Publications

Introduction. Slow Cortical Potential (SCP) neurofeedback and Galvanic Skin Response (GSR) biofeedback training were used to investigate self-regulatory control over central and peripheral arousal processes in two groups of healthy participants. Method. One group completed the SCP neurofeedback training procedure; the other group performed the GSR biofeedback procedure. Both groups underwent treatment while the other variable was passively recorded. The participants were instructed to either increase (Up trials) or decrease (Down trials) arousal. Twenty sessions were completed by each of the 18 participants over an 8-week period. Results. Participants in each group performed better on the variable they were trained on. In the GSR group, a significant increase in performance over blocks was obtained for both trial types (Up and Down). In the SCP group a better performance on the Down trials was obtained. When comparing performance of both trial types, the SCP-trained participants showed a marginal increase and the GSR-trained participants a significant increase over time preliminary-training. Conclusion. Overall, the results showed that GSR regulation is easier to learn than SCP training with neurofeedback, that both variables can be trained in a bidirectional design, and that the SCP training subjects were predominantly able to learn performance at the Down trials. Preliminary results from the cross-correlations are inconsistent over trial types, trained parameters, and participants. However, the general trend shows a more positive correlation at the end of training compared to the start of training. Cross-correlation analysis suggests that this training encourages positive correlation between the SCP and GSR. Future research directions should be aimed at improving motivational conditions, implementing contingent reward principles, and controlling confounding variables.

The approach-withdrawal and valence-arousal models highlight that specific brain laterality profiles may distinguish depression and anxiety. However, studies remain to be conducted in multiple clinical populations that directly test the diagnostic specificity of these hypotheses. The current study compared electroencephalographic data under resting state, eyes closed conditions in patients with major depressive disorder (MDD) (N=15) and post-traumatic stress disorder (PTSD) (N=14) relative to healthy controls (N=15) to examine the specificity of brain laterality in these disorders. Key findings included (1) reduced left-frontal activity in MDD, (2) a positive correlation between PTSD severity and right-frontal lateralisation, (3) greater activity in PTSD patients relative to MDD within the right-parietotemporal region, and (4) globally increased alpha power in MDD. Findings partially support the diagnostic applicability of the theoretical frameworks. Future studies may benefit from examining task-driven differences between groups.

ObjectiveIn a pilot study it was investigated whether assessment of EEG-vigilance is useful for the prediction of treatment outcome in ADHD patients.MethodsResting EEG recordings of 49 unmedicated ADHD patients and 49 age-matched controls were analyzed. Vigilance level was determined for 1-s segments with a computer-based algorithm, distinguishing six stages from higher vigilance stages A1, A2 and A3 with dominant alpha activity to lower stages B1 and B2/3 with low amplitude non-alpha and increasing theta and delta activity and further onto stage C characterizing sleep onset. Treatment outcome was measured as changes in continuous performance test (CPT) results from baseline after at least 4weeks of medication.ResultsADHD patients spend less time in higher A1-stages (ADHD=66%, controls=81%) and showed more switching between vigilance stages (ADHD=26.02%, controls=19.09%), indicating a more unstable vigilance regulation. Patients with less stable vigilance showed a worse pre-treatment CPT performance but achieved a better post-treatment result compared to patients with more stable vigilance regulation. These differences did not reach statistical significance.ConclusionsSigns of vigilance instability where found in ADHD patients compared to controls. Those patients with a higher degree of vigilance instability seemed to benefit more from stimulant medication.SignificanceThis is the first investigation of EEG-vigilance in ADHD-patients. Results are limited by a short recording time but the results strongly suggest further investigation of the vigilance regulation in ADHD patients.

