Measurement properties of a two-dimensional movement analysis system: A Systematic Review & Meta-analysis.

Abstract Objectives To critically appraise, compare and summarize the quality of the measurement properties of the Dartfish software across various populations and motion tasks. Data Sources Systematic electronic searches were performed in PsychInfo, Embase, Medline@ Ovid, CINAHL and Google Scholar databases from January 1999 to January 2020. Study Selection Prospective measurement studies published in English peer-reviewed journal that reported on at least one psychometric property (reliability, validity, measurement error) using Dartfish were included. Independent reviewer performed searches and identified studies. Data Extraction We followed the COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) 2018 guideline for abstracting and assessing data quality. Independent extraction was performed by two individual authors. The extracted data involved the author, year, study population, setting, sample size, measurement properties, and information on camera positions, analyzed movement variables and the corresponding strategy for addressing perspective error. Data Synthesis In total, 23 studies were included in this review. Studies were pooled to examine inter-rater reliability estimates for different tasks: (single-leg squat angle, 2 studies, 115 participants, ICC 0.94, 95% CI: 0.62 - 0.99), (single-leg vertical drop jump angle, 2 studies, 94 participants, ICC 0.92, 95% CI: 0.20 - 0.99) and (vertical drop jump angle, 2 studies, 100 participants, ICC 0.88, 95% CI: 0.83 - 0.92). Concurrent validity (2D Dartfish vs 3D Vicon) in 45 healthy/Parkinson patients was established during push and release task, single leg stance and single leg stance with acutely induced dizziness and correlation 0.59 – 0.98 reported. In measurement error, for tracking angles across various movements, an error of about 10° re-test variation was reported in three studies. Conclusion Dartfish is a reliable software for assessing a variety of tasks across multiple contexts of assessments. Evidence suggests that the estimates of motion obtained with Dartfish are valid for single plane movements.