Psychometric properties of the qualitative assessment of manual dexterity in the MABC-2 test

Objective: To reveal possible limitations of the qualitative assessment of the MABC-2 test tasks of the age band 2 (7-10 years), we examined the inter- and intra-rater reliability and construct (known-groups) validity, specifically for observation of the manual dexterity (MD) tasks.

Methods: The MD tasks of the MABC-2 executed by children with and without motor difficulties in manual dexterity (MD- and MD+; N = 6) were recorded by a video camera. A group of investigators (N = 9) performed qualitative observational assessment of children's movements from video recordings, in two observation sessions apart by four weeks (time 1, time 2).

Results: The statistical tests rejected the hypothesis on significant inter-rater reliability in the number of marked signs in the MD tasks. Regarding the intra-rater reliability, the number of marked signs in the MD tasks was not significantly different between observation in time 1 and time 2 in all investigators. 95% agreement limits for the number of marked movement signs in the two repeated observations ranged from Mdiff ± 0.73 up to Mdiff ± 2.63 signs. A good construct validity of the qualitative assessment of movements in the MD tasks was indicated by significantly higher number of movement signs marked in the MD- children as compared to the MD+ children, with exception of the graphomotor task.

Conclusions: The qualitative assessment within the MABC-2 test is a useful tool for the identification of manual dexterity impairment and weaker aspects of hand-eye coordination. However, the qualitative observational assessment of the MABC-2 tasks demands specific training of users.