Insomnia is a sleeping disorder, usually studied from a behavioural perspective, with a focus on somatic and cognitive arousal. Recent studies have suggested that an impairment of information processes due to the presence of cortical hyperarousal might interfere with normal sleep onset and/or consolidation. As such, a treatment modality focussing on CNS arousal, and thus influencing information processing, might be of interest. Seventien insomnia patients were randomly assigned to either a tele-neurofeedback (n = 9) or an electromyography tele-biofeedback (n = 8) protocol. Twelve healthy controls were used to compare baseline sleep measures. A polysomnography was performed pre and post treatment. Total Sleep Time (TST), was considered as our primary outcome variable. Sleep latency decreased pre to post treatment in both groups, but a significant improvement in TST was found only after the neurofeedback (NFB) protocol. Furthermore, sleep logs at home showed an overall improvement only in the neurofeedback group, whereas the sleep logs in the lab remained the same pre to post training. Only NFB training resulted in an increase in TST. The mixed results concerning perception of sleep might be related to methodological issues, such as the different locations of the training and sleep measurements.

Since the first reports of neurofeedback treatment in Attention Deficit Hyperactivity Disorder (ADHD) in 1976, many studies have investigated the effects of neurofeedback on different symptoms of ADHD such as inattention, impulsivity and hyperactivity. This technique is also used by many practitioners, but the question as to the evidence-based level of this treatment is still unclear. In this study selected research on neurofeedback treatment for ADHD was collected and a meta-analysis was performed. Both prospective controlled studies and studies employing a pre-and post-design found large effect sizes (ES) for neurofeedback on impulsivity and inattention and a medium ES for hyperactivity. Randomized studies demonstrated a lower ES for hyperactivity suggesting that hyperactivity is probably most sensitive to nonspecific treatment factors. Due to the inclusion of some very recent and sound methodological studies in this meta-analysis, potential confounding factors such as small studies, lack of randomization in previous studies and a lack of adequate control groups have been addressed, and the clinical effects of neurofeedback in the treatment of ADHD can be regarded as clinically meaningful. Three randomized studies have employed a semi-active control group which can be regarded as a credible sham control providing an equal level of cognitive training and client-therapist interaction. Therefore, in line with the AAPB and ISNR guidelines for rating clinical efficacy, we conclude that neurofeedback treatment for ADHD can be considered “Efficacious and Specific” (Level 5) with a large ES for inattention and impulsivity and a medium ES for hyperactivity.

Phonological theories of dyslexia assume a specific deficit in representation, storage and recall of phonemes. Various brain imaging techniques, including qEEG, point to the importance of a range of areas, predominantly the left hemispheric temporal areas. This study attempted to reduce reading and spelling deficits in children who are dyslexic by means of neurofeedback training based on neurophysiological differences between the participants and gender and age matched controls. Nineteen children were randomized into an experimental group receiving qEEG based neurofeedback (n = 10) and a control group (n = 9). Both groups also received remedial teaching. The experimental group improved considerably in spelling (Cohen's d = 3). No improvement was found in reading. An indepth study of the changes in the qEEG power and coherence protocols evidenced no fronto-central changes, which is in line with the absence of reading improvements. A significant increase of alpha coherence was found, which may be an indication that attentional processes account for the improvement in spelling. Consideration of subtypes of dyslexia may refine the results of future studies.

Background. Operant conditioning of one's slow cortical potential (SCP) or sensorimotor rhythm (SMR) can be used to control epilepsy or to manipulate external devices, as applied in BCI (Brain-Computer Interface). A commonly accepted view that both SCP and SMR are reflections of central arousal suggests a functional relationship between SCP and SMR networks. Method. The operant conditioning of SCP or SMR was tested with a single electroencephalographic (EEG) channel wireless biofeedback system. A series of trainings taught 19 participants to control SCP or SMR over vertex during 20 neurofeedback sessions. Each session consisted of 96 trials to decrease cortical arousal (SCP positivity/SMR enhancement) and 64 trials to increase cortical arousal (SCP negativity/SMR suppression). In each trial, participants were required to exceed an individual threshold level of the feedback parameter relative to a 500-msec prefeedback baseline and to hold this level for 2 sec (SCP) or 0.5 sec (SMR) to obtain reinforcement. Results. Ten of the 19 participants achieved control over their EEG. In the SCP-trained group, 4 of 9 participants increased the differentiation between their SCP responses on positivity-required versus negativity-required trials. SMR suppression and enhancement was achieved by 3 and 4 of the 10 SMR-trained participants. The SMR-trained responders did not show differentiation in their SMR responses, but did show a differentiation in their SCP response—while trained on SMR. Conclusions. The results showed the proposed method was successful to teach control of SCP or SMR. Bidirectional control was very difficult to achieve with the present SMR training procedure. SCP positivity and SMR enhancement were easier to learn. The results suggest that SMR training modulates excitability thresholds in the striatal-thalamocortical motor loop, whereas changes in the loop's excitability thresholds by SCP training do not affect the thalamic bursting that underlies the SMR.

