Dosage Effects of an Early and Intense Motor Skill Intervention in Young Children with ASD

Background: Despite evidence to suggest one of the earliest indicators of an ASD diagnoses is a delay in achieving early motor milestones, there remains very few evidence-based treatments targeting motor behavior as the primary outcome for young children with ASD.

Objectives: Therefore, the primary objective of this study was to investigate the effectiveness of an early and intensive motor skill intervention employing research supported strategies from Classroom Pivotal Response Teaching (CPRT) on motor skills (i.e. locomotor and object control skills) in young children with ASD aged 4-6.

Methods: Twenty young children with ASD aged 4-6 participated in this study. The experimental group (n=9) participated in an intense, 8-week intervention consisting of direct motor skill instruction in a 1:1 ratio for 4-hours/ day, 5-days/ week. The control group (n=11) did not receive the intervention. The environment modeled a youth sports camp, where participants received individual feedback followed by small group gross motor play using CPRT supported strategies. Fundamental motor skills (locomotor and object-control skills) were assessed in both groups using the Test of Gross Motor Development-2 at pre-intervention, post-intervention, and 4-weeks following the intervention (maintenance period). To investigate treatment dosage in the experimental group, bi-weekly assessment of motor outcomes occurred at weeks 2, 4, and 6 of the intervention. A general linear model analysis was conducted to examine differences in each group on motor skill performance. Pairwise t-tests were used to determine treatment dosage.

Results: Linear modeling demonstrated a statistically significant difference in motor performance following the intervention and after a 4-week maintenance period. For locomotor skills in the experimental group, there was a +16.82(SE=1.71) unit gain at post-intervention (p<0.001), and a -0.27 unit difference over the maintenance period. For object-control skills, there was a +18.27(SE=1.65) unit difference at post-intervention (p<0.010), and a -3.36(SE=1.18) unit difference over the maintenance period (p<0.05).  The control group did not demonstrate significant gains in motor performance. Non-significant changes in motor skill performance at the post-intervention maintenance period demonstrated a preservation of skills in the absence of directed motor therapy. Pairwise t-tests were used to assess dosage response to the intervention. For locomotor skills, significant gains were observed from weeks 0-2 [t(1,10)=+3.54,p<0.05], weeks 2-4 [t(1,10)=+2.48,p<0.05], and weeks 6-8 [t(1,10)=+2.82,p<0.05], demonstrating continued locomotor gains throughout 8-weeks of intervention. For object-control skills, significant gains were observed from weeks 0-2 [t(1,10)=+3.59, p<0.05] and weeks 2-4 [t(1,10)=+2.16,p<0.05]. Although significant results continued through 8 weeks when compared to baseline [t(1,10)=+11.57,p<0.05], object-control gains plateaued after 4-weeks of intervention.  

Conclusions: Following an 8-week motor skill intervention, children with ASD demonstrated and maintained improved motor skill performance. Significant locomotor gains continued throughout the study with minimal plateau. Significant object-control gains continued through 4-weeks of intervention then plateaued thereafter. Dosage response suggests motor performance can be modified in as few as 2-weeks of treatment with continued improvement with treatment duration of 8-weeks for locomotor skills and 4-weeks for object-control skills Findings should inform policy makers to include motor programming as part of the early intervention services delivered to young children with ASD.