Publications with Somnofy

This continuously updated list contains published research papers that discuss Somnofy.

  1. Validation of Somnofy against PSG. Somnofy is a novel noncontact bedside sleep assistant that monitors vital signs fully automated during sleep. Somnofy reaches substantial agreement with PSG on staging sleep (Cohen’s κ = .63). Somnofy may thus be considered a valid tool for furthering the sleep field in specific research questions and areas previously impractical to study.
    1. Ståle Toften, Ståle Pallesen, Maria Hrozanova, Frode Moen, Janne Grønli: “Validation of sleep stage classification using noncontact radar technology and machine learning (Somnofy®)”, available online 6 March 2020, epub ahead of print, Sleep Medicine. DOI: 10.1016/j.sleep.2020.02.022
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  2. Validation of noncontact longitudinal respiratory rate measurement with Somnofy. We argue for respiratory rate as the most important vital sign to detect clinical deterioration. The measurements from the radar-based sleep monitor Somnofy are being compared to respiratory inductance plethysmography (RIP). Respiratory rate deviations from individual baselines can be comfortably identified with Somnofy.
    1. Toften S, Kjellstadli J, Thu O, Ellingsen O. Noncontact Longitudinal Respiratory Rate Measurements in Healthy Adults Using Radar-Based Sleep Monitor (Somnofy): Validation Study. JMIR Biomed Eng 2022;7(2):e36618. DOI: 10.2196/36618
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  3. Detecting sleep apnea events using noncontact radar technology, pulse oximetry, and Machine Learning. The pilot study included 14 participants and resulted in a Cohen’s kappa for a second-by-second classification of event/no event of .81 or almost perfect agreement. For classifying no event/hypopnea/apnea and no event/hypopnea/obstructive apnea/central apnea/mixed apnea, Cohen’s kappa was 0.43 (moderate agreement) and 0.36 (fair agreement), respectively. All participants were correctly classified in terms of sleep apnea severity. The results indicate that radar technology and pulse oximetry could reliably provide information on a second-by-second basis for no event/event which could be valuable for the management of sleep apnea.
    1. Ståle Toften, Jonas T. Kjellstadli, Stig S. Tyvold, Mads H. S. Moxness, “A Pilot Study of Detecting Individual Sleep Apnea Events Using Noncontact Radar Technology, Pulse Oximetry, and Machine Learning”, Journal of Sensors, vol. 2021, Article ID 2998202, 9 pages, 2021. https://doi.org/10.1155/2021/2998202
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  4. Associating sleep in junior endurance athletes with mental strain and training load utilizing a prospective, observational design. Unobtrusive, objective sleep measurements with novel radar technology were obtained, and subjective daily reports of mental strain and training load were collected. The role of subjective sleep quality was investigated to identify whether the reciprocal associations between sleep, mental strain, and training load depended on being a good versus poor sleeper.
    1. Hrozanova, Maria & Klöckner, Christian & Sandbakk, Oyvind & Pallesen, Ståle & Moen, Frode (2020). Reciprocal Associations Between Sleep, Mental Strain, and Training Load in Junior Endurance Athletes and the Role of Poor Subjective Sleep Quality. Frontiers in Psychology. 11. 1-14. 10.3389/fpsyg.2020.545581.
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  5. Elite-level chess players exhibit high emotional and cognitive stress loads related to performance development. Sleep is a crucial recovery strategy, previously implicated in athletic performance. The main purpose of the current study was to investigate the associations between performance development and objectively measured sleep in a sample of 14 Norwegian chess players over a period of 120 consecutive days. The sleep patterns of the chess players with positive performance development were different from the players with negative development.
    1. Moen, Frode & Olsen, Maja & Hrozanova, Maria (2020). Associations Between Sleep Patterns and Performance Development Among Norwegian Chess Players. Frontiers in Psychology. 11. 1855. 10.3389/fpsyg.2020.01855.
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  6. The influence of the menstrual cycle on women’s sleep has been investigated in junior endurance athletes. The authors assessed subjective sleep quality, as well as objective sleep parameters, mental strain, training load and menstrual cycle in junior endurance athletes over 61 consecutive days. The primary aim was to investigate sex differences in objective sleep parameters, including sleep stage distributions, in junior endurance athletes, considering the possible confounding roles of mental strain, training load and subjective sleep quality. The secondary aim was to compare objectively measured sleep during menstrual bleeding and in the different phases of the menstrual cycle in naturally menstruating female endurance athletes.
    1. Hrozanova M, Klöckner CA, Sandbakk Ø, Pallesen S, Moen F (2021). Sex differences in sleep and influence of the menstrual cycle on women’s sleep in junior endurance athletes. PLoS ONE 16(6): e0253376. https://doi.org/10.1371/journal.pone.0253376
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  7. The study investigated the associations between female elite soccer players’ perceived fatigue and their sleep, and the associations between players’ sleep and soccer games. Sleep was monitored with an unobtrusive impulse radio ultra-wideband Doppler radar (Somnofy). Perceived fatigue was based on a self-report mobile phone application that detected daily experienced fatigue. Deep and REM sleep, and respiration rate in non-REM sleep, are key indicators of perceived fatigue in female elite soccer players. Sleep is disrupted during game night, likely due to the high physical and mental loads experienced during soccer games. Sleep normalizes during the 1st and 2nd night after soccer games, likely preventing further negative performance-related consequences.
    1. Moen, F., Olsen, M., Halmøy, G., & Hrozanova, M. (2021). Variations in Elite Female Soccer Players’ Sleep, and Associations With Perceived Fatigue and Soccer Games. Frontiers in Sports and Active Living, 3. DOI:10.3389/fspor.2021.694537
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  8. One study investigated changes in blood serum proteome after 6 hours of sleep deprivation in healthy females. Out of a total of 725 proteins identified in the human blood serum, 34 proteins were significantly differentially expressed after 6h of sleep deprivation at night. Acute sleep deprivation (in females) affects several known biological processes- and molecular function categories which are similarly changed through oxidative stress, immune suppression, neurodegenerative related disorders, and cancer.
    1. Bjørkum, A.A., Carrasco Duran, A., Frode, B. et al. Human blood serum proteome changes after 6 hours of sleep deprivation at night. Sleep Science Practice 5, 14 (2021). https://doi.org/10.1186/s41606-021-00066-2
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  9. An observational study of sleep characteristics in elite endurance athletes during an altitude training camp at 1800 m found changes in the form of reduced total sleep time, but absolutely increased deep sleep and respiration rate during NREM sleep. It is hypothesized that, despite overall small changes in sleep parameters at altitude compared to near-sea level, the accumulated reduction in sleep time and quality might influence recovery in elite athletes.
    1. Hrozanova, M., Talsnes, R.K., Karlsson, Ø., McGawley, K., & Moen, F. (2021). An observational study of sleep characteristics in elite endurance athletes during an altitude training camp at 1800 m. Sleep health. 
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