Pilot Study of the Effect of Transcutaneous Stimulation of the Vagus Nerve on Pain Perception and Parameters of the Autonomic Nervous System

Controlled, Randomized Study of Pain Perception and Psychophysiological Reactions of the Autonomic Nervous System Under Transcutaneous, Electrical Stimulation of the Vagus Nerve in Healthy Volunteers

The increased incidence of pain syndromes requires the investigation of pathophysiological coherences as well as searching for new therapies. In the recent years neurostimulating techniques have been a promising approach regarding their analgesic effect. Combined with therapeutic standard procedures they can increase these effects and can have a positive impact on co-morbid diseases. The stimulation of the vagus nerve was proved as an efficient analgesic method in animal experiments and open clinical pilot studies amongst humans. Despite the lack of controlled approaches applying the method against defined pain syndromes, the stimulation of the vagus nerve has shown up as an effective method treating other psychiatric diseases like depression. The processing of stress, which is involved directly and indirectly in the pathogenesis of pain, seems to be susceptible for vagal stimulation. Compared with invasive methods the transcutaneous stimulation offers obvious advantages concerning appliance and occurrence of side effects. There are no studies so far dealing with the neuromodulatory effect on the handling of pain or the clinical therapy of defined (chronic) pain related diseases using the t-VNS system. The study hypothesis implies a change of experiencing pain when applying the t-VNS in healthy subjects.

Inclusion Criteria:

• Age: Minimum: 18 years Maximum: no limit
• Both Gender
• Normal psychiatric medical history
• Normal neurological report

Exclusion Criteria:

• Psychiatric disease incl. pain-related diseases
• Subject is on medication
• Abuse of drugs or alcohol until 12 weeks before enrollment in the study
• Actual wearing conditions
• Pronounced lack of sleep within the last 2 days of enrollment
• Excessive consumption of alcohol in the last 2 days
• Peripheral neuropathy
• Severe neurological diseases (cerebrovascular diseases, traumatic brain injury, epilepsy, Morbus Parkinson, dementia, systemic neurologic diseases etc.)
• migraine
• carpal tunnel syndrome or other entrapment syndromes
• missing Informed Consent
• Pregnancy
• active implant (like cochlea implant, VNS, pacemaker)
• severe internistic diseases (e.g. arterial hypertension, respiratory failure)
• malignant diseases within the last five years
• severe acute infections (e.g. HIV, hepatitis)
• diseases of the ENT bodysystem: Hearing loss of the left ear which is treated with an hearing instrument, all dermatologic and infectious diseases which affect the area around the pinna and the ear canal
• Other circumstances that in the opinion of the investigator might be an obstacle for enrolling the subject