polysomográfia

Polysomnography, also known as poly-somnogram or polysomography, is an overnight sleep study performed in a clinical sleep laboratory or at home using a portable device. The procedure records multiple physiological signals simultaneously, providing a comprehensive assessment of sleep architecture and uncovering disorders that affect sleep quality and safety.

During a Polysomnography session, electrodes are placed on the scalp to record electroencephalography (EEG); on the eyes for electrooculography (EOG); and on the chin and limbs for electromyography (EMG). Additional sensors capture heart rate via electrocardiography (ECG), respiratory effort through bands around the chest and abdomen, airflow with a nasal cannula or thermistor, and oxygen saturation with a pulse oximeter. In many laboratories the study is supplemented with video monitoring to document behavioral events.

The sleep specialist reviews the data to determine sleep stages, period of wakefulness, and any abnormal events such as apneas, hypopneas, or periodic limb movements. A key outcome is the apnea‑hypopnea index (AHI), which quantifies the number of breathing disruptions per hour of sleep. The results inform diagnosis and guide treatment of conditions such as obstructive and central sleep apnea, narcolepsy, REM‑behavior disorder, restless‑leg syndrome, and parasomnias.

Polysomnography has a long history, beginning with rudimentary recordings of brain activity in the early 20th century and expanding into the multidimensional studies used today. Though highly informative, the procedure can be resource intensive and may be uncomfortable for some patients. Despite these limitations, it remains the gold standard for diagnosing a wide range of sleep disorders.