14. Sleep-physiology and disorders (K).pptx

sleep physiology

1. SLEEP

2. SLEEP Approximately one-third of our lives Sleep is nature’s way of relaxing our body and recharging our mind. Lack of quality sleep can result in lower quality of life. It is very important to detect and manage sleep related problems at the earliest.

3. Definitions Wakefulness : is a state in which the person is aware of and responds to sensory input from the environment. Sleep : is a state of behavioral quiescence accompanied by an elevated arousal threshold and a species-specific sleep posture (recumbent sleep posture, closed eyes, diminished responsiveness to external stimuli and decrease in or absence of movements)

4. EEG waves alpha activity Smooth electrical activity of 8–12 Hz recorded from the brain; generally associated with a state of relaxation.   beta activity Irregular electrical activity of 13–30 Hz recorded from the brain; generally associated with a state of arousal. theta activity EEG activity of 3.5–7.5 Hz that occurs intermittently during early stages of slow-wave sleep and REM sleep.   delta activity Regular, synchronous electrical activity of less than 4 Hz recorded from the brain; occurs during the deepest stages of slow-wave sleep.

5. Physiology Sleep is non-homogenous: 2 distinct states NREM Sleep Constitutes 80% of sleep duration Stage 1 (5%) is brief transition from wakefulness to sleep Stage 2 (50-55%)- characteristic bursts of 12-16Hz ‘ Sleep spindles ’ and high amplitude 0.5-1 Hz ‘ K-complexes ’. Stage 3 and stage 4 ( Slow Wave Sleep or delta sleep) constitute 20% of sleep duration and has slow 0.5-4Hz high amplitude waves.

6. Sleep is non-homogenous: 2 distinct states REM Sleep Constitutes 20% of sleep duration Tonic REM- hypotonia and EEG desynchroniztion Phasic REM- bursts of REM and myoclonic twitches of facial and limb muslces Like SWS, REM is considered a restorative sleep stage

7. Sleep waves

8. Sleep waves- frequency

9. Ultradian Rhythm Cycling between NREM sleep and REM sleep during the night Typically, 4-6 cycles occur in 90-110 minute intervals The first REM is usually 70 minutes after sleep onset REM duration lengthens in subsequent cycles Longest period of SWS occurs in the first cycle and decreases in the successive cycles

10. Sleep stages during a single night

11. Biological Clock

12. Biological clock Circadian Rhythms and Zeitgebers Zeitgeber ( tsite gay ber ) A stimulus (usually the light of dawn) that resets the biological clock that is responsible for circadian rhythms. Suprachiasmatic nucleus (SCN) A nucleus situated atop the optic chiasm. It contains a biological clock that is responsible for organizing many of the body ’ s circadian rhythms.

13. Circadian Rhythm Pineal gland A gland attached to the dorsal tectum ; produces melatonin and plays a role in circadian and seasonal rhythms. Melatonin A hormone secreted during the night by the pineal body; plays a role in circadian and seasonal rhythms

14. Circadian Rhythm

15. Other Zeitgeber effects (social interactions, alarm clocks, eating/drinking patterns etc)

16. Sleep-wake Disorders Classification Primary Dyssomnias Parasomnias Secondary

17. Sleep-wake Disorders Dyssomnias Insomnia disorder Hypersomnolence Disorder Narcolepsy Breathing related sleep disorders Circadian rhythm related sleep disorders

18. Sleep-wake Disorders Parasomnias Nightmare Disorder Sleep terror Disorder Sleep walking Disorder Parasomnia NOS (RLS, Sleep Paralysis etc)

19. Sleep-wake Disorders Secondary Sleep disorders associated with psychiatric disorders Sleep disorders associated with neurological disorders Sleep disorders associated with other medical disorders Substance induced sleep disorders

20. Insomnia Difficulty in falling asleep Frequently waking up during the night Early morning awakening Daytime drowsiness Non-refreshing sleep

21. Narcolepsy

22. Narcolepsy A sleep disorder characterized by periods of irresistible sleep, attacks of cataplexy, sleep paralysis, and hypnagogic hallucinations. hereditary autoimmune disorder. A peptide known as orexin or hypocretin , produced by neurons whose cell bodies are located in the hypothalamus; their destruction causes narcolepsy. Treatment- behavioral modification, avoid substances/sedatives, CNS Stimuants , antidepressants .

23. Maintain regular sleep timings Avoid coffee/tea, alcohol & smoking Exercise regularly Avoid day-time naps Keep your bedroom comfortable & free from noise/light Avoid heavy meals before going to bed Sleep hygiene

24. Thank You