Clinical trial NCT02515890: Memory Modulation by Pain During Anesthesia
Official title: Modulation of Long-term Memory by the Experience of Pain During Sedation With Anesthetics
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: PHASE1
Conditions: Amnesia
Pain
Anesthesia
Keywords: midazolam
dexmedetomidine
memory
ketamine
Lead sponsor: University of Pittsburgh
Sponsor class: OTHER
Collaborators: name: Foundation for Anesthesia Education and Research
First posted: 2015-08-05
Enrollment: 32
Sex: ALL
Minimum age (years): 18
Maximum age (years): 39
Standard ages: ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: CROSSOVER
Intervention model description: There are 3 single drug arms completed by a few participants. The majority of participants participated in a crossover design with two drugs, midazolam \& ketamine.
Primary purpose: BASIC_SCIENCE

Brief 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.

Detailed 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.

Eligibility 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

Primary outcomes:
measure: Memory Testing
timeFrame: At memory testing 1 day later
Secondary outcomes:
Other outcomes:
Locations:
city: Pittsburgh
country: United States
facility: University of Pittsburgh
state: Pennsylvania
Study officials:
affiliation: University of Pittsburgh
name: Keith M Vogt, MD, PhD
role: PRINCIPAL_INVESTIGATOR
References: