Sleep apnea is a common sleep disorder characterized by repeated interruptions in breathing during sleep. These pauses can last from a few seconds to minutes, occurring multiple times an hour. A sleep study, also known as polysomnography, serves as the primary diagnostic tool for accurately identifying sleep apnea.
Typical Study Durations
The duration of a sleep study varies depending on the type of test performed. An in-lab polysomnography (PSG) is typically an overnight assessment. Patients usually arrive at a sleep center in the evening and leave the following morning, covering a full night’s sleep. The total time commitment, including preparation and departure, ranges from 8 to 9 hours.
Alternatively, a home sleep apnea test (HSAT) involves using a portable device at home for one or more nights. While the actual recording period is also overnight, the patient’s direct interaction time is minimal since they set up the equipment themselves.
What Happens During a Sleep Study
An in-lab polysomnography monitors various physiological signals throughout the night. Upon arrival at the sleep center, a technician applies several sensors to the patient’s body. These include electrodes on the scalp to measure brain waves (EEG), sensors near the eyes to track eye movements, and electrodes on the chin and legs to record muscle activity.
Belts are placed around the chest and abdomen to monitor breathing effort, while a small clip on a finger or earlobe measures blood oxygen levels. Airflow sensors are positioned near the nose and mouth. Throughout the night, a sleep technologist observes the data from a separate control room. For a home sleep apnea test, the setup is simpler, involving portable sensors to record breathing, heart rate, and oxygen levels, which the patient operates independently.
Factors Affecting Study Length
Several factors can influence the standard duration of a sleep study or necessitate additional testing. A common scenario is a “split-night study,” where the first part of the night is used to diagnose sleep apnea. If severe sleep apnea is confirmed early, the second half of the night is used for Continuous Positive Airway Pressure (CPAP) titration, where different pressure settings are tested to find the most effective treatment. This combines diagnosis and initial treatment into a single overnight session.
In some instances, a single night’s data may be inconclusive, or there might be a suspicion of other sleep disorders beyond sleep apnea, such as narcolepsy. In such cases, additional testing, like a Multiple Sleep Latency Test (MSLT), might be required, often following an overnight PSG and involving a series of daytime naps. Technical issues, such as equipment malfunction or patient discomfort that prevents adequate sleep, could also lead to the need for a repeat study, thereby extending the overall diagnostic timeline.
After Your Sleep Study
Once the sleep study is complete, the recorded data undergoes a thorough analysis. Sleep technologists review the extensive information collected throughout the night, which includes hundreds of pages of data. This detailed analysis is then interpreted by a board-certified sleep physician, who uses the findings to determine if a sleep disorder is present and its severity.
Patients can generally expect to receive their results and interpretation within one to two weeks, although this timeframe can vary depending on the facility. A follow-up consultation with the sleep physician is typically scheduled to discuss the diagnosis, explore suitable treatment options, and outline the next steps in managing the condition.