Effects of a structured 20-session slow-cortical-potential-based neurofeedback program on attentional performance in children and adolescents with attention-deficit hyperactivity disorder: retrospective analysis of an open-label pilot-approach and 6-month follow-up

Johanna S Albrecht,1–3 Sarah Bubenzer-Busch,1,2 Anne Gallien,1,4 Eva Lotte Knospe,1,2 Tilman J Gaber,1,2,5 Florian D Zepf1,2,6,7 1Clinic for Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, RWTH Aachen University, Aachen, 2JARA Translational Brain Medicine, Aachen & Jülich, 3Center for Pediatrics and Adolescent Medicine Elisabeth Hospital Rheydt, Mönchengladbach, 4Clinic for Neurology, Medical Center City Region Aachen, Würselen, 5NeuroCare Group, Munich, Germany; 6Centre and Discipline of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, School of Paediatrics and Child Health & School of Psychiatry and Clinical Neurosciences, Faculty of Medicine, Dentistry and Health Sciences, The University of Western Australia, 7Department of Health in Western Australia, Specialised Child and Adolescent Mental Health Services, Perth, WA, Australia Objective: The aim of this approach was to conduct a structured electroencephalography-based neurofeedback training program for children and adolescents with attention-deficit hyperactivity disorder (ADHD) using slow cortical potentials with an intensive first (almost daily sessions) and second phase of training (two sessions per week) and to assess aspects of attentional performance. Patients and methods: A total of 24 young patients with ADHD participated in the 20-session training program. During phase I of training (2 weeks, 10 sessions), participants were trained on weekdays. During phase II, neurofeedback training occurred twice per week (5 weeks). The patients’ inattention problems were measured at three assessment time points before (pre, T0) and after (post, T1) the training and at a 6-month follow-up (T2); the assessments included neuropsychological tests (Alertness and Divided Attention subtests of the Test for Attentional Performance; Sustained Attention Dots and Shifting Attentional Set subtests of the Amsterdam Neuropsychological Test) and questionnaire data (inattention subscales of the so-called Fremdbeurteilungsbogen für Hyperkinetische Störungen and Child Behavior Checklist/4–18 [CBCL/4–18]). All data were analyzed retrospectively. Results: The mean auditive reaction time in a Divided Attention task decreased significantly from T0 to T1 (medium effect), which was persistent over time and also found for a T0–T2 comparison (larger effects). In the Sustained Attention Dots task, the mean reaction time was reduced from T0–T1 and T1–T2 (small effects), whereas in the Shifting Attentional Set task, patients were able to increase the number of trials from T1–T2 and significantly diminished the number of errors (T1–T2 & T0–T2, large effects). Conclusion: First positive but very small effects and preliminary results regarding different parameters of attentional performance were detected in young individuals with ADHD. The limitations of the obtained preliminary data are the rather small sample size, the lack of a control group/a placebo condition and the open-label approach because of the clinical setting and retrospective analysis. The value of the current approach lies in providing pilot data for future studies involving larger samples. Keywords: SCP, neurofeedback, ADHD, children, adolescents, attentio

Effects of dietary tryptophan and phenylalanine-tyrosine depletion on phasic alertness in healthy adults - A pilot study

Background: The synthesis of the neurotransmitters serotonin (5-HT) and dopamine (DA) in the brain can be directly altered by dietary manipulation of their relevant precursor amino acids (AA). There is evidence that altered serotonergic and dopaminergic neurotransmission are both associated with impaired attentional control. Specifically, phasic alertness is one specific aspect of attention that has been linked to changes in 5-HT and DA availability in different neurocircuitries related to attentional processes. The present study investigated the impact of short-term reductions in central nervous system 5-HT and DA synthesis, which was achieved by dietary depletion of the relevant precursor AA, on phasic alertness in healthy adult volunteers; body weight–adapted dietary tryptophan and phenylalanine–tyrosine depletion (PTD) techniques were used.Methods: The study employed a double-blind between-subject design. Fifty healthy male and female subjects were allocated to three groups in a randomized and counterbalanced manner and received three different dietary challenge conditions: acute tryptophan depletion (ATD, for the depletion of 5-HT; N=16), PTD (for the depletion of DA; N=17), and a balanced AA load (BAL; N=17), which served as a control condition. Three hours after challenge intake (ATD/PTD/BAL), phasic alertness was assessed using a standardized test battery for attentional performance (TAP). Blood samples for AA level analyses were obtained at baseline and 360 min after the challenge intake.Results: Overall, there were no significant differences in phasic alertness for the different challenge conditions. Regarding PTD administration, a positive correlation between the reaction times and the DA-related depletion magnitude was detected via the lower plasma tyrosine levels and the slow reaction times of the first run of the task. In contrast, higher tryptophan concentrations were associated with slower reaction times in the fourth run of the task in the same challenge group.Conclusion: The present study is the first to demonstrate preliminary data that support an association between decreased central nervous system DA synthesis, which was achieved by dietary depletion strategies, and slower reaction times in specific runs of a task designed to assess phasic alertness in healthy adult volunteers; these findings are consistent with previous evidence that links phasic alertness with dopaminergic neurotransmission. A lack of significant differences between the three groups could be due to compensatory mechanisms and the limited sample size, as well as the dietary challenge procedures administered to healthy participants and the strict exclusion criteria used. The potential underlying neurochemical processes related to phasic alertness should be the subject of further investigations

