Functional Connectivity of the Interoceptive Network in RLS

Despite extensive research into the pathophysiology of RLS, no unified mechanism has been identified to explain the prominent clinical features of the disorder, including both sensorimotor and non-motor symptoms. One plausible hypothesis is that RLS symptoms are related to abnormal brain function in processing internally generated stimuli, particularly interoception. Distorted perceptions of the internal bodily state can lead to maladaptive behaviors, which may manifest in a wide range of medical disorders, including RLS, attention-deficit/hyperactivity disorder (ADHD), insomnia, eating disorders/obesity, fibromyalgia, and psychiatric conditions. The interoceptive abilities of RLS patients, specifically their capacity to perceive and assess their internal bodily state, have not been extensively studied, despite their potential to deepen our understanding of the sensorimotor discomfort in the legs and associated non-motor symptoms. The IntoRLS project will therefore precisely characterize the temporal variation in symptom severity and interoceptive awareness in RLS patients, alongside their sleep/wake cycle disturbances, using ambulatory assessments. This ecological assessment will be linked to time-of-day variations in intrinsic insular connectivity, assessed via functional brain imaging. At the inclusion visit, eligible participants (both patients and matched controls) will be provided with a study-dedicated smartphone for a two-week period, as well as a wearable actigraph to monitor their activity/rest cycles. Participants will complete self-reported questionnaires assessing the severity of RLS symptoms, ADHD symptoms, anxiety and depression, daytime sleepiness, and arousal predisposition. At the end of the participation period (J+14), participants will undergo functional brain imaging sessions in the morning and evening. Between the two sessions, each participant will complete the Multidimensional Assessment of Interoceptive Awareness (MAIA-2) questionnaire and perform the Heartbeat Detection Task to evaluate interoceptive accuracy.