Fatigue Investigation Using Digital Outcomes

This study investigates objective methods to measure and monitor fatigue in patients with post-COVID-19 condition (long COVID) and multiple sclerosis (MS), and includes a group of healthy volunteers for comparison. Fatigue is a common and debilitating symptom of both conditions, but current assessment methods rely mainly on questionnaires, which can be limited by subjectivity and recall bias. The study uses a smartphone application (the FIDO app) together with wearable devices to continuously collect data on fatigue and its fluctuations during daily life, in order to evaluate the potential of digital, objective measures compared to standard assessments. Participation lasts approximately eight weeks and includes two in-person clinic visits along with a continuous data collection phase. At the initial visit, participants complete baseline assessments and questionnaires and are introduced to the study's digital tools. During the following weeks, participants wear two wearable devices continuously (24 hours a day) and use the FIDO app to complete short daily tasks (approximately 7 minutes every two days) and brief questionnaires (approximately 5 minutes per day). All participants collect a stool sample at home at weeks 4 and 8 for gut microbiome analysis, and complete the Fatigue Scale for Motor and Cognitive Functions at week 4. At the final study visit, participants repeat a subset of the baseline assessments, provide feedback on the digital technology used, and return the study devices.