Motor Control Adherence to the Two-thirds Power Law Differs in Autistic Development

Area of Science:

• Neurodevelopmental Disorders
• Motor Control and Kinematics
• Computational Neuroscience

Background:

• Autism Spectrum Disorder (ASD) is often associated with motor atypicalities.
• Motor control deficits may impact social communication in autistic individuals.
• The two-thirds power law (2/3 PL) describes a fundamental principle of human motor execution.

Purpose of the Study:

• To computationally characterize motor control in autistic children using smart tablet technology.
• To assess adherence to the two-thirds power law (2/3 PL) in children with and without autism.
• To identify developmental trajectories of motor control in early childhood.

Main Methods:

• Utilized a smart tablet activity (drawing/tracing ellipses) with 24 autistic and 33 typically developing children (ages 4-8).
• Extracted finger movement kinematic data from iPad interactions.
• Computed adherence to the 2/3 PL, velocity modulation, acceleration, jerk, and movement variability.

Main Results:

• Autistic children exhibited greater velocity modulation, increased acceleration and jerk, and higher kinematic variability than controls.
• Typically developing children showed significant motor control development, unlike the autistic group.
• The autistic group demonstrated diminished motor control, less smooth movements, and developmental stasis.

Conclusions:

• This study introduces a novel, accessible tool for objective, quantifiable motor assessment in children using smart tablet technology.
• Findings reveal a distinct motor signature in autism, characterized by impaired motor control and developmental differences.
• Results highlight the potential of computational analysis of tablet-based movements for understanding autism in childhood.