Polysomnography

Polysomnography (PSG), a sleep study,  is a test used to diagnose specific types of sleep disorders. Polysomnometry records brain waves, blood oxygen levels, heart rate, eye and leg movements, and breathing flow during sleep.

Polysomnography can be done in a hospital sleep disorders unit or at a sleep center (Sleep Lab). A sleep study is usually done at night but can sometimes be done during the day for people who work the night shift and typically sleep during the day.

Why is polysomnography important?

Sleep apnea is a prevalent condition that often prompts doctors to recommend a polysomnogram. Your physician may suggest a sleep study if you experience sleep difficulties, poor sleep quality, or loud snoring. This comprehensive assessment records various sleep parameters and bodily functions, including your breathing patterns. This valuable information aids in diagnosing specific sleep disorders, particularly those related to respiratory issues, and guides treatment decisions.

When experiencing sleep-related issues, your doctor may recommend a sleep study based on specific symptoms. These symptoms include:

• Snoring: Often associated with sleep apnea or other breathing disorders during sleep.
• Fatigue and Excessive Daytime Sleepiness: Persistent tiredness and drowsiness.
• Periodic Limb Movement Disorder: Characterized by leg movements (bending and straightening) during sleep, sometimes linked to restless legs syndrome—an irresistible urge to move the legs while awake, typically in the evening.
• Narcolepsy: Excessive daytime sleepiness, with sudden episodes of falling asleep.
• REM Sleep Behavior Disorder: Involves acting out dreams during sleep.
• Abnormal Sleep Behavior: Such as sleepwalking or rhythmic movements during sleep.
• Long-Term Insomnia of Unknown Cause: Difficulty falling asleep or maintaining sleep.

You’ll visit a sleep lab, where technicians will guide you through the process. Before attaching sensors, you’ll change into comfortable clothing and maintain personal hygiene.

Technicians will attach several sensors to your body:

• Electrodes: These go on your head, chest, and legs. They record brain activity, heart rate, breathing rate, and oxygen levels.
• Electrocardiogram (ECG): Monitors heart electrical activity.
• Electroencephalogram (EEG): Tracks brain wave patterns during sleep.
• Electrooculogram (EOG): Detects eye movements.
• Electromyogram (EMG): Monitors muscle movements.
• Thoracic Abdominal Movement Belt (RIP): Measures chest and abdominal expansion during breathing.
• SpO2 Machine: Clips onto your finger to check oxygen levels.
• Surveillance Cameras: Video monitoring helps technicians correlate data with your sleep behavior.

Throughout the night, these sensors collect data while you sleep, providing valuable insights for diagnosis and treatment.

How long does a polysomnogram last?

A polysomnogram (sleep study) duration varies based on its purpose and the required data. Typically, the study takes place overnight. You’ll check in at the sleep center between 8 and 10 p.m. and wake up between 6 and 8 a.m. the next day. The goal is to record at least seven hours of sleep, although this isn’t always feasible. Occasionally, additional nights may be necessary for further data collection. Your provider will discuss the results and determine if another study is needed.

What if the patient can’t sleep during the polysomnogram?

Very few people complain that they have difficulty sleeping during a polysomnogram. This is because the lab environment is unfamiliar, or the sensors and wires may cause discomfort while the patient sleeps.

If you encounter difficulty sleeping during a sleep study at the Lab, rest assured that the technologists are there to assist you. They may suggest relaxation techniques, such as deep breathing or gradual muscle relaxation. They might also provide a mask that delivers a gentle flow of air to facilitate easier breathing.

In addition, some labs support performing polysomnography at home so that you feel most comfortable and familiar when sleeping, thereby providing more accurate measurement results of your sleep disorder.

How to prepare for a sleep study?

Your doctor or sleep technician will provide specific instructions for the sleep test. Read them carefully to ensure accurate results.Stick to your usual sleep routine at home. Continue taking your regular medications unless advised otherwise.

On the day of the study, steer clear of caffeine (found in coffee, tea, chocolate, and some soft drinks) and alcohol. These substances can disrupt sleep patterns.

Get enough sleep the night before the study. Avoid staying up late or overworking.

If your sleep study is at a lab, pack an overnight bag with comfortable sleep clothes. Consider 

Can a sleep study be performed at home?

Sometimes, sleep studies can be conducted in the comfort of your home. Known as home sleep studies or mobile monitoring, these tests involve a technician bringing the necessary equipment to your residence. Before you go to bed, the technician will install the monitoring device, which tracks your sleep patterns throughout the night. Additionally, respiratory polygraphs—used to assess breathing—can be easily set up at home with guidance from the technicians.

Both home-based and laboratory-based measurements have their advantages and drawbacks:

Home Measurements: Sleeping in your familiar bed makes falling asleep more accessible and comfortable.

Lab Measurements: In a controlled lab environment, you can rest assured that your sleep will be continuously monitored, ensuring the most accurate data collection. This method is particularly beneficial if you’re visiting from out of town.

Summary

Polysomnography offers valuable insights into your sleep patterns and helps diagnose and manage sleep disorders. Understanding the process, knowing when to undergo a sleep study, and following recommended guidelines empower you to approach the experience confidently and enhance your overall sleep health. Remember, a restful night’s sleep is crucial for overall well-being.

If you’re experiencing sleep issues that impact you or those around you, feel free to reach out for further advice. Whether you’re from another province or a domestic or foreign tourist, we’re here to assist.