Autonomic characterization in adults with attention deficit hyperactivity disorder assessed by heart rate variability...

This pilot study has examined whether adults with attention deficit hyperactivity disorder (ADHD) manifest heart rate variability (HRV) abnormalities reflecting arousal dysregulation during a three-behavioral-state paradigm using a random number generation task.

Frequency-domain HRV parameters, including low-frequency (LF: 0.04-0.15 Hz), high-frequency (HF: 0.15-0.4 Hz), LF/HF, and heart rate (HR), were measured in 20 subjects diagnosed with ADHD. Measurements were conducted during a 5-min paradigm comprising the initial resting state (Rest), task state (Task), and resting state after task (After). The data were compared with that from 20 age- and gender-matched control subjects. The Adult ADHD Self-Report Scale (ASRS), Autism Spectrum Quotient (AQ), and Profiles of Mood States (POMS) were used for psychological assessment.

Significantly higher LF/HF scores were observed in the ADHD subjects during Rest. The incremental response of LF/HF during Task, present in the control subjects, was not observed in the ADHD subjects. The HF and HR scores in both ADHD and control subjects exhibited similar profiles, with a decrease in HF and an increase in HR during Task. Additionally, positive correlations were found between the HRV scores and the ASRS and POMS scores. No relationship was observed between the HRV and AQ scores.

High LF/HF at Rest with no change at Task, together with normal profiles of HF and HR during the three-behavioral state paradigm, may serve as a potential autonomic biomarker for ADHD. These HRV changes could be related to attention and arousal dysregulation in patients with ADHD.