Researchers measured movement with wrist and ankle sensors in 70 adults with ADHD, aged 18 to 50. There was no comparison group without ADHD, and people taking stimulants were tested during a medication break. Most of them, 70%, also held a smart fidget ball for a larger study. That data was not used here, but one of the three fidget measures differed by whether a person had the ball. Each person did a 120 trial computer task. Accuracy was very high, averaging 96.3%.
The three measures were how many fidgets, how variable they were, and how intense. All three were higher on trials answered correctly than on trials answered incorrectly. The clearest gap was in the number of fidgets. The weakest was in intensity (p=0.04). The error side of that comparison is thin. Errors averaged about 4.5 out of 120, and that left only 56 people who made any.
Fidget counts and fidget variability also rose from the first 30 trials to the last 30, while accuracy did not change. Counts went from 2.3 to 3.5 per trial. Intensity did not rise.
The fidget measures tracked ADHD rating scales moderately, and a little better than task performance did. The authors read fidgeting as a possible way of keeping arousal and attention up, but the design is correlational and cannot show cause. Many comparisons ran without a stated correction for multiple testing.
Source: Son H, Calub C, Fan B, et al.. A quantitative analysis of fidgeting in ADHD and its relation to performance and sustained attention on a cognitive task. Frontiers in Psychiatry (2024). doi:10.3389/fpsyt.2024.1394096