appeared to be instable, presumably due to diminished confidence in the training (SCP- or sham-training). Our results indicate that SCP training in healthy adults might lead to functional changes in neuronal circuits serving cognitive preparation even after a limited number of sessions.
View Full Paper →Pilot Project to Ascertain the Utility of Tower of London Test to Assess Outcomes of Neurofeedback in Clients with Asperger's Syndrome
Introduction. Behavioral and cognitive improvements in clients with Asperger's Syndrome (AS), employing continuous performance tests (CPTs), intelligence and academic measures, and electroencephalographic data, have been reported following 40 sessions of neurofeedback (NFB) training combined with coaching in metacognitive strategies. However, measures of executive functions (EFs) in this population have not been commonly employed and NFB is still not commonly used as a treatment for AS. Therefore, this pilot project used Tower of London - Drexel University (ToLDX), an individually administered test of EFs, in addition to the previously mentioned measures. The goal of the current study was to investigate the utility of ToLDX as an assessment tool for clients with AS as well as further study the effects of NFB and training in metacognitive strategies on executive functioning in clients with AS. Method. Nineteen consecutive clients at the ADD Centre, Toronto, Canada (M age = 12 years 0 months) recruited over a 21/2-year period all had full clinical assessment, completed age appropriate questionnaires, and were tested pre- and post-40 NFB sessions. Results. Following the training, clients with AS were able to plan more efficiently, inhibit premature responses, and shift set with greater ease, as well as solve problems more quickly as measured by their ToLDX scores. On CPTs, clients with AS showed a trend toward less impulsivity. Finally, improvement in their scores on ToLDX was not affected by age or IQ. Conclusion. These data are important because they provide an extension of results of previous studies (Reid, 2005), demonstrate the utility of tests of executive functions in a clinical setting with clients with AS, and suggest directions for further controlled research in this area.
View Full Paper →Hemoencephalography–A New Therapy for Attention Deficit Hyperactivity Disorder (ADHD): Case Report
Background. Hemoencephalography (HEG) is cortical circulatory biofeedback using refracted light tuned to oxygenated hemoglobin, emitted into the skull and detected at the scalp using a photoelectric cell. Red light at 660 nm is used as the probe, with changes in the returning refracted light representing changes in cortical circulation. Method. A single-subject design case study was employed. TL, at age twelve, had a well-established diagnosis of ADHD given by pediatric neurologists, and required significant stimulant medication that was clinically effective. He was performing well in school on Concerta 36 mg at 7 a.m. and Ritalin 5 mg at 4 p.m. Off medication, he had significant abnormalities on IVA testing (Attention Quotient or AQ = 78) and in the quantitative electroencephalogram (QEEG). Using HEG, the patient engaged the system to exercise increases in signals corresponding to cortical circulation in the prefrontal cortex. QEEG, Continuous Performance Testing (CPT) and clinical status measurements were made before and after 10 sessions of HEG therapy. HEG exercise was typically given in weekly to bi-weekly sessions for 10 minutes in each of three standard prefrontal EEG locations: FP1, FP2 and FPz. Results. During the 10 therapy sessions TL's HEG data showed positive gain indicating success at raising the biofeedback signal. Following the 10 sessions, TL showed a normal QEEG with improved Z scores for relative power and normal IVA testing off medication (mean AQ 99.75 ± 7.85 on three dates), which persisted in the 18-month follow-up. His medication was lowered to Focalin 2.5 mg twice daily. Conclusion. This work documents a patient who showed clinically significant improvement after only 10 sessions using a new form of neurobiofeedback, hemoencephalography. If confirmed in controlled studies, this represents a breakthrough in treatment options for ADHD. Future studies should explore synergies between HEG and EEG neurofeedback therapies.
View Full Paper →Intentional Increase of Cerebral Blood Oxygenation Using Hemoencephalography (HEG): An Efficient Brain Exercise Therapy
Intentional enhancement of regional cerebral blood oxygenation (rCBO2) in specific cerebral locations was studied as a brain exercise. A review of literature showed the effect of brain exercise on brain physiology. Hemoencephalography (HEG), a graphic analog of brain blood flow of oxygenated hemoglobin indicated by non-invasive infrared spectroscopy, was used to guide intentionally increasing rCBO2. A musical note and visual graphic keyed to changes in cortical blood oxygenation was provided to the participant. A primary aim of this study was to demonstrate the capacity of subjects with brain disorders to increase oxygenation of selected brain tissue using HEG and test the hypothesis that multiple repetitions of these brain exercises improved sustained attention measured with a continuous performance test. The impulsivity score for subjects in the exercise group was in the normal range after 10 sessions. In a small set of subjects, low arousal SPECT images showed increased vascularity after 30 half-hour sessions of intentional enhancement of local blood oxygenation.
View Full Paper →Neurofeedback Training with Virtual Reality for Inattention and Impulsiveness
In this research, the effectiveness of neurofeedback, along with virtual reality (VR), in reducing the level of inattention and impulsiveness was investigated. Twenty-eight male participants, aged 14–18, with social problems, took part in this study. They were separated into three groups: a control group, a VR group, and a non-VR group. The VR and non-VR groups underwent eight sessions of neurofeedback training over 2 weeks, while the control group just waited during the same period. The VR group used a head-mounted display (HMD) and a head tracker, which let them look around the virtual world. Conversely, the non-VR group used only a computer monitor with a fixed viewpoint. All participants performed a continuous performance task (CPT) before and after the complete training session. The results showed that both the VR and non-VR groups achieved better scores in the CPT after the training session, while the control group showed no significant difference. Compared with the other groups, the VR group presented a tendency to get better results, suggesting that immersive VR is applicable to neurofeedback for the rehabilitation of inattention and impulsiveness.
View Full Paper →Changes after EEG biofeedback and cognitive retraining in adults with mild traumatic brain injury and attention deficit hyperactivity disorder
Introduction. Adults diagnosed with mild traumatic brain injury (mTBI) or Attention Deficit Hyperactivity Disorder (ADHD) were treated with EEG Biofeedback and cognitive retraining. Methods. Psychological and neuropsychological tests were completed at pre-treatment and post-treatment and compared to a normal control group that did not receive training, but tested on two occasions. Results. The results found significant improvement on full scale attention and full scale response accuracy of a continuous performance task in the mTBI and ADHD groups compared to the control group. A self report showed a significant decline in symptoms in the mTBI and ADHD groups compared to the control group. Errors on a problem solving task decreased only in the mTBI group. Discussion. The treatment model used in this study showed significant improvement in the sustained attention of individuals diagnosed with mTBI and ADHD after twenty treatment sessions.
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