Dozee as a Screening Tool for Sleep Apnea Detection and Classification

Obstructive Sleep Apnea (OSA) isa condition where the upper airway muscles relax resulting in airflowobstruction. Central Sleep Apnea is a condition where there is no evidence of completeobstruction but associated with reduced airflow and respiratory effort. Complexsleep apnea syndrome is a combination of both obstructive and central sleep apnea[1]. According to AASM manual apnea and hypopnea are defined as follows: Apneais flow limitation of more than or equal to 90% for atleast 10 seconds whereashypopnea is fall in signal excursion for more than or equal to 30% with 3% dropin saturation or 4% desaturation with an arousal.[2].

Polysomnography (PSG) is the goldstandard for detecting and assessing sleep apnea. It is performed overnight onsubjects in a resource-intensive specialised sleep centre, with the subjectswearing encephalography (EEG) electrodes, oronasal airflow sensors, thoracicand abdominal respiratory inductive plethysmography (RIP) belts,electrocardiography (ECG) sensors, an oxygen saturation finger-clip sensor, abody position sensor. This arrangement is very distracting to the individualand interferes with a decent night’s sleep. Furthermore, the PSG approachnecessitates the use of well-trained personnel and is a costly procedure [3]. BecausePSG is such a resource-intensive process, researchers are constantly lookingfor a simpler, less demanding, and intrusive way to screen for sleep apneafirst, and then propose PSG based on the severity of the screening test.

Ballistocardiography (BCG) is apromising approach that uses a non-invasive way to quantify the body motioncaused by blood ejection during each cardiac cycle [8]. BCG can be used to measurethe micro body motions produced during each cardiac contraction [9], as well asdetect breathing, snoring, and limb movements [4,5], and it can also be madeto work in a contact-free and non-wearable manner. Thus, BCG can be utilised toovercome the PSG system’s problems in a non-invasive way.

Dozee, developed by Turtle ShellTechnologies employs the concept of BCG. Dozee which is placed beneath themattress, detects micro-vibrations, from which proprietary algorithms deriveparameters such as heart rate, respiration, stress levels, restlessness, and sleepquality. It has been validated for heart rate (HR), respiration rate (RR), andmovement measurement. Contact accessories such as SpO2 are also included. Whencompared to the PSG, Dozee is far more user-friendly and comfortable for thesubjects. Since BCG is contactless there is very little risk to the patients.

1. Jayaraj R, Mohan J, KanagasabaiA. A Review on Detection and Treatment Methods of Sleep Apnea. J Clin DiagnRes. 2017;11(3):VE01â€VE03.

2. Gould GA, Whyte KF, Rhind GB, etal. The sleep hypopnea syndrome. Am Rev Respir Dis. 1988;137(4):895â€898.doi:10.1164/ajrccm/137.4.895.

3. Wang, Z., Zhou, X., Zhao, W.,Liu, F., Ni, H., & Yu, Z. (2017). Assessing the severity of sleep apneasyndrome based on ballistocardiogram. PLOS ONE, 12(4), e0175351. doi:10.1371/journal.pone.0175351

4. V. Saran, G. Kumar, U. Dhawan andG. Parchani, "Unsupervised Identification of Cardiac Contraction throughBallistocardiography," 2018 IEEE-EMBS Conference on Biomedical Engineeringand Sciences (IECBES), Sarawak, Malaysia, 2018, pp. 42-47, doi: 10.1109/IECBES.2018.8626652.

5. Saran V., Kumar G., Parchani G.(2019) Unsupervised Extraction of Respiration Cycles ThroughBallistocardiography. In: Luhach A., Jat D., Hawari K., Gao XZ., Lingras P.(eds) Advanced Informatics for Computing Research. ICAICR 2019. Communicationsin Computer and Information Science, vol 1075. Springer, Singapore. https://doi.org/10.1007/978-981-15-0108-1\_14