Polysomnography (PSG) is a comprehensive sleep study used to diagnose and evaluate various sleep disorders. Conducted overnight in a specialized sleep lab or, increasingly, in a home-based setting, this non-invasive test records multiple physiological functions during sleep, providing critical insight into how a person sleeps and what might be disrupting their rest.
What Is Polysomnography?
Polysomnography is essentially a multi-parametric test that monitors several bodily functions as a person sleeps. These include brain activity (electroencephalography or EEG), eye movements (electrooculography or EOG), muscle activity (electromyography or EMG), heart rate (electrocardiography or ECG), respiratory effort, airflow, blood oxygen levels, and body position. These parameters help sleep specialists understand what is happening apnee del sonno in the body at each stage of sleep—light, deep, and REM (Rapid Eye Movement).
The procedure typically starts in the evening and ends in the morning. Small electrodes and sensors are attached to the patient’s scalp, face, chest, limbs, and fingers. While it may look cumbersome, the test is painless, and the equipment is designed to be as comfortable as possible to ensure natural sleep.
Why Is Polysomnography Important?
Sleep is crucial for physical health, cognitive function, and emotional well-being. However, millions suffer from undiagnosed sleep disorders such as obstructive sleep apnea (OSA), narcolepsy, restless legs syndrome, insomnia, and parasomnias (like sleepwalking or night terrors). These conditions can lead to fatigue, depression, impaired concentration, cardiovascular problems, and a reduced quality of life.
Polysomnography helps pinpoint the specific nature of a sleep disorder. For instance, in OSA, the test will show frequent interruptions in breathing accompanied by drops in oxygen saturation and frequent arousals from sleep. In contrast, patients with narcolepsy may enter REM sleep unusually quickly and experience fragmented sleep.
Advancements in Home-Based PSG
Traditionally, polysomnography was only available in specialized clinics. However, the rise of home sleep testing has expanded accessibility. Portable devices now allow patients to undergo simplified versions of PSG in their own beds. While not as comprehensive as lab-based studies, these home tests are sufficient for diagnosing common conditions like sleep apnea and are often more cost-effective and convenient.
Interpretation and Follow-Up
After the study, the recorded data is analyzed by sleep technologists and reviewed by a sleep physician. The results are compiled into a detailed report that includes sleep efficiency, stages of sleep, number of arousals, and any abnormalities. Based on the findings, the physician may recommend treatments such as Continuous Positive Airway Pressure (CPAP) therapy, lifestyle changes, medication, or behavioral therapy.
Polysomnography is a vital diagnostic tool in sleep medicine. By providing a detailed picture of what happens during sleep, it helps uncover hidden issues that can significantly impact daily functioning and long-term health. As awareness of sleep’s importance continues to grow, polysomnography remains at the forefront of diagnosing and managing sleep disorders, improving lives through better rest.