There are four levels of sleep studies that are able to diagnose obstructive sleep apnoea (OSA).
Level Four
Level four is the most basic type of sleep study. It is only really a screening tool for OSA using oximetry that directly measures heart rate and oxygen levels, using this data to infer respiratory obstructions and arousals out of sleep. It is easy for these types of studies to miss subtle obstructions and give low-accuracy insight into sleep quality or total sleep time. A level four study is usually a disposable device worn around the wrist or on a single finger.
Level Three
A level three study is a basic home-based sleep study that measures breathing airflow and effort, oxygen and heart rate. It can accurately detect the presence of OSA but like level 4 has low accuracy when it comes to sleep quality or total sleep time.
Level Two
This is the level of sleep study offered by Home Sleep. Along with breathing, oxygen and heart rate data, we can also directly measure brain and muscle activity and body position. Brain activity tells us exactly when someone is asleep, as well as which of the 4 stages of sleep they are in. OSA often varies between sleep stages and sleeping position, so having this extra data can help highlight the right treatment strategies. Home Sleep’s studies also look at jaw muscle activity which can screen for sleep-related bruxism (or teeth-grinding). We also have the option of measuring leg movements which can diagnose periodic limb movement disorder.
Level One
The only difference between a level one and level two study is a level one study is conducted in a sleep lab with a sleep technician observing the sleep study in real time. Level one studies are useful in particularly severe cases or in cases when there is a suspected sleep disorder not related to breathing or leg movements. For diagnosing OSA, level one and two sleep studies give the same information. The benefit of a level one study is if a sensor falls off or there is another technical issue during the study, there is a trained technician who can solve the issue before it ruins the rest of the study. The downside of a level one study compared to level two is the experience of sleeping in a hospital compared to sleeping at home in one’s own bed.
