Effects of Brain Stimulation During Nocturnal Sleep on Memory Consolidation in Elderly Healthy Subjects

Study Overview
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Brief Summary
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The beneficial effect of nocturnal sleep on memory consolidation is well-documented 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. Recent evidence in young healthy subjects suggest that the sleep-associated 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 SWS. If elderly, healthy subjects benefit from transcranial slow oscillatory stimulation (tSOS) during nocturnal sleep as well has not been studied so far. The primary aim of the present study is to investigate the influence of a weak slow oscillating brain stimulation (tSOS) on declarative memory consolidation applied during periods of nocturnal SWS in elderly healthy subjects.

Official Title
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Impact of Transcranial Slow Oscillating Stimulation on Memory Consolidation During Nocturnal Slow Wave Sleep in Elderly Healthy Subjects

Conditions
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Elderly Subjects

Intervention / Treatment
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* Device: Stimulation
* Device: SHAM


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: elederly, healthy Subjects unobtrusive, neuropsychological screening age: 50-90 years right handed Exclusion Criteria: untreated severe internal or psychiatric diseases epilepsy other severe neurological diseases eg., previous major stroke, brain tumour, dementia contraindications to MRI

Ages Eligible for Study
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Minimum Age: 50 Years
Maximum Age: 90 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: 0,75 Hz stimulation<br>slow transcranial oscillating stimulation ( 0,75Hz) during periods of Slow Wave Sleep | Device: Stimulation<br> <br> * Other names: oscillating direct current brain stimulation;|
| Sham Comparator: SHAM stimulation<br>SHAM stimulation during periods of Slow Wave Sleep | Device: SHAM<br>* no 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, spindels, eeg-correlates, further memory systems | Amount of slow wave sleep assessed by standard polysomnographic criteria in 0,75 Hz vs SHAM stimulation during SWS. Spindel activity during sleep indicated via several spindel parameters like number, duration, frequency of spindles; compared between 0,75 Hz and SHAM stimulation during SWS. 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). 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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old Subjects, Controls, brain stimulation, tSOS, tDCS, sleep, memory, memory consolidation