An arousal is a abrupt shift in EEG frequency during sleep, lasting between 3 and 15 seconds. It may include alpha, theta, or beta activity (but not spindles). Frequent micro-arousals fragment sleep, leading to severe daytime sleepiness, and are commonly caused by Obstructive Sleep Apnea (OSA) or Periodic Limb Movement Disorder (PLMD). Sleep-Related Epilepsy
Waveform | Frequency (Hz) | Amplitude | Associated Clinical State -----------|----------------|-----------------|--------------------------------- Beta (β) | 13 – 30 Hz | Low (< 20 µV) | Active thinking, focus, eyes open Alpha (α) | 8 – 12 Hz | Medium (20-60µV)| Relaxed wakefulness, eyes closed Theta (θ) | 4 – 7 Hz | Variable | Light sleep (N1, N2), drowsiness Delta (δ) | 0.5 – 4 Hz | High (> 75 µV) | Deep sleep (N3 / Slow-Wave Sleep) Specialized Sleep Waveforms
According to the AASM (American Academy of Sleep Medicine), sleep is divided into N1, N2, N3 (NREM), and REM. eeg and sleep physiology ppt
A full sleep cycle lasts ~90 minutes; 4–6 cycles occur per night.
Relaxed wakefulness with eyes closed (attenuates when eyes open). 4 – 7 Hz Drowsiness, light sleep, and deep relaxation. Delta ( ) 0.5 – 3.5 Hz Deep, slow-wave sleep; high amplitude ( 3. The Architecture of Sleep: Macro and Micro An arousal is a abrupt shift in EEG
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Distinct bursts of 11–16 Hz activity (most commonly 12–14 Hz) lasting at least 0.5 seconds. They are the hallmark of Stage N2 sleep and represent thalamocortical gating. Sleep-Related Epilepsy Waveform | Frequency (Hz) | Amplitude
Dominant during relaxed wakefulness with eyes closed.
When designing a presentation on sleep physiology, dedicating a section to pathology bridges the gap between basic science and clinical medicine.
High muscle tone (EMG) and frequent voluntary eye movements or blinks (EOG). Stage N1: Transition to Sleep (Light Sleep)
