Journal: Scientific Reports

Article Title: Detection of sleep apnea using smartphone-embedded inertial measurement unit

doi: 10.1038/s41598-025-99801-3

Figure Lengend Snippet: Respiratory amplitude (cyan line in ( A )) and frequency (dark green line in ( B )) extracted from IMU acceleration signal of an Android smartphone in a representative subject with sever sleep apnea during a PSG examination. In ( A ), the magenta and blue lines are the fast and slow envelopes (95th percentiles within 3-s and 30-s moving windows) of the respiratory amplitude, respectively. The black vertical lines with blue triangles are respiratory events (REs) detected as a > 30% reduction in the fast envelope from the slow envelope lasting 10–90 s. In ( B ), blue line is the upper envelope (95th percentile of 30-s moving window) of the respiratory frequency. Vertical black bars with green triangles are REs detected as > 30% reduction in the respiratory frequency from the envelope lasting 10–90 s. To avoid double counting of RE by both respiratory amplitude and frequency, the RE detection by the respiratory frequency was suppressed while the fast envelope of the respiratory amplitude was > 30% below the slow envelope. In ( C ), vertical red bars are RE (apnea and hypopnea episodes) detected by the simultaneous PSG.

Article Snippet: We examined three IMU-embedded devices: a GPS device (Amue Link ® LM-001, Sony Network Communications Inc., Tokyo, Japan), an Android smartphone (Xperia 8 ® Lite, Sony Corporation, Tokyo, Japan), and an iOS smartphone (iPhone SE ® 3rd generation, iOS 17.2.1, Apple Inc., Cupertino, CA, USA).

Techniques:

Journal: Scientific Reports

Article Title: Detection of sleep apnea using smartphone-embedded inertial measurement unit

doi: 10.1038/s41598-025-99801-3

Figure Lengend Snippet: Respiratory amplitude (cyan line in ( A )) and frequency (dark green line in ( B )) extracted from the IMU acceleration signal of an Android smartphone during normal breathing in a subject undergoing a PSG examination. In ( A ), the magenta and blue lines, which show the fast and slow envelopes of the respiratory amplitude, respectively, overlap, and RE is not detected. ( B ) The blue line, which shows the upper envelope of the respiratory frequency, overlaps with the respiratory frequency itself, and RE is also not detected. RE is not detected in the simultaneous PSG ( C ).

Article Snippet: We examined three IMU-embedded devices: a GPS device (Amue Link ® LM-001, Sony Network Communications Inc., Tokyo, Japan), an Android smartphone (Xperia 8 ® Lite, Sony Corporation, Tokyo, Japan), and an iOS smartphone (iPhone SE ® 3rd generation, iOS 17.2.1, Apple Inc., Cupertino, CA, USA).

Techniques:

Journal: Scientific Reports

Article Title: Detection of sleep apnea using smartphone-embedded inertial measurement unit

doi: 10.1038/s41598-025-99801-3

Figure Lengend Snippet: Relationships between apnea-hypopnea index (AHI) of polysomnography and the hourly frequency of RE-positive breaths obtained from smartphone IMU signals in the training ( A – C ) and test groups ( A ʹ– C ʹ); ( A , A ʹ) Amue Link, ( B , B ʹ) Xperia, and ( C , C ʹ) iPhone. r correlation coefficient, RE respiratory event, RMSE root mean squared error.

Article Snippet: We examined three IMU-embedded devices: a GPS device (Amue Link ® LM-001, Sony Network Communications Inc., Tokyo, Japan), an Android smartphone (Xperia 8 ® Lite, Sony Corporation, Tokyo, Japan), and an iOS smartphone (iPhone SE ® 3rd generation, iOS 17.2.1, Apple Inc., Cupertino, CA, USA).

Techniques:

Journal: Scientific Reports

Article Title: Detection of sleep apnea using smartphone-embedded inertial measurement unit

doi: 10.1038/s41598-025-99801-3

Figure Lengend Snippet: Bland-Altman plots between polysomnographic AHI and smartphone-IMU REIs in the training ( A – C ) and test groups ( A ʹ– C ʹ); ( A , A ʹ) Amue Link, ( B , B ʹ) Xperia, and ( C , C ʹ) iPhone. Horizontal dotted lines indicate mean difference and dashed lines indicate the limits of agreement (± 1.96 SD) between two measures.

Article Snippet: We examined three IMU-embedded devices: a GPS device (Amue Link ® LM-001, Sony Network Communications Inc., Tokyo, Japan), an Android smartphone (Xperia 8 ® Lite, Sony Corporation, Tokyo, Japan), and an iOS smartphone (iPhone SE ® 3rd generation, iOS 17.2.1, Apple Inc., Cupertino, CA, USA).

Techniques: