The conventional global standard for diagnosing OSA was in-lab polysomnography (PSG). Home sleep tests (HSTs) can, however, be used to evaluate this issue in the right patient. The same breathing apparatus, pulse oximetry devices, and motion and positional sensors are used in both PSG and HSTs. The results of each test are examined in the same way. Several investigations have found a strong link between the outcomes of multichannel HSTs and PSGs.
Even so, an observed sleep study is necessary if a patient is unable to follow the directions for home sleep testing owing to age or cognitive problems.
An Overview of Home Sleep Study Tests
The necessity for, and relevance of, a HST, according to health professionals, should be premised on the health history of an individual and consultation by a healthcare professional, either personally or through telemedicine. A HST is a clinical diagnosis that must be instructed by a physician to diagnose OSA or assess the efficacy of the treatment. It should never be used for general screening of undiagnosed people.
A HST has the benefit of being a portable sleep apnea device allowing monitoring to take place in the patient’s own home with minimal equipment, resulting in a more relaxed sleeping environment. In addition, sleep apnea diagnostic devices are far less costly and more generally available than PSGs used in facilities. They can be used to diagnose OSA and titrate positive airway pressure (PAP) therapy at home. There are also no reported complications related to sleep testing at home.
HSTs however have a limited capacity to quickly identify and address operational faults, as well as the incapability to detect various forms of sleep disorders and greater involvement for the patient in terms of device installation and use, which may make some patients uneasy.
Furthermore, because sleep and waking states are not directly examined, the complete sleep duration cannot be estimated from a HST recording. Inadequately prepping the patient for HST or misplacing the equipment can result in unclear findings or erroneous readings, just as they might with PSG. However, with a portable sleep apnea device, there is usually no attendant available to resolve these difficulties as they emerge, so the individual may have to redo the study.
Levels of HST Devices
There are four levels of sleep apnea diagnostic devices available; Level 1 through Level 4. They include:
Level 1
A level I sleep test involves the continuous and simultaneous monitoring and recording of numerous physiological and pathophysiological sleep characteristics, as well as physician assessment, analysis, and reporting. It is performed in a medical institution and is usually composed of a lead electroencephalogram (EEG), electrooculogram (EOG), submental electromyogram (EMG), and electrocardiogram (ECG). It should additionally measure and record the following sleep-related characteristics:
- Flow of air
- Breathing effort
- Oxygen saturation by oximetry
- Can be done as an entire night of monitoring for diagnosis alone or as a split overnight study for diagnosis and therapy evaluation.
Level 2
A level 2 sleep study is typically conducted in the comfort of one’s home but some level 2 sleep studies may be done in a sleep lab or sleep clinic. A level 2 sleep study examines cerebral and muscle movement in addition to respiratory activity, oxygen saturation, and heart rate. A level 2 sleep study is so effective it can track leg and body movement, detect periodic limb movement disorder (PLMD), and give a more in-depth examination of the overall length and quality of your sleep.
Level 3
A Level 3 Sleep Study, commonly known as a portable monitoring device or HSAT, can be used to identify obstructive sleep apnea (OSA). Many people prefer this strategy if they don’t have serious symptoms and can do the test on their own at home. If one suspects they have moderate to severe sleep apnea, it’s typically preferable to have a full sleep study done in a lab to provide the most precise findings, as portable monitors tend to underestimate the severity of OSA when contrasted to a sleep test done in a lab.
Level 3 Sleep Studies, which measure oxygen saturation, heart rate, airflow, and exertion while also collecting data about snoring, are now a more useful and available technique to confirm OSA. One utilizes a sleep kit at home to record the respiratory activities, oxygen saturation, and heart rate throughout the night with a level 3 sleep study. A level 3 sleep study measures both snoring and airflow and determines whether you have obstructive sleep apnea.
Level 4
Level IV devices are used to monitor only one or two parameters, for example, oxygen levels or airflow, and they usually contain oximetry, but not just oximetry. As the technology continues to advance, however, modern devices have at least three channels.
Conclusion
Sleep apnea diagnostic devices use a varied number of channels to evaluate respiratory measurements, oxygen levels, pulse rate, chest, and abdominal movement and snoring.
Nose prongs, similar to those used to administer nasal oxygen, are commonly employed to measure airflow. An oral thermistor may be used to detect mouth breathing, and a sensor measures pressure changes. For the majority of HSTs, a pulse oximeter is placed on a finger or earlobe to measure oxygen saturation. A single-lead ECG with an electrode placed to the upper chest can be used to measure heart rate.
Snoring may be detected with a microphone worn around the neck. Respiratory effort is measured using chest and abdominal belts, which helps to distinguish between central and obstructive apneic episodes.
The total absence of movement of either belt is considered a central apneic episode. An obstructive apneic episode, on the other hand, is defined as paradoxical movement during breathing, such as belly expansion during inhalation but no chest expansion.
