Psychometric properties of the abbreviated Chinese version McCarron-Dial System on people with mental handicap

Abstract

The purpose of this study is to examine the use of McCarron-Dial System (MDS) for exploring the vocational outcome of people with mental handicap (MH) in Hong Kong. MDS is a well-known evidence based neuropsychological vocational evaluation system. It identifies three neuropsychological factors (verbal-spatial-cognitive, sensori-motor and emotional-coping) as predictors of vocational competency in various levels of vocational placement, these include supported employment (SE), sheltered workshop (SWS) and day activity centre (DAC). A total of 136 individuals with mild to moderate grade mental handicap who had been placed/ worked in SE, SWS or DAC over 3 months were recruited. The mean age of the participants was 24.02 years (SD = 7.51). They were assessed by the abbreviated version of the MDS (six subtests in Chinese version) on verbal-spatia-cognitive, sensori-motor and emotional-coping abilities. Work adjustment process was captured from 2 subjects who were engaged in supported employment. In the content validity of the Chinese version of Observational Emotional Inventory-Revised (COEI-R), which was one of the subtests of the MDS, the result showed that there was good relevance and representativeness during expert panel review. In the panel review, which was consisted of six occupational therapists, the percentage of agreement in both relevance and representativeness on Chinese version of OEI-R was ranged from 67%-100%. In the inter-rater reliability of COEI-R, the intra-class correlation (ICC) in two-way mixed effect model was 0.78 (p < 0.01). The Results indicated that the overall accuracy of the MDS for classification was 75.7% (Wilks' Lambda = 0.22, p < 0.01), and day activity centre was 90.2% (Wilks' Lambda = 0.22, p < 0.01) accurately classified, the highest among the three placements. Three subtests, namely Street Survival Skill Questionnaire (SSSQ) (Wilks Lambda = 0.27, p < 0.01), McCarron Assessment of Neuromuscular Development (MAND) (Wilks Lambda = 0.24, p< 0.01) and Haptic Visual Discrimination Test (HVDT) (Wilks Lambda = 0.28, p< 0.01) significantly contributed to the model. The findings affirmed that the neuropsychological variables, especially sensori-motor and emotional-coping factors, were useful for differentiating among the three levels of vocational placement for people with MH. Two cases, one with "better" MDS profile and the other with "less satisfactory" MDS profile, were illustrated to explore the differences among work adjustment process on supported employment with application of MDS profiles. The observations made during the follow-up period (post 3 months after job participation) suggested that both cases managed to demonstrate their adjustment to work setting during first three months of placement, although they had different MDS profiles. There were positive changes in their values, needs and behaviors which geared towards their job tenure. The two case illustrations showed different attitudes of changes. Case A (the one with "less satisfactory" MDS profile) adopted a reactive change pattern whereas Case B (the one with "better" MDS profile) adopted a more proactive change pattern.