Conversion Disorder

The goal of this observational study is to learn about functional neurological disorders in patients with common non-functional movement disorders ("functional overlay"). The main questions it aims to answer are: * What is the frequency of functional neurological disorders in patients with non-functional movement disorders (functional overlay)? * What are the characteristics of functional neurological disorders in patients with non-functional movement disorders? Participants will be examined clinically and electrophysiologically, the examinations consist of: * a neurological examination * neuropsychological testing * electrophysiological tremor diagnostic * questionnaires about psychological, biological and social risk factors Researchers will compare patients with functional motor disorders to patients wit non-functional movement disorders to see if they differ from each other regarding the functional symptoms.

The purpose of this study is to determine whether a course of rehabilitation using a device called a brain-computer interface can change the level of control people feel over bodily movements, in functional neurological disorder.

Conversion disorder refers to impaired voluntary motor or sensory functions that are not compatible with a well-known neurological condition. This disorder affects up to 30% of hospitalized patients in neurology departments and symptoms persist in 35% of patients after 12 years of evolution. Despite a poor prognosis, no treatments have been validated to date. The development of non-invasive brain stimulation techniques has allowed the creation of treatments focused on dysfunctional brain regions associated with motor conversion disorder. Hypoactivation of prefrontal dorso-lateral cortex underlies the course of functional motor symptoms. Results of the HYCORE study conducted at Nîmes University Hospital (including 20 patients, clinicaltrial.gov NCT02329626) confirmed these results and related hypoactivation of PFDLC to persistent motor disability at 3 months and 6 months follow-up. Activation of the PFDLC could restore executive control and thus promote the recovery of motor symptoms. However, in most repeated Transcranial Magnetic Stimulation (rTMS) the primary motor areas were targeted and the clinical improvement was related to self-suggestion induced by the motor response produced. Among the different techniques, transcranial Direct Current Stimulation (tDCS) is a medical neuromodulation device that delivers a direct, low-intensity electric current to cortical areas, facilitating neuronal activity. Recently, PFDLC stimulation via tDCS has been used to treat several neuropsychiatric disorders and shown to be effective in depression. In addition, this technique has several advantages compared to rTMS: its use is simpler and costs 5 to 8 times less, the device is portable and there is no titration procedure. The tolerance of the tDCS is also better with no risk of epileptic seizure, neuronal depolarization being absent.