Clinical trial NCT05336370: Decoding Mechanisms of Pain Modulation
Official title: Decoding Mechanisms of Pain Modulation Through Hypnosis and Vagus Nerve Stimulation
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Pain, Acute
Lead sponsor: University of Oslo
Sponsor class: OTHER
First posted: 2022-04-20
Enrollment: 156
Sex: ALL
Minimum age (years): 18
Maximum age (years): 70
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: PARALLEL
Intervention model description: The HypnoPain trial is designed as an experimental randomized controlled, statistician blinded superiority trial with three parallel groups
Primary purpose: TREATMENT

Brief summary: The main objective of this experimental trial is to gain further insights into the mechanisms of pain modulation, and more specifically, whether expectations of coping is one of the involved mechanisms. This will be investigated by comparing two different interventions known to influence pain perception; hypnosis and non-invasive stimulation of the vagus nerve, prior to a pain exposure task (hand immersion in cold water). Expectations will be assessed both pre- and post intervention.

Detailed description: Pain is a subjective experience, influenced by biological, psychological and social factors. This multidimensional view of pain has led to various efforts to affect people's pain experience. Nonpharmacological interventions, such as hypnosis, have proven successful in reducing pain whilst providing few, if any, negative side effects. Hypnosis involves a state of highly focused attention, with a constriction in peripheral awareness and a heightened responsiveness to social cues. This particular state can exert a powerful influence on the mind and body, yet the mechanisms responsible for this effect remains to a large degree unknown. The aim of this study is to investigate the effect of hypnosis given prior to a painful procedure (cold pressor test, CPT), to investigate the effect on pain perception and tolerance, but most importantly, to investigate if the effect is mediated by a change in expectations of coping. Previous studies have provided support for the the effect of hypnosis on expectations, but they have focused exclusively on stimulus expectancies (expectations of pain intensity), while the current study will focus on response outcome expectancies (expectations of coping) in line with the Cognitive Activation Theory of Stress (CATS).

Whilst hypnosis may dampen the stress response through expectancies (top-down), another way of dampening the stress response is through transcutaneous vagus nerve stimulation (tVNS) (bottom-up). Vagus nerve stimulation is proposed as another nonopioid pain treatment with minimal side effects. The vagus nerve is the 10th cranial nerve, connecting the viscera and the brain and influencing multiple systems of the body including the cardiac, immunologic, and endocrine system, and the activity of many visceral organs. This makes the vagus nerve a possibly important mediating (transmitting) and modulating nerve of pain signals . Stimulation of the vagus nerve is believed to modulate pain by inhibiting inflammation, oxidative stress, and sympathetic activity, and possibly also by inducing a brain activation pattern that may be incongruent with the pain matrix (i.e. brain regions commonly active during pain). VNS might also mediate the effects of the opioid system in pain modulation. These mechanisms have in common that they are hypothesized to affect neuronal hyperexcitability, resulting in a reduced pain perception, which is supported by experimental animal studies.

Eligibility criteria: Inclusion Criteria:

* Adults aged 18-70 years
* Fluent Norwegian language skills

Exclusion Criteria:

* History of cardiovascular disease
* Chronic pain conditions (any diagnoses resulting in chronic pain)

Primary outcomes:
measure: Pain tolerance
timeFrame: up to 10 minutes (During exposure (hand immersion in cold water))
Secondary outcomes:
measure: Pain intensity
timeFrame: Immediately after the cold pressor test
measure: Pain bothersomeness
timeFrame: Immediately after the cold pressor test
Other outcomes:
measure: Expectancies of coping
timeFrame: Within 5 minutes pre- and within 5 minutes post intervention
measure: Expectancies of coping: pre-conscious
timeFrame: Within 5 minutes pre- and within 5 minutes post intervention
Locations:
city: Oslo
country: Norway
facility: University of Oslo
Study officials:
References: