Sleep Disorders

About Sleep Disorders

Many people have problems falling asleep, staying asleep or simply sleeping well. There are more than 85 recognized sleep disorders; the most common include insomnia, sleep apnea, narcolepsy and restless legs syndrome.


Insomnia – the inability to sleep, or to sleep satisfactorily – is the most common sleep disorder. It varies from restless or disturbed sleep to difficulty in falling asleep and a reduction in the usual time spent sleeping. In the extreme, it may involve complete wakefulness.

Requirements for sleep vary widely. Most adults need the traditional seven or eight hours of sleep a night, but some adults are “short sleepers” and function well on only three or four hours. Many people overestimate the amount of sleep they need and underestimate the amount they actually get during a restless night. Generally there is no need for concern, even if an unbroken night’s sleep is rare. However, if loss of sleep impairs a person’s ability to function well during the day, treatment may be needed.


Narcolepsy is a disorder that causes an irresistible need to sleep. People with narcolepsy can fall asleep at work, while talking or, most dangerously, while driving a car. These “sleep attacks” can last from 30 seconds to more than 30 minutes. Sufferers may also experience periods of cataplexy (loss of muscle tone) ranging from a slight buckling at the knees to a complete “rag doll” limpness throughout the body.

Narcolepsy is a chronic disorder affecting the part of the brain where regulation of sleep and wakefulness take place. It can be thought of as an intrusion of dreaming sleep (REM) into the waking state. Onset can occur at any time throughout life, but peak onset is during the teen years. Narcolepsy is probably caused by a combination of genetic and environmental factors.

Restless Legs Syndrome

People experience restless legs syndrome (RLS) in many different ways, but most sufferers describe very unpleasant “creepy, crawly” sensations that occur in the legs when they are sitting or lying still, especially at bedtime. RLS can be very painful, but the pain is unlike that of a leg cramp. RLS is also different from the feeling of a limb having “fallen asleep” when the blood supply is cut off and from the “pins and needles” or burning sensation sometimes experienced by diabetics. The pain and unpleasant feelings of RLS appear most often in the calves and can be temporarily relieved by stretching and moving the legs.

Sleep Apnea

Sleep apnea is a breathing disorder and is typically accompanied by loud snoring. People with sleep apnea experience brief periods throughout the night in which breathing stops, thus depriving them of needed oxygen. There are two major types of sleep apnea: obstructive and central.

  • Obstructive sleep apnea is the most common type of sleep apnea and is due to an obstruction of the throat during sleep. The narrowing of the upper airway can be a result of several factors, including inherent physical characteristics, excess weight and alcohol consumption before sleep.
  • Central sleep apnea is caused by a delay in the breathing signal from the brain.

Both obstructive and central apneas cause people to wake up briefly to breathe, sometimes hundreds of times throughout the course of the night. Usually, there is no memory of these brief awakenings. People with sleep apnea may develop high blood pressure and are at an increased risk for other diseases, such as stroke.

Sleep Disorders Center

Lahey Hospital & Medical Center’s Sleep Disorders Center is one of the most experienced and comprehensive centers in New England for the evaluation and treatment of patients with sleep disorders. Housed within the Department of Neurology, the nationally accredited center combines the expertise of sleep specialists in neurology, pulmonary medicine, otolaryngology and psychiatry.

Continuous Positive Airway Pressure (CPAP) Clinic

Our Continuous Positive Airway Pressure (CPAP) Clinic provides support and guidance for patients using CPAP equipment to treat sleep apnea.