Memory Modulation by Pain During Anesthesia

Pain Clinical Trial

— MMA  

Official title:

Modulation of Long-term Memory by the Experience of Pain During Sedation With Anesthetics

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT02515890
• Other study ID #: PRO14050609
• Status: Completed
• Phase: Phase 1
• Start date: November 19, 2015
• Est. completion date: December 12, 2018

Study information

• Verified date: June 2020
• Source: University of Pittsburgh
• Contact: n/a
• Is FDA regulated: No
• Study type: Interventional

Clinical Trial Summary

The purpose of this study is to determine the effects of pain on facilitating long-term auditory memory in the presence and absence of distinct intravenous anesthetics. The ability to identify previously presented words from a list assessed the degree of memory formation. In a subset of subjects, functional magnetic resonance imaging was used to identify the neural correlates of memory inhibition or facilitation by the combination of pain and anesthetic used.

Description:

This study adds specific details to the current incomplete body of knowledge examining the effect of pain on memory formation under the influence of anesthetic agents.

Pain and anesthetic agents were administered as experimental variables in this study. Healthy adult subjects were played repeated lists of words and performed several decision-making tasks that encourage memory encoding. Some words were consistently paired with painful electric shock, and was anticipated to improve subsequent memory performance specifically for those items. The same experiment was repeated in all subjects during the administration of 1-2 possible agents that reduce memory formation: dexmedetomidine, a predominantly sedative agent, and midazolam, a well-known amnestic agent, and ketamine, a well-known dissociative analgo-sedative. The extent to which pain modulates memory performance under the effects of the anesthetic agents was the primary outcome of interest.

Further, a subset of the subjects performed the same experimental procedures while undergoing functional magnetic resonance imaging, which continuously reflects neuronal activity throughout the brain. Classic memory areas were predicted to be activated by the auditory processing task, but how these neural circuits change under the two anesthetic agents with the concomitant experience of pain were of interest. It was anticipated that pain recruits a parallel memory pathway using limbic structures, known for their involvement in fear conditioning. Additionally, stronger and more diffuse cortical processing likely occurs with concomitant pain, as level of sedation was reduced by this strong stimulus. Discovering the anatomic correlates specific to each experimental variable (pain and anesthetic), and their interplay, may help refine our model of brain function during the dynamics of pain and sedation.

Recruitment information / eligibility

• Status: Completed
• Enrollment: 32
• Est. completion date: December 12, 2018
• Est. primary completion date: December 12, 2018
• Accepts healthy volunteers: Accepts Healthy Volunteers
• Gender: All
• Age group: 18 Years to 39 Years

Eligibility

Inclusion Criteria:

• Healthy adult volunteers, with normal memory and hearing, whose native language is English

Exclusion Criteria:

• pregnancy

• significant memory or hearing loss

• sleep apnea

• chronic pain

• metal or electronic implants

• claustrophobia

• Currently taking: antidepressants, anti-psychotics, antihistamines, anti-anxiety medication, stimulants, sleep-aids, or pain medication

Related Conditions & MeSH terms

• Amnesia
• Anesthesia
• Pain

Intervention

Drug:
• Dexmedetomidine
Selected subjects received this drug during a portion of the study
• Midazolam
Selected subjects received this drug during a portion of the study

Device:
• Peripheral nerve stimulation
Experimental acute pain stimulus was delivered using a nerve stimulator. These painful shocks were paired randomly with some of the auditory experimental cues.

Drug:
• Ketamine
Selected subjects received this drug during a portion of the study

Locations

Country	Name	City	State
United States	University of Pittsburgh	Pittsburgh	Pennsylvania

Sponsors (2)

Lead Sponsor	Collaborator
University of Pittsburgh	Foundation for Anesthesia Education and Research

Country where clinical trial is conducted

United States, 

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	Memory Testing	Subjects completed the Remember, Know, New (RKN) task during next day testing. Their d' memory score was calculated based on their ability to discriminate between previously heard words and new words. A higher d' score indicates stronger recollection. D' scores were compared across the control condition (saline) and the drug conditions dexmedetomidine, midazolam, and ketamine. Performance was also calculated according to words associated with Pain and No Pain conditions.	At memory testing 1 day later