Physiological signal monitoring system

Abstract

A health monitoring and biofeedback system comprising a photoplethysmography (PPG) sensor, a processing device, and a Web site server for determining, displaying and analyzing various cardiovascular parameters. The PPG sensor is installed within a manually operated user input device such as a mouse or keyboard, measures a user's blood volume contour and transmits it to a processing device such as a personal computer or a personal digital assistant (PDA). The system determines a plurality of cardiovascular indices including mean blood pressure, heart rate, body temperature, respiratory rate, and arterial compliance on the basis of signal characteristics of the systolic wave pulse and the systolic reflected wave pulse present within the digital volume pulse derived from the PPG pulse contour. Signal characteristics of the systolic reflected wave pulse can be determined through various pulse analysis techniques including derivative analysis of the digital volume pulse signal, bandpass filtering or respiratory matrix frequency extraction techniques. By subtracting the systolic reflected wave pulse contour from the digital volume pulse contour, characteristics of the systolic wave pulse can also be identified. The system also provides for the accurate determination of systolic and diastolic blood pressure by using a non-invasive blood pressure monitor to calibrate the relationships between arterial or digital blood pressure and characteristics of the user's digital volume pulse contour. In this way, a wide variety of cardiovascular and respiratory data can be obtained. The system also facilitates the transmittal of such data to the system web site for further analysis, storage, and retrieval purposes.

1 . A manually operated user input device for simultaneously sensing a physiological characteristic of a user and for providing input of data unrelated to the physiological characteristic, said device comprising: 
 a) a housing having a surface in at least intermittent contact with a portion of the user's finger;    b) at least one PPG sensor disposed on said surface for sensing the physiological characteristic of the user; and    c) manually operated means for inputting data to the user input device, said data unrelated to the physiological characteristic.    
     
     
         2 . The user input device of  claim 1 , wherein said PPG sensor comprises an LED and a photodiode.  
     
     
         3 . The user input device of  claim 2 , wherein said user input device comprises two PPG sensors.  
     
     
         4 . The user input device of  claim 1 , wherein said PPG sensor comprises two LEDs and a photodiode.  
     
     
         5 . The user input device of  claim 1 ,  2  or  3 , wherein each said PPG sensor is operating in reflective mode.  
     
     
         6 . The user input device of  claim 1 ,  2  or  3 , wherein said user device includes baffle means adapted to house each said LED and each said photodiode so as to prevent direct coupling of light between each said LED and each said photodetector.  
     
     
         7 . The user input device of  claim 1 , wherein said user input device is powered by the universal serial bus of a personal computer.  
     
     
         8 . The user input device of  claim 1 , wherein said user input device further comprises biasing means for holding said user's finger against each said PPG sensor with constant and predictable pressure and for shielding said PPG sensors from ambient light.  
     
     
         9 . The user input device of  claim 1 , wherein a finger cuff bladder device is used to determine a transfer function relating said blood volume contour with said pressure pulse contour of the user's radial artery.  
     
     
         10 . The user input device of  claim 1 , wherein said user device is a mouse.  
     
     
         11 . The user input device of  claim 1 , wherein said user device is a track ball.  
     
     
         12 . The user input device of  claim 1 , wherein said user device is a track pad.  
     
     
         13 . The user input device of  claim 1 , wherein said user device is a keyboard.  
     
     
         14 . The user input device of  claim 1 , wherein said user device is a joystick.  
     
     
         15 . The user input device of  claim 1 , wherein said user device is a personal digital assistant.