Clinical Evaluation of HRV Biofeedback in Functional Neurological Disorders Compared to Placebo

Evaluation of the clinical effects of the Heart Rate Variability biofeedback training with patients suffering from Functional neurological Disorders compared with placebo.

Although Functional Neurological Disorders (FND) represent one of the most common reasons for consultation in Neurology, the pathological mechanisms remain unexplained. Recent studies suggest disrupted emotional processes in patients with FND and disturbed autonomic nervous system profiles, highligting the hypothesis of autonomic endophenotypes among the FND population.

The Heart Rate Variability Biofeedback (HRV-BFB) is an innovative and non-invasive approach, based on the self-regulation of autonomic physiological processes. It has shown promising results in clinical and non-clinical populations but has never been assessed in an adult FND population.

Therefore, this approach appears particularly promising for understanding the mechanisms underlying FND and developing personalized therapy.

The main objective is to investigate the clinical effects of HRV-BFB on FND patients compared to placebo in a single-blind crossover design.

The investigators predict that depending on their autonomic profile, patients will respond to HRV-BFB to varying degrees.

Firstly, patients with FND will prospectively undergo an comprehensive clinical evaluation considering symptoms, functional capacity, quality of life, and an assessment of the physical and psychological comorbidities. Then patients will complete an emotional task and undergo multimodal autonomic measures. Cluster analyses will be conducted to identify both dysfunctional and functional autonomic profiles associated with the clinical exploration, enabling confirmation of the endophenotypes hypothesis and allowing for specific characterization of the profils. The clinical evaluation of the beneficial effects of HRV BFB will rely on repeated mesures of symptoms, functional capacity, and quality of life at scheduled points in time before and after the both interventions (HRV-BFB and pseudo-BFB). The emotional task and autonomic measures will be repeated simultaneously.

Eligibility Criteria:
Inclusion Criteria:

* Functional Neurological Disorders (FND) diagnosis must be medically established
* Participants must have a smartphone (android ou Iphone)
* Participants must be of the age of majority
* Participants must have signed an informed consent
* Sufficiently fluent in French to understand study documents and instructions
* Consistency in performing repeated questionnaires
* Normal or corrected-to-normal visual acuity

Exclusion Criteria:

* Specially protected participants: juveniles, pregnant womens, nursing mothers, law's protection peoples
* Participants suffering from a severe psychiatric disease needing specialised attention
* History of severe neurosurgical pathology
* Alcohol dependence or drug use
* Participants suffering from or have suffered from a severe disease causing autonomic dysfunctions (heart failure, asthma, blood disease, renal failure, peripheral neuropathy, vagotomy, thyroid disorder, alcoholism, liver disease, amyloidosis)
* Participants taking medication which could be impact autonomic nervous system activity (anticholinergic, antiarrhythmics, clonidine, beta-blockers, tricyclic anti-depressants, metronidazole)
* Participants placing under judicial or administrative supervisions