Visualisation of upper limb activity using spirals - a new approach to the assessment of daily prosthesis usage

BACKGROUND: Current outcome measures used in upper limb myoelectric prosthesis studies include clinical tests of function and self-report questionnaires on real world prosthesis use. Research in other cohorts has questioned both the validity of self-report as an activity assessment tool and the relationship between clinical functionality and real-world upper limb activity. Previously we reported the first results of monitoring upper-limb prosthesis use. However, the data visualisation technique used was limited in scope. OBJECTIVES: To introduce two new methods for the analysis and display of upper limb activity monitoring data and to demonstrate the potential value of the approach with example real world data. METHODS: Upper limb activity monitors, worn on each wrist, recorded data on two anatomically intact (AI) participants and two prosthesis users (PU) over one week. Participants also filled in a diary to record upper limb activity. Data visualisation were carried out using histograms, and Archimedean spirals to illustrate temporal patterns of upper limb activity. RESULTS: AI participants’ activity was largely bilateral in nature, interspersed with frequent bursts of unilateral activity of each arm. At times when the prosthesis was worn PU showed very little unilateral use of the prosthesis (≈20-40 min/week compared to ≈350 min/week unilateral activity on each arm for AI participants), with consistent bias towards the intact arm throughout. The Archimedean spiral plots illustrated participant-specific patterns of non-use in PU. CONCLUSIONS: The data visualisation techniques allow detailed and objective assessment of temporal patterns in the upper limb activity of prosthesis users