Sensory training system for use at home by people with complex regional pain syndrome in England: protocol for a proof-of-concept study

INTRODUCTION: Complex regional pain syndrome (CRPS) is a disabling and distressing chronic pain condition characterised by a range of sensory, motor, autonomic and trophic symptoms. UK guidelines recommend therapy interventions to help normalise touch perception through self-administered tactile and thermal desensitisation activities. Interventions have been developed, aiming to help individuals broaden their sensory experience, thereby relieving chronic pain. However, therapy-led interventions often experience practical constraints and poor adherence. In response, a sensory training system (STS) device has been designed for unsupervised independent home-use. METHODS: This proof-of-concept study aims to explore whether people with CRPS use the device at home for 30 minutes a day for 30 days. Secondary aims are to determine whether the STS device will change tactile acuity and perceived levels of pain intensity, pain interference, sensitivity or feelings towards the affected limb. We will seek to recruit 20 eligible participants. Participants will be asked to measure tactile acuity using a two-point discrimination assessment, complete an online questionnaire before and after use of the device and complete a daily diary. On completion of the 30-day use, participants will be invited to take part in a semi-structured interview to explore their experiences of using the device. ANALYSIS: Pain intensity and pain interference will be scored using the online Assessment Center Scoring Service or using the look-up table in the PROMIS scoring manual. The remaining questionnaire data, including tactile acuity results, and device-use data, including frequency and duration of use, will be analysed using descriptive statistics. Qualitative data will be thematically analysed. ETHICS AND DISSEMINATION: London-Stanmore Research Ethics Committee provided a favourable opinion on 19 April 2021 (ref 21/LO/0200). The NHS Health Research Authority, UK, approved this study on 7 June 2021. Dissemination will include peer-reviewed publications, presentations at conferences, social media and reports to the funder and patient charities. TRIAL REGISTRATION NUMBER: ISRCTN89099843.