Gross Motor Skills Predict Adaptive Behavior in Institutionalized Children With Severe Intellectual Disability: A Cross-Sectional Study

Overview

This study examines whether gross motor skills are linked to everyday functioning (adaptive behavior) in children with severe intellectual disability (ID) living in social welfare institutions. We recruited 227 orphaned children aged 6-12 years from six welfare institutions in China. Gross motor competence was assessed using the Test of Gross Motor Development-Second Edition (TGMD-2), which includes locomotor skills and object control skills. :contentReference\[oaicite:1\]{index=1} Adaptive behavior was assessed using the Adaptive Behavior Questionnaire for Children (ADQ), which provides an overall ADQ Index and scores for independence, cognition, and socialization. Assessments were conducted on site by a trained research team between May and June 2024. TGMD-2 sessions were video recorded and scored by trained raters, and caregivers completed the ADQ with assistance to ensure completeness. :contentReference\[oaicite:3\]{index=3} We will evaluate associations between TGMD-2 scores and ADQ outcomes and assess whether the TGMD-2 total score can help screen for children at risk of low adaptive functioning (ADQ Index \< 70). All procedures were approved by the local university ethics committee (approval number: 102772024RT062), and informed consent was obtained from institutional administrators and caregivers.

Background: Children with severe intellectual disability (ID) living in institutional settings often experience substantial limitations in both motor competence and adaptive functioning. Efficient ways to identify children at higher functional risk may help guide prioritization of supportive services within resource-limited institutions. Study Design: This is an observational, cross-sectional study conducted in six social welfare institutions (orphanages) in China using a convenience sampling approach. A total of 227 orphaned children aged 6-12 years with severe ID were recruited. Severe ID was defined based on DSM-5 clinical diagnosis with standardized intelligence test scores ranging from 20 to 34. Additional inclusion criteria included basic auditory and visual abilities and the capacity to follow simple motor instructions. Exclusion criteria included severe musculoskeletal disorders, neurological comorbidities (e.g., active epilepsy), other physical conditions limiting motor assessment participation, or major surgery within the previous six months. Procedures and Assessments: All assessments were conducted on site by a professionally trained research team between May and June 2024. :contentReference\[oaicite:9\]{index=9} Gross motor competence was measured using the Test of Gross Motor Development-Second Edition (TGMD-2), which includes locomotor and object control subtests. Testing followed a standardized instruction-demonstration-imitation protocol. TGMD-2 sessions were video recorded; two trained raters independently scored performance, and a third rater adjudicated disagreements to enhance scoring accuracy. Adaptive behavior was assessed using the Adaptive Behavior Questionnaire for Children (ADQ), which includes three domains (independence, cognition, and socialization) and yields an overall Adaptive Deviation Quotient (ADQ Index) based on standardized scoring procedures. An ADQ Index \< 70 was used to classify low adaptive behavior. The ADQ was completed with face-to-face assistance provided to caregivers to ensure data completeness and reliability. Analysis Plan: Descriptive statistics will summarize participant characteristics. Pearson correlations will examine associations between TGMD-2 scores (total and subtests) and ADQ outcomes. Multiple linear regression models will evaluate the unique contribution of TGMD-2 scores to overall adaptive functioning and ADQ domains while adjusting for age and sex. Receiver operating characteristic (ROC) analysis will be used to evaluate the ability of TGMD-2 total score to identify low adaptive behavior (ADQ Index \< 70) and to estimate an optimal screening threshold using standard ROC indices. Ethics: All procedures were conducted in accordance with the Declaration of Helsinki and approved by the local university ethics committee (approval number: 102772024RT062). Written informed consent was obtained from institutional administrators and caregivers.