A Brief Introduction to Sleep Disorders

What is a sleep disorder?
Any difficulty related to sleeping, including:

difficulty falling or staying asleep,
falling asleep at inappropriate times,
excessive total sleep time, or
abnormal behaviors associated with sleep.

Types of Sleep Disorders

Sleep Apnea (one of the most common types of sleep disorders)

There are three types of sleep apnea:
Obstructive sleep apnea (OSA) is the most common type of sleep apnea and is caused by an obstruction in the airway, which actually stops the air flow in the nose and mouth. Throat and abdominal breathing continue normally.
Central sleep apnea (CSA) is a much less common type than OSA. CSA is due to a brain signal problem: the brain signal that instructs the body to breathe is delayed. Different from obstructive sleep apnea, oral breathing and throat and abdominal breathing all cease at the same time. The periods of breathing interruption may last a few seconds to a minute or so, and breathing may be too shallow to provide oxygen to the blood and tissues.
Mixed sleep apnea is the combination of Obstructive sleep apnea and Central sleep apnea. Mixed sleep apnea is most commonly found in infants or young children who have abnormal breathing control.

Signs and Symptoms: Heavy snoring and breath holding episodes during sleep.
Clinical: Can cause daytime fatigue and sleepiness, auto accidents, high blood pressure, stroke, congestive heart failure, heart attacks, mood disorders, chronic headaches, impotency, nocturnal acid reflux.
Diagnostic Test: Polysomnogram

Upper Airway Resistance Syndrome
Signs and Symptoms: Heavy snoring and frequent brain arousals
Clinical: Increase daytime sleepiness, fatigue, and auto accidents
Diagnostic Test: Polysomnogram

Excessive Snoring
Signs and Symptoms: Heavy snoring
Clinical: Socially disruptive snoring resulting in poor sleep of bed partners
Diagnostic Test: Polysomnogram to exclude sleep apnea

Idiopathic Hypersomnia
Definition: Excessive daytime sleepiness despite enough sleep time on regular basis
Clinical: Can cause motor vehicle accidents, impairment of social, school, and job performance.
Diagnostic Tests: Polysomnogram and Multiple Sleep Latency Test

Narcolepsy
Definition: Excessive sleepiness and fatigue with or without sleep paralysis, sleep hallucinations, and episodes of sudden muscle weakness
Clinical: Can cause motor vehicle accidents, impairment of social, school, and job performance.
Diagnostic Tests: Polysomnogram and Multiple Sleep Latency Test

Periodic Limb Movement in Sleep
Definition: Sleep disruptions caused by increase in nocturnal muscle activity in arms and legs. This results in more daytime fatigue and inappropriate sleepiness.
Clinical: Can cause motor vehicle accidents, impairment of social, school, and job performance.
Diagnostic Test: Polysomnogram

Parasomnia

NREM
Definition: Intrusion of wakefulness behavior during non-REM (non-dream) sleep. (e.g. sleepwalking)
REM Sleep behavior disorder
Definition: Acting out dreams during REM (dream) sleep

Clinical: Parasomnia can result in injury during sleep to self and/or others
Diagnostic Test: Extended Video Polysomnogram

Sleep-Wake Cycle Disorders
Definition: Unusual sleep cycles not conforming to regular night sleep cycle
Clinical: Can result in inappropriate sleepiness during morning hours or late afternoon hours. e.g. night-owls, early-birds, shift workers. May result in reduction of social, school and job performance.
Diagnostic Tool: Clinical Evaluation

Disorders of Initiating and Maintaining Sleep (Insomnia)
Definition: Inability to obtain a refreshing good night sleep on regular basis due to various causes including psychiatric and non-psychiatric problems
Clinical: Can cause increase in daytime fatigue and poor vigilance.
Diagnostic Tool: Clinical Evaluation

Nocturnal Seizures
Definition: Seizure activity during sleep
Diagnostic Test: Extended Video Polysomnogram