Trial Outcomes & Findings for Memory & Conditioning Under Anesthesia (NCT NCT04062123)

Last Updated: 2025-04-18

Results Overview

Recognition memory testing, using the Remember-Know procedure, in which subjects indicate whether they recognize previously experienced experimental items among novel items (not previously in the experiment). This allows calculation of interdependent measures of recollection \& familiarity using the signal detection statistic, d'. d' is calculated as the cumulative Gaussian distribution of false positive responses subtracted from the cumulative Gaussian distribution of correctly identified previously-experienced items. d' is on a (theoretically infinite) scale of standard deviation units, with negative values representing performance worse than chance guessing and positive values representing stand deviations of performance above chance.

Recruitment status

COMPLETED

Study phase

PHASE1

Target enrollment

92 participants

Primary outcome timeframe

24-hrs post-experiment

Results posted on

2025-04-18

Participant Flow

Participant milestones

Participant milestones
Measure	Propofol Subjects in this group received propofol during the drug portion of the experiment.	Dexmedetomidine Subjects in this group received dexmedetomidine during the drug portion of the experiment.	Fentanyl Subjects in this group received fentanyl during the drug portion of the experiment.
Overall Study STARTED	30	29	33
Overall Study COMPLETED	30	28	33
Overall Study NOT COMPLETED	0	1	0

Reasons for withdrawal

Reasons for withdrawal
Measure	Propofol Subjects in this group received propofol during the drug portion of the experiment.	Dexmedetomidine Subjects in this group received dexmedetomidine during the drug portion of the experiment.	Fentanyl Subjects in this group received fentanyl during the drug portion of the experiment.
Overall Study Withdrawal by Subject	0	1	0

Baseline Characteristics

Memory & Conditioning Under Anesthesia

Baseline characteristics by cohort

Baseline characteristics by cohort
Measure	Propofol n=30 Participants Subjects in this group received intravenous propofol, during a portion of the study. Dose was targeted to an effect site concentration of 1.0 mcg/ml, using pharmacokinetic modelling that accounts for subject's age, gender, height, \& weight.	Dexmedetomidine n=29 Participants Subjects in this group received intravenous dexmedetomidine, during a portion of the study. Dose was targeted to an effect site concentration of 0.15 ng/ml, using pharmacokinetic modelling that accounts for subject's age, gender, height, \& weight.	Fentanyl n=33 Participants Subjects in this group received intravenous fentanyl, during a portion of the study. Dose was targeted to a brain effect site concentration of 0.9 ng/ml, using pharmacokinetic modelling that accounts for subject's age, gender, height, \& weight.	Total n=92 Participants Total of all reporting groups
Age, Continuous	25.0 years STANDARD_DEVIATION 6.2 • n=5 Participants	25.6 years STANDARD_DEVIATION 6.5 • n=7 Participants	23.9 years STANDARD_DEVIATION 5.0 • n=5 Participants	24.8 years STANDARD_DEVIATION 5.9 • n=4 Participants
Sex: Female, Male Female	14 Participants n=5 Participants	15 Participants n=7 Participants	16 Participants n=5 Participants	45 Participants n=4 Participants
Sex: Female, Male Male	16 Participants n=5 Participants	14 Participants n=7 Participants	17 Participants n=5 Participants	47 Participants n=4 Participants
Ethnicity (NIH/OMB) Hispanic or Latino	1 Participants n=5 Participants	3 Participants n=7 Participants	3 Participants n=5 Participants	7 Participants n=4 Participants
Ethnicity (NIH/OMB) Not Hispanic or Latino	22 Participants n=5 Participants	22 Participants n=7 Participants	27 Participants n=5 Participants	71 Participants n=4 Participants
Ethnicity (NIH/OMB) Unknown or Not Reported	7 Participants n=5 Participants	4 Participants n=7 Participants	3 Participants n=5 Participants	14 Participants n=4 Participants
Race (NIH/OMB) American Indian or Alaska Native	0 Participants n=5 Participants	0 Participants n=7 Participants	0 Participants n=5 Participants	0 Participants n=4 Participants
Race (NIH/OMB) Asian	5 Participants n=5 Participants	6 Participants n=7 Participants	8 Participants n=5 Participants	19 Participants n=4 Participants
Race (NIH/OMB) Native Hawaiian or Other Pacific Islander	0 Participants n=5 Participants	0 Participants n=7 Participants	0 Participants n=5 Participants	0 Participants n=4 Participants
Race (NIH/OMB) Black or African American	0 Participants n=5 Participants	0 Participants n=7 Participants	3 Participants n=5 Participants	3 Participants n=4 Participants
Race (NIH/OMB) White	18 Participants n=5 Participants	17 Participants n=7 Participants	15 Participants n=5 Participants	50 Participants n=4 Participants
Race (NIH/OMB) More than one race	0 Participants n=5 Participants	2 Participants n=7 Participants	4 Participants n=5 Participants	6 Participants n=4 Participants
Race (NIH/OMB) Unknown or Not Reported	7 Participants n=5 Participants	4 Participants n=7 Participants	3 Participants n=5 Participants	14 Participants n=4 Participants
Region of Enrollment United States	30 participants n=5 Participants	29 participants n=7 Participants	33 participants n=5 Participants	92 participants n=4 Participants

