SLEEP MEDICINE Flashcards
3 DISTINCT STATES OF BRAIN ACTIVITY
- WAKEFULNESS
- SLOW WAVE SLEEP (NREM; NON RAPID EYE MOVEMENT)
- REM SLEEP (PARADOXICAL SLEEP)
EXAMPLES OF WHAT OCCURS WHEN PROGRESSING FROM ONE STATE OF BRAIN ACTIVITY TO ANOTHER (3 STATES; AWAKE, NREM, REM)
- LUCID DREAMING, SLEEP PARALYSIS, AUTOMATIC BEHAVIOUR, DROWSY DRIVING, MEMORY (ability to transfer info from short term to long term memory)
SLEEP PARALYSIS?
Sleep paralysis is a normal part of the REM sleep. However, it is considered to be a disorder when it occurs outside of REM sleep.
- experienced by 7-10% of people
IS SLEEP AN ACTIVE OR A PASSIVE PROCESS?
- ACTIVE
- NOT SIMPLY ‘TURNING OFF THE BRAIN’
- DIFFERENT RESPONSIVENESS TO DIFFERENT CUES DURING SLEEP (E.G. IF SOMEONE SHOUTS YOUR NAME VS SOMEONE JUST MAKING NOISE)
- IN SOME ANIMALS (LIKE AQUATIC MAMMALS, BIRDS..) SLEEP ISN’T NECESSARILY A WHOLE BRAIN PROCESS, CAN OCCUR IN JUST PARTS OF THE BRAIN (E.G. DOLPHINS SLEEP HALF A BRAIN AT THE TIME)
- SLEEP PATTERNS VARY HUGELY ACROSS SPECIES
STAGES OF SLOW WAVE/NREM SLEEP?
(4)
1: DROWSINESS (MEMORY IMPAIRED, BUT ONE IS MORE OR LESS AWARE OF THEIR SURROUNDINGS)
2: LIGHT SLEEP (FIRST STAGE OF PROPER SLEEP)
3: DEEPER SLEEP
4: DEEPEST SLEEP
WAVE LENGTH AMPLITUDE INCREASES AND FREQUENCY DECREASES AS ONE PROGRESSES INTO DEEPER SLEEP (VISIBLE ON EEG)
- CHARACTERISED BY SYNCHRONISED CELL FIRING
- MUSCLE TONE PRESERVED
SPINDLES AND K COMPLEXES?
- CHARACTERISTIC OF STAGE 2 NREM SLEEP
Spindles and K-complexes are ubiquitous NREM sleep EEG features and are signs of progression into stable sleep with the reaching of stage 2.
K complex is the “largest event in healthy human EEG”.
K complexes are large waves that stand out from the background and often occur in response to environmental stimuli such as sounds in the bedroom. Sleep spindles are brief bursts of fast activity that appear something like the shape of an “eye” as they rapidly increase in amplitude and then rapidly decay.
CHARACTERISTICS OF REM SLEEP?
- HIGH FREQUENCY, LOW AMPLITUDE EEG
- DESYNCHRONISED CELL FIRING
- ILL DEFINED ‘DEPTH’
- RAPID EYE MOVEMENTS
- SKELETAL MUSCLE PARALYSIS (due to inhibition of descending alpha motor neurons)
- MUSCLE TWITCHES
Breathing is irregular during rapid eye-movement (REM) sleep, whereas it is stable during non-REM sleep.
‘There is paradoxical inward rib cage motion during inspiration, with resultant increased work of breathing, particularly during REM sleep when intercostal muscle activity is decreased.’
WHAT MAKES US SLEEP?
- LARGELY UNDER VOLUNTARY CONTROL, UNLESS THERE IS EXTREME DEPRIVATION
3 PROCESS SYSTEM: HOMEOSTATIC: SLEEP PROPENSITY (S) CIRCADIAN: BODY CLOCK (C) (AS A DAY GOES ON, THE PRESSURE TO SLEEP FROM S AND C INCREASES) ULTRADIAN: SLEEP ARCHITECTURE
SLEEP PROPENSITY?
Sleep propensity (SP) can be defined as the readiness to transit from wakefulness to sleep, or the ability to stay asleep if already sleeping.
COMPENSATION FOR SLEEP DEPRIVATION?
ALL LOST SLEEP WON’T BE RECOUPED IN JUST ONE NIGHT AS THE PRESSURE TO SLEEP DECREASES (CIRCADIAN RYTHM) BEFORE COMPLETE RECOVERY CAUSING WAKING
WAKEFULNESS PERIOD DURING SLEEP ARE NOT REMEMBERED IF THEY LAST LESS THAN:
30 SECONDS
IS REM SLEEP MORE ABUNDANT IN THE INITIAL OR LAST HOURS OF SLEEP?
LAST HOURS (TOWARDS THE END OF THE NIGHT/ TOWARDS THE MORNING)
GROUPS OF SLEEP DISORDERS?
- DISORDERS OF INITIATING AND MAINTAINING SLEEP (DIMS)
- DISORDERS OF EXCESSIVE SLEEPINESS (DOES)
- PARASOMNIAS (a sleep disorder that involves unusual and undesirable physical events or experiences that disrupt your sleep)
- CIRCADIAN RHYTHM DISTURBANCES
- SLEEP RELATED FACTORS IN SYSTEMIC DISEASE
DIMS (DISORDERS OF INITIATING AND MAINTAINING SLEEP)
- INSOMNIA (ACUTE AND CHRONIC)
- DEPRESSION (ASSOCIATED WITH EARLY MORNING WAKENING)
- POOR SLEEP HYGIENE (TOO MANY DISTRACTIONS IN THE BEDROOM)
- DRUG INDUCED (ANTIBIOTICS, STEROIDS, ANTI HYPERTENSION DRUGS.. CAN DISRUPT SLEEP)
- FATAL FAMILIAL INSOMNIA (VERY RARE!!, INHERITED DEGENERATIVE BRAIN DISORDER, SUFFERERS BEGIN TO DEVELOP SEVERE INSOMNIA IN THEIR TEENS AND GENERALLY DIE IN MID TWENTIES) –> FFI is classified as a transmissible spongiform encephalopathy (TSE) or a prion disease. Prion diseases are caused by the accumulation of misfolded prion proteins in the brain
WHAT IS CONSIDERED CHRONIC INSOMNIA?
INSOMNIA PERSISTING FOR MORE THAN 6 WEEKS
