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Consciousness, Level AlteredPhase 4LOC-2013NCT01889004

The Neural Mechanisms of Anesthesia and Human Consciousness

A Phase 4 study testing Dexmedetomidine and Propofol in people with Consciousness, Level Altered, run by University of Turku at 1 site in Finland.

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Official record
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Trial summary

The explanation of consciousness poses one of the greatest challenges to science and philosophy in the 21st century. It remains unclear what consciousness is and how it emerges from brain activity. Read more about this study

Who is it for?
Ages 20 to 30 years, men onlyHealthy volunteers can take part
Conditions the study is for
Consciousness, Level Altered
What is being tested?
Dexmedetomidine and Propofol
Type of treatment
Injection or infusion
Could I receive a placebo?
No, everyone receives an active treatment
How many people
47 participants
Where
1 siteFinland
Study dates
Feb 2014to Jan 2016
Phase
Phase 4
Are there results?
None posted in the registry

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 30 years
  • Men only
  • Healthy volunteers accepted
  • Adult

Who may be able to join

  • Male
  • Age 20-30 years
  • Good general health i.e. American Society of Anesthesiologists (ASA) physical status I
  • Fluent in Finnish language
  • Right handedness
  • Written informed consent
  • Good sleep quality

Who cannot join

  • Chronic medication
  • History of alcohol and/or drug abuse
  • Strong susceptibility for allergic reactions
  • Serious nausea in connection with previous anesthesia
  • Strong susceptibility for nausea
  • Any use of drugs or alcohol during the 48 hours preceding anesthesia
Show all 19Show fewer
  • Use of caffeine products 10-12 hours prior the study, 24 hours before sleep studies
  • Smoking
  • Clinically significant previous cardiac arrhythmia / cardiac conduction impairment
  • Clinically significant abnormality in prestudy laboratory tests
  • Positive result in the drug screening test
  • Blood donation within 90 days prior to the study
  • Participation in any medical study with an experimental drug or device during the preceding 60 days
  • The study subject has undergone a prior PET or SPECT study
  • Any contraindication to magnetic resonance imaging (MRI)
  • Hearing impairment
  • Detected unsuitability based on initial electrophysiological measurements
  • Detected unsuitability based on MRI scanning results
  • Sleep disorder or severe sleep problem

Trial locations and contacts

1 site in 1 country.

Finland1 site

  • Turku PET Centre

    Turku, FI-20521

Other trials in Finland

About this study

Official title: The Neural Mechanisms of Anesthesia and Human Consciousness (LOC-2013)

The explanation of consciousness poses one of the greatest challenges to science and philosophy in the 21st century. It remains unclear what consciousness is and how it emerges from brain activity. By studying anesthesia and sleep, the investigators aim to reveal what happens in the brain when consciousness is lost and when it returns. During the study, a series of Positron Emission Tomography (PET), Magnetic Resonance Imaging (MRI) and electroencephalography (EEG) studies will be carried out on healthy male subjects to reveal the neural correlates of consciousness. Consciousness of the subjects will be manipulated with normal sleep and anesthetic agents dexmedetomidine and propofol.

First, various neurophysiological tools to separate consciousness, connectedness and responsiveness during normal sleep will be tested. The most suitable methods and subjects will be selected and then tested during anesthetic-induced sedation and loss of responsiveness (LOR). The anesthetics (dexmedetomidine or propofol) will be administered as target-controlled infusions (TCI) with step-wise concentration-increments until LOR is detected. Then, TCIs are repeated in the same subjects but adjusted according to the individual drug target concentrations sufficient for LOR, and a series of PET perfusion imaging measurements will be performed to obtain the brain activity information in various states of consciousness. The same subjects will then be imaged with PET for brain activity after sleep deprivation (awake), during various sleep stages and immediately after awakening. Finally, ten dexmedetomidine subjects will be given the drug once more, and functional MRI (fMRI) data will be collected at various states of consciousness before and during verbal and nonverbal vocalizations. EEG will be continuously collected in all sessions. The depth of anesthesia will be measured using quantitative EEG and bispectral index (BIS) monitoring.

The results may lead to the discovery of new and better objective indicators of the depth of anesthesia and consciousness, and new insights into the understanding of neural mechanisms behind drug-induced loss of consciousness and ultimately the mechanisms of action of (general) anesthetics as well as consciousness itself.

Read the detailed description

(not needed)

Keywords
Cerebral blood flow, Consciousness, Dexmedetomidine, EEG, Event related potentials, Functional magnetic resonance imaging, General anesthesia, Positron emission tomography, Propofol
Medical subject headings
Consciousness Disorders

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • DexmedetomidineDrug

    Also called Dexdor

    Escalating concentrations until loss of responsiveness

  • PropofolDrug

    Also called Propofol-Lipuro

    Escalating concentrations until loss of responsiveness

Study groups in NCT01889004
Study groupRoleWhat they receive
DexmedetomidineExperimentalIntravenous dexmedetomidine using target controlled infusion
Receives: Drug: Dexmedetomidine
PropofolExperimentalIntravenous propofol using target controlled infusion
Receives: Drug: Propofol

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Regional cerebral blood flow

    Altogether 14 PET scans during two separate study days. Cerebral blood flow changes will be used as surrogates for changes in regional brain activity.

