Olimex OpenEEG: Difference between revisions

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== Sleep stage identification ==
== Sleep stage identification ==
[[File:Sample Olimex data.jpg|thumb|Sleep stages in Olimex]]
Follow the instructions in the section [https://polysleep.org/wiki/Olimex_OpenEEG#Running_SleepEEGTools_to_mark_sleep|Running SleepEEGTools to mark sleep] to launch the SleepEEGTools program and select a recording. This will open the marking window. From there, you can choose a sleep stage and click on different parts of the spectrogram to mark the stages manually. Once you're finished, click Save and Quit to store your annotations.
If you're unsure about how to mark sleep stages or have atypical recordings, feel free to join our [https://discord.com/invite/2kzXcg7Juf Discord server] and ask for help from experienced community members.
=== Sleep stages ===
As shown in the image, each sleep stage has a distinct pattern. With some practice, you'll be able to recognize these patterns and mark them accurately.
==== Wake/NREM1 ====
These two stages can appear quite similar. The wake state typically looks blank or appears messy with high-frequency activity. NREM1 is also mostly blank, but usually with less high-frequency noise.
==== NREM2/NREM3 ====
NREM2 ([https://en.wikipedia.org/wiki/Non-rapid_eye_movement_sleep#Stages light sleep]) and NREM3 ([https://en.wikipedia.org/wiki/Slow-wave_sleep slow-wave sleep]) are part of a continuum and are primarily differentiated by the amount of delta wave activity. In NREM2, delta waves are present but not dominant. NREM3 is characterized by a significant amount of delta activity, often exceeding 20% of the total brainwave activity.<ref name="nrem" />
Both NREM2 and NREM3 (SWS) show a bold frequency band between 10 and 15 Hz. This band is typically thicker in NREM2 and thinner in SWS. Additionally, SWS tends to show more intense low-frequency activity in the 0–10 Hz range.
==== REM ====
REM sleep is usually easy to identify in the spectrogram, especially within the core of a sleep cycle. REM episodes occur between NREM stages and are marked by a distinctive bow-shaped frequency band around 20–25 Hz near the end of the cycle.
=== Identification in naps ===
[[File:Rem beta.webp|thumb|REM nap, beta waves (20–28 Hz)]]
[[File:Wake.webp|thumb|Awake state, no well-defined beta waves]]
[[File:Nrem1 2.webp|thumb|NREM1 and NREM2 during a nap]]
Distinguishing sleep stages during a nap can be more challenging than during a full night of core sleep, but it is still possible. REM sleep is marked by beta activity, specifically in the 20–28 Hz range<ref name="remnrem" />, which helps identify REM naps.
The wake state appears similar but lacks clearly defined beta waves. It typically looks disorganized, featuring high frequencies without a distinct structure.
NREM naps usually begin with NREM1, which appears mostly blank, similar to wakefulness but with a clearer and more subdued pattern, as shown in the third image. The nap then progresses into NREM2. Both NREM2 and NREM3 are characterized by prominent sigma waves (12–16 Hz)<ref name="remnrem" />. Delta waves (0.3–3 Hz) are also present, being strong in NREM3 and weaker in NREM2.
REM naps are most common in the morning hours (between 3–11 a.m.), while NREM naps tend to occur in the afternoon.


== References == <!--T:3-->  
== References == <!--T:3-->  
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<ref name="skinprep">{{cite web |url=https://thephysiologist.org/study-materials/electrodes-and-interference/ |title=Electrodes and Skin Prep |website=The Student Physiologist |access-date=2025-06-21}}</ref>
<ref name="skinprep">{{cite web |url=https://thephysiologist.org/study-materials/electrodes-and-interference/ |title=Electrodes and Skin Prep |website=The Student Physiologist |access-date=2025-06-21}}</ref>
<ref name="openvibedownload">{{cite web |url=https://openvibe.inria.fr/downloads/ |title=OpenViBE Downloads |website=OpenViBE |access-date=2025-06-21}}</ref>
<ref name="openvibedownload">{{cite web |url=https://openvibe.inria.fr/downloads/ |title=OpenViBE Downloads |website=OpenViBE |access-date=2025-06-21}}</ref>
<ref name="nrem">{{cite web |url=https://neupsykey.com/introduction-to-sleep-and-polysomnography-3/ |title=
Introduction to Sleep and Polysomnography |website=Neupsy Key |access-date=2025-06-22}}</ref>
<ref name="remnrem">{{cite journal |vauthors=Uchida S, Maloney T, Feinberg I |date=1994 |title=Sigma (12–16 Hz) and beta (20–28 Hz) EEG discriminate NREM and REM sleep |journal=Brain Research |volume=659 |issue=1-2 |pages=243-248}}</ref>
}}
}}


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