Abstract: A system for non-invasively determining the oxygenation state of tissue located beneath the surface of the skin, such as muscle tissue, of an exercising person or other subject is disclosed. In a preferred embodiment, a user-wearable detector array and related circuitry which use near-infrared radiation to collect oxygenation data are provided. The apparatus also includes displays for displaying information regarding the oxygenation state in several ways. In one embodiment a user wearable wristband indicator connected to the detector array which is located at another location, such as on the leg, and provides information directly to the user. In another embodiment, a telemetry device allows remote monitoring of a subject during an activity, the oxygenation information being displayed to a coach or other observer. A separate, user-wearable battery pack, which is preferably designed to provide power for the duration of the activity being monitored, is also provided.

Abstract: The present invention to provides methods and apparatus for studying photon migration using signal modulation techniques such as time, frequency and phase modulation. The photon migration data may then be converted, using the principles of time-resolved spectroscopy, to determine the concentration of an absorptive constituent in a scattering medium, such as the concentration of hemoglobin in a brain of other tissue. The methods and apparatus disclosed provide as a specific embodiment, a dual wavelength phase modulation system which allows the clinical application of the advantages of time resolved spectroscopy in an economical and commercially feasible embodiment.

Abstract: The present invention to provides methods and apparatus for studying photon migration using signal modulation techniques such as time, frequency and phase modulation. The photon migration data may then be converted, using the principles of time-resolved spectroscopy, to determine the concentration of an absorptive constituent in a scattering medium, such as the concentration of hemoglobin in a brain of other tissue. The methods and apparatus of the present invention provide as a specific embodiment, a dual wavelength phase modulation system which allows the clinical application of time resolved spectroscopy in a commerically feasible embodiment.