Neurocognitive DysfunctionPhase 2NCT02768727
A Test of Neural Inertia in Humans With Xenon
A Phase 2 study testing Xenon in people with Neurocognitive Dysfunction, run by University of Pennsylvania at 1 site in United States.
Trial summary
The dual objectives of this study are to determine if the phenomenon of neural inertia is present in humans and to determine whether the order of neurocognitive function is invariant among anesthetic agents. Read more about this study
- Who is it for?
- Ages 20 to 40 yearsHealthy volunteers can take part
- Conditions the study is for
- Neurocognitive Dysfunction
- What is being tested?
- Xenon
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 29 participants
- Where
- 1 siteUnited States
- Study dates
- Apr 2016to 1 Dec 2021
- Phase
- Phase 2
- Are there results?
- Yes, posted in the registrySummary in the doctors' view
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 20 to 40 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- Healthy volunteers ages 20-40 years old
- American Society of Anesthesiologists (ASA) Physical Status I or II (i.e. healthy)
- Body Mass Index <30 kg/m2
- Easily visible uvula
Who cannot join
- Any physical signs that would suggest a difficult airway (e.g. mouth opening <3cm, short distance between the chin and neck, poor mandibular subluxation, thick neck)
- History of reactive airway disease
- Current or history of neuropsychiatric disorders
- History or current use of psychotropic medications,
- History or current obstructive sleep apnea
- Current or history of cardiovascular disease or arrhythmias,
Show all 17Show fewer
- Current or history of chronic sleep disorders
- History of postoperative nausea/vomiting
- Family history of problems with anesthesia (including but not limited to malignant hyperthermia),
- Current or history of Motion sickness
- Current tobacco use
- Current pregnancy or currently breastfeeding
- Positive urine toxicology screen
- History of seizure disorder, head injury, or brain tumor
- Alcohol consumption greater than 12 drinks per week or more than 4 drinks on any single day
- Inability to provide informed consent
- Inability to achieve mask seal on intervention day
Trial locations and contacts
1 site in 1 country.
United States1 site
University of Pennsylvania, Perelman School of Medicine
Philadelphia, Pennsylvania, 19104
About this study
The dual objectives of this study are to determine if the phenomenon of neural inertia is present in humans and to determine whether the order of neurocognitive function is invariant among anesthetic agents. This study will enroll 24 healthy volunteers, ages 20-40 years, who will receive xenon gas (concentrations ranging from 0% to 60%) delivered via inhaled route through the ENHANCER 3000.
Read the detailed description
This is a multimodal, nonrandomized study of healthy subjects. After meeting enrollment criteria, subjects will receive a baseline neurocognitive testing on a computer for 15 minutes and will then receive a wrist watch actigraphy device to record their rest/activity patterns over 8-14 days. On the study day (roughly two weeks later), repeat baseline neurocognitive testing will be performed after subjects are fitted with a high density EEG head cap. The actual intervention (delivery of inhaled xenon gas in stepwise increasing followed by decreasing doses) should occur over 2 hours along with verbal tests to assess the presence/absence of consciousness at each xenon concentration. Xenon doses have been chosen specifically to evaluate the point at which individuals lose and then regain consciousness. Doses are escalated up through those used in human anesthesiology (75%) that permit surgery. After exposure, serial neurocognitive testing will occur every 30 minutes for 3 hours post emergence. Subjects are discharged from the study's intervention day to home only upon reaching standard post-anesthesia care unit criteria (modified Aldrete score ≥9). A post-procedure follow up phone call will occur within 24 hours of anesthetic exposure to ensure that the subject remains well. The individual's involvement is completed upon returning the Actigraphy watch 1 week after the exposure day. The expected duration of subject participation is up to 3 weeks.
- Conditions
- Neurocognitive Dysfunction
- Being tested
- Xenon
- Keywords
- neurocognitive function, neural inertia, xenon gas
- Medical subject headings
- Cognition Disorders
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
XenonDrug
drug given in concentrations of 0% to 60% over period of 2 hours
| Study group | Role | What they receive |
|---|---|---|
| Xenon | Experimental | Xenon anesthesia to determine if neural inertia is present in humans as visualized by CT imaging. Receives: Drug: Xenon |
What is being measured
The primary outcome is the main question the study is designed to answer.
Xenon Concentrations at Which Consciousness is Lost and Regained
To determine in healthy human volunteers if the brain concentrations of xenon (as determined by CT imaging) are identical at the point of loss and return of consciousness. If the values are significantly different, then we conclude that there is evidence for hysteresis in circuits regulating arousal.
Measured: 4 hours
Secondary outcomes (3)
Neurocognitive Recovery Upon Emergence From Xenon as Measured by Neurocognitive Battery Testing
To determine if the order of neurocognitive recovery upon emergence from xenon general anesthesia is sequential or simultaneous and if the former is true to determine if the pattern is identical to that of isoflurane (as measured in a previously completed study (PMID: 33970101).
Measured: 4 hours
Effects of Xenon on Gross Rest / Activity as Measured Using Wristwatch Actigraphy
To determine if transient exposure to xenon anesthesia induces a change in rest-activity rhythms (as measured from actigraphy) as has been previously reported for isoflurane. The plan was to collect wrist actigraphy for 1 week before the xenon exposure day and for 1 week following the xenon exposure day. Wrist actigraphy data would be fit with a cosinar analysis function (see Fig 5 from our previous work, PMID: 33970101).
Measured: 1 week prior to xenon exposure and 1 week post xenon exposure
Effects of Xenon on Brain Electrical Activity as Measured by EEG Delta Power
EEG delta power was modeled as a function of estimated brain xenon concentration using nonlinear sigmoidal dose-response curves. Two models were evaluated:
- a single curve fit to combined induction (increasing xenon concentration) and emergence (decreasing xenon concentration) data, and
- separate curves fit to induction and emergence phases.
