How is a sleep study helpful in diagnosing sleep disorders? A sleep study, or what we call a polysomnogram, is often very helpful in diagnosing many sleep disorders. We measure activity while the patient is asleep. The activity we measure includes brain function, eye movements, breathing, heart rate, and leg movements. This information is then given to a board certified sleep specialist who renders an interpretation and a treatment plan. Without this data from the polysomnogram, no such diagnosing could be made.