Detecting individual change in children with mild to moderate motor impairment: the standard error of measurement of the Movement ABC

Objective. To assess whether the Movement ABC can be used to monitor indivi dual change in motor performance. Design: Motor-impaired children were tested three limes in succession with the Movement ABC without any intervention. Setting: Two schools for special education and one school for children who are chronically ill. Subjects: Three girls and 20 boys aged 6-8 years. Main outcome measures: Scores were measured per item (0 --> 5), added to cl uster scores (0 --> 10 or 15), added to form the total scores (0 --> 40). M ean scores, standard errors of measurement (SEMs) and least detectable diff erences (LDDs) were calculated per item, per cluster and for the total scor es. A repeated measures analysis of variance was performed to test for the effects of time. Results. The total scores improved significantly from the first session (me an: 15.4 points) to the second (mean: 13.3), but not from the second to the third (mean: 13.2). Average item scores ranged from 0.6 to 2.7 points with SEMs of 0.79 --> 1.54 and LDDs of 2.20 --> 4.27. Average cluster scores ra nged from 3.4 to 5.3 with SEMs of 1.51 --> 1.84 and LDDs of 4.18 --> 5.11. The SEM of the total scores equalled 3.13 with an LDD of 8.68. Conclusions: The total score of the Movement ABC is sufficiently sensitive to monitor individual change; the cluster scores have moderate sensitivity and individual items are inappropriate to monitor individual change. The si gnificant effect of time is interpreted as an effect of learning.