Traumatic Long-term Memory of Pain in Humans

Official title

Traumatic Long-term Memory of Pain - Pain Conditioning Study in Humans

Overview

Few studies have focused on understanding the mechanisms underlying pain memory in humans. Thus, this project aims to investigate the link between pain memorisation and memorisation of the associated context by addressing the issue of pain conditioning. The study is composed of two successive parts: one pilot then one experimental. The goal is to understand pain memorisation processes by analysing the parallel between pain memorisation and memorisation of a traumatic event. By using immersive virtual reality, investigators aim to show that contextual pain conditioning is associated with : 1- a specific neural networks; 2- a reactivation of vegetative and behavioural reactions related to pain as well as electro-physiological markers when re-exposure to the specific pain-conditioning-context; 3- an implicit hypermnesia of the pain-associated context and a struggle to extinguish conditioning; 4- a favoured elaboration of false memories of the contextual pain. The emitted hypothesis suggests that a cortical and behavioural mnemonic trace is created during encoding of pain in association with its context, and that the latter can reactivate although the pain itself has disappeared. This implicit cortical mnemonic trace, evoked by the simple pain-associated context, could explain the notion of pain print persisting at long-term in patients suffering from chronic pain.

Interventions

• Other Validation of virtual environment and auditive stimulation with virtual reality glasses (Pilot phase)
  The goal of this phase is the development of the experimental protocol in virtual reality. Virtual environment will be checked and auditive stimulation will be graduated.
• Other Electrical cutaneous stimulation and auditive stimulation (Principal Experimental phase)
  This phase is the principal step of the study: during moving in virtual environment, electrical stimulation on one hand and auditive stimulation will be applied. EEG, ECG and skin conductance will be measured during conditioning phase and extinction phase (day 1, 30 minutes each phase). Behavioral measures will be done throughout the 3 sessions (day 1, day 2 and day 30)
• Other Electrical cutaneous stimulation and auditive stimulation (Secondary Experimental phase)
  This phase is the same of the Principal Experimental phase except for the EEG that will not be performed.

Primary outcome measures

• Measurement of electrophysiological (EEG) changes during a pain conditioning set up and its extinction [Time frame: day 1]
• Measurement of vegetative (electrodermal, electrocardiac) changes during a pain conditioning set up and its extinction [Time frame: day 1]

Secondary outcome measures (6)

• Assessment of short-term memory of an environment according to whether it is associated with a painful stimulation or not [Time frame: day 2]
• Assessment of long-term memory of an environment according to whether it is associated with a painful stimulation or not [Time frame: day 30]
• Assessment subject capacity to create false memory of environment according to the associated stimulation (pain or no pain) [Time frame: day 2]
• Assessment subject capacity to create false memory of environment according to the associated stimulation (pain or no pain) [Time frame: day 30]
• Eye-tracking measurements, to assess the exploration of different contexts according to their nature [Time frame: Day 1]
• Assessment of the total duration needed for total extinction [Time frame: 30 minutes]

Eligibility criteria

Inclusion criteria

• Healthy subject
• Subject between 18 and 50 years old
• Subjects having given their written consent
• Subjects with health insurance

Exclusion criteria

• Prior addiction to drugs
• Prior neurological issues
• Chronic pain (neuropathic or non-neuropathic)
• Pregnant/breast-feeding women
• Absence of efficient contraception method for the duration of the study (1 month) for participants of procreation age (no inclusion limitation for male participants of procreation age)
• Subjects under chronic analgesic treatment or having taken an analgesic treatment in the 24 h preceding the experiment
• Heart issues
• Subjects under justice surveillance
• Subjects participating in another study which inclusion period overlaps with the one from this study

Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.

Healthy volunteers: Yes

Study design

Allocation

Non-randomized

Model

Sequential

Masking

Open label

Primary purpose

Basic science

Study locations

France · 1 center

• Hôpital Neurologique, — Bron

Identifiers

NCT: NCT04189965 · 69HCL19_0413

Primary sources (government registries)

• ClinicalTrials.gov (US NIH)

View this study on ClinicalTrials.gov ↗