title: Noninvasive measurement of heartbeat, respiration, snoring and body movements of a subject in bed via a pneumatic method.
abstract: We have developed a noninvasive pneumatics-based system by which to measure heartbeat, respiration, snoring, and body movements of a subject in bed. A thin, air-sealed cushion is placed under the bed mattress of the subject and the small movements attributable to human automatic vital functions are measured as changes in pressure using a pressure sensor having an almost flat frequency response from 0.1 to 5 kHz and a sensitivity of 56 mV/Pa. Using the newly developed system, heartbeat, respiration, apnea, snoring and body movements are clearly measured. In addition, the optimal signal-to-noise (S/N) ratio by which to evaluate the reliability of the heart rate measurement is presented. Heart rates were measured for four different body postures, 13 different subjects, four different bed mattresses, and three different sensor positions. For these measurements, the S/N ratios ranged from 15.9 to 23.5 dB, and so were determined to be reliable.
authors.affiliation: System Control Engineering Department, Faculty of Engineering, Hosei University, 3-7-2 Kajinocho Koganei, Tokyo 184-8584, Japan. bob@k.hosei.ac.jp
authors.forename: Kajiro
authors.initials: K
authors.lastname: Watanabe
authors.forename: Takashi
authors.initials: T
authors.lastname: Watanabe
authors.forename: Harumi
authors.initials: H
authors.lastname: Watanabe
authors.forename: Hisanori
authors.initials: H
authors.lastname: Ando
authors.forename: Takayuki
authors.initials: T
authors.lastname: Ishikawa
authors.forename: Keita
authors.initials: K
authors.lastname: Kobayashi
mesh_terms: D001513:Beds; D003936:Diagnosis, Computer-Assisted / Q000295:instrumentation / Q000379:methods*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008365:Manometry / Q000295:instrumentation / Q000379:methods*; D009068:Movement / Q000502:physiology*; D017286:Polysomnography / Q000295:instrumentation / Q000379:methods*; D015656:Respiratory Mechanics / Q000502:physiology*; D012913:Snoring / Q000503:physiopathology*