A Soft Thermal Modulation and Physiological Sensing System for Neuro-Vascular Assessment

A non-invasive, soft, thermal modulation system was designed and evaluated for use in physiological experiments to assess neuro-vascular health. The system stimulates biomechanisms involved in thermoregulation by varying the temperature of the skin with a soft, fluidically-controlled thermal pad. The silicone-based thermal pad was strategically embedded with graphite particles to improve the base thermal conductivity. The temperature control mechanism was achieved by implementing a proportional-integral control loop with feedback from a thermistor in touch with the skin. To verify the system operation, physiological signals were collected from a human subject to monitor local blood volume changes and autonomic nervous system activity in response to temperature modulation. The mechanisms associated with thermoregulation were quantified by extracting features from the measured biosignals. This work compares the design of the soft, fluid-based system to a previous rigid design. The presented design reduces the mass of the on-body system and eliminates painful pressure on the skin, while inducing physiological modulation as shown by the bio-signal results. The system provides a wearable interface for a multitude of physiology experiments that could require temperature modulation.