The primary objective is to investigate the effect of olfactory conditioning during sleep on the circadian-related cortisol awakening response (CAR). Secondarily, we will investigate the effect of the conditioning on physiological parameters (e.g.…
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Brief title
Condition
- Other condition
Synonym
Health condition
Het onderzoek wordt bij gezonde mensen uitgevoerd. Uitkomsten uit deze lijn van onderzoek bieden nieuwe handvatten voor therapeutische interventies voor patiënten met verlate slaap-fase syndroom of seizoensgebonden depressie.
Research involving
Sponsors and support
Intervention
Outcome measures
Primary outcome
The main study parameter is change in the CAR (evocation measurement compared
to baseline measurement) in the experimental compared with the control group.
Secondary outcome
Secondary outcomes are physiological parameters (e.g. HR), and psychological
parameters (e.g. affect).
Background summary
Preliminary evidence suggests that endogenous hormone secretion, such as
cortisol or insulin, might be behaviorally conditionable in humans. With regard
to conditioning of physiological circadian reactions, preliminary evidence is
available in rodents only. It is currently unclear whether it is possible to
condition circadian reactions in humans, but if proven possible, this approach
might be used as a new and minimally invasive treatment method for patients
suffering from dysregulated circadian rhythms, such as delayed-phase sleep
disorder and seasonal affective disorder.
Study objective
The primary objective is to investigate the effect of olfactory conditioning
during sleep on the circadian-related cortisol awakening response (CAR).
Secondarily, we will investigate the effect of the conditioning on
physiological parameters (e.g. heart rate (HR)) and psychological parameters
(e.g. affect). We will also explore the impact of personality and several sleep
parameters (sleep quality and sleep duration) on the conditionability of the
CAR, since these parameters have been shown to affect the size of the CAR.
Study design
A previously validated two-phase randomized controlled conditioning paradigm
will be applied in the home environment of participants. After being screened,
eligible participants will fill in several questionnaires. Participants will be
randomized to either the experimental or the control group on the basis of a
random number sequence, generated before the start of the study. During the
first week of the study all participants will be required to fill in a short
(max 5 minutes) daily diary, assessing among other things sleep parameters.
Besides the diary, participants* sleep-wake cycle will be objectively monitored
during the 1st and 2nd week of the study using the MotionWatch8. As a baseline
measurement for primary and secondary outcome parameters, on Friday morning of
the first week, after regular awakening via an alarm clock, participants will
start with collection of saliva from awakening up to 45 minutes after
awakening, by means of 4 non-invasive cotton sampling measures. They will also
fill in several short questionnaires and they will sleep with an HR sensor for
assessment of the physiological secondary outcomes. In the second week, all
participants are again required to fill in a short daily diary. Moreover, the
first three days (association phase; Monday until Wednesday night),
participants are exposed to a distinctive scent (conditioned stimulus, CS;) by
means of a controlled scent delivery system from thirty minutes before
awakening up to their regular awakening time (via an alarm clock), in order to
associate this scent to the natural steep rise in cortisol levels before
awakening (unconditioned stimulus, US). On Thursday night - one week after the
baseline CAR-assessment to control for weekly activity patterns - participants
will set their alarm clock four hours earlier than their regular awakening time
and either be exposed to the CS (experimental group) or a different distinctive
scent (non-CS; control group) (evocation phase). At this time, their CAR is
again measured in 4 saliva samples. Again, they will also fill in several short
questionnaires. After the last saliva measurement they are allowed to go back
to sleep. During the nights in the association phase and evocation phase,
participants will sleep with an HR sensor for assessment of the physiological
secondary outcomes. In Figure one, a schematic overview of the design is
presented (see section Study Design of the METC protocol).
Intervention
The intervention consists of a conditioning paradigm, in which as association
is learned between a scent and the circadian CAR. See Study design of the
summary for the description of this paradigm.
Study burden and risks
Risks associated with the study protocol are minimal. Participants will report
to university once, after which the remainder of the protocol will be carried
out at home. Participants will be asked to set an alarm clock on their regular
awakening time on four days, and will be woken up four hours before their
regular awakening time during the evocation phase. After the saliva
measurements in the evocation phase, participants will be allowed to sleep
again after 45 minutes. Potential risk of this early awakening (evocation
phase) could be somewhat more fatigue than on other days. The scents are
hypoallergenic and all measures are non-invasive. The controlled scent
technology delivery systems (Air/Q-100 & Air/Q-160, Prolitec Inc., Milwaukee,
WI, US) have received CE-marking. Participants can stop the study at any time
for any reason. Participation entails an approximate total time investment of
five hours. Studying the effects of conditioning of the cortisol awakening
response will shed more light on the possibilities and boundaries of
conditioning circadian-related endocrine parameters. This approach could be
used to potentially shift circadian rhythms, and thus could lead to a new,
minimally invasive treatment for patients suffering from dysregulated circadian
rhythms.
Wassenaarseweg 52
Leiden 2333 AK
NL
Wassenaarseweg 52
Leiden 2333 AK
NL
Listed location countries
Age
Inclusion criteria
* Male gender
* Aged between 21 and 34 years of age
* Good understanding of written and spoken Dutch.
Exclusion criteria
* Refusal to give written informed consent
* Severe somatic or psychiatric conditions that would adversely affect
participant*s safety or that might interfere with the study protocol
* Olfactory impairments
* Known sensitivity or hypervigilance to one of the ingredients of the scents
used in this experiment
* Heavy use of (illegal) drugs including cannabis and habits of heavy drinking
* Irregular sleep pattern or sleep problems
* Use of medication that interferes with the study protocol
* Factors known to influence the CAR:
o Having an acute illness, or experienced an illness in the past seven days
(e.g. influenza, common cold)
o Experienced jet lag or shift work in the past seven days
o Use of (oral) glucocorticoid medication
o HPA-axis related endocrine disorders (e.g., Cushings disease or Addisons
disease)
o Brain damage, particularly hippocampal brain damage
o Obesity
Design
Recruitment
metc-ldd@lumc.nl
metc-ldd@lumc.nl
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Other (possibly less up-to-date) registrations in this register
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In other registers
| Register | ID |
|---|---|
| CCMO | NL62812.058.17 |