13th January 2024

Home studies

Home studies tend to be a cheaper and more available alternative. The portable devices can be taken home and used to assess airflow, respiratory effort, oximetry and cardiac rhythm (or even used just to measure overnight oximetry!). The sleep staging component is the absent measure. Home studies are particularly useful in patients with a high pre-test probability of diagnosis.

Portable or home studies will not measure sleep and stages. From the other data points though we can derive:

• Respiratory Event Index (REI): the number of apnoeas or hypopneas during recorded time. Because this time doesn’t record sleep itself (the recorded time is longer than the total time spent), this can underestimate the ratio of apnoeas/hypopneas to actual time asleep.

Image Source: Wikimedia Commons (2017). Polysomnography tester, Licensed under a creative commons licence. Available for free at: https://upload.wikimedia.org/wikipedia/commons/0/0d/Polysomnography_tester.jpg  (Accessed: 9 August 2022).