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Heart rate reactivity in attention deficit disorder subgroups
R A Dykman1, P T Ackerman, D M Oglesby
1Department of Pediatrics, Arkansas Children's Hospital, Little Rock 72202.
Insights
Heart rate patterns in children with Attention Deficit Disorder (ADD) subtypes reveal distinct physiological responses. Cardiac measures may help validate these subtypes, differentiating disruptive and non-disruptive presentations.
Area of Science:
- Neuroscience
- Psychophysiology
- Developmental Psychology
Background:
- Attention Deficit Disorder (ADD) is a neurodevelopmental disorder with heterogeneous presentations.
- Understanding the physiological underpinnings of ADD subtypes is crucial for accurate diagnosis and intervention.
- Heart rate (HR) variability and reactivity are sensitive indicators of autonomic nervous system function and arousal levels.
Purpose of the Study:
- To investigate beat-to-beat heart rate (HR) patterns in response to a warned reaction time (RT) task in children with different Attention Deficit Disorder (ADD) subtypes.
- To explore potential sex differences in cardiac responses within ADD subgroups.
- To determine if cardiac measures can serve as objective markers for differentiating between disruptive and non-disruptive ADD presentations.
Main Methods:
- Analysis of beat-to-beat heart rate (HR) over 9 seconds during a warned reaction time (RT) paradigm.
- Stimuli included tones of varying intensity (55, 78, 100 db) preceded by a visual warning signal.
- Comparison of normal controls with three ADD subgroups: ADD-only, ADD with hyperactivity (ADDH), and ADD with hyperactivity and aggression (ADDHA).
Main Results:
- Significant sex and group differences in HR levels and reactivity were observed.
- Girls generally exhibited higher HR levels than boys.
- The ADD-only group showed lower HRs than other ADD groups, with ADD-only boys demonstrating distinct deceleration and acceleration patterns compared to other ADD boys.
- Control girls displayed the highest HR levels and reactivity; control boys and ADD-only boys had similar cardiac profiles.
Conclusions:
- Cardiac measures, specifically HR reactivity, can differentiate between ADD subtypes.
- ADD-only girls may present with underarousal, while ADD-only boys do not exhibit this pattern.
- Findings suggest the utility of psychophysiological measures for external validation of disruptive and non-disruptive ADD subtypes.
Abstract:
Beat-to-beat heart rate (HR) was analyzed for 9 contiguous seconds in a warned reaction time (RT) paradigm. Imperative stimuli were tones of three intensity levels (55, 78, and 100 db); a visual warning signal occurred 5 sec before tone onset. Baseline and reward conditions were run. Normal controls were contrasted with three Attention Deficit Disorder (ADD) subgroups: ADD-only, ADD with hyperactivity (ADDH), ADD with hyperactivity and aggression (ADDHA). The ADD subgroups were predicted to show less deceleration in HR because of their problem sustaining readiness to respond. Significant sex x group differences in HR levels and change scores were found. Overall, girls had higher HR levels than boys and the ADD-only group (boys and girls) had lower HRs than the other ADD groups. But, the ADD-only boys had more marked deceleration to the warning signal and acceleration to the tones than the other ADD boys, whereas the ADD-only girls were no more reactive than the ADDH and ADDHA girls. Control girls had the highest HR levels and were the most reactive to stimuli. Control boys and ADD-only boys had similar HR levels and reaction patterns. ADD-only girls appear to be underaroused, whereas ADD-only boys do not. Results suggest that cardiac measures can provide external validation of disruptive and nondisruptive ADD subtypes.