Behavior as a window to the mind - objective daily life assessment of attention and hyperactivity/impulsivity.

Background: For decades, researchers have been searching for objective laboratory markers to measure and define attention deficit and hyperactivity disorder. However, in clinical practice, the most commonly used tools are still psychological scales, which are neither objective nor laboratory-based. This reliance on scales may stem from the fact that they are currently the only available method in this field for collecting daily-life data, and such data plays an irreplaceable role in defining mental disorders. Fortunately, wearable devices now offer the possibility of collecting objective daily-life data. In our study, we aim to monitor children's activity synchrony (AcSyn) and activity volume (AcVo) using accelerometers in a school setting to examine the correlation between these daily-life markers and the symptoms related to attention deficit and hyperactivity disorder.

Methods: This study included an entire class of children of 1st grade (n = 39). Children were required to wear the accelerometer on their wrist to record their activities during school time for 3 weeks using 1-second epoch, based on which we calculated AcSyn and AcVo, and conducted correlation analysis with Attention Deficit and Hyperactivity Disorder Rating Scale.

Results: In-class AcSyn was significantly correlated with teacher-reported inattention score (r=-0·480, P = 0·001), but not hyperactivity/impulsivity score. In-class/recess AcVo is significantly related to parent-reported hyperactivity/impulsivity score (r = 0·448-0·482, P ≤ 0·002), but not inattention score.

Conclusions: AcSyn and AcVo are potential markers to measure children's attention/hyperactivity/impulsivity performance in daily-life. Moreover, when combined with event labels and analyzed on micro or macro time scales, AcSyn and AcVo have the potential to provide profound insights.