A sleep study, also known as polysomnography (PSG), is a medical test used to monitor and evaluate various physiological parameters during sleep. This diagnostic procedure is employed to identify and assess sleep disorders, monitor sleep patterns, and gather essential data about a person's sleep-related physiological activities.
Sleep studies serve several purposes, including:
Diagnosis of Sleep Disorders. Sleep studies help diagnose various sleep disorders, such as obstructive sleep apnea (OSA), narcolepsy, insomnia, restless legs syndrome (RLS), and parasomnias (sleep-related behaviors like sleepwalking or night terrors).
Evaluation of Sleep Quality. They assess the quality and structure of sleep, including sleep stages (e.g., rapid eye movement [REM] sleep, non-REM sleep) and any disruptions.
Identification of Health Risks. Sleep studies can identify health risks associated with sleep disorders, such as the cardiovascular risks associated with OSA.
The sleep study usually takes place overnight, but this may vary according to what your medical professional advises. Be sure to bring enough supplies to last through the duration of your appointment. Typically, patients arrive at the clinic in the evening and are prepared for the study by a sleep technologist. Electrodes, sensors, and other monitoring equipment are attached to specific areas of the body. The patient is then monitored while sleeping.
During a sleep study, patients are connected to various monitoring devices that record physiological data, such as:
Electroencephalogram (EEG): Measures brain activity and helps determine sleep stages.
Electrooculogram (EOG): Records eye movements to detect REM sleep.
Electromyogram (EMG): Monitors muscle activity and body movements.
Electrocardiogram (ECG or EKG): Tracks heart rate and rhythm.
Respiratory sensors: Record breathing patterns, airflow, chest and abdominal movements, and oxygen levels.
Snoring microphone: Detects snoring sounds.
Limb movement sensors: Track leg and arm movements during sleep.
Sleep studies differentiate between different sleep stages, such as REM and non-REM sleep (which is further divided into several stages). This information helps diagnose sleep disorders and evaluate sleep quality.
Interpretation & Reporting
The data collected during the sleep study is analyzed by sleep specialists, who look for abnormalities in sleep architecture, breathing patterns, heart activity, limb movements, and other parameters. They use this data to diagnose sleep disorders and assess sleep quality.
Following the analysis, the sleep specialist generates a report summarizing the findings and offering recommendations for treatment or further evaluation. Treatment options may include lifestyle changes, medication, or the use of devices like continuous positive airway pressure (CPAP) for OSA.