This clinical study will test if adding a non-invasive stimulation of the vagus nerve through the ear during physiotherapy brings an improvement to FND (Functional Neurological Disorder) patients with motor symptoms.
First, the investigators will test the normal functioning of the motor regions of the brain in FND patients and in healthy volunteers for comparison, using a painless method called TMS (Transcranial Magnetic Stimulation). Then, the investigators will further test how brain regions communicate with each other in FND patients, using fMRI (functional Magnetic Resonance Imaging, also painless). Additionally, the investigators will ask both FND patients and healthy volunteers to answer questions about their health and wellbeing, and will assess the exact symptoms of FND patients. The FND patients will then be assigned to two groups randomly, and neither they nor the researchers will know in which group they are. Both groups will do 5 sessions of their usual physiotherapy - one group with a real stimulation of the vagus nerve, and the other group with a fake stimulation. This is important to obtain reliable results. At the end, both groups of patients will be tested again to see if the way brain regions communicate with each other has changed. They will also answer again questions about their health and wellbeing, and their symptoms will be assessed again, to see if any changes happen. The results of the two groups of patients will be compared to isolate the effects of vagus nerve stimulation from the effects of physiotherapy alone.
Over 18 years of age.
Capable of judgement.
Willing to participate in the study (by signing the informed consent form).
FND diagnosis by a certified neurologist or psychiatrist.
Severe neuropsychiatric comorbidities.
Pregnancy or breastfeeding.
Prior knowledge on the effects of attention on the motor system.
Prior history of epilepsy or epileptic seizures in the person and their family.
Factorial
Vagial Nerve Stimulation (VNS) active stimulation
DevicetaVNS sends gentle electric stimuli to the vagus nerve branch located in the outer ear, which are transmitted to the nucleus of the solitary tract in the brainstem, and from there to the rest of the brain. The electrode site is the cymba conchae in in the outer ear. VNS thus acts to enhance the activity of the parasympathetic nervous system.
Vagial Nerve Stimulation (VNS) sham stimulation
DevicetaVNS sends gentle electric stimuli for several minutes, during which time the patient will feel a tickling sensation. Then, for the rest of the session, the hidden device will be switched off (there will be no stimulation).
Self-reported quality of life
The change in self-reported quality of life, measured through intervention sessions with the Euro Quality of Life questionnaire (EQ-5D-5L), compared between the active stimulation group and the sham stimulation group. This questionnaire includes 5 subscales (1-best, 5-worstest) about mobility, self-care, usual activities, pain/discomfort, anxiety/depression. In addition it includes a continue scale evaluation (0-worst to 100-best) about the patient evaluation on his health.
Neurophysiology investigation of the pathology by comparing Motor-Evoked Potential between FND patients and healthy participant
The study will examine cortical inhibition as measured by motor-evoked potentials (MEPs) during a short-interval intracortical inhibition (SICI) transcranial magnetic stimulation (TMS) protocol (single-pulse and paired-pulse). The investigators will examine how the outcome differs under different attentional demands in patients with functional neurological disorder (FND) and healthy participants.
Neurophysiology investigation of the pathology by comparing resting motor threshold between FND patients and healthy participant
The study will examine the resting motor threshold (in millivolts), which is the level of stimulation required to trigger motor-evoked potentials using a single-pulse transcranial magnetic stimulation (TMS) technique. The investigators will examine how this outcome differs between patients with functional neurological disorder (FND) and healthy participants.
Comparison of motor performance between patients and healthy controls
The differences in motor performance between FND patients and healthy controls were measured by the accuracy with which they maintained an isometric contraction during index finger abduction at 10% of maximum force.
Satisfaction rating of patients on the intervention
Patients will be asked to rate their satisfaction after the intervention on a scale from 1 to 10.
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University of Fribourg
Lead sponsor
Hôpital Cantonal de Fribourg
Collaborator
This trial is not recruiting at the moment. You can still explore other options:
