Cortical Excitability and Decision Making After Total Sleep Deprivation and Sleep Restriction

Study Overview
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Brief Summary
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The investigators examine changes in decision making, vigilance and cortical excitability in healthy male subjects undergoing total acute sleep deprivation (40 hours) on the one hand, and chronic partial sleep restriction (7 nights with 5 instead of 8 hours in bed per night) on the other hand, in a cross over controlled manner. The investigators hypothesize that total sleep deprivation, as well as partial sleep restriction lead to impairments in decision making and vigilance, and enhanced cortical excitability. Beside these three primary outcomes, the investigators also assess changes in sleep by EEG, dim light melatonin onset, skin temperature, subjective mood and sleepiness, working memory, and also collect saliva samples.

Conditions
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Acute and Partial Sleep Deprivation

Intervention / Treatment
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* Behavioral: Sleep Deprivation


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Male (in female subjects, menstrual cycle influences sleep) Age between 18-35 years Right-handedness Good general health Signed Informed Consent after being informed Exclusion Criteria: Contraindications on ethical grounds Clinically significant concomitant disease states (e.g., renal failure, hepatic dysfunction, cardiovascular disease, etc) Known or suspected non-compliance, drug or alcohol abuse (> 5dl wine/ >1l beer daily) Regular medication intake Enrolment into a clinical trial within last 4 weeks History of seizure or a family history of epilepsy Diseases or lesions of the nervous system (acute or residual included neurological and psychiatric diseases) History of any moderate or heavy head trauma Sleep disorders (e.g. Insomnia, sleep apnea, restless leg syndrome, narcolepsy, etc.) Sleep complaints in general or EDS Irregular sleep-wake rhythm (e.g. shift working) Long (> 9 hours per night) or short sleepers (< 7hours per night) Sleep efficiency ≤ 80% Travelling with time lag less than 1 month ago (or planning to do so within 1 month prior to the study) Body Mass Index < 19 or > 30 kg/m2 5 drinks or food items containing caffeine per day 10 cigarettes per day Student of one of the following subjects: Mathematics, Physics, Computer Science, Economics, or Psychology (since students of these subjects have profound knowledge of probability calculations, which could interfere with our measurements in decision making) The following additional exclusion criteria apply only to subjects with TMS sessions History of frequent and/or heavy headache respectively migraine History of claustrophobia Hearing disorder Magnetic Resonance Imaging (MRI) contraindication (such as pacemaker implanted pumps, shrapnel, etc.; full MRI screening form will be filled out - see -Entrance questionnaires) No clear TMS evoked potential in the target area during the screening assessment These subjects will be invited to participate in the study with no TMS sessions, the other protocol being identical

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 35 Years

Sexes Eligible for Study
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Male

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: SDSR<br>first total then partial Sleep deprivation | Behavioral: Sleep Deprivation<br> <br> |
| Experimental: SRSD<br>first partial then total Sleep deprivation | Behavioral: Sleep Deprivation<br> <br> |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in cortical excitability after Chronic Sleep Deprivation as measured by TMS evoked responses in the EEG | amount of activation in the electroencephalography (EEG) evoked by single-pulse transcranial magnetic stimulation (TMS) | Change from Baseline to after 7 nights of chronic Sleep Deprivation | 
| Change in Reaction Times after Chronic Sleep Deprivation as measured by the Psychomotor Vigilance Task | Reaction times in the Psychomotor vigilance task | Change from Baseline to after 7 nights of chronic Sleep Deprivation | 
| Change in risk taking and financial impulsivity as measured by the Amount of risky options chosen in the risk task and the amount of financial impulsive choices in the Delay Discount Task | Risk Task (adapted from Levy et al.) Delay Discounting Task (Kirby et al.) | Change from Baseline to after 7 nights of chronic Sleep Deprivation | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Slow Wave Activity during Sleep as measured by the power in the EEG in the frequency range of 1-4.5 Hz | Slow wave activity recorded during the night in the electroencephalography | Baseline, 1st Recovery Night of total Sleep Deprivation, 5th, 6th, 7th night of partial Sleep Deprivation, 1st Recovery Night from partial Sleep Deprivation | 
| Dim Light Melatonin Onset as measured by the melatonin concentration in hourly collected saliva samples | Melatonin concentration curve in saliva samples collected hourly prior to going to bed | Baseline, 1st evening after partial Sleep Deprivation, 7th to 14th evening after partial Sleep Deprivation | 
| Skin Temperature profiles as measured by skin temperature sensors (Celsius) | Skin temperature (Celsius) is measured every 5 minutes | from 1 week prior to partial Sleep Deprivation to 8-14 days after | 
| Mood ratings as measured by a visual analog scale | Mood Ratings from 1-10 | 2 Baseline Days (prior to both parts), 1st Day of total Sleep Deprivation, 1st Day of Recovery from total Sleep Deprivation, 6th, 7th & 8th Day of partial Sleep Deprivation, 8th to 14th Day of Recovery from partial Sleep Deprivation | 
| subjective sleepines as measured by the stanford sleepiness scale | Stanford sleepiness scale | 2 Baseline Days (prior to both parts), 1st Day of total Sleep Deprivation, 1st Day of Recovery from total Sleep Deprivation, 6th, 7th & 8th Day of partial Sleep Deprivation, 8th to 14th Day of Recovery from partial Sleep Deprivation | 
| Working Memory performance as measured by errors of comission and omission the n-back Task | 2-back and 3-back task: measures of comission and omission | 2 Baseline Days (prior to both parts), 1st Day of total Sleep Deprivation, 1st Day of Recovery from total Sleep Deprivation, 6th, 7th & 8th Day of partial Sleep Deprivation, 8th to 14th Day of Recovery from partial Sleep Deprivation | 
| metabolic profile as measured by metabolites in saliva | Screening for metabolites that are changes due to sleep loss | Baseline Day 1, 1st Day of total Sleep Deprivation, 8th Day of partial Sleep Deprivation |