The accuracy of BresoDX® versus the PSG standard has been tested and validated in several clinical trials.
Below are links to the scientific research studies and publications.
Alshaer H, Fernie GR, Tseng WH, Bradley TD, Sleep Medicine. 2015; 15:2041
The objectives of this study were to: 1) test the validity of BresoDX, a portable sleep apnea monitoring system, for determining the apnea-hypopnea index (AHI) versus that derived from simultaneous polysomnography (PSG), and 2) determine the accuracy and reliability of using BresoDX to quantify the AHI in the unattended home setting. 135 subjects underwent full overnight PSG and simultaneous recording by BresoDx, in the sleep laboratory. A subset of 100 subjects had subsequent overnight unattended BresoDX recordings in their own homes on a separate night.
There was 95% correlation (see Figure) between the AHI determined by BresoDx (AHI-BresoDx) and that by simultaneous PSG (AHI-PSG). Of the 100 subjects who underwent home testing by BresoDx, the mean home AHI did not differ from that derived from PSG (12.8 ± 12.1 vs 13.9 ± 13.8, p = 0.60). Using the diagnostic AHI cutoffs of ≥ 10, 15 and 30 (for identifying severe cases), the areas under the receiver operating curves were 0.84, 0.86 and 0.86, respectively, indicating very good sensitivity and specificity for home diagnosis of sleep apnea.
BresoDX is highly accurate in determining the AHI compared to simultaneous PSG, and has good sensitivity and specificity in diagnosing sleep apnea at various AHI cutoffs when used unattended at home. It is therefore a feasible and reliable means for diagnosing sleep apnea at home.
Alshaer H, Fernie GR, Maki E, Bradley TD, Sleep Medicine. 2013; 14:562.
The objective of this study was to test the validity of a single-channel portable monitoring system that captures breath sounds (BSs) during sleep on a microphone that is embedded in a face-frame and written on to a microprocessor. BSs were recorded from 50 patients undergoing simultaneous polysomnography (PSG) for suspicion of sleep apnea. Using novel software, BSs were analyzed to identify apneas and hypopneas from which the acoustic apnea-hypopnea index (AHI-a) was calculated. The AHIs from PSG (AHI-p) were scored by three technicians blinded to the scoring of the other two technicians according to two criteria: 1) a tidal volume (TV) based criterion that required at least a 50% reduction in the TV signal for at least 10 seconds but not requiring an oxygen desaturation or an arousal from sleep to score a hypopnea (TV50), and 2) AASM criteria that included at least a 30% reduction in the TV signal for at least 10 seconds plus either a 3% oxygen desaturation or an arousal from sleep to score a hypopnea.
BresoDX derived AHI correlated strongly with that from PSG according to both the TV50 criteria (R=0.94) and AASM criteria (R=0.93). Based on a cutoff of AHI-p≥10, overall accuracy of BresoDx AHI was 90% and negative predictive value was 100%.
Acoustic analysis of BSs via a portable monitoring system is a reliable method for quantifying the AHI and diagnosing sleep apnea compared to simultaneous PSG. Scoring hypopneas with or without oxygen desaturation and arousals had a negligible effect on the correlation and accuracy of the portable monitoring system in determining the AHI.
Hummel R, Bradley TD, Packer D, Alshaer H. Conf. Proc. IEEE Eng. Med. Biol. Soc. 2016, 2236.
Breath sounds from BresoDX in 29 patients were analyzed to distinguish central from obstructive apneas and hypopneas. Compared to PSG, 92% of central and obstructive events were classified correctly. This study demonstrates the ability of breath sound analysis to accurately distinguish central from obstructive events.
Zhu K, Bradley TD, Patel M, Alshaer H, Sleep and Breathing. 2017; Epublished ahead of print.
In 26 subjects, movement of the head into the lateral position while the body remained supine resulted in a significant reduction in the apnea hypopnea index (AHI) from a mean of 36 to 26 (p=0.008) compared to when head and body positions were both supine. These results demonstrate an important influence of head position on the AHI independently of body position in OSA patients.
Ryan CM, Milton K, Bradley TD, Alshaer H. Sleep and Breathing. 2017; 21:453.
Sleep apnea (SA) is common in stroke patients, but often undiagnosed due to disability and inaccessibility of PSG. 23 stroke patients used BresoDX, and 78% of them had SA (AHI≥15) on simultaneous PSG. The correlation between AHI from BresoDX and PSG was 0.91. BresoDX had 90% sensitivity, 85% specificity and 87% accuracy for diagnosing SA (AHI≥15) vs PSG.
Therefore, BresoDX is both feasible and accurate to diagnose SA in stroke patients.
Alshaer H, Pandya A, Bradley TD, Rudzicz F. IEEE ICASSP. 2014, 3577.
Breath sounds recorded from a portable device (BresoDX) were analyzed by a computer algorithm to detect snoring compared to human ear. Mean accuracy for separating data into 2 classes, snoring and non-snoring, reached 97.8%. Therefore this computer scoring system provides very high accuracy for automatic detection of snoring.
Hummel R, Bradley TD, Fernie GR, Chang SJ, Alshaer H, Conf. Proc. IEEE Eng. Med. Biol. Soc. 2015, 5416.
We tested an actigraph embedded in a portable device, BresoDX, to measure head motion to detect sleep/wake state in 75 patients with sleep apnea (SA) vs simultaneous PSG.
The results show that head actigraphy was 92% accurate in detecting sleep compared to PSG. This indicates very good performance equivalent to wrist actigraphy in detecting sleep status in SA patients.
Alshaer H, Levchenko A, Bradley TD, Pong S, Tseng WH, Fernie GR. J. Clin. Monit. Comput. 2013; 27:303.
We studied 49 subjects who used a portable device (BresoDX) at home of whom 32 also had simultaneous PSG on another night. 11 also had a second home test. There was a strong relationship between portable AHI and PSG AHI (R=0.96). 9 of the 11 (82%) subjects had equivalent results on both home nights. Our results confirm strong agreement between AHI derived from the portable device vs PSG, and excellent usability of the portable device for assessment at home.
Alshaer H, Rudzicz F, Falk T, Tseng WH, Bradley TD. 35th IEEE EMBS Conference, Osaka, Japan
July 3-7, 2013; 2080.
Alshaer H, Fernie GR, Bradley TD. J Clin Monit Comput. 2011; 25(5):285.
Alshaer H, Garcia M, Radfar H, Fernie GR, Bradley TD. Proc IEEE, Intl Conf on Acoustics, Speech, and Signal Processing, 2011; Prague, 681.
Alshaer H, Fernie GR, Bradley TD, Int. J. Healthcare Technology and Management. 2010, 11, 163.
Alshaer H, Fernie GR, Sejdic E, Bradley TD. Proc IEEE Toronto International Conference – Science and Technology for Humanity (TIC-STH), Toronto, Canada, 2009; 279.