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What Is Polysomnogram?

Polysomnography is one of the most common tests prescribed by sleep apnea specialists before or after sleep apnea tests or sleep studies. In fact, some people refer to polysomnography as a sleep study in itself. Sleep specialists perform this test in hospitals, dedicated sleep clinics, or free-standing facilities, but you can also sit for an at-home sleep apnea study or home sleep apnea test. The result of this non-invasive, non-surgical procedure is termed a polysomnogram.

What is the Purpose of Polysomnography?

Polysomnography not only helps diagnose sleep disorders but also determines the effectiveness of treatment plans and the need for future adjustments. Through effective observation and innovative equipment, this procedure can provide specific information to sleep technologists, including the following:

  • Unusual behavior or movements

  • Blood oxygen levels

  • Snoring while sleeping

  • Brain waves (EEG)

  • Sleep stages

  • Breathing rates and patterns

  • Leg movements

  • Body positioning

  • Heart rates and rhythms

  • Eye movements

All of these observations are conducted during sleep; a sleep technologist monitors your vital signs and sleeping conditions to chart data and evaluates it for diagnosis and treatment.

Polysomnography may diagnose the following sleep disorders:

  • Parasomnias

  • Bruxism

  • REM Behavior Disorder (RBD)

  • Central Sleep Apnea

  • Periodic Limb Movement Disorder (PLMD)

  • Circadian Rhythm Sleep-Wake Disorders

  • Obstructive Sleep Apnea

  • Complex (or Mixed) Sleep Apnea

  • Narcolepsy

  • Idiopathic Hypersomnia

Although this list depicts a number of common sleep disorders that can be diagnosed through polysomnography, it is not an exhaustive list.

When Should Polysomnography be Performed?

A sleep specialist or medical professional may order polysomnography for various reasons, including potential concerns about the following conditions:

  • Unexplained Chronic Insomnia

  • Sleep Apnea

  • Unusual Behaviors while Sleeping

  • Narcolepsy

  • Periodic Limb Movement Disorder

  • REM Sleep Behavior Disorder

What Happens During a Polysomnography?

Polysomnography is typically conducted by a medical professional or specialized sleep specialist in a major hospital or sleep center. A patient’s appointment generally begins in the evening, approximately two hours before their usual bedtime. The patient sleeps in a private room at the sleep center overnight and may bring in whatever items they deem necessary for their bedtime routine, including their pajamas and bedding.

While the patient sleeps, a technician administers the polysomnography by evaluating their sleep. The technician is able to hear and see inside the patient’s room and even talk to and hear the patient during the night. A technician typically measures the following during polysomnography:

  • Snoring and other noises

  • Brain waves

  • Limb movement

  • Eye movements

  • Body positioning

  • Skeletal muscle activity

  • Breathing patterns - including pauses or absences

  • Heart rhythm and rate

  • Blood oxygen level

  • Blood pressure

The technician typically places small electrodes on the patient’s legs, scalp, chest, and temples to record the data as mentioned above effectively. These sensors are equipped with adhesive patches that allow them to stick to your skin while sleeping. The technician may also use elastic belts around the patient’s chest and stomach to record their chest movements and breathing patterns.

A small removable clip on the patient’s finger monitors their blood oxygen levels. These sensors are connected to flexible and thin wires that transmit data to a computer. Some technicians at sleep centers may also set up specialized equipment to make video recordings, allowing your sleep specialist to diagnose and review the potential changes in your body position during the night.

You may not be as comfortable sleeping in a sleep center as in your home or bed and may face difficulty falling or staying asleep there. However, your inability to sleep does not typically affect the data, as accurate polysomnography results do not require a full night’s sleep. Once the process is complete, the technician will remove the sensors in the morning, freeing the patient to continue their normal daily activities during the day.

How Can You Prepare for Your Polysomnography?

Patients typically do not need comprehensive preparation for polysomnography. All you need to do is literally sleep at your designated sleep center overnight to allow your sleep specialist and technician to record all data related to your sleep schedule. Since it might be difficult or uncomfortable to fall or stay asleep at a new location, you can bring in whatever puts you at ease or makes you comfortable for the night.

It is also essential to avoid alcohol and caffeine consumption during the afternoon and evening before your polysomnography as they may interfere with your normal sleep schedule and information taking.

What Do Polysomnography Results Mean?

It may take around three weeks for a patient to receive the results of a polysomnography. A technician compiles the information from your night of evaluation at the sleep center and evaluates it to graph it into sleep cycles. A sleep center medical professional then evaluates this data, the patient’s medical history, and their sleep history to make a suitable diagnosis. Abnormal or unusual polysomnographs may hint at the following sleep-related illnesses:

  • Sleep apnea or other breathing disorders

  • Narcolepsy or other relevant sources of unusual daytime fatigue

  • Seizure disorders

  • Periodic limb movement disorder or other movement disorders

If your doctor has prescribed polysomnography to diagnose sleep apnea, he may particularly look for the following in your results:

  1. The frequency of hypopnea episodes, which take place when your breathing is partially blocked for ten seconds or more

  2. The frequency of apnea episodes, which takes place when your breathing is completely blocked for ten seconds or more

This data allows your doctor to evaluate your results in accordance with the apnea-hypopnea (AHI) index. The AHI score, along with data regarding muscle movement and brain waves, determines the possibility of a patient having sleep apnea. An AHI score lower than 5 is considered normal, whereas one exceeding 5 holds abnormality. If your AHI score is higher than 5, your medical professional will chart your abnormal results to determine the degree of sleep apnea:

  • An AHI score ranging from 5 to 15 hints at mild sleep apnea.

  • An AHI score between 15 to 30 indicates moderate sleep apnea.

  • An AHI score higher than 30 indicates serious sleep apnea and requires immediate medical attention.

American-board certified and fellowship-trained sleep specialists at SleepRx provide top-notch medical services for the treatment of sleep apnea and other related sleep disorders. You can also sit for an at-home sleep study or home sleep apnea test if you do not wish to leave the comfort of your home or make an appointment with a sleep apnea specialist for an online sleep apnea test.

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