Developing the Japanese Version of the VABS-II (1): Developmental Changes of the Normally Developing Sample

Background:  

Currently, there is no comprehensive adaptive behavior scale available in Japan to help making a decision on a necessary level of support for individuals with disabilities. The unavailability of adaptive behavior scales has led to an underestimation on needs in adaptive functioning of individuals with disabilities, particularly those who exhibit a significant discrepancy between their cognitive ability and adaptive functioning (i.e., those who exhibit higher IQ but have deficits in adaptive functioning). The Vineland Adaptive Behavior Scales, Second Edition (VABS-II; Sparrow, Cicchetti, & Balla, 2005) is one of the most widely used adaptive behavior scale in the US and other countries and is used not only for identifying individuals with cognitive disabilities, but also assessing needs of individuals with pervasive developmental disorder (PDD) and other developmental disabilities.

Objectives:  

The authors and colleagues started a standardizing process of the Japanese version of the VABS-II, and the purpose of the present study was to examine a developmental perspective of each subdomain.

Methods:

The participants were 1,219 normally developing children/individuals (614 males, 605 females) aged 0 to 87 years in 28 prefectures (out of 47) in Japan. The selection of the participants was modeled after the original VABS-II and matched to the demographics of Japan regarding age and male-to-female ratio. For those from 0 months to two years old, the data were collected for each month up to one-year-old (e.g., 1-month-old, 2-month old), and every other month up to two-year-old because they usually exhibit rapid developmental change.

Results:  

The scores on the VABS-II of normally developing individuals are expected to increase as they age. The results of two-way ANOVA (age × subdomains) showed that both the scores of overall adaptive functioning and the scores of each subdomain exhibited a smooth developmental increase, indicating the validity of this scale. Additionally, in the Motor area, which was measured only for those aged (a) zero-to-six-years and (b) over 50 years, there was a decrease on the scores of those who were over 50 years old. Lastly, there were no differences by gender in any subdomains.

Conclusions:  

This scale was proven to be sensitive to developmental changes, and, moreover, it was sensitive to changes by aging as well. There was also no measurement bias by gender.