Q 1.37. Sleep disorders

Normal Sleep Stages

Sleep is divided into two main types: REM (Rapid Eye Movement) and non-REM sleep, which includes three stages:

  1. NREM Stage 1 (N1): Transition from wakefulness to sleep, lasting a few minutes with slow eye movement and reduced muscle activity.
  2. NREM Stage 2 (N2): Light sleep where heart rate slows and body temperature drops, preparing for deep sleep.
  3. NREM Stage 3 (N3): Deep sleep essential for physical restoration, immune function, and energy building. It’s difficult to be awakened in this stage.
  4. REM Sleep: Associated with dreaming, characterized by rapid eye movements and temporary paralysis of voluntary muscles.


Sleep Patterns

Sleep patterns refer to the distribution of sleep stages throughout the night. The typical patterns are:

  • Monophasic: One block of sleep per day.
  • Biphasic: Two periods of sleep per day.
  • Polyphasic: Multiple naps or sleep periods per day.

Adults typically experience 4-6 sleep cycles per night, each lasting about 90 minutes.


Sleep Diagnostic Methods

To diagnose sleep disorders, several methods are used:

  1. Overnight Oximetry: Measures oxygen levels and heart rate.
  2. Polysomnography (PSG): Monitors brain waves, oxygen levels, heart rate, breathing, and limb movements during sleep.
  3. Multiple Sleep Latency Testing (MSLT): Measures how quickly a person falls asleep.
  4. Actigraphy: Wears a device to track movement and infer sleep patterns.
  5. Sleep Diary: Self-reported sleep times and patterns.
  6. Home Study: Sleep study conducted at home.


Good Sleep Hygiene

Good sleep hygiene involves practices that promote restful sleep:

  • Maintain a consistent sleep schedule.
  • Establish a relaxing bedtime routine.
  • Limit exposure to screens before bedtime.
  • Exercise regularly but not too close to bedtime.
  • Avoid caffeine and large meals before sleep.
  • Ensure the sleep environment is quiet, dark, and comfortable.


Sleep Disorders


  1. Insomnia: This disorder involves difficulty falling asleep or staying asleep throughout the night. Patients with insomnia experience disrupted sleep patterns and may suffer from daytime fatigue and impaired concentration.


  1. Sleep Apnea: Sleep apnea is characterized by abnormal breathing patterns during sleep. There are several types of sleep apnea, including obstructive sleep apnea (OSA) and central sleep apnea (CSA). OSA occurs due to blocked airways, while CSA results from a failure of the brain to signal the muscles to breathe.


  1. Restless Legs Syndrome (RLS): RLS is a sleep movement disorder where individuals experience an irresistible urge to move their legs, especially during periods of rest or sleep. This condition can significantly disrupt sleep quality.
  1. Narcolepsy: Narcolepsy is a chronic neurological disorder that affects the brain’s ability to regulate sleep-wake cycles. It leads to excessive daytime sleepiness, sudden muscle weakness (cataplexy), and vivid hallucinations during sleep onset.


  1. Parasomnias: These are abnormal behaviors during sleep. Examples include sleepwalking, night terrors, and sleep-related eating disorders. Medical students should be aware of these conditions as they can impact overall well-being and academic performance.


Treatment of Sleep Disorders

The treatment of sleep disorders is multifaceted and depends on the specific type and underlying cause. Here are the general approaches:


Medical Treatments

  • Medications: Depending on the disorder, medications such as sleeping pills, melatonin supplements, or sedatives may be prescribed, usually for short-term relief.
  • Continuous Positive Airway Pressure (CPAP): For sleep apnea, a CPAP machine keeps the airway open by providing a constant stream of air through a mask.
  • Dental Devices: Also for sleep apnea, certain devices can adjust the position of the lower jaw and tongue.
  • Surgery: In cases where anatomical issues contribute to a disorder, such as sleep apnea, surgery may be an option.


Behavioral and Lifestyle Changes

  • Cognitive Behavioral Therapy for Insomnia (CBT-i): This is often the first line of treatment for insomnia, helping to change thoughts and behaviors that disrupt sleep.
  • Sleep Hygiene Education: Patients learn about practices that contribute to better sleep, such as maintaining a regular sleep schedule and creating a restful environment.
  • Relaxation Techniques: Methods such as meditation, deep breathing exercises, and progressive muscle relaxation can help reduce anxiety and induce sleep.
  • Stimulus Control Therapy: This involves limiting the bed to sleep and sexual activity only, thereby strengthening the association between bed and sleep.
  • Sleep Restriction: Reducing the time spent in bed can increase sleep efficiency.


Other Therapies

    • Light Therapy: Exposing patients to bright light at certain times can help adjust their circadian rhythms, particularly useful for circadian rhythm disorders.
    • Physical Activity: Regular exercise can improve sleep quality, though it should be avoided close to bedtime.


Devices and Procedures

    • Actigraphy: Monitoring of sleep-wake patterns using a wearable device to inform treatment decisions.
    • Positive Airway Pressure Devices: For sleep-related breathing disorders, these devices provide air pressure to keep the airways open during sleep.


Sleep Changes with Aging

As individuals age, several changes in sleep patterns and quality are commonly observed:

  1. Longer Sleep Latency: Older adults may take longer to fall asleep.
  2. Shallow Sleep: There is a reduction in deep (slow-wave) sleep, making sleep less restorative
  3. Increased Nighttime Awakenings: Frequent waking during the night is common, often due to increased sensitivity to environmental disturbances or the need for nighttime bathroom trips
  4. Early Sleep Timing: A tendency to fall asleep and wake up earlier than in younger years.
  5. Decreased Total Sleep Time: Total sleep time may decrease slightly, with many older adults getting between 6.5 to 7 hours per night.
  6. Changes in Circadian Rhythms: The body’s internal clock, which regulates the sleep-wake cycle, may shift, leading to earlier sleep times.
  7. Reduced Melatonin Production: Aging is associated with decreased secretion of melatonin, a hormone that promotes sleep.
  8. Health-Related Sleep Disruptions: Chronic health conditions and the medications used to treat them can also affect sleep quality and duration.

Remember that sufficient sleep duration and good sleep quality are essential for cognitive functioning, physical health, and overall well-being. Medical professionals play a crucial role in diagnosing and managing sleep disorders to improve patients’ quality of life.



1 mayoclinic.org

2 nhlbi.nih.gov

3 medicalnewstoday.com

4 link.springer.com

5 sleepfoundation.org



Verified by Dr. Petya Stefanova