Comparison of Weighted and Unweighted Task Load Indices for Single-Site Surgery Tasks

Abstract

Background: The National Aeronautics and Space Administration Task Load Index (NASA-TLX) a nd Surgery Task Load Index (SURG-TLX) are two subjective workload m easurement instruments. Both instruments provide unweighted andweightedworkload measurements. Weighted TLX m easures have seldomly been used byresearchers typically becauseof its high correlation with unweighted TLX a nd addedexperimentaltime to collect pairwise weightings. Therefore, theaim of thestudy wa s to compare weighted TLX scores with unweighted TLX scores and each’s sensitivity for demographic and experimentalfactors. Methods: Two simulated la paroscopic single site surgery tasks were completedusing four surgicalmethods by 25 participants. Pearson correlations, principle componentanalyses and mixed effect models were used to compare the unweightedandweighted TLXscores across tasks a nd methods. Results: There was a high correlation(r > 0.950, p < 0.001) betweentheunweighted TLXscores and the weighted TLX scores. The weighted TLX scores showed better sensitivity to both demographic and experimental factors for both TLX instruments. Conclusion: The overall weighted NASA-TLX and SURG-TLX scores differed from their respective unweighted scores even with a high correlation. The weighted TLXshowed potentialto better discriminate subjective workloadfor single-site ta sks. Future research is needed to identify and validatea more streamlinedweightingmethodparticularly for complex experimental taskslike single-site surgery.