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