1,721,079 research outputs found
Electrophysiology Echoes Brain Dynamics in Children and Adolescents With Tourette Syndrome—A Developmental Perspective
No full textOpen-Access-Publikationsfonds 202
Transcranial magnetic stimulation in child and adolescent psychiatry: Excitability of the motor system in tic disorders and/or attention deficit hyperactivity disorders
No full textMotor system excitability can be investigated in vivo by means of single and paired pulse transcranial magnetic stimulation (TMS). Whereas the cortical silent period reflects the general degree of inhibitory mechanisms mainly within the sensorimotor loop, intracortical excitability measures the focused degree of inhibitor and facilitatory mechanisms within the motor cortex. In child and adolescent psychiatric disorders with uncontrollable motor behavior such as tics in tic disorder or motoric hyperactivity in attention deficit hyperactivity disorder (ADHD), different dysfunctional patterns of motor system excitability could be demonstrated compared to age-matched healthy controls: (1) In tic disorder, a shortened cortical silent period was observed, providing evidence of deficient inhibitory mechanisms within the sensorimotor loop, probably primarily at the level of the basal ganglia. (2) In ADHD, a decreased intracortical inhibition was found, probably reflecting deficient inhibitory mechanisms within the motor cortex (but enhancement of intracortical inhibition after oral intake of 10 mg methylphenidate). In order to investigate neurophysiological aspects of comorbidity, (3) motor system excitability was also measured in children with combined ADHD and tic disorder. The Findings of a reduced intracortical inhibition as well as a shortened cortical silent period in these comorbid children provide evidence of additive effects at the level of motor system excitability. These decreased inhibitory mechanisms within the entire sensorimotor loop and especially the motor cortex could be essential neurobiological substrates of the deficient inhibitory motor control and regulation, respectively, in tic disorder and ADHD
Co-Occurrence of Tic Disorders and Attention-Deficit/Hyperactivity Disorder—Does It Reflect a Common Neurobiological Background?
No full textBackground: The co-existence of tic disorders and attention-deficit/hyperactivity disorder (TD + ADHD) has proven to be highly important in daily clinical practice. The factor ADHD is not only associated with further comorbidities, but also has a long-term negative psychosocial effect, while the factor TD is usually less disturbing for the major part of the patients. It remains unclear how far this is related to a different neurobiological background of the associated disorders or whether TD + ADHD reflects a common one. Objective: This review provides an update on the neurobiological background of TD + ADHD in order to better understand and treat this clinical problem, while clarifying whether an additive model of TD + ADHD holds true and should be used as a basis for further clinical recommendations. Method: A comprehensive research of the literature was conducted and analyzed, including existing clinical guidelines for both TD and ADHD. Besides genetical and environmental risk factors, brain structure and functions, neurophysiological processes and neurotransmitter systems were reviewed. Results: Only a limited number of empirical studies on the neurobiological background of TD and ADHD have taken the peculiarity of co-existing TD + ADHD into consideration, and even less studies have used a 2 × 2 factorial design in order to disentangle the impact/effects of the factors of TD versus those of ADHD. Nevertheless, the assumption that TD + ADHD can best be seen as an additive model at all levels of investigation was strengthened, although some overlap of more general, disorder non-specific aspects seem to exist. Conclusion: Beyond stress-related transdiagnostic aspects, separate specific disturbances in certain neuronal circuits may lead to disorder-related symptoms inducing TD + ADHD in an additive way. Hence, within a classificatory categorical framework, the dimensional aspects of multilevel diagnostic-profiling seem to be a helpful precondition for personalized decisions on counselling and disorder-specific treatment in TD + ADHD
Sources and behavior of pollutants in several catchments in the Western Harz Mountains, F.R.G
