What test is commonly used to diagnose sleep apnea?

Polysomnography is the gold standard for diagnosing sleep apnea. This comprehensive test records various physiological parameters during sleep, including brain activity, eye movement, muscle activity, heart rate, respiratory effort, airflow, and blood oxygen levels. By monitoring these factors, polysomnography can provide detailed insights into sleep patterns and disturbances, allowing healthcare providers to accurately identify the presence and severity of sleep apnea.

In contrast, the other options have limited utility in diagnosing this condition. A CT scan is primarily used for imaging purposes and would not provide the necessary information about sleep disturbances. Pulmonary function tests evaluate lung function but do not assess sleep quality or patterns. A sleep diary can help gather subjective reports of sleep habits but lacks the objective data necessary for a definitive diagnosis of sleep apnea. Thus, polysomnography is the most reliable and comprehensive diagnostic tool available.