Obstructive Sleep Apnea (OSA)
Obstructive sleep apnea (OSA) is repetitive cessation of breathing or shallow breathing during sleep that lasts for at least 10 seconds, is associated with repeated arousals from sleep and fall in blood oxygen level. It results from repeated episodes of upper airway obstruction during sleep. This obstruction may be caused by large tonsils or a large tongue, excess fat tissue in the upper airway, blocked nasal passages or anatomy of the jaw and airway.

Symptoms: include snoring, observed pauses in breathing and gasping for breath during sleep, snorts and arousals, non-refreshing sleep, day-time sleepiness, fatigue, and sometimes dry mouth and headache on waking up in the morning. There may be associated difficulty with memory and concentration and with focusing and thinking during daytime. Sleep Apnea is associated with increased risk of heart disease, hypertension, stroke and premature death. Adequate treatment of sleep apnea can improve both symptoms and associated medical conditions.

OSA is diagnosed using an overnight sleep study, called a polysomnogram (PSG). Although a patient’s symptoms and medical history can suggest they might have OSA, until a sleep study is done, the formal diagnosis cannot be made.

Insomnia
Insomnia is the most common sleep disorder. Symptoms: Patients have difficulty with falling asleep, staying asleep (waking up in the middle of the night unable to go back to sleep ) or both. Sleep is non-refreshing. Patients wake up feeling un-refreshed. It is associated with problems functioning during the day, such as fatigue, poor concentration, focusing and thinking and irritability.

Restless Leg Syndrome (RLS)
Symptoms: include uncomfortable leg sensations ( a “creepy crawly” feeling) in legs, less commonly in arms, accompanied by an irresistible urge to move legs or arms to relieve discomfort. Symptoms improve with movement. Symptoms usually occur when resting quietly, usually late in the day, attempting to fall asleep or during passive restricted activities (on an airplane, in the movies etc.).

Periodic Limb Movements of Sleep (PLMS)
Usually coexists with RLS. Symptoms: include semi-rhythmic contractions of the limb musculature during sleep, often accompanied by limb jerks, most often involving the feet.

Idiopathic Daytime Hypersomnia/Central Nervous System hypersomnolence
Symptoms: include excessive daytime sleepiness.

Narcolepsy
Symptoms: include excessive and sudden, sometimes irresistible sleepiness that may come on at inappropriate times, e.g., while driving, sleep paralysis (awakening from sleep physically unable to move for 1-2 minutes), hypnagogic hallucinations (episodes of being in a dream-like state but still awake), cataplexy (sudden loss of muscle strength triggered by emotion, especially laughter), and fragmentation of sleep at night.

Delayed Sleep Phase Syndrome (DSPS) and other circadian rhythm disorders
The brain has an internal clock that regulates several biorhythms including the timing of an individual’s sleep-wake cycle. In most cases, the environment provides clues in the form of sunlight, activity, and temperature to help align this internal clock with the external environment. In situations when the two clocks are out of sync, individuals have difficulty sleeping during “conventional” sleep hours.

Circadian rhythm disorders can come in a variety of forms based on the pattern of the sleep clock misalignment, including:

• Night owl form (“delayed sleep phase syndrome”)
• Morning lark form (“advanced sleep phase syndrome”)
• Shift work disorder
• Jet lag

The commonest circadian rhythm disorder is delayed sleep phase syndrome.
Symptoms: include unconventional timing of sleep/wake schedule, for example falling asleep at 2:00 am and sleeping until 10:00 am. The misalignment between the internal clock and the environment can lead to a number of difficulties including insomnia, daytime sleepiness, and fatigue.

REM Sleep Behavioral Disorder (RSBD)
Symptoms: include acting out of dreams while asleep. Muscle paralysis does not occur, as it does during normal REM sleep. The behavior may be violent and potentially dangerous to the patient or bed partner, characterized by yelling, cursing, punching, running and other actions triggered by the content of the patients’ dream.

Parasomnias
Parasomnia refers to behaviors occurring at the time of sleep. Parasomnias include: Nightmares, Night terrors, Sleep walking, Somniloquy (talking during sleep), Bruxism (teeth grinding), and Sleep-related eating disorders (uncontrolled episodes of eating during the night of which the patient may or may not be aware). In general, these behaviors occur during the transition from sleep-wake or during transitions within the different stages of sleep.

Symptoms: include abnormal behaviors associated with sleep such as night terrors, sleep walking, sleep talking.

In most cases, parasomnias are infrequent and benign and do not require medical attention. A formal evaluation by a sleep specialist should be considered in the following situations: Episodes result in injury to the individual or others; Episodes result in significant sleep disruption to the individual or members of their household and in significant daytime dysfunction.