Activity and reactivity of the autonomic nervous system in children and adolescents with ADHD in different situations of rest and stress experience

Abstract

The present study aimed at investigating the autonomic function in children and adolescents with attention deficit-/ hyperactivity disorder (ADHD) in comparison to a sample of healthy subjects. The experimental group, consisting of the study subjects suffering from ADHD (n = 24), and the comparison group (n = 38) were both between the age of 7-15 years. Before and during the psychological examination of the two groups, psychological and internally generated questionnaires had to be filled out by the participants. After approximately an hour of recording of the heart rate variability (HRV), the frequency and time domain parameters as well as the mean heart rate in 1- and 5-minutes intervals were used to examine the autonomic responses to various resting, stress-inducing and pleasing tasks. Using a 2 x 10 repeated measures ANOVA, no significant group effects could be determined in the analysis of HRV parameters. However the findings showed some significant interactions between the experimental conditions and the groups in the parameters RMSSD, HF n.u. and log LF/HF. By further analysis, important group differences in various conditions were detected. To sum up, the subjects with ADHD tended to experience more stress during the action and pleasing tasks and less stress during the resting experimental conditions. However, in contrast to these objective physiological measurements, the subjects in the experimental group subjectively indicated that they had perceived less stress in all experimental conditions.