Sleep Study (Polysomnography)

What it is

Sleep problems are hard to investigate for an obvious reason: the person with the problem is asleep and cannot report what happened. A polysomnogram solves that by recording the night instead. Sensors are taped to the scalp, face, chest, limbs, and a finger, and they capture brain activity, eye movement, airflow and breathing effort, blood oxygen, heart rate, and leg movements together on one timeline. Read side by side, those tracings show which stage of sleep the person was in at any moment and what was happening to their breathing at the time. This code covers the version attended by a technologist in a sleep laboratory, who watches through the night and fixes sensors that come loose.

Why it is done

• To diagnose obstructive sleep apnea in someone with loud snoring, witnessed pauses in breathing, or daytime sleepiness
• To investigate excessive daytime sleepiness that has no clear cause
• To look for periodic limb movement disorder or unusual behavior during sleep
• As part of the workup for narcolepsy, which is usually followed by daytime testing

What to expect

You arrive at the sleep center in the evening, a couple of hours before your usual bedtime, and a technologist spends thirty to sixty minutes placing the sensors with paste and tape. The room is set up like a bedroom. Wires are gathered into a bundle so you can turn over and get up to use the bathroom. Most people sleep less well than at home and still produce a perfectly usable recording. Sensors come off in the morning and you leave early. The skin can be mildly irritated where they sat. A sleep physician scores and reads the study afterward, so results take days, not hours.

Questions worth asking

• Would a home sleep test answer my doctor's question? It is a different code at a fraction of the price, though it records less.
• If sleep apnea shows up part way through the night, the technologist may switch to fitting a CPAP mask. That changes the code — will I be told before it happens, and what is the price difference?
• Does my plan require prior authorization for an in-lab study, and has it been obtained?
• Is there a separate professional fee for the physician who interprets the recording, on top of the sleep center charge?
• Is the center hospital-based or freestanding, and does the facility's price include the interpretation?