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The term sleep disorder covers a wide range of conditions and symptoms, but sleep disorders can be broken down into various types.

  • Primary sleep disorders aren't caused by another medical or psychological condition.

  • Secondary sleep disorders are the result of another medical problem, such as depression, thyroid problems, stroke, arthritis, or asthma.



Primary disorders can be divided into parasomnias and dyssomnias.

  • Parasomnia sleep disorders cause abnormal activities during sleep, such as sleep terrors or sleep walking.

  • Dyssomnia sleep disorders cause trouble falling asleep or staying asleep. Perhaps the most well known dyssomnia is obstructive sleep apnea.



Obstructive Sleep Apnea (OSA):

The condition known as OSA is characterized by recurrent episodes of complete (apnea) or partial (hypopnea) upper airway obstruction during sleep. OSA is often associated with oxygen desaturation and recurrent arousals, which are usually quantifiable and confirmed on polysomnography (PSG). The prevalence of OSA syndrome (OSAS; ie, PSG confirmation of OSA in the presence of excessive daytime sleepiness) is estimated to be about 4% in men and 2% in women. Risk factors are obesity and craniofacial abnormalities that narrow the upper airway, such as retrognathia or adenotonsillar enlargement. Other risk factors are a large neck circumference, menopause, smoking, and endocrine disorders, such as hypothyroidism and acromegaly. OSA has been associated with hypertension, ischemic heart disease, stroke, and diabetes. The classic history that often suggests the diagnosis of OSAS includes snoring, excessive daytime sleepiness, witnessed apneas and choking/gasping episodes, and unrefreshing sleep regardless of duration. OSAS typically, but not always, occurs in an obese or overweight person. Confirmation of diagnosis is by PSG showing at least 5 apneas or hypopneas per hour (an apnea-hypopnea index [AHI] ≥5).

Abnormalities of the central nervous system:

Problems with the central nervous system can trigger a sleep disorder. Central sleep apnea occurs when breathing temporarily stops for 10 seconds or more many times during a night's sleep. This is caused by an abnormality in the brain, which prevents it from regulating oxygen levels and automatically triggering breathing. This diminished oxygen is a condition called hypoxia. It can worsen conditions such as epilepsy, or lead to problems such as chest pain or heart attack in people who have coronary artery disease. Central sleep apnea may also be caused by problems in carbon dioxide regulation.


Periodic limb movements in sleep (PLMS):

Periodic limb movements in sleep occur when the arms and legs move frequently and involuntarily during sleep. PLMS can cause the arms and legs to twitch, jerk, or flex. This can occur as often as several times per minute for up to several hours. The cause of PLMS is unknown, but experts think it is likely related to the nervous system. PLMS can play a part in insomnia. It can cause daytime sleepiness and fatigue because the symptoms interrupt sleep.


Restless legs syndrome (RLS):

Restless legs syndrome is a neurological disorder. It causes leg pain, a crawling feeling in the legs, or an urge to move the legs when you're trying to go to sleep. The symptoms tend to occur when you sit or lie down. They are relieved by walking or moving the legs. The symptoms are worse at night. RLS may make it hard to fall asleep or stay asleep. It also causes excessive sleepiness during the daytime.



This sleep disorder can be acute, or short-term, or chronic, lasting weeks or months. It can be linked to an outside cause, such as stress, medicine, or a medical condition. When insomnia is the result of an outside cause, it is called secondary insomnia. Primary insomnia is not caused by outside events. It can be hard to identify the cause of primary insomnia.

Here is more information about some types of insomnia:

  • Psycho-physiological insomnia occurs when someone under emotional stress becomes anxious, concentrates too intently on trying to sleep, and is unable to sleep because of the level of stress and anxiety.

  • Paradoxical insomnia, formerly known as sleep-state misperception, is a sleep disorder characterized by a significant difference between the time a person thinks he or she has been asleep and how much time he or she has actually slept. People with this problem may complain that they can't fall asleep and feel sleepy during the day because of lack of sleep, but they are actually sleeping and have no evidence of a sleep disorder. 


