Polysomnography

Polysomnography is a specialized sleep study used to diagnose sleep disorders. It records brain electrical activity, oxygen level in blood, heart rate, and breathing during sleep. It also measures eye and leg movements. Sleep studies may be conducted in a sleep disorders unit in a hospital or at a sleep center. The test is usually performed at night, but it may also be done during the day.

Why is polysomnography done?

Polysomnography studies sleep phases and cycles, tracks breathing, heart rate, oxygen saturation, and other parameters. It also helps determine if your sleep patterns are disrupted and what might be causing it.

Polysomnography is conducted when there is suspicion of the following conditions:

• Sleep apnea- characterized by repeated cessation and resumption of breathing during sleep or other sleep-related breathing disorders;
• Periodic limb movement disorder - this condition is sometimes associated with restless legs syndrome. Restless legs syndrome causes uncontrollable leg movements upon awakening, typically in the evening or at bedtime.
• Narcolepsy- People with narcolepsy experience overwhelming daytime drowsiness.

Risks associated with the test

Polysomnography is a non-invasive, painless test, with the most common side effect being skin irritation. This can be caused by the adhesive used to attach the test sensors to the skin.

How to prepare for the test

Avoid consuming drinks or food containing alcohol or caffeine during the afternoon and evening before a sleep study. Alcohol and caffeine can change your sleep patterns. They may make symptoms of some sleep disorders worse. Also, don't nap in the afternoon before a sleep study.

Before the sleep study, it is recommended to take a bath or shower. Do not apply lotions, gels, perfumes, or makeup before the test. They can interfere with the test's sensors,

What should be considered during polysomnography:

The room where polysomnography is conducted is typically isolated, dark, and quiet during the test to promote optimal sleep conditions.

The sleeping area typically has a low-light video camera, allowing polysomnography specialists to observe the patient even when the room lights are out.

Before sleep, sensors are attached to the scalp, temples, chest, and legs using a mild adhesive material such as glue or tape. These sensors are connected by wires to a computer. The wires are long enough to let you move around in bed. A small clip is also placed on the finger or ear to monitor level of oxygen in your blood.

While you sleep, specialist monitors:

• Brain waves;
• Eye movements;
• Heart rate;
• Breathing pattern;
• Blood oxygen level;
• Body position;
• Chest and abdominal movements;
• Limb movements;
• Snoring and other noises.

After polysomnography

After polysomnography in a sleep center, the sensors are removed and then you may leave the sleep center. You can return to your usual activities after polysomnography.

Results of the study

The information gathered during the sleep study is initially first by polysomnography specialists. They use the data to create to chart your sleep phases and cycles. Then the information is reviewed by the sleep center physician. 

At a follow-up appointment, your physician reviews the results with you. Based on the data gathered, your physician will discuss any treatment or further evaluation that you may need.