    Measured: Several measurements during two separate days within 2 months

Secondary outcomes (3)

  1. EEG

    Measured: Continuous data collection during five separate days within 2 months

  2. Functional magnetic resonance imaging (fMRI)

    Measured: Several measurements during one day

  3. Event related potentials

    Measured: Several time points during five separate days within 2 months

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted28 Jun 2013 (estimated)
  2. Study startFeb 2014
  3. Primary completionJan 2016
  4. Study completionJan 2016

Resources

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 4
Primary purpose
Basic science
Allocation
Randomised
Intervention model
Parallel groups
Masking
None (open label)
Enrolment
47 participants (actual)
IDs, dates and publications
ClinicalTrials.gov ID
NCT01889004
Sponsor's protocol ID
LOC-2013
Other IDs
266467, 2013-001496-21, KLnro 72/2013
Acronym
LOC-2013
Status last verified
Jan 2016
First submitted
23 Jun 2013
Last updated
11 Jan 2016
Results posted
No
Data monitoring committee
No

Publications

  • Langsjo JW, Alkire MT, Kaskinoro K, Hayama H, Maksimow A, Kaisti KK, Aalto S, Aantaa R, Jaaskelainen SK, Revonsuo A, Scheinin H. Returning from oblivion: imaging the neural core of consciousness. J Neurosci. 2012 Apr 4;32(14):4935-43. doi: 10.1523/JNEUROSCI.4962-11.2012.

    PubMed 22492049

  • Valli K, Radek L, Kallionpaa RE, Scheinin A, Langsjo J, Kaisti K, Kantonen O, Korhonen J, Vahlberg T, Revonsuo A, Scheinin H. Subjective experiences during dexmedetomidine- or propofol-induced unresponsiveness and non-rapid eye movement sleep in healthy male subjects. Br J Anaesth. 2023 Aug;131(2):348-359. doi: 10.1016/j.bja.2023.04.026. Epub 2023 May 31.

    PubMed 37268445

  • Kallionpaa RE, Valli K, Scheinin A, Langsjo J, Maksimow A, Vahlberg T, Revonsuo A, Scheinin H, Mashour GA, Li D. Alpha band frontal connectivity is a state-specific electroencephalographic correlate of unresponsiveness during exposure to dexmedetomidine and propofol. Br J Anaesth. 2020 Oct;125(4):518-528. doi: 10.1016/j.bja.2020.05.068. Epub 2020 Aug 7.

    PubMed 32773216

  • Kallioinen M, Scheinin A, Maksimow M, Langsjo J, Kaisti K, Takala R, Vahlberg T, Valli K, Salmi M, Scheinin H, Maksimow A. The influence of dexmedetomidine and propofol on circulating cytokine levels in healthy subjects. BMC Anesthesiol. 2019 Dec 5;19(1):222. doi: 10.1186/s12871-019-0895-3.

    PubMed 31805854

  • Kallionpaa RE, Scheinin A, Kallionpaa RA, Sandman N, Kallioinen M, Laitio R, Laitio T, Kaskinoro K, Kuusela T, Revonsuo A, Scheinin H, Valli K. Spoken words are processed during dexmedetomidine-induced unresponsiveness. Br J Anaesth. 2018 Jul;121(1):270-280. doi: 10.1016/j.bja.2018.04.032. Epub 2018 May 23.

    PubMed 29935582

  • Radek L, Kallionpaa RE, Karvonen M, Scheinin A, Maksimow A, Langsjo J, Kaisti K, Vahlberg T, Revonsuo A, Scheinin H, Valli K. Dreaming and awareness during dexmedetomidine- and propofol-induced unresponsiveness. Br J Anaesth. 2018 Jul;121(1):260-269. doi: 10.1016/j.bja.2018.03.014. Epub 2018 May 10.

    PubMed 29935581

Questions about this trial

What is this clinical trial studying?

A Phase 4 study testing Dexmedetomidine and Propofol in people with Consciousness, Level Altered, run by University of Turku at 1 site in Finland.

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 7 inclusion and 19 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 11 Jan 2016. 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 Finland. 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 4 studies take place after a treatment is approved, to learn more about its long-term benefits and risks in everyday use.

Not every study follows the same path, and some studies (observational studies, device studies) have no phase.

Are results available for this study?

The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.

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?

Regional cerebral blood flow (time frame: Several measurements during two separate days within 2 months). It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT01889004, which also lists 6 linked publications.

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 11 Jan 2016.

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