Reliability and agreement of the Nine Hole Peg Test in patients with unilateral spastic cerebral palsy

Upper extremity involvement is one of the most common motor impairments in children with unilateral spastic cerebral palsy (CP). One tool for the assessment of manual function in CP is the Nine Hole Peg Test (NHPT). However, the reliability of the NHPT in patients with unilateral CP is unknown. This study aimed to analyze the intra-rater inter-session reliability of the NHPT in unilateral spastic CP, for its use in clinical practice and research. A total of 27 participants with spastic unilateral CP were included. Reliability was verified by the intraclass correlation coefficient (ICC), standard error of measurement, and minimum detectable change. The agreement was analyzed by the Bland-Altman method. An excellent intra-rater reliability was observed for the non-affected side (ICC = 0.94) and the affected side (ICC = 0.96). The minimal detectable change was 4 and 12 s for the non-affected and affected side, respectively. There were no significant biases between repetitions.   Conclusions: The NHPT showed excellent intra-rater inter-session reliability in patients with spastic unilateral CP. In addition, the test shows adequate agreement and proportionally small errors to assess manual dexterity. What is Known: • The Nine Hole Peg Test (NHPT) is widely used to assess dexterity in patients with neurological conditions. • The NHPT has demonstrated appropriate measurement properties in healthy children and adults with neurological conditions. What is New: • The NHPT presents excellent reliability, small measurement errors, and adequate agreement for the assessment of patients with cerebral palsy. • The measurement error of the NHPT in unilateral cerebral palsy may be up to 13% of the total time to perform it.