How Can I Monitor Sleep Apnea at Home?

In the individuals suffering from sleep apnea, due to fat deposition between the muscle fibers, the tongue and the throat muscles have poor tone. These muscles go flaccid as the person sleeps, causing the airways to collapse. Such a person has a period of no breathing for a short time that awakens him for a second and he drifts off to sleep again. The prolonged cycle of awakening and sleeping throughout the night limits the amount of time spent in deeper sleep stages. Untreated OSA is a risk factor for hypertension, stroke, heart failure, poor work performance, and accidents.

Hence, it is important to diagnose sleep apnea in time and treat it.

Sleep apnea can be monitored in sleep studies. These can be done in sleep laboratories under the supervision of a sleep specialist or using home sleep monitors (HSMs). HSMs need a prescription by your doctor. The home sleep monitors are easily accessible and cheaper compared to a study conducted at a sleep laboratory. These monitors have the following portals to monitor the body’s responses in sleep:

• Respiratory channels: There are nasal prongs and a sensor to provide nasal oxygen that measure the pressure changes during breathing in sleep.
• A pulse oximeter attached to your finger or earlobe measures your blood oxygen saturation.
• Single-lead electrocardiography or ECG is used for this measuring your pulse rate.
• The chest and abdominal belts are used to measure breathing effort and movement in your sleep.
• Snoring assessment is done using microphone placed on the neck.

The monitor uses the above tools to study your breathing efforts while you sleep. It will measure pauses in your breathing and whether your breathing is shallow. These devices then calculate your apnea-hypopnea index (AHI). AHI tells whether you have obstructive sleep apnea and, if so, how serious it is.

The American Association of Sleep Medicine advocates the following guidelines to diagnose OSA:

• Mild: AHI of 5-15 apnea events per hour
• Moderate: AHI of 15-30 apnea events per hour
• Severe: AHI of greater than 30 apnea events per hour

For most adults, an AHI of 5 or more is typically considered abnormal. Severe sleep apnea may often need radical lifestyle changes and surgical intervention.

The following types of home sleep monitors are available in the market:

• Type II monitors are the most elaborate home sleep monitors, and hence seldom used at home. They consist of seven channels that measure your brain activity (electroencephalogram or EEG channel), your eye movements (electrooculography or EOG channel), your muscle twitches (electromyogram), heart rate (ECG), respiratory effort using special channels, and oxygen saturation (pulse oximeter) in sleep.
• Type III monitors are limited channel devices. They have a minimum of four monitored channels, including airflow channels (respiratory movement or respiratory movement and airflow), ECG, and pulse oximetry channels.
• Type IV devices measure only one or two parameters (e.g., oxygen saturation or airflow). These are the most used home sleep monitors.

Depending on the type of home sleep monitor used, this procedure is around 86-100% sensitive and around 64-100% specific to diagnose sleep apnea.

A thorough study should be done at the sleep laboratory under the supervision of a sleep specialist to confirm the diagnosis of home sleep studies.