No full textThe "Case Study Harz Mountains" investigates the effects of airborne pollutants (heavy metals and acidifying chemicals) on the catchment of a drinking water reservoir. The path of heavy metals into the lake sediments can be traced back to the well waters via inflowing stream sediments with similarly high heavy metal contents. In heavily polluted areas, groundwater with a pH from 3.6 to 5.2 has the following typical contents (μg1-1) Al (1000), Cd (2), Co (3), Cr (0.3), Cu (3) Fe (250), Mn (500), Ni (12), Pb (25), and Zn (100). These concentrations are comparable to those of acidic percolation water below the root zone of exposed forest ecosystems. Wells with pH > 5.5 do not have such elevated concentrations of metals. Water acidification has already caused heavy metal mobilization within the brooks. An acidification front creeps down towards the lake, the intermediate repository for the heavy metals and other pollutants. Compared with the local bedrock, the lake sediments have high concentrations of heavy metals. With continuing water acidification and a decrease in pH of the lake water from 6.5 to 5, a sharp increase in heavy metal, Al, Fe, and Mn concentrations in the water column is to be expected. Sequential extraction (ammonium acetate, ammonium oxalate, H2O2) of metals from the lake sediments shows that the majority of the trace metals are in ion-exchangeable from
Methylphenidate and intracortical excitability: opposite effects in healthy subjects and attention-deficit hyperactivity disorder
No full textObjective: To test the effects of a standard dosage of the psychostimulant methylphenidate (MPH) - which significantly enhances intracortical inhibition but had no effects on intracortical facilitation in children with attention-deficit hyperactivity disorder (ADHD) - on intracortical excitability in healthy subjects. Method: In 12 healthy subjects, aged 20-40 years, intracortical inhibition and facilitation were investigated before and 70 min after the intake of 10 mg MPH using the technique of transcranial magnetic stimulation (TMS) with the paired-stimulus paradigm. Results: In comparison of the two TMS measurements, a significant enhancement in intracortical facilitation but no effects on intracortical inhibition could be stated under MPH administration. Conclusion: This study provides first evidence for opposite effects of MPH on intracortical excitability in healthy adult subjects showing enhanced intracortical facilitation in contrast to ADHD children in whom enhanced intracortical inhibition has recently been shown
The Usage of Neurofeedback in Children with ADHD: The Method and its Evaluation
No full textThe Usage of Neurofeedback in Children with ADHD: The Method and its Evaluation Neurofeedback is a computer-based behavior training, which is gaining increasing interest in the treatment of children with attention-deficit/hyperactivity disorder (ADHD). This article gives an introduction to neurofeedback and summarizes the state of research, discussing inter alia methodical aspects (e. g., requirements to a control training). Evaluation studies conducted so far indicate clinical efficacy. For example, neurofeedback training was superior to a computerized attention training in a randomized controlled trial (medium effect size). Follow-up investigations suggest that treatment effects remain stable (at least six months). At the clinical level, comparable improvements could be obtained for the neurofeedback protocols theta/beta training and training of slow cortical potentials. Neurophysiological findings document different mechanisms of theta/beta training and slow cortical potential training. Future studies should further elucidate the specificity of training effects related to the kind of training and certain disorders and address how to optimize and individualize neurofeedback training
Increased event-related theta activity as a psychophysiological marker of hyperactivity in children
No full textEffects of neurofeedback on the dysregulation profile in children with ADHD: SCP NF meets SDQ-DP – a retrospective analysis
No full textLack of intracortical inhibition in migraine - a transcranial magnetic stimulation study
No full textNeurofeedback in children with ADHD: validation and challenges
No full textNeurofeedback (NF), a type of neurobehavioral training, has gained increasing attention in recent years, especially concerning the treatment of children with ADHD. Promising results have emerged from recent randomized controlled studies, and thus, NF is on its way to becoming a valuable addition to the multimodal treatment of ADHD. In this review, we summarize the randomized controlled trials in children with ADHD that have been published within the last 5 years and discuss issues such as the efficacy and specificity of effects, treatment fidelity and problems inherent in placebo-controlled trials of NF. Directions for future NF research are outlined, which should further address specificity and help to determine moderators and mediators to optimize and individualize NF training. Furthermore, we describe methodological (tomographic NF) and technical ('tele-NF') developments that may also contribute to further improvements in treatment outcome.German Research Foundation [HE 4536/2, MO 726/2, RO 698/4
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