Effects of Brain Stimulation During Daytime Nap on Memory Consolidation in Younger, Healthy Subjects

Study Overview
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Brief Summary
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The beneficial effect of daytime sleep on memory consolidation has been shown in young, healthy subjects. Especially, periods rich in slow-wave sleep (SWS) have shown a memory enhancing effect on hippocampus-dependent declarative memory. Slow oscillatory activity typically occuring during SWS has been implicated in the consolidation effect. In this study we investigate if the consolidation effect can be amplified by the application of a weak transcranial oscillatory electric current within the frequency range of SWS in humans (0,7-0,8 Hz) during daytime SWS.

Official Title
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Impact of Transcranial Slow Oscillating Stimulation on Memory Consolidation During Daytime Slow Wave Sleep in Younger, Healthy Subjects

Conditions
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Healthy Subjects

Intervention / Treatment
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* Device: brain stimulation
* Device: no stimulation


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: healthy Subjects unobtrusive, neuropsychological screening age: 18-35 years right handed Exclusion Criteria: untreated severe internal or psychiatric diseases epilepsy other severe neurological diseases eg., previous major stroke, brain tumour contraindications to MRI

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

Sexes Eligible for Study
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All

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: Treatment
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: SHAM stimulation<br>SHAM stimulation during periods of Slow Wave Sleep | Device: no stimulation<br>* sham Stimulation<br>|
| Experimental: 0,75 Hz stimulation<br>slow transcranial oscillating stimulation ( 0,75Hz) during periods of Slow Wave Sleep | Device: brain stimulation<br>* oscillating direct current brain stimulation<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Retention of declarative memories after 0.75 Hz stimulation during SWS, vs after sham stimulation during SWS | Retention between stimulation conditions (0.75 Hz during SWS, vs sham stimulation during SWS) in the declarative memory task. | 4 weeks | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Amount of Slow wave Sleep | 1. Amount of slow wave sleep assessed by standard polysomnographic criteria in 0,75 Hz vs SHAM stimulation during SWS. | 4 weeks | 
| 2. sleep spindles | 2. Spindle activity during sleep indicated via several spindle parameters like number, duration, frequency of spindles; compared between 0,75 Hz and SHAM stimulation during SWS. | 4 weeks | 
| 3. EEG-correlates | 3. Neuronal correlates (EEG-power in slow oscillation frequency bands induced by 0,75 Hz vs SHAM stimulation during SWS; EEG-correlates of encoding and retrieval of a declarative memory task). | 4 weeks | 
| 4. further memory systems | 4. Performance in further memory systems (procedural), compared between 0,75 Hz and SHAM stimulation during SWS. | 4 weeks | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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tDCS, sleep, daytime sleep, nap, memory, memory consolidation, young healthy subjects, brain stimulation, tSOS