Symptoms differ depending on the severity and type of sleeping disorder. They may also vary when sleep disorders are a result of another condition.

However, general symptoms of sleep disorders include:

  • difficulty falling or staying asleep

  • daytime fatigue

  • strong urge to take naps during the day

  • unusual breathing patterns

  • unusual or unpleasant urges to move while falling asleep

  • unusual movement or other experiences while asleep

  • unintentional changes to your sleep/wake schedule

  • irritability or anxiety

  • impaired performance at work or school

  • lack of concentration

  • depression

  • weight gain


Most sleep disorders can be diagnosed by a comprehensive sleep history, which includes a detailed account of routine sleep-related habits (eg, bedtime, wake time, and number of awakenings), sleep duration, sleeping environment, daytime activities, psychosocial stressors, current drug use, and abnormal behavior in sleep. Important collateral information is often provided by a bed partner, other observer, or family member regarding behavior that the patient may be unaware of, such as snoring or acting out dreams. Sleep questionnaires detailing pertinent sleep-related information and sleep logs are often useful, especially in documenting sleep-wake patterns in the circadian-rhythm sleep disorders.

The Epworth Sleepiness Scale is often used to assess the level of daytime sleepiness and to monitor the response to therapeutic interventions.  A score of 10 or more indicates that the patient is considered sleepy. Diagnosis of most sleep disorders can be made on the medical history alone, which is based on pattern recognition of clinical characteristics determined from the comprehensive sleep history and a physical examination



Sleep studies are indicated mainly to confirm the nature and severity of sleep-related breathing disorders, help diagnose narcolepsy, and to document parasomnias and seizures.  Tests include:

  • Polysomnography (PSG) is the monitoring of physiologic parameters (with EEG, electromyography [EMG], electro-oculography [EOG], electrocardiography [ECG], airflow, respiratory effort, and pulse oximetry) and physiologic or pathologic events in the sleeping patient. Different NREM and REM sleep stages can be identified based on specific EEG, EMG, and EOG characteristics. Monitoring respiratory parameters and ECG allows simultaneous documentation of sleep-related cardiorespiratory disturbances in conditions such as OSA.
  • The multiple sleep latency test (MSLT) provides an objective measure of sleepiness. The MSLT is considered the gold standard in the objective evaluation of excessive daytime sleepiness. Mean sleep latency (MSL) less than 5 minutes is considered pathologic and correlates with severe sleepiness. The primary indication for the MSLT is to evaluate patients for a diagnosis of narcolepsy. In narcolepsy there is a very short MSL and at least 2 SOREMPs.

  • The maintenance of wakefulness test (MWT) is a variation of the MSLT and measures the ability of a person to stay awake in the setting of sleep disorders associated with excessive daytime sleepiness, such as narcolepsy and OSA. During nap trials of 20 minutes, a normal MSL is 18 minutes (representing 1 standard deviation below normal). An MSL of less than 11 minutes is considered impaired wakefulness. Values between 11 and 18 minutes are of questionable significance.


Medical treatment for sleep disturbances might include any of the following:

  • sleeping pills

  • melatonin supplements

  • allergy or cold medication

  • medications for any underlying health issues

  • breathing device or surgery (usually for sleep apnea)

  • a dental guard (usually for teeth grinding)

Lifestyle adjustments can greatly improve your quality of sleep, especially when they’re done along with medical treatments. You may want to consider:

  • incorporating more vegetables and fish into your diet, and reducing sugar intake

  • reducing stress and anxiety by exercising and stretching

  • creating and sticking to a regular sleeping schedule

  • drinking less water before bedtime

  • limiting your caffeine intake, especially in the late afternoon or evening

  • decreasing tobacco and alcohol use

  • eating smaller low carbohydrate meals before bedtime

  • maintaining a healthy weight based on your doctor’s recommendations


Going to bed and waking up at the same time every day can also significantly improve your sleep quality. While you might be tempted to sleep in on the weekends, this can make it more difficult to wake up and fall asleep during the workweek.

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