Normal sleep stage แพทย์หญิง กาญจนา พิทักษ์วัฒนานนท์ อายุรแพทย์ผู้เชี่ยวชาญระบบประสาท แพทย์ประจำศูนย์สมอง โรงพยาบาลสมิติเวชศรีราชา

Why sleep ? Brain development Memory / cognition / long term potential Immunity Conservation energy Repair & Restoration

Sleep hygiene Regular sleep time Proper sleep environment Stimulation control Avoidance of time in bed worrying Avoidance of poorly timed alcohol and caffeine Regular exercise but not within 3 hours of bedtime Wind-down time Late-night high-tryptophan snack

Circadian clock Human circadian clock generates a rhythm slightly longer than 24 hours when it has no external cue to set it. Most people can adjust to 23- or 25- hour day but not to a 22- or 28- hour day. Bright light late in the day can lengthen the circadian rhythm.

Duration of sleep Circadian rhythm Circadian clock Zeitgeber Circannual rhythm The purpose of the circadian rhythm is to keep our internal workings in phase with the outside world. Light is critical for periodically resetting our circadian rhythms. A zeitgeber is a term used to describe any stimulus that resets the circadian rhythms. Exercise, noise, meals, and temperature are others zeitgebers.

Light & sleep : suprachiasmatic nucleus

SCN Mechanisms of the circadian rhythms include the following: The Suprachiasmatic nucleus. Genes that produce certain proteins. Melatonin levels.

Biological clock Physiological pathway of the biological clock: Light levels  retina  suprachiasmatic nucleus of hypothalamus  pineal gland  secretion of melatonin

The suprachiasmatic nucleus (SCN) is part of the hypothalamus and the main control center of the circadian rhythms of sleep and temperature.

Biological clock

Go East : Phase advance

Electroencephalographic rhythms

Brain waves

Brain waves : frequency 0.15-0.3 Hz - depression 4.5-6.5 Hz - wakeful dreaming, vivid images 4-8 Hz - dreaming sleep, deep meditation, subconscious mind 5.0-10.0 Hz - relaxation 5.8 Hz - dizziness 7 Hz - increased reaction time 8.6-9.8 Hz - induces sleep, tingling sensations 15.0-18.0 Hz - increased mental ability 18 Hz - significant improvements in memory 55 Hz - Tantric yoga

Benefit of meditation Meditation = practices that train attention to heighten awareness and bring mental processes under greater voluntary control Yoga, Zen, transcendental meditation (TM) Potential physiological benefits Similar to effective relaxation procedures

Polysomnography : PSG EEG ( electro-encephalography ) EOG ( electro-oculograms ) Chin EMG ( electro-myograms ) Left & Right anterior tibialis EMG Intercostal EMG ECG ( electro-cardiogram ) Pulse oximetry ( oxygen saturation ) Nasal & Oral thermistors ( airflow ) Chest & Abdominal strain guages

Polysomnography : PSG

Sleep cycle / Hypnogram

Awake EEG: - rhythmic alpha waves (8-12Hz) // only if the eyes are closed - beta waves (20-30Hz) EOG: - eye movement (observation process) EMG: - continual tonically activity of muscles

Sleep stage I : NREM I Loss of eye blink Attenuation of Alpha rhythm Slow rolling eye movements Fronto central Theta activity Increased Beta activity Vertex waves

NREM1 sleep EEG: - the absence of alpha activity - Vertex sharp waves EOG: - slow eye movement EMG: - relatively lower amplitude

Sleep stage II : NREM II Sleep spindles K complexes Vertex waves Brief , 12 – 16 Hz , synchronous bursts of activity , usually maximal in the central , or less commonly frontal , regions K complexes Often accompany sleep spindles . A sharp negative wave followed by a high-voltage slower wave Vertex waves Named for tendency to phase reverse in central regions. Sharp waves May occur in trains K complexs & Vertex waves may result from brief sleep disturbances

NREM2 sleep EEG: - sleep spindles (oscillating with the frequency between 12-15 Hz) - K-complexes (high voltage, sharp rising and sharp falling wave) - relatively low voltage mixed frequency EOG: - the absence eye movements EMG: - constant tonic activity

Sleep stage III : NREM III > 20 % but < 50 % of the background rhythm is Delta activity

NREM3 sleep EEG: - consists of high-voltage (>=75uV) - slow delta activity (<=2 Hz) // electrodes Fpz-Cz or Pz-Oz EOG: - the absence eye movement - delta waves from EEG EMG: - low tonic activities

Sleep stage IV : NREM IV > 50% of the background rhythm is Delta activity

REM sleep Bursts of rapid eye movement Loss of muscle activity “ Desynchronization ” of the background rhythm. The predominant delta rhythm of slow wave ( stage III & IV ) sleep is replaced by faster frequency ( beta and theta ) rhythms normally seen during the wakeful state. Sawtooth waves

REM sleep EEG: - relatively low voltage - mixed frequency EOG: - contains rapid eye movements EMG: - tonically suppressed (Sleep Paralysis)

Hypnogram / Sleep cycle

Brain development : REM

Dream : REM

Why dream ?

Sleep disorder Insomnia – difficulty falling or staying asleep Narcolepsy – falling asleep uncontrollably Sleep Apnea – reflexive gasping for air that awakens Nightmares – anxiety arousing dreams – REM Night Terrors – intense arousal and panic – NREM Somnambulism – sleepwalking

Sleep disorder