Test-retest reliability of upper limb robotic exoskeleton assessments in children and youths with brain lesions

In children with congenital or acquired brain lesions, impaired upper limb function can affect independence. Assessing upper limb function is important for planning and evaluating neurorehabilitative interventions. Robotic devices increase measurement-objectivity and enable measuring parameters reflecting more complex motor functions. We investigated the relative and absolute test-retest reliability of assessments to measure upper limb functions in children and adolescents with brain lesions with the exoskeleton ChARMin. Thirty children (9 females, mean age +/- SD = 12.5 +/- 3.3 years) with congenital brain injuries (n = 15), acquired (n = 14), both (n = 1) and impaired upper limb function participated. They performed the following ChARMin assessments and repeated them within three to seven days: active and passive Range of Motion (ROM), Strength, Resistance to Passive Movement, Quality of Movement, Circle, and Workspace. We calculated the systematic difference, Intraclass Correlation Coefficient (ICC) and Smallest Real Difference (SRD) for each parameter. Six parameters of three assessments showed systematic errors. ICCs ranged from little to very high and SRD values varied considerably. Test-retest reliability and measurement errors ranged widely between the assessments. Systematic differences indicated that random day-to-day variability in performance would be responsible for reduced reliability of those parameters. While it remains debatable whether robot-derived outcomes should replace certain routine assessments (e.g., ROM, strength), we recommend applying certain technology-based assessments also in clinical practice. Trial registration: This study was registered prospectively at ClinicalTrials.gov (identifier: NCT02443857) on May 14, 2015.