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

Purpose: To investigate reliability and validity of two grip strength devices in children with and without unilateral cerebral palsy (uCP) aged 2-6 years.

Method: We assessed grip strength in 20 pre-school-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.