The assessment of grip strength in preschool-aged children with and without unilateral cerebral palsy

Aim: To investigate reliability and validity of two grip strength devices in children with and without unilateral cerebral palsy (uCP) aged 2 to 6 years. Method : We assessed grip strength in 20 preschool-aged children with predominantly spastic uCP (mean age 4y0±1y2m) and 20 age-matched children without uCP (mean age 3y11m±1y3m) using the Martin Vigorimeter and MyoGrip to investigate test-retest reliability (intraclass correlation coefficients; ICC), known-group validity (comparative statistics) and convergent validity (correlation analyses) in a cross-sectional design. Results: In both groups, test-retest reliability was excellent for both devices and both hands (ICC 0.91-0.97). Grip strength of the non-preferred hand was lower in children with uCP for both devices (p<0.001). Grip strength was decreased in the non-preferred compared to the preferred hand in children with uCP for both devices (p<0.001). In children without uCP, grip strength was lower in the non-preferred compared to the preferred hand only for the MyoGrip (p=0.02). The relation between both devices for both hands was good to very high (r=0.62-0.92, p<0.007). Conclusion: Both devices can be implemented in clinical practice to assess grip strength in preschool-aged children with uCP. Only the MyoGrip detected differences between both hands in children without uCP and might be more sensitive.