The first aim of this clinical trial is to test the feasibility and signal validity of a new approach to neurofeedback training (NF) using intensive EEG-based theta-beta NF for children with ADHD in the context of NF camps during school holidays. The second aim is to compare the efficacy of two neurofeedback protocols in reducing ADHD symptoms. Previous study results highlight that children with ADHD frequently show increased Theta-Beta-Ratios (TBR) in the qEEG, probably associated with attention difficulties, which may be ameliorated following neurofeedback training. However, the current state of research shows heterogenous findings regarding the efficacy of standard TBR NF for children with ADHD. Further study results suggest that personalized NF training protocols, based on the individual alpha peak frequency (iAPF), may be more effective in reducing ADHD symptoms than standardized ones.
Therefore, in this proof-of-concept study of children with ADHD a standard TBR NF protocol is compared with an iAPF-personalized TBR NF (iAPF-TBR NF) protocol (based on the previously obtained iAPF). The study is designed as a randomized controlled intervention trial (RCT) with three assessment points (pre \[T1\], post \[T2\] and 6-month follow-up \[T3\]). Primary endpoints include the reduction of ADHD symptoms assessed by parent-, teacher- and self-report questionnaires. Furthermore, it is hypothesized that NF training is associated with better performance in a sustained attention and executive function test and a reduced TBR in qEEG, particularly following iAPF-TBR NF.
The main questions are:
* Is it feasible to train groups of up to 12 children with two sessions NF per day for an eight-day-period during their school holidays? * Does iAPF-TBR NF provide a valid neuromodulatory signal compared to the standard-TBR-NF protocol? Do the frequency boundaries demonstrate spectral stability across the 16 training sessions? * Does the personalized iAPF-TBR NF training reduce ADHD symptoms measured immediately after the training more than standard-TBR-NF training? (comparison T2-T1) * Does the personalized iAPF-TBR NF training reduce ADHD symptoms measured 6 months after the NF training more than standard TBR-NF training? (comparison T3-T1) * Does the reduction in ADHD symptoms measured immediately after the NF-training persist until the 6-month follow-up? Do possible differences between iAPF-TBR NF training and standard TBR NF training remain? (comparison T3-T2)
Post-hoc analyses of the courses are carried out. In addition, selectivity analyses will be carried out for clinical subgroups (e.g. different ADHD profiles)
Children aged 6-13 years. Confirmed ADHD diagnosis (ICD 10: F90.0, F90.1, or F98.8)
German-speaking children with normal or corrected vision.
Children with neurological disorders (e.g., Epilepsy)
Children without an ADHD diagnosis
Caregivers with inability to provide informed consent or complete questionnaires
Participation in neurofeedback that was conducted in the year prior to the intended participation or is still ongoing.
Parallel
Standard TBR-NF
BehavioralTraining is based on the classic Theta-Beta-Ratio protocol, where the reward frequencies are fixed for the entire training group (Hao et al., 2022): Frequency bands with fixed division: Theta 4 - 8 Hz Alpha 8 - 13 Hz Beta 13 - 30 Hz Gamma 30 - 45 Hz * Upgrade Beta Frequencies: 13 - 30 Hz * Downgrade Theta Frequencies: 4 - 8 Hz * Aim: Reduce Theta-Beta Ratio * 10-20-electrode positions: Cz with reference and ground electrodes at A1 and A2 * Duration: 15 min.
iAPF -TBR-NF
BehavioralReward frequencies are adjusted based on the child's iAPF to create a customized training protocol: Calculation of the frequency bands using T1-iAPF (Hao et al., 2022): Frequency bands with individual division: Theta 4 - 0.8 \* iAPF Hz Alpha 0.8 \* iAPF - 1.3 \* iAPF Hz Beta 1.3 \* iAPF - 3.0 \* iAPF Hz Gamma 3.0 \* iAPF - 45 Hz * Upgrade individually calculated beta frequencies * Downgrade individually calculated theta frequencies * Aim: Reduce Theta-Beta Ratio * 10-20-electrode positions: Cz with reference and ground electrodes at A1 and A2 * Duration: 15 min.
Adverse effects
Effects that lead to symptom enhancements, as well as negative side effects of the neurofeedback training, are considered as adverse effects. The absence of adverse effects is one indicator of feasibility.
Drop-Out rate
The rate of participants discontinuing the neurofeedback training and study participation is measured. The drop-out rate is one indicator (acceptability) of feasibility.
Number of included segments
The continuous EEG recorded during active neurofeedback training is scanned offline for artefacts, and the proportion of artefact-free segments is considered as an indicator of data quality (and thus feasibility) during neurofeedback training. Higher numbers of included segments indicate a larger amount of artifact-free data, suggesting higher data quality.
Diagnostic system for mental disorders according to ICD-10 and DSM-5 for children and adolescents - III External report form ADHD specific (DISYPS-III FBB-ADHS; Döpfner et al., 2017)
Parent- and teacher-reported total score of ADHD symptoms, inattention, hyperactivity-impulsivity. It also captures functional impairment and distress. These can be used to determine whether or not the criteria for an ADHD diagnosis are met. In the analysis of this study, the scales for the three cardinal symptoms: inattention, hyperactivity-impulsivity and the total ADHD symptom score will be focussed. The subscales consist of 9 items (inattention) and 11 items (hyperactivity-impulsivity), which are rated between the categories 0 = "not accurate at all" and 3 = "especially accurate". Point-values between 0 and 27 can be reached for inattention and between 0 and 33 for hyperactivity/impulsivity. The total ADHD score uses the 20 items of both subscales and though can reach point-values between 0 and 60. The scales' scores show an increase in severity of symptoms (inattention, hyperactivity/impulsivity and total ADHD) as the point-values increase.
Behavior Rating Inventory of Executive Function (BRIEF; Drechsler et al., 2013)
Parent questionnaire to assess two main indices (Behavioral and Cognitive Regulation Indices), which form the Global Executive Composite Score. The items of this questionnaire are rated within three answer categories ranging from 1 = "never" to 3 = "often". The Global Executive Composite Score consists of 86 (point-values: 86-258. The Behavioral Regulation Index contains 28 items (point-values: 28-84), whereas the Cognitive Regulation Index includes 44 items (point-values: 44-132). Higher scores indicate increasing problems with behavioral and cognitive regulation and overall executive functions.
Continuous Performance Test (CPT, Knye et al., 2003)
Computerized attention test for objective measurement of Reaction Times and Variability, Commission Errors and Omission Errors.
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Bielefeld University
Lead sponsor
Philipps University Marburg
Collaborator
