NCT07001891

Functional Connectivity of the Interoceptive Network in RLS

Functional Connectivity of the Interoceptive Network in Restless Legs Syndrome (RLS) : an Anatomical-clinical Prospective Study Based on Daily-life Assessment

• Status: Recruiting
• Phase: N/A
• Study type: Interventional
• Enrollment: 30 (estimated)
• Sponsor: University Hospital, Bordeaux · Academic / Other
• Sex: All
• Age: 18 Years – 70 Years
• Healthy volunteers: Accepted

Summary

Restless Legs Syndrome (RLS) is a sensorimotor disorder primarily characterized by an irresistible urge to move the legs while at rest. A key hypothesis suggests that RLS symptoms are linked to abnormal brain function in processing internally generated stimuli, particularly interoception. This distorted perception of the internal bodily state leads to maladaptive behaviors, which may manifest across a wide range of medical and psychiatric disorders. Here, the investigators hypothesize that dysfunction in the insular cortex (IC) may result in a failure of behavioral adaptation, primarily expressed as an urge to move the legs and hyperarousal, even when the body and mind need rest. This project aims to assess the relationship between interoceptive abilities and diurnal fluctuations in IC functional connectivity (FC) in patients with RLS compared to healthy controls. The investigators will also examine correlations between the FC of the interoceptive network, measured in the morning and evening on the same day, using multilayer network analysis, daily fluctuations in RLS symptom severity, and objective measurements of the sleep/wake cycle, gathered through a two-week ambulatory assessment using mobile technologies such as Ecological Momentary Assessment (EMA) and actigraphy, along with scores from self-reported questionnaires. The findings may provide strong evidence to support or refute the hypothesis of interoceptive dysfunction in RLS patients.

Detailed description

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.

Conditions

• Restless Legs Syndrome

Interventions

Type	Name	Description
OTHER	Clinical assessment	RLS history, RLS treatments, and International Restless Legs Syndrome Rating Scale (IRLSRS) will be recorded
BEHAVIORAL	auto-questionnaires (PSQI, ISI, ESS and HADS)	To evaluate sleep quality, daytime somnolence and mood disorders (Pittsburgh Sleep Quality Index (PSQI), Insomnia Severity Index (ISI), Epworth Sleepiness Scale (ESS) and Hospital Anxiety and Depression Scale (HADS)).
DEVICE	Ecological Momentary Assessment (EMA)	4 electronic interviews administered per day during 14 days by a study-dedicated Android OS smartphone
DEVICE	activity-rest cycle	To further investigate the mutual influence of sleep quality on RLS symptoms and mood, the activity-rest cycle will be monitored by wearable actigraph to be placed on the non-dominant wrist during a period of 13 days and 14 nights.
BEHAVIORAL	auto-questionnaires (ASRS, PSAS, APS, MAIA-2)	Interoceptive awareness and accuracy estimation : Adult ADHD Self-Report Scale (ASRS), Pre-Sleep Arousal Scale (PSAS), Arousal Predisposition Scale (APS) et Multidimensional Assessment of Interoceptive Awareness version 2 (MAIA-2)
DEVICE	MRI	Morning and evening functional brain imaging

Timeline

• Start date: 2025-09-16
• Primary completion: 2026-10-01
• Completion: 2026-10-01
• First posted: 2025-06-03
• Last updated: 2025-09-17

Locations

1 site across 1 country: France