Studying the effects of dietary body weight-adjusted acute tryptophan depletion on punishment-related behavioral inhibition

Background: Alterations in serotonergic (5-HT) neurotransmission are thought to play a decisive role in affective disorders and impulse control. Objective: This study aims to reproduce and extend previous findings on the effects of acute tryptophan depletion (ATD) and subsequently diminished central 5-HT synthesis in a reinforced categorization task using a refined body weight–adjusted depletion protocol. Design: Twenty-four young healthy adults (12 females, mean age [SD]=25.3 [2.1] years) were subjected to a double-blind within-subject crossover design. Each subject was administered both an ATD challenge and a balanced amino acid load (BAL) in two separate sessions in randomized order. Punishment-related behavioral inhibition was assessed using a forced choice go/no-go task that incorporated a variable payoff schedule. Results: Administration of ATD resulted in significant reductions in TRP measured in peripheral blood samples, indicating reductions of TRP influx across the blood–brain barrier and related brain 5-HT synthesis. Overall accuracy and response time performance were improved after ATD administration. The ability to adjust behavioral responses to aversive outcome magnitudes and behavioral adjustments following error contingent punishment remained intact after decreased brain 5-HT synthesis. A previously observed dissociation effect of ATD on punishment-induced inhibition was not observed. Conclusions: Our results suggest that neurodietary challenges with ATD Moja–De have no detrimental effects on task performance and punishment-related inhibition in healthy adults

Neural correlates of reactive aggression in children with attention-deficit/hyperactivity disorder and comorbid disruptive behaviour disorders

ObjectiveAttention deficit hyperactivity disorder (ADHD) is often linked with impulsive and aggressive behaviour, indexed by high comorbidity rates between ADHD and disruptive behaviour disorders (DBD). The present study aimed to investigate underlying neural activity of reactive aggression in children with ADHD and comorbid DBD using functional neuroimaging techniques (fMRI).MethodEighteen boys with ADHD (age 9–14 years, 10 subjects with comorbid DBD) and 18 healthy controls were administered a modified fMRI-based version of the ‘Point Subtraction Aggression Game’ to elicit reactive aggressive behaviour. Trials consisted of an ‘aggression phase’ (punishment for a fictitious opponent) and an ‘outcome phase’ (presentation of the trial outcome).ResultsDuring the aggression phase, higher aggressive responses of control children were accompanied by higher activation of the ventral anterior cingulate cortex and the temporoparietal junction. Patients displayed inverted results. During the outcome phase, comparison between groups and conditions showed differential activation in the dorsal striatum and bilateral insular when subjects gained points. Losing points was accompanied by differential activation of regions belonging to the insula and the middle temporal sulcus.ConclusionData support the hypothesis that deficient inhibitory control mechanisms are related to increased impulsive aggressive behaviour in young people with ADHD and comorbid DBD

Estimation of freezing storage time and quality changes in hake (Merluccius merluccius, L.) by low field NMR

The potential of low field NMR (LF NMR) as a fast monitoring technique to estimate the quality of hake (Merluccius merluccius) frozen stored at -10 °C for up to 6 months was evaluated. LF NMR clearly detected three populations of water: water strongly bound to macromolecules (T 2b), trapped water (T 21) and free water (T 22). As storage time increased, and concomitant with an increase in the T 22 and a decrease in the T 21 water populations, the water holding capacity (WHC) and apparent viscosity values decreased and the shear strength increased, reflecting the characteristic loss of juiciness and tougher texture developed by hake during frozen storage. Two mathematical models were constructed: a simple regression using the biexponential analysis of the relaxation times (T 21, T 22) and amplitudes (A 21, A 22) and a partial least square regression (PLS) of CONTIN analysis. Both models seemed suitable to estimate the quality of the product. © 2012 Elsevier Ltd. All rights reserved.Peer Reviewe