Polysomnography (psg) - Sleep Physiology

What is Polysomnography?

Polysomnography (PSG) is a comprehensive recording of the biophysiological changes that occur during sleep. It is often referred to as a sleep study and is used to diagnose and evaluate various sleep disorders. The test monitors several physiological parameters including brain activity, eye movements, muscle activity, heart rhythm, and breathing patterns.

Why is Polysomnography Important?

PSG is considered the gold standard for diagnosing sleep disorders such as obstructive sleep apnea (OSA), narcolepsy, periodic limb movement disorder, and REM sleep behavior disorder. It provides detailed information that can help in the accurate diagnosis and treatment of these conditions, which can significantly improve a patient’s quality of life and overall health.

How is Polysomnography Conducted?

Polysomnography is typically conducted in a specialized sleep lab. The patient is asked to arrive in the evening and spend the night at the facility. Various sensors are attached to the patient’s body to measure different physiological parameters. The data collected is then analyzed by a sleep specialist to identify any abnormalities.

What Parameters are Monitored?

The key parameters monitored during PSG include:

Electroencephalography (EEG): Records brain wave activity.
Electrooculography (EOG): Measures eye movements.
Electromyography (EMG): Monitors muscle activity, especially in the chin and legs.
Electrocardiography (ECG): Records heart rate and rhythm.
Respiratory effort and airflow: Measures breathing patterns and oxygen levels.
Snoring sounds: Captured using a microphone.

What Happens After the Test?

After the test, the data collected is analyzed by a sleep specialist. A detailed report is generated, indicating the presence or absence of sleep disorders. Based on the findings, a treatment plan is developed, which may include lifestyle changes, Continuous Positive Airway Pressure (CPAP) therapy, medications, or other interventions.

Are There Any Risks or Side Effects?

Polysomnography is a non-invasive and generally safe procedure. Some patients may experience minor discomfort due to the sensors and wires attached to their body, but serious risks or side effects are rare. Occasionally, patients may find it difficult to sleep in the lab environment, but the data collected is usually sufficient for a diagnosis.

Who Should Undergo Polysomnography?

PSG is recommended for individuals who exhibit symptoms of sleep disorders such as excessive daytime sleepiness, loud snoring, observed apneas, restless legs, or unusual behaviors during sleep. It is also used to evaluate the effectiveness of treatments already in place.

What Are the Limitations of Polysomnography?

While PSG is highly informative, it has some limitations. The test can be expensive and is typically conducted in a controlled environment, which may not fully represent the patient's natural sleep. Additionally, some sleep disorders may not be evident during a single night of testing, necessitating further evaluation.

Conclusion

Polysomnography is a crucial tool in the field of Sleep Medicine, providing detailed insights into various sleep disorders. By accurately diagnosing these conditions, PSG helps in formulating effective treatment plans that can greatly enhance a patient’s quality of sleep and overall well-being.