High-Impedance, Dry Physiological Recording Optrode

This proposal addresses the development of a dry, high-impedance electrode for physiological monitoring in operational environments. In particular, a device is proposed that uses optical fiber based voltage sensing technology to provide an optoelectronic interface to standard electrical recording devices. This optical-based-electrode (optrode) can be placed in contact with the skin and record physiological signals without requiring any special skin preparation. When placed in the helmet, a suite of such optrodes would provide the high-impedance, high-sensitivity interface needed to monitor the physiological status of various warfighters, including aviators, in battlefield scenarios. The optrode consists of a miniature electro-optic crystal based intensity modulator mounted at the end of an optical fiber. The optical interface uses the electro-optic effect to convert weak bioelectric potentials, produced at the skin surface, to measurable electrical signals. Common-mode rejection of unwanted electrical signals is provided by applying the outputs of the optrodes to remote differential amplifiers connected to conventional physiological recording devices. Because the electro-optic crystal presents a very high impedance and very low capacitance, the optrode need not be in good physical contact with the head. Therefore, the points of contact can be dry. It should thus be feasible to obtain routine, real-time physiological recording with the minimum of setup time. BENEFITS: The -need for time-cionsuming and troublesome electrode attachment and allow medical personnel to routinely monitor various important physiological parameters. The system would allow for a wide spectrum of monitoring capabilities for patients outside of a restrictive hospital setting. For example, this technology can be used in many civilian applications involving health and safety patient monitoring by fireman, police and rescue workers during emergency situations.