Interrater reliability and criterion validity of the hand-held three-dimensional scanning method for evaluating hand volume in patients with stroke

Objectives: This study aims to assess the interrater reliability and criterion validity of a three-dimensional (3D) scanning method in evaluating hand volume in patients with stroke. Patients and methods: This observational study was conducted with 20 stroke patients (11 males, 9 females; mean age: 59.5±13.3 years; range, 28 to 74 years) between February 2023 and June 2023. Two trained therapists (Operators A and B) used a hand-held 3D laser scanner to measure bilateral hand volumes sequentially to assess the consistency of measurements between operators. Operator A also used a split cup to measure bilateral hand volumes to assess the accuracy of measurements between 3D scanning and the gold standard water displacement (WD) method. Results: The intraclass correlation coefficient between the two operators was 0.923 (p<0.001) for the volume of the non-affected hand measured using the 3D scanning method and 0.945 (p<0.001) for the affected hand. The volume of the non-affected hand measured by Operator A using the 3D scanning method highly correlated with the volume measured by the WD (r=0.938, p<0.001), and the volume of affected hand measured by using the 3D scanning method highly correlated with the volume of that measured by the WD (r=0.927, p<0.001). Conclusion: The 3D scanning method has good interrater reliability and criterion validity in the measurement of hand volume of affected and non-affected hands in patients with stroke.