This study demonstrates that the EEG phenotypes as described by Johnstone, Gunkelman & Lunt are identifiable EEG patterns with good inter-rater reliability. Furthermore, it was also demonstrated that these EEG phenotypes occurred in both ADHD subjects as well as healthy control subjects. The Frontal Slow and Slowed Alpha Peak Frequency and the Low Voltage EEG phenotype discriminated ADHD subjects best from controls (however the difference was not significant). The Frontal Slow group responded to a stimulant with a clinically relevant decreased number of false negative errors on the CPT. The Frontal Slow and Slowed Alpha Peak Frequency phenotypes have different etiologies as evidenced by the treatment response to stimulants. In previous research Slowed Alpha Peak Frequency has most likely erroneously shown up as a frontal theta sub-group. This implies that future research employing EEG measures in ADHD should avoid using traditional frequency bands, but dissociate Slowed Alpha Peak Frequency from frontal theta by taking the individual alpha peak frequency into account. Furthermore, the divergence from normal of the frequency bands pertaining to the various phenotypes is greater in the clinical group than in the controls. Investigating EEG phenotypes provides a promising new way to approach EEG data, explaining much of the variance in EEGs and thereby potentially leading to more specific prospective treatment outcomes.

Background. This study reports on a new method for golf performance enhancement employing personalized real-life neurofeedback during golf putting. Method. Participants (n = 6) received an assessment and three real-life neurofeedback training sessions. In the assessment, a personal event-locked electroencephalographic (EEG) profile at FPz was determined for successful versus unsuccessful putts. Target frequency bands and amplitudes marking optimal prefrontal brain state were derived from the profile by two raters. The training sessions consisted of four series of 80 putts in an ABAB design. The feedback in the second and fourth series was administered in the form of a continuous NoGo tone, whereas in the first and third series no feedback was provided. This tone was terminated only when the participants EEG met the assessment-defined criteria. In the feedback series, participants were instructed to perform the putt only after the NoGo tone had ceased. Results. From the personalized event-locked EEG profiles, individual training protocols were established. The interrater reliability was 91%. The overall percentage of successful putts was significantly larger in the second and fourth series (feedback) of training compared to the first and third series (no feedback). Furthermore, most participants improved their performance with feedback on their personalized EEG profile, with 25% on average. Conclusions. This study demonstrates that the “zone” or the optimal mental state for golf putting shows clear recognizable personalized patterns. The learning effects suggest that this real-life approach to neurofeedback improves learning speed, probably by tapping into learning associated with contextual conditioning rather than operant conditioning, indicating perspectives for clinical applications.