PRIMARY outcome

Timeframe: 24-hrs post-experiment

Outcome measures

Outcome measures
Measure	Placebo Control n=92 Participants Data obtained from subjects across all three drug groups, during portion of experiment receiving no drug.	Propofol n=30 Participants Data from subjects assigned to propofol group, from experimental session in which they were under a steady-state effect site concentration of propofol of 1.0 mcg/ml.	Dexmedetomidine n=29 Participants Data from subjects assigned to dexmedetomidine group, from experimental session in which they were under a steady-state effect site concentration of dexmedetomidine of 0.15 ng/ml.	Fentanyl n=33 Participants Data from subjects assigned to fentanyl group, from experimental session in which they were under a steady-state effect site concentration of fentanyl of 0.9 ng/ml.
Explicit Memory Performance	1.16 units on a scale Interval 0.97 to 1.34	.51 units on a scale Interval 0.182 to 0.842	1.04 units on a scale Interval 0.73 to 1.35	.98 units on a scale Interval 0.68 to 1.28

SECONDARY outcome

Timeframe: Immediately after each experimental item

The Z-score is calculated by linear regression of the task timing against the MRI signal time-course (MRI data is in arbitrary units with no maximum or minimum) at each voxel (single data point in brain). The outcome is listed for the hippocampus, but similar scores are calculated throughout the brain. Z-score of 0 indicates no task-related changes. Z-scores further from zero indicate a larger difference in brain activity, with positive values indicating decreases under the drug condition, while negative Z-scores indicate increases under drug, compared to control. This outcome is reported as a number, as it is calculated using all the data across subjects combined into one statistical measure for the overall strength of difference in MRI signal change between two groups of data. Dispersion measures cannot be calculated for the summary Z-score.

Outcome measures

Outcome measures
Measure	Placebo Control n=30 Participants Data obtained from subjects across all three drug groups, during portion of experiment receiving no drug.	Propofol n=29 Participants Data from subjects assigned to propofol group, from experimental session in which they were under a steady-state effect site concentration of propofol of 1.0 mcg/ml.	Dexmedetomidine n=33 Participants Data from subjects assigned to dexmedetomidine group, from experimental session in which they were under a steady-state effect site concentration of dexmedetomidine of 0.15 ng/ml.	Fentanyl Data from subjects assigned to fentanyl group, from experimental session in which they were under a steady-state effect site concentration of fentanyl of 0.9 ng/ml.
Brain Activation in the Hippocampus for Successful Memory Formation: Placebo Condition Minus Drug Condition	3.8 Z-score for difference	-4.9 Z-score for difference	-5.0 Z-score for difference	—

SECONDARY outcome

Timeframe: Immediately after each experimental item

Population: Acquisition of EKG data was not possible in the scanner, due to interference from the magnetic field. This is why the outcome cannot be reported.

Heart rate changes (measured by electrocardiogram, EKG) were planned to be determined following experimental stimuli that delivered as part of the experiment. A 1-6 second window of physiologic data will be analyzed for changes in the peak of the EKG response (R-wave), allowing calculation of instantaneous heart rate. Increases in heart rate are well-known to correlate to sympathetic nervous system activity increases.

Outcome measures

Outcome data not reported

SECONDARY outcome

Timeframe: Immediately after each experimental item

Population: Acquisition of skin conductance data was not possible in the scanner, due to interference from the magnetic field. This is why the outcome cannot be reported.

Electrodermal activity (galvanic skin) response was planned to be determined following experimental stimuli that delivered as part of the experiment. A 1-6 second window of physiologic data will be analyzed for changes in electrodermal activity, measured from the palm of subjects' hand. this well-established measure indicates sweat gland activity and is correlated to sympathetic nervous system activity increases.

Outcome measures

Outcome data not reported

Adverse Events

Propofol

Serious events: 0 serious events

Other events: 0 other events

Deaths: 0 deaths

Dexmedetomidine

Serious events: 0 serious events

Other events: 0 other events

Deaths: 0 deaths

Fentanyl

Serious events: 0 serious events

Other events: 2 other events

Deaths: 0 deaths

Serious adverse events

Adverse event data not reported

Other adverse events

Other adverse events
Measure	Propofol n=30 participants at risk Subjects in this group received intravenous propofol, during a portion of the study. Dose was targeted to an effect site concentration of 1.0 mcg/ml, using pharmacokinetic modelling that accounts for subject's age, gender, height, \& weight.	Dexmedetomidine n=29 participants at risk Subjects in this group received intravenous dexmedetomidine, during a portion of the study. Dose was targeted to an effect site concentration of 0.15 ng/ml, using pharmacokinetic modelling that accounts for subject's age, gender, height, \& weight.	Fentanyl n=33 participants at risk Subjects in this group received intravenous fentanyl, during a portion of the study. Dose was targeted to a brain effect site concentration of 0.9 ng/ml, using pharmacokinetic modelling that accounts for subject's age, gender, height, \& weight.
Gastrointestinal disorders nausea	0.00% 0/30 • Adverse event data was collected throughout the entire study period, at 5 study visits taking place over up to 3 months.	0.00% 0/29 • Adverse event data was collected throughout the entire study period, at 5 study visits taking place over up to 3 months.	6.1% 2/33 • Number of events 2 • Adverse event data was collected throughout the entire study period, at 5 study visits taking place over up to 3 months.

Additional Information

Keith Vogt, MD, PhD

University of Pittsburgh

Phone: 4126473147

Email: [email protected]

Results disclosure agreements

Principal investigator is a sponsor employee
Publication restrictions are in place