Sleep Medicine
Normal Sleep
- Newborns sleep most of the time; by age 14, needed sleep levels off to ~ 8hrs/day (25% REM) and declines with age
- Range of needed sleep is 6 to 12 hours for adults. No one needs less than 4hrs.
- Circadian Rhythm generated in anterior hypothalamus (suprachiasmatic nucleus) lasts 24h and is reset by light, activity, melatonin
- Variability of sleepiness across the day: greatest at 2-3 pm and am (i.e. Exxon Valdez and 3 mile island happened at 3 am)
- NREM SLEEP: 4 stages; each stage has increasing synchronization of EEG (See NEURO-307); slightly decreases with age.
- REM: desynchronized EEG; associated with atonia, autonomic variability, dreaming and penile erection.
- Normal Sleep: consist of 3-4 NREM/REM cycles lasting 90-120 min. Start with NREM, % of REM increases progressively.
- not all dreaming occurs during REM, only about 80-90% does.
- Sleep amounts (% of time slept): NREM stage 1 = 5%, stage 2 =45%, stage 3 = 5%, stage 4 = 20%, REM =25%
"Can’t Stay Awake"
- Obstructive Sleep Apnea (very common > 3% of general population)
- 90% chance of having this if you experience loud disruptive snoring interrupted by moments of apnea and have HTN.
- patients experience difficulty concentrating, decreased libido; most are male and over weight but not always
- can fall asleep while engaged in both active and passive activities (driving, reading, operating heavy equipment)
- posterior pharynx which is normally open, narrows when falling asleep causing venturi affect Þ uvula and soft palate vibrating, causing snoring. Partial closing causes hypopnea, complete closing causes apnea.
- Treatment: Weight loss, avoid sedatives, sleep on side, **positive air pressure (CPAP)** very effective
- surgery:
- Uvulopharyngoplasty (reduction of uvula and soft palate) works for snoring, poor for OSA),
- Jaw advancement (50% effective) – surgeons demand you try CPAP first
- Narcolepsy
- Major symptoms: (1) Daytime Sleepiness and (2) Cataplexy = atonia while awake; can occur with laughing or emotional stress
- Minor symptoms:
- (1) Sleep paralysis: atonia persisting upon waking in morning (only eyes move) – 10% of population experiences this once
- (2) hallucinations (dream while awake)
- (3) Nocturnal Awakenings
- (4) Automatic behavior
- classically this is a sleep attack that can be treated by 1-3 naps a day. Must get adequate sleep at night to work.
- Diagnosis: Multiple Sleep Latency Test: 4-5 naps 2 hrs apart; measure how quickly patient falls asleep, look for REM
- Normal is 10 min to sleep and 0-1 REM seen on a nap; narcoleptics fall asleep in 5min and have >2 REM episodes
- HLA typing is only useful to rule out narcolepsy.
- Treatments: Stimulants: Ritalin, Amphetamine, (Cylert not used), Provigil first choice; Cataplexy-antidepressants ß REM
- Insufficient Sleep/Delayed Sleep Phase Syndrome (Group of Sleep/Wake Cycle disorders)
- characterized by difficulty falling asleep or sleeping at night (insomnia) and daytime sleepiness
- affects 80-90% of high school students/ like a jet lag that does not go away.
- Treatment: Chronotherapy (simulates flying you around the world) go to bed 3-4 hrs later each day: difficult to do
- Provigil is new stimulant
"Can’t Fall Asleep"
- Psychophysiologic Dysomnia: means you can’t fall asleep as a result of a learned habit associating stress with the bed.
- patient may worry (even about falling asleep) when going to bed, which keeps him/her awake
- typically patients fall asleep better on vacation
- Treatment: behavioral: good sleep habits, relaxation therapy, keep a strict sleep/wake schedule.
- Insomnia at end of Sleep: classically early morning – almost always caused by depression especially if you stay awake
- any condition causing excessive daytime sleepiness will have complaint similar to depression
- Insomnia in maintaining Sleep: wake up during the night, stay awake, then go back to sleep
- characterized by: leg movements, reflux, cough, most commonly a disorganized sleep/wake cycle (frequently a habit)
- only needs to be treated if patient is actually having a problem, which is likely if sleep is broken up into >3 periods
- Movement Syndrome: usually involves legs. Commonly asymptomatic but can cause repetitive arousal – need to treat
- Treatment: Benzodiazapenes (Klonopin) , antiparkinson agents, opiates always work
- Irregular sleep wake Cycle: significant issue with Alzheimer’s patients (#2 reason they get institutionalized)
Problems During Sleep
- Seizures: repetitive and stereotypic nondirective behavior, urinary incontinence, wake with headache, muscle pain and fatigue.
- Parasomnias: not associated with abuse or pathology, runs in families. Non-directive behavior (not voluntary)
- Sleep walking: common in children, occurs in NREM, treat with Klonopin, Tricyclics, or Benign neglect if appropriate
- Night terrors: NREM event, child wakes screaming (amnesic for episode), can persist into adulthood, treat parents anxiety
- Disorders that Cause Bizarre Behavior During Sleep:
- Dissaciative Disorder: a waking behavior, usually has strong history of physical or sexual abuse; involves very complicated behaviors (hypnotic). A cry for help by people who have major psychiatric problems.
- PTSD: post traumatic stress disorder