Repetitive transcranial magnetic stimulation (rTMS) treatment for depression has been under investigation in many controlled studies over the last 20 years. Little is known about the neurobiological action of rTMS in patients. We therefore investigated pre- and post-treatment effects on QEEG, ERP's and behavior (BDI and NEO-FFI). rTMS treatment was applied in 8 subjects for an average of 21 sessions to the left Dorsolateral Prefrontal Cortex (left DLPFC). Clients were assessed on a QEEG and Oddball ERP evaluation pre- and post-treatment. Clients were stimulated over the left DLPFC with 10 Hz rTMS (100% MT). Furthermore, rTMS treatment was complimented by psychotherapy. All subjects showed full remission within 20 sessions and there was a significant reduction in depressive symptomatology (BDI score) after 10 and 15 sessions and a clear decrease in the Neuroticism and an increase on the extraversion scale of the NEO-FFI personality questionnaire. Pre- and post-QEEG measurements did not reveal treatment specific effects, but only an indirect right frontal increase in delta power. On the other hand, ERP measures did reveal treatment specific effects by showing an increased positivity in the post-treatment ERP's specifically left frontal. The P2 amplitude demonstrated a significant left frontal increase in amplitude, whereas for the negative N1 and N2 a significant decrease in amplitude was observed. The results of this pilot study demonstrate that rTMS can be a safe and efficacious treatment modality for depression. Furthermore, a specific left frontal increase in positivity for the ERP's was found (increased P2 and decreased N1 and N2 components) most likely related to the rTMS over the left DLPFC. Furthermore, there was no change in the alpha asymmetry lending support to the fact that frontal alpha asymmetry can be considered a trait marker for depression. The findings from this pilot study require future replication with larger sample sizes.

In de psychologische praktijk duiken gelei­delijk nieuwe vormen van behandelingen op, zoals magnetische hersenstimulatie, deep­brain­stimulation en eeg­biofeedback. Hierdoor wordt een meer lokale behandeling van aandoeningen mogelijk, louter gericht op bepaalde gebieden of netwerken in het brein. een ontwikkeling die hier complementair aan is, is die van personalized medicine. In onder­staande bijdrage wordt de mogelijke beteke­nis van deze nieuwe methoden onderzocht aan de hand van twee voorbeelden: de behan­deling van ADHD en die van depressie.

This study was undertaken using the INTEGRATE Model of brain organization, which is based on a temporal continuum of emotion, thinking and self regulation. In this model, the key organizing principle of self adaption is the motivation to minimize danger and maximize reward. This principle drives brain organization across a temporal continuum spanning milliseconds to seconds, minutes and hours. The INTEGRATE Model comprises three distinct processes across this continuum. Emotion is defined by automatic action tendencies triggered by signals that are significant due to their relevance to minimizing danger-maximizing reward (such as abrupt, high contrast stimuli). Thinking represents cognitive functions and feelings that rely on brain and body feedback emerging from around 200 ms post-stimulus onwards. Self regulation is the modulation of emotion, thinking and feeling over time, according to more abstract adaptions to minimize danger-maximize reward. Here, we examined the impact of dispositional factors, age and genetic variation, on this temporal continuum. Brain Resource methodology provided a standardized platform for acquiring genetic, brain and behavioral data in the same 1000 healthy subjects. Results showed a "paradox" of declining function in the "thinking" time scale over the lifespan (6 to 80+ years), but a corresponding preservation or even increase in automatic functions of "emotion" and "self regulation". This paradox was paralleled by a greater loss of grey matter in cortical association areas (assessed using MRI) over age, but a relative preservation of subcortical grey matter. Genetic polymorphisms associated with both healthy function and susceptibility to disorder (including the BDNFVal(66)Met, COMTVal(158/108)Met, MAOA and DRD4 tandem repeat and 5HTT-LPR polymorphisms) made specific contributions to emotion, thinking and self regulatory functions, which also varied according to age.

QEEG and neuropsychological tests were used to investigate the underlying neural processes in dyslexia.

The present study employs standardized data acquired from the Brain Resource International Database to study the relationship between mobile phone usage, personality, and brain function (n = 300). Based on the frequency and duration of mobile phone usage, three groups were formed. The findings suggest a subtle slowing of brain activity related to mobile phone use that is not explained by differences in personality. These changes are still within normal physiological ranges. Better executive function in mobile phone users may reflect more focused attention, possibly associated with a cognitive training effect (i.e., frequently making phone calls in distracting places), rather than a direct effect of mobile phone use on cognition.

Increasing age is the strongest risk factor for Alzheimer's disease (AD). Yet, departure from normal age-related decline for established markers of AD including memory, cognitive decline and brain function deficits, has not been quantified.

