Fig. 2: Study and participant characteristics.

a The 66 publications by year, categorized by the type of portable technology investigated. b Percentage of publications implementing different combinations of three approaches to assess motor development using portable technologies (automate, illuminate, and/or predict outcomes). c Geographic distribution of publications based on all authors’ institutional affiliations. d Cumulative distribution of participant ages across publications, assuming a normal distribution centered on the midpoint of the age range reported in the text. e Target risk groups and diagnoses across publications, categorized by the approach used to assess motor development. PMA Postmenstrual age, ASD Autism spectrum disorder, NDDs Neurodevelopmental disorders.