Simulated Pain in Robotic Orthopaedic Shoulder Rehabilitation

This dataset contains surface electromyography (sEMG) recordings acquired during the execution of shoulder orthopaedic rehabilitation exercises by healthy subjects while moving a robotic manipulator. Data were collected from 25 healthy participants aged 21–41 years. The exercises were provided by an expert physiotherapist and consisted of shoulder abduction, shoulder flexion, and scapular retraction – the latter also known as “row” or “rower.” During the exercises, subjects received an oral signal indicating when they had to simulate pain-related behaviours. Given that pain-induced abnormal muscle activation occurs during movement [1] and considering the consequent pain-related behaviours that patients usually adopt [2, 3], pain occurrences were simulated by replicating three typical behaviours observed during shoulder rehabilitation, which were agreed upon with the expert physiotherapist. To the best of the author’s knowledge, the databases most used for automatic pain detection research contain biological data recorded under artificial pain induction, that is, pain elicited by an external source. However, during real orthopaedic rehabilitation sessions, pain is never voluntarily and externally induced. During movement, pain directly affects the muscles and consequently impacts motor capacity [1]. Abnormal muscle activity is the basis for metrics considered among the most objective tools for pain assessment, such as the nociceptive flexion reflex (NFR) [2], and is normally measured using sEMG signals. Therefore, only sEMG signals were collected. The aim of this dataset is to provide a simple yet efficient source for designing machine learning algorithms for pain detection. Moreover, to the best of the author’s knowledge, no currently publicly available dataset contains signals recorded during rehabilitation exercises performed using a robot. sEMG signals were acquired using a Trigno Centro system (Delsys Europe, Greater Manchester, UK) with four wireless, single-channel Avanti EMG sensors. The sensors were placed on the active shoulder of the participants and positioned over muscles commonly addressed during orthopaedic shoulder rehabilitation, as indicated by the expert physiotherapist: the anterior deltoid, rear deltoid, upper trapezius, and lower trapezius.