No medical condition or disease involved. The study subjects are healthy volunteers.
Conditions
Sponsors
Harry Scheinin
Eligibility
Sex/Gender
Male
Inclusion criteria
Inclusion criteria: Healthy male volunteers will be considered eligible for the study. The subjects must meet all of the following criteria: 1. Male 2. Age 20–30 years 3. Good general health i.e. American Society of Anesthesiologists (ASA) physical status I 4. Fluent in Finnish language 5. Right handedness 6. Written informed consent 7. Good sleep quality Are the trial subjects under 18? no Number of subjects for this age range: F.1.2 Adults (18-64 years) yes F.1.2.1 Number of subjects for this age range 40 F.1.3 Elderly (>=65 years) no F.1.3.1 Number of subjects for this age range
Exclusion criteria
Exclusion criteria: The subject must be excluded if any of the following criteria are met: 1. Chronic medication 2. History of alcohol and/or drug abuse 3. Strong susceptibility for allergic reactions 4. Serious nausea in connection with previous anesthesia 5. Strong susceptibility for nausea 6. Any use of drugs or alcohol during the 48 hours preceding anesthesia 7. Use of caffeine products 10–12 hours prior the study, 24 hours before sleep studies 8. Smoking 9. Clinically significant previous cardiac arrhythmia / cardiac conduction impairment 10. Clinically significant abnormality in prestudy laboratory tests 11. Positive result in the drug screening test 12. Blood donation within 90 days prior to the study 13. Participation in any medical study with an experimental drug or device during the preceding 60 days 14. The study subject has undergone a prior PET or SPECT study 15. Any contraindication to magnetic resonance imaging (MRI) 16. Hearing impairment 17. Detected unsuitability based on initial electrophysiological measurements (Parts 2–5) 18. Detected unsuitability based on MRI scanning results (Parts 3–6) 19. Sleep disorder or severe sleep problem
Design outcomes
Primary
| Measure | Time frame |
|---|---|
| Main Objective: The aim of this study is to reveal what happens in the brain when consciousness is impaired during sleep and during anesthetic-induced sedation, which brain structures are responsible for the most primitive conscious state and what makes our rich conscious experiences possible. Finding tools for the distinction of consciousness, connectedness and responsiveness would be groundbreaking and would represent a major leap forward in the study of human consciousness.;Secondary Objective: Not applicable.;Primary end point(s): Due to the exploratory nature of the study no primary variables are defined. This is explained and justified in the study protocol. Analysis of PET and other data is described in detail in section 11. During the study, a series of Positron Emission Tomography (PET), Magnetic Resonance Imaging (MRI) and electroencephalography (EEG) studies will be carried out on 200–240 healthy male subjects to reveal the neural correlates of consciousness. Consciousness of the subjects will be manipulated with normal sleep and anesthetic agents dexmedetomidine acting through a2-agonism, with propofol and sevoflurane both mainly acting through the enhancement of gamma-aminobutyric acid (GABA) system, and with S-ketamine acting through N-methyl-D-aspartate (NMDA) receptor antagonism. The study consists of six (6) parts. First, various neurophysiological tools to separate consciousness, connectedness and responsiveness during normal sleep will be tested in Part 1. The most suitable methods and subjects will be selected and then tested during anesthetic-induced sedation and loss of responsiveness (LOR) in Part 2. The anesthetics (dexmedetomidine or propofol) will be administered as target-controlled infusions (TCI) with step-wise concentration-increments at 10–20 min intervals until LOR is detected in 40 (20 for dexmedetomidine and 20 for propofol) subjects. In Part 3, the TCIs are repeated in the same 40 subjects but adjusted according to the individual d | — |
Secondary
| Measure | Time frame |
|---|---|
| Secondary end point(s): Not applicable. See E.5.1.;Timepoint(s) of evaluation of this end point: not applicable. See E.5.1. | — |
Countries
Finland
Contacts
Public ContactTurku PET Centre
University of Turku
Outcome results
None listed