A New Movement Monitoring System for Patients in Hospitals and Welfare Facilities
Yoshiharu Yonezawa, Yasuaki Miyamoto, Hiromichi Maki, Hidekuni Ogawa, Ishio Ninomiya, Kouji Sada, Shingo Hamada · JAPANES JOURNAL OF MEDICAL INSTRUMENTATION · 2002
A non-restrictive system designed with a new concept has been developed to monitor posture and body movement of in-bed hospitalized patients and welfare facility residents. The system employs electrically conductive textile electrodes, impedance converters, band pass filters, envelope detectors and a low-power 8-bit single chip microcomputer. The electrodes are placed between the bed sheet and the bed mattress or Futon, to record AC (alternating current) signal induced by electrostatic coupling from the 100V AC power line to the patient. The patient's change in posture and body movements, before trying to get out of bed or Futon and after leaving the bed or Futon, are detected by the microcomputer from changes in the induced AC voltage. The microcomputer then informs the nursing station or care person, via the nurse call system or PHS (personal handy phone), that the patient has changed their body position or left from bed or Futon.