New treatments for Alzheimer's disease require early detection of cognitive decline. Most studies seeking to identify markers of early cognitive decline have focused on a limited number of measures. We sought to establish the profile of brain function measures which best define early neuropsychological decline. We compared subjects with subjective memory complaints to normative controls on a wide range of EEG derived measures, including a new measure of event-related spatio-temporal waves and biophysical modeling, which derives anatomical and physiological parameters based on subject's EEG measurements. Measures that distinguished the groups were then related to cognitive performance on a variety of learning and executive function tasks. The EEG measures include standard power measures, peak alpha frequency, EEG desynchronization to eyes-opening, and global phase synchrony. The most prominent differences in subjective memory complaint subjects were elevated alpha power and an increased number of spatio-temporal wave events. Higher alpha power and changes in wave activity related most strongly to a decline in verbal memory performance in subjects with subjective memory complaints, and also declines in maze performance and working memory reaction time. Interestingly, higher alpha power and wave activity were correlated with improved performance in reverse digit span in the subjective memory complaint group. The modeling results suggest that differences in the subjective memory complaint subjects were due to a decrease in cortical and thalamic inhibitory gains and slowed dendritic time-constants. The complementary profile that emerges from the variety of measures and analyses points to a nonlinear progression in electrophysiological changes from early neuropsychological decline to late-stage dementia, and electrophysiological changes in subjective memory complaint that vary in their relationships to a range of memory-related tasks.

Cognitive decline in speeded abilities, executive function, and memory is believed to typify normal aging. However, there is significant variability in cognitive function with advanced age and some reports of relatively intact cognitive function among a subset of older individuals. The present study consists of a cluster analysis to examine the patterns of cognitive function in middle-aged and older individuals. Analyses revealed 3 clusters of middle-aged adults, including an intact group, persons with poor motor speed, and a group with reduced executive function. Three clusters were also identified for older adults, including a group with poor executive function, persons with reduced speed performance (attention, executive function, motor), and a group with global cognitive decline. No evidence emerged for a cluster of older adults with intact performance in all domains or with isolated memory deficits. Findings generally support the frontal aging hypothesis and may provide important information about healthy cognitive aging.

This study examined the effects of age, gender and education on subjects spanning nine decades on a new cognitive battery of 12 tests. One thousand and seven participants between 6 and 82 completed the battery under standardized conditions using an automated, computerized touchscreen. Sensitive indicators of change were obtained on measures of attention and working memory, learning and memory retrieval, and language, visuospatial function, sensori-motor and executive function. Improvement tended to occur through to the third and fourth decade of life, followed by gradual decrement and/or stabilized performance thereafter. Gender differences were obtained on measures of sustained attention, verbal learning and memory, visuospatial processing and dexterity. Years of education in adults was reflected in performance on measures of verbal function. Overall, the test battery provided sensitive indicators on a range of cognitive functions suitable for the assessment of abnormal cognition, the evaluation of treatment effects and for longitudinal case management.

Spatial discrimination of ibotenic acid-lesioned C57BL/6 (B6) and DBA/2 (D2) mice was tested in two-choice water maze and plus maze tasks. B6 but not D2 mice learned the spatial discrimination in the water maze, but strains did not differ in learning a spatial discrimination in the plus maze paradigm. Ibotenic acid lesions of the hippocampus impaired percentage correct choices in the water maze spatial discrimination task in B6 but not in D2 mice, the latter of which may have been due to a floor effect. Furthermore, lesioned mice were more thigmotaxic, the distance travelled until a choice was made was longer and animals made more errors of omission. Despite the poor performance during water maze acquisition, lesioned animals, as well as sham-lesioned D2 mice, eventually acquired some place response in the water maze, as was evident when the location of the platform was reversed. However, hippocampus-lesioned mice of both strains were impaired when tested in the plus maze spatial discrimination task. Thus, ibotenic acid-induced lesions of the hippocampus impair acquisition of spatial discrimination in mice. These deficits were strain-dependent and likely comprise impaired accuracy as well as changes in non-mnemonic types of behaviour. Importantly, lesions in both strains impaired spatial learning, and whether a deficit was seen in mice of the D2 strain seemed to depend on the demands of the task.