Pittsburgh, Pennsylvania 15213


Purpose:

The purpose of this study is to determine the effects of pain on facilitating long-term auditory memory in the presence and absence of two distinct intravenous anesthetics. The ability to identify previously presented words from a list will asses the degree of memory formation. In a subset of subjects, functional magnetic resonance imaging will be used to identify the neural correlates of memory inhibition or facilitation by the combination of pain and anesthetic used. The primary hypothesis is that pain will enhance memory formation, and that this will be mediated by additional neural pathways compared to those used to encode words not paired with pain. The study will occur over 4-5 visits and involves no long-term follow.


Study summary:

This study will add specific details to the current incomplete body of knowledge examining the effect of pain on memory formation under the influence of anesthetic agents. Pain is common during surgery, and preventing memory during such procedures is a fundamental goal of anesthetic care, as awareness under anesthesia can cause life-long psychiatric disturbance. However, currently available monitors cannot always detect when a patient is at risk for awareness or memory under anesthesia. This is largely due to an incomplete description of the circumstances that favor memory formation versus those that effectively inhibit it. Pain and two anesthetic agents will be administered as experimental variables in this study. Healthy adult subjects will be played repeated lists of words and perform several decision-making tasks that encourage memory encoding. Some words will be consistently paired with painful electric shock, and this is anticipated to improve subsequent memory performance specifically for those items. The same experiment will be repeated in all subjects during the administration of two agents that reduce memory formation: dexmedetomidine, a predominantly sedative agent, and midazolam, a well-known amnestic agent. The extent to which pain modulates the sedative and amnestic effects of the two anesthetic agents will be the primary outcome of interest. The memory facilitation due to pain is hypothesized to be greater for dexmedetomidine. Psychometric testing for stress, anxiety, depression, and sleepiness will be performed in the subjects, and regression analysis will be used to determine which of these may explain the commonly observed inter-individual response variability to pharmacologic sedation and amnesia. Further, a subset of the subjects will perform the same experimental procedures while undergoing functional magnetic resonance imaging, which will continuously reflect neuronal activity throughout the brain. Classic memory areas are 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 will be of interest. It is anticipated that pain will recruit a parallel memory pathway using limbic structures, known for their involvement in fear conditioning. Additionally, stronger and more diffuse cortical processing will likely occur with concomitant pain, as level of sedation will be reduced by this strong stimulus. Discovering the anatomic correlates specific to each experimental variable (pain and anesthetic), and their interplay, will refine the investigators' model of brain function during the dynamics of surgery and may someday allow more predictive monitoring.


Criteria:

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


NCT ID:

NCT02515890


Primary Contact:

Principal Investigator
Keith M Vogt, MD, PhD
University of Pittsburgh

Keith M Vogt, MD, PhD
Email: vogtkm@upmc.edu


Backup Contact:

James W Ibinson, MD, PhD


Location Contact:

Pittsburgh, Pennsylvania 15213
United States

Keith M Vogt, MD, PhD
Email: vogtkm@upmc.edu

Site Status: Recruiting


Data Source: ClinicalTrials.gov

Date Processed: November 21, 2017

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