Model fit was compared using Akaike Information Criterion (AIC) to assess whether a single (model 1) or phase-specific relationship (model 2) best described the data. Smaller Akaike Information Criterion values indicate a more likely model fit. Typically AIC differences greater than 4 are considered significant.
Measured: 4 hours
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted11 May 2016 (estimated)
- Study startApr 2016
- Primary completion1 Dec 2019
- Study completion1 Dec 2021
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
- Other trials for Neurocognitive DysfunctionStudies of the same condition, open and under way.
- More trials run by University of PennsylvaniaThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 2
- Primary purpose
- Basic science
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Enrolment
- 29 participants (actual)
Sponsor and investigators
- Lead sponsor
- University of Pennsylvania
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
- Investigators
- Maz B Kelz, MD, PhD, Principal investigator, University of Pennsylvania
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT02768727
- Sponsor's protocol ID
- 824229
- Status last verified
- Aug 2026
- First submitted
- 15 Apr 2016
- Last updated
- 31 Aug 2026
- Results posted
- Yes, on ClinicalTrials.gov
- Data monitoring committee
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 31 Aug 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Test of Neural Inertia in Humans With Xenon
- ClinicalTrials.gov ID
- NCT02768727
- Acronym / sponsor ID
- 824229
- Conditions
- Neurocognitive Dysfunction
- Keywords
- neurocognitive function, neural inertia, xenon gas
- Phase
- Phase 2
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 29 participants (actual)
- Lead sponsor
- University of PennsylvaniaUniversity, hospital or other
- Study start
- Apr 2016
- Primary completion
- 1 Dec 2019 (actual)
- Study completion
- 1 Dec 2021 (actual)
- First posted
- 11 May 2016 (estimated)
- Results
- Posted 31 Aug 2026
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The dual objectives of this study are to determine if the phenomenon of neural inertia is present in humans and to determine whether the order of neurocognitive function is invariant among anesthetic agents. This study will enroll 24 healthy volunteers, ages 20-40 years, who will receive xenon gas (concentrations ranging from 0% to 60%) delivered via inhaled route through the ENHANCER 3000.
Detailed description
This is a multimodal, nonrandomized study of healthy subjects. After meeting enrollment criteria, subjects will receive a baseline neurocognitive testing on a computer for 15 minutes and will then receive a wrist watch actigraphy device to record their rest/activity patterns over 8-14 days. On the study day (roughly two weeks later), repeat baseline neurocognitive testing will be performed after subjects are fitted with a high density EEG head cap. The actual intervention (delivery of inhaled xenon gas in stepwise increasing followed by decreasing doses) should occur over 2 hours along with verbal tests to assess the presence/absence of consciousness at each xenon concentration. Xenon doses have been chosen specifically to evaluate the point at which individuals lose and then regain consciousness. Doses are escalated up through those used in human anesthesiology (75%) that permit surgery. After exposure, serial neurocognitive testing will occur every 30 minutes for 3 hours post emergence. Subjects are discharged from the study's intervention day to home only upon reaching standard post-anesthesia care unit criteria (modified Aldrete score ≥9). A post-procedure follow up phone call will occur within 24 hours of anesthetic exposure to ensure that the subject remains well. The individual's involvement is completed upon returning the Actigraphy watch 1 week after the exposure day. The expected duration of subject participation is up to 3 weeks.
Study design
- Primary purpose
- Basic science
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| Xenon | Experimental | Drug: XenonXenon anesthesia to determine if neural inertia is present in humans as visualized by CT imaging. |
Who may qualify
- Ages
- 20 to 40 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (4 listed)
- Healthy volunteers ages 20-40 years old
- American Society of Anesthesiologists (ASA) Physical Status I or II (i.e. healthy)
- Body Mass Index <30 kg/m2
- Easily visible uvula
Key exclusion criteria (17 listed)
- Any physical signs that would suggest a difficult airway (e.g. mouth opening <3cm, short distance between the chin and neck, poor mandibular subluxation, thick neck)
- History of reactive airway disease
- Current or history of neuropsychiatric disorders
- History or current use of psychotropic medications,
- History or current obstructive sleep apnea
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Xenondrug given in concentrations of 0% to 60% over period of 2 hours | Drug | Xenon |
Primary outcome
Xenon Concentrations at Which Consciousness is Lost and Regained
Time frame: 4 hours
To determine in healthy human volunteers if the brain concentrations of xenon (as determined by CT imaging) are identical at the point of loss and return of consciousness. If the values are significantly different, then we conclude that there is evidence for hysteresis in circuits regulating arousal.
3 secondary outcomes
Neurocognitive Recovery Upon Emergence From Xenon as Measured by Neurocognitive Battery Testing
Time frame: 4 hours
Effects of Xenon on Gross Rest / Activity as Measured Using Wristwatch Actigraphy
Time frame: 1 week prior to xenon exposure and 1 week post xenon exposure
Effects of Xenon on Brain Electrical Activity as Measured by EEG Delta Power
Time frame: 4 hours
Results and safety
Loading the posted results from ClinicalTrials.gov…
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 31 Aug 2026.
- Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Maz B Kelz, MD, PhD principal investigator
University of Pennsylvania
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 2 study testing Xenon in people with Neurocognitive Dysfunction, run by University of Pennsylvania at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 4 inclusion and 17 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 31 Aug 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
Yes. Results are posted in the registry (first posted 31 Aug 2026). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Xenon Concentrations at Which Consciousness is Lost and Regained (time frame: 4 hours). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 31 Aug 2026.