Fractal fluctuations in exploratory movements predict differences in dynamic touch capabilities between children with Attention-Deficit Hyperactivity Disorder and typical development

PLoS One. 2019 May 21;14(5):e0217200. doi: 10.1371/journal.pone.0217200. eCollection 2019.

Abstract

Children with Attention-Deficit Hyperactivity Disorder (ADHD) struggle to perform a host of daily activities. Many of these involve forceful interaction with objects and thus implicate dynamic touch. Therefore, deficits in dynamic touch could underlie functional difficulties presented by ADHD children. We investigated whether performance on a dynamic touch task (length perception by wielding) differ between children with ADHD and age-matched controls. We further examined whether this difference could be explained by fractal temporal correlations (wielding dynamics). Forty-two children (ADHD: 21; typically developing: 21) wielded unseen wooden rods and reported their perceived length in the form of magnitude productions. The rods varied in the magnitude of the first principal moment of inertia (I1). Three-dimensional displacements of hand and rod positions were submitted to Detrended Fluctuation Analysis to estimate trial-by-trial temporal correlations. Children with ADHD reported shorter length for rods with higher I1 than their typically developing peers, indicative of reduced sensitivity to mechanical information supporting dynamic touch. Importantly, temporal correlations in wielding dynamics moderated children's usage of I1. This finding points to a role of exploratory movements in perceptual deficits presented by children with ADHD and, thus, should be considered a new potential target for interventions.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Attention Deficit Disorder with Hyperactivity / physiopathology*
  • Child
  • Female
  • Fractals*
  • Humans
  • Male
  • Motor Activity / physiology*
  • Psychomotor Performance
  • Touch Perception / physiology*
  • Weight Perception / physiology*

Grants and funding

Financial support for this study was granted by the Brazilian government agency National Council for Scientific and Technological Development (http://www.cnpq.br) through grants awarded to MCM (306948/2014-1) and BSA (204909/2017-1). Additional funding for research development was granted to MCM (CDS - PPM-00611-17) by the Research Support Foundation from the State of Minas Gerais (http://www.fapemig.br). This study was also financed in part by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - Brasil (http://www.capes.gov.br/) - Finance Code 001. DGKS acknowledges the generous internal support from Grinnell College (www.grinnell.edu) to cover submission costs. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.