Delayed Sleep Phase

To diagnose delayed sleep phase syndrome, a healthcare provider or sleep specialist will ask you to describe your symptoms and keep a sleep diary or sleep log. A sleep log is a record of the time when you:

• Go to bed.
• Fall asleep.
• Wake up.

It helps to keep a notepad and pen near your bed so you don’t forget to record the time. The time when you fall asleep should be an estimate you write down in the morning, as you won’t be able to realistically write down the exact time when you fall asleep. Your healthcare provider will let you know how long you need to keep a sleep log.

To confirm a diagnosis, your healthcare provider may ask you to wear a device called an actigraph that records cycles of rest and activity. This can confirm what times you fall asleep and wake up. You can wear this device for seven to 14 days.

In addition, your provider might perform dim light melatonin testing (DLMO), polysomnography (PSG or sleep study) and a multiple sleep latency test (MSLT). These tests help differentiate DSPS from other hypersomnia conditions.

Common sleep disorders like obstructive sleep apnea can make the presentation of DSPS worse, so a healthcare provider may diagnose and treat that condition as well.