JMIR Publications

ABSTRACT

Background:

Objective measures specifically assessing selective voluntary motor control (SVMC) are scarce. Therefore, we have developed an interval-scaled assessment based on accelerometers.

Objective:

This study provides a preliminary evaluation of the validity and reliability of this novel game-like assessment measuring lower limb SVMC in children with cerebral palsy.

Methods:

We included 20 children with cerebral palsy (mean age 12y5mo [SD 3y4mo], Gross Motor Function Classification System (GMFCS) levels I to IV) and 31 neurologically intact children (11y1mo [3y6mo]). They played the assessgame and steered an avatar by selective hip, knee, or ankle joint movements captured with accelerometers. The assessgame’s scores provide information about the accuracy of the selective movement of the target joint and the amplitude and frequency of involuntary movements occurring in uninvolved joints. We established discriminative validity by comparing assessgame scores with those obtained from neurologically intact children, concurrent validity by correlations with clinical scores and therapists’ opinions, and test-retest reliability.

Results:

The assessgame could distinguish between children with CP and neurologically intact children. The correlations between the assessgame’s involuntary movement score and the therapist’s rating of the occurrence of involuntary movements during the game were moderate (Spearman’s ρ=0.56, P=.01), while correlations with the Selective Control Assessment of the Lower Extremity (SCALE) and GMFCS were low and not significant (|ρ|≤0.39). Intraclass correlation coefficients were above 0.85 and indicated good relative test-retest reliability. Minimal detectable changes (MDC) amounted to 25% (accuracy) and 44% (involuntary movement score) of the mean total scores. The percentage of children able to improve by the MDC without reaching the maximum score was 100% (n=17/17) for the accuracy score and 94% (n=16/17) for the involuntary movement score.

Conclusions:

The assessgame proved reliable and showed discriminative validity in this preliminary evaluation. Concurrent validity was moderate with the therapist’s opinion but relatively poor with the SCALE. We assume that the assessment´s game-like character demanded various other motor control aspects that are less considered in current clinical assessments. Clinical Trial: NA