Psychometric Properties of Gross Motor Development Test (Second Edition) in Children ‎with Visual Impairment in Tehran ‎

Due to the significant effect of motor skills on developmental areas in children with visual impairment, the need to measure gross motor skills and the lack of valid and reliable tools in this field is essential. This study conducted with the aim of determining psychometric characteristics of the second version of the Test of Gross Motor Development (TGMD-2) in children with visual impairment aged 7-10 years in Tehran.

In this descriptive and psychometric analysis study, criterion-related validity and Spearman correlation were used. Concurrent validity was assessed using the second edition of Movement Assessment Battery for Children (MABC-2). In previous studies, content and face validities were performed and construct validity was not possible to measure because of the limited sample size. To evaluate the reliability of the TGMD-2, a one blinded researcher measured the gross motor skills of 50 girls and boys aged 7-10 years with visual impairment with a one-month interval in three schools of visual impaired children (Mohebbi, Khazaeli and Narjes). Cronbach's alpha for internal reliability and Intraclass Correlation Coefficient (ICC) for external reliability were used. Data were analyzed using SPSS version 22 with a 95% confidence interval and a significance level of 0.05.

Concurrent validity of the sub-scales of TGMD-2 and MABC-2 tests were significant (P <0.05) in a high level. Pearson correlation coefficient between subscales of locomotion and balance and between object control and aiming-catching of the TGMD-2 and of MABC-2 were 0.80 and 0.75, respectively. Internal and external reliability of TGMD-2 were confirmed. Cronbach's alpha for the locomotion and object control subscale were 0.97 and 0.96, respectively. The Intra Class Correlation Coefficient (ICC) of the TGMD-2 was 0.97(P <0.05).Also, inter rater and intra rater were 95% and 97%, respectively for TGMD-2.

The TGMD-2 can be a useful tool for measurement of the gross motor skills of children with visual impairment in 7-10 years old. This tool can be used in clinics and treatment centers; it can also be used for research purposes.