title: An objective measure of hyperactivity aspects with compressed webcam video.
abstract: BACKGROUND
  Objective measures of physical activity are currently not considered in clinical guidelines for the assessment of hyperactivity in the context of Attention-Deficit/Hyperactivity Disorder (ADHD) due to low and inconsistent associations between clinical ratings, missing age-related norm data and high technical requirements.
  
  
  METHODS
  This pilot study introduces a new objective measure for physical activity using compressed webcam video footage, which should be less affected by age-related variables. A pre-test established a preliminary standard procedure for testing a clinical sample of 39 children aged 6-16 years (21 with a clinical ADHD diagnosis, 18 without). Subjects were filmed for 6 min while solving a standardized cognitive performance task. Our webcam video-based video-activity score was compared with respect to two independent video-based movement ratings by students, ratings of Inattentiveness, Hyperactivity and Impulsivity by clinicians (DCL-ADHS) giving a clinical diagnosis of ADHD and parents (FBB-ADHD) and physical features (age, weight, height, BMI) using mean scores, correlations and multiple regression.
  
  
  RESULTS
  Our video-activity score showed a high agreement (r = 0.81) with video-based movement ratings, but also considerable associations with age-related physical attributes. After controlling for age-related confounders, the video-activity score showed not the expected association with clinicians' or parents' hyperactivity ratings.
  
  
  CONCLUSIONS
  Our preliminary conclusion is that our video-activity score assesses physical activity but not specific information related to hyperactivity. The general problem of defining and assessing hyperactivity with objective criteria remains.
authors.affiliation: Department of Child and Adolescent Psychiatry, University Hospital Münster, Schmeddingstrasse 50, 48149 Münster, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Wehrmann
authors.affiliation: Department of Child and Adolescent Psychiatry, University Hospital Münster, Schmeddingstrasse 50, 48149 Münster, Germany.
authors.forename: Jörg Michael
authors.initials: JM
authors.lastname: Müller
keywords: ADHD; Hyperactivity; Objective measure; Physical activity; Video