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Coexistence of tics and hyperactivity in children: no additive at the psychophysiological level
J Yordanova1, C Dumais-Huber, A Rothenberger
1Bulgarian Academy of Science, Brain Research Institute, Sofia, Bulgaria.
Insights
Children with tic disorder (TD) and hyperactivity (HA) show distinct cortical activity patterns. Combined TD + HA symptoms resemble pure TD more than hyperactivity disorder, impacting brain activation.
Area of Science:
- Neuroscience
- Developmental Psychology
- Clinical Psychology
Background:
- Tic disorder (TD) and hyperactivity (HA) are common neurodevelopmental conditions.
- Frontal lobe control over preparatory cortical activity is crucial for cognitive tasks.
- Understanding the interplay of TD and HA on brain function is essential for targeted interventions.
Purpose of the Study:
- To investigate the effects of TD and HA on slow cortical potentials (SNPs) in children.
- To examine early and late SNP components (eSNP, ISNP) related to frontal lobe control.
- To differentiate the impact of TD and HA, both independently and combined, on cortical activation.
Main Methods:
- Studied four groups: healthy controls, pure TD, pure ADHD, and combined TD + HA.
- Recorded slow cortical potentials (SNPs) during an auditory warned reaction time task.
- Analyzed SNP amplitude, scalp distribution, and reaction time correlations across 8 electrode locations.
Main Results:
- TD, not HA, was associated with reduced SNP amplitudes, indicating less sufficient cortical activation.
- Pure ADHD patients showed altered SNP scalp distribution, suggesting inefficient task-related area involvement.
- Children with combined TD + HA exhibited SNP patterns similar to those with pure TD, not ADHD.
Conclusions:
- The neurophysiological effects of TD and HA on cortical activation are distinct.
- Combined TD + HA symptoms appear more closely related to pure TD than to ADHD.
- Findings suggest TD + HA may not be a subtype of HA disorder but share characteristics with TD.
Abstract:
The objective of the present work was to study the effects of tic disorder (TD) and hyperactivity (HA) on slow cortical potentials in children with combined TD + HA symptoms. Being related to different processes of frontal lobe control over preparatory cortical activity, early and late components of the slow negative potentials (eSNP, ISNP) were examined. SNP amplitude was analyzed as reflecting the sufficiency of preparatory cortical activation; scalp distribution of SNP and relationships to reaction times were studied as revealing the efficiency of task-related region-specific activation. It was hypothesized that if the effects of TD and HA were independent, additive effects on SNP amplitudes would be observed in children with coexisting TD and HA symptoms (TD + HA). Differences in SNP scalp distribution between control and patient groups were predicted to occur mainly over the frontal brain areas. Four groups of children (n = 10/11 in each group) were studied: healthy controls, pure TD, pure attention deficit hyperactivity disorder (ADHD), and combined tic and hyperactivity symptoms. SNPs were recorded in an auditory warned reaction time task (S1-S2-RT) from 8 electrode locations. According to the results, the effects of TD and HA on the sufficiency of task-dependent cortical activation were different, with only the TD factor related to lower SNP amplitudes. Nevertheless, deviant patterns of scalp distribution were found for pure ADHD patients, which suggested an inefficiency in involving the adequate task-related areas. For TD + HA children, like pure TD, lower SNP amplitudes and similar distribution and correlation patterns were present. Thus, according to amplitude, topography, and correlation criteria, TD + HA does not appear to be a subgroup of HA disorder but seems more similar to pure tic disorder.