Sensory function influences unimanual and bimanual dexterity in unilateral cerebral palsy

Abstract

The recently developed Tyneside Pegboard Test (TPT) assesses both unimanual and bimanual dexterity in children with unilateral cerebral palsy (uCP). Our aim was to explore the TPT psychometric properties and the impact of sensorimotor impairments on unimanual and bimanual dexterity. Forty-nine children with uCP (mean age 9y8m, SD 1y11m, 30 males, 23 right-sided uCP) performed the unimanual and bimanual TPT providing task duration. For the psychometric properties, known-group validity was evaluated using ANCOVA (between MACS levels) and concurrent and construct validity with Spearman's correlations (r) with known and valid tests (Jebsen-Taylor Hand Function test (JTHFT), Assisting Hand Assessment (AHA), ABILHAND-Kids and Children's Hand Use Experience Questionnaire (CHEQ). The impact of sensorimotor impairments (spasticity, grip force, stereognosis and mirror movements) was investigated using multiple linear regression (α<0.05, R 2). Unimanual and bimanual dexterity differed between MACS levels (known-group validity) (p<0.001). The TPT tasks correlated to the JTHFT (concurrent validity, r=0.86-0.88), the AHA, ABILHAND-Kids and CHEQ (construct validity, r=-0.38-(-0.78)). Stereognosis was the main factor influencing all tasks (p<0.001, R²=37%-50%). Unimanual dexterity was further explained by grip strength (p<0.05, R 2 =8%-9%) and mirror movements in the more-impaired hand (p<0.05, R 2 =4%-8%), while bimanual dexterity was additionally explained by mirror movements in the more-impaired hand (p<0.01, R 2 =10%-16%) and spasticity (p=0.04, R 2 =5%). The TPT is a valid assessment to measure unimanual and bimanual dexterity. This study further highlights that stereognosis is the main determinant for unimanual and bimanual dexterity in children with uCP.