Reproducibility of measurements on physical performance in head and neck cancer survivors; measurements on maximum mouth opening, shoulder and neck function, upper and lower body strength, level of physical mobility, and walking ability

BACKGROUND: Survivors of Head and Neck Cancer experience specific problems in functional performance. The aim of this study was to obtain the test-retest reliability of measurements on Maximal Mouth Opening (MMO), shoulder and neck function, lower and upper body strength, level of mobility and walking ability. MATERIALS AND METHODS: Test-retest study design. Measurements on MMO (intra- and extra orally), Active range of motion of shoulders and neck, 30 Seconds Chair Stand Test, Grip Strength, Timed Up and Go test, and Six Minute Walk test. RESULTS: In total 50 participants were included. The mean age was 68.6. ± 9.9 years and median time since end of treatment was 3.0 years (Q1–Q3: 1.0–5.25 years). We found good to excellent test-retest reliability on the core set of measurements (Intraclass Correlation Coefficient (ICC) 0.77 to 0.98). Measurement of MMO with cardboard card, forward flexion shoulder and Six Minute Walk test had a relatively small measurement error (Smallest Detectable Change (SDC) % 5.4% - 15.1%). Measurement of MMO with a caliper, shoulder abduction, shoulder external rotation, later flexion and rotation of the neck, grip strength, 30 Seconds Chair Stand Test, and Timed up and Go test had a relatively large measurement error (SDC% 19.8% - 44.7%). CONCLUSION: This core set of measurements on physical performance is found reliable and therefore able to differentiate in physical performance. The reported measurement errors should be taken into consideration when interpreting the results of repeated measurements. IMPLICATIONS FOR CANCER SURVIVORS: A core set of physical measurements can be used to measure physical performance in survivors of Head and Neck Cancer.