Motor capacities of upper limbs in tetraplegics: a new scale for the assessment of the results of functional surgery on upper limbs

Study design: Metrological investigation. Objectives: To study the validity and the reliability of a Motor Capacities Scale (MCS) specifically designed for tetraplegics who undergo a functional surgery of upper limbs. Setting: Bouffard-Vercelli Centre, Cerbere, France. Methods: From diverse sources (observation of patients, review of literature, discussions with occupational therapists and physicians), we compiled a list of 300 activities relating to daily living tasks. From this list, 80 items of motor capacities were retained. They correspond to the abilities of a patient to perform basic and functional tasks regardless of contextual factors (environmental and personal factors). In a preliminary study, items were reviewed by occupational therapists and by 40 tetraplegics for criticism. An open study and an intermediate study were conducted to assess, respectively, the feasibility and the reliability of the MCS. A prefinal study was focused on construct validity. Convergent and divergent hypotheses were formulated and tested against other measures. Four criteria were identified for the elimination of some of the 36 remaining items: a variance of the item equal to 0, a low reproducibility, a high level of redundancy studied by item-to-item correlation and a low level of comprehension. Results: In all, 52 tetraplegics were included in the prefinal study. Global inter-rater reproducibility was excellent (intraclass correlation coefficient of 0.99). In accordance with the criteria of elimination, the number of items was reduced to 31. Correlations with the Sollerman test and the Asia Motor Score were, respectively, 0.959 and 0.7444 (P<0.0001). Correlation with the interval since the onset of the tetraplegia and the educational level were, respectively, 0.20 and 0.195 (P=0.163). Conclusion: MCS displays a good apparent and content validity, and excellent reproducibility and construct validity. Metrological properties were good enough to allow the evaluation of sensitivity to change in the final study.