First thing you should know: Not all Home Sleep Tests are created equal:
Type 4: Records 3 channels. Airflow, thoracic or abdominal movement, and SpO2. This is one of the two main HSTs (home sleep tests) utilized by HMO insurances in the Sacramento area. Logically, we can all a see that this doesn’t have anything to do with sleep. This type of test is more of a home breathing test with an all night oximeter added to it. I certainly wouldn’t want to have a sleep disorder diagnosed with this type of device. This is very often auto-scored, which means that whatever the computer spits out is what goes on the report. These are notoriously very faulty. See example below of this. The clear breathing events are completely missed. (click to enlarge). The top and bottom segments of the screenshot are the same channels at different speeds. (top is the entire night, the bottom is only a 1 minute window.
You can also see how minimal the testing equipment is in the bottom image. In this case, minimal is not better.
This test is also only used as a screening device. Positive for sleep apnea? Negative for sleep apnea? Doesn’t matter. You’re going back to the lab because the results are virtually always found to be “inconclusive.” Why? No EEG. Without EEG, no breathing abnormalities can be validated or dismissed. The report is just as inconclusive. See the example below of this. (click to enlarge)
Type 3: Records 4 channels. Same as Type 4, but adds ECG/heart rate. This is the other test that is used more frequently, though not so much in the Central Valley. It’s the same as above, but they add ECG. You’ll find these mostly in Cardiologists offices since they like to have an all night tracing of ECG during sleep.
Type 2: Records minimum of 7 channels. EEG, EOG, EMG, ECG, respiratory airflow and effort, and SpO2. At the bare minimum, this test outperforms Type 3 and 4 tests with ease. Sleep times are correct with EEG. This means that the Apnea Hypopnea Index and the Respiratory Disturbance Index are accurate. EEG also means that the stages of sleep you entered and for how long are known. This coupled with body position is very important when considering treatment options for patients found positive for Sleep Apnea. Picture of Sleep Testing Patient.