*Article* **A Wearable Prefrontal Cortex Oxygen Saturation Measurement System Based on Near Infrared Spectroscopy**

**Yi Han 1,2,† , Qian Zhai 1,† , Yinkai Yu <sup>1</sup> , Shuoyu Wang <sup>2</sup> and Tao Liu 1,\***

	- <sup>2</sup> Department of Intelligent Mechanical Systems Engineering, Kochi University of Technology, Kochi 782-8502, Japan; wang.shuoyu@kochi-tech.ac.jp

**Abstract:** The measurement of blood oxygen saturation in the prefrontal cortex (PFC), especially during sleep, is of great significance for clinical research. Herein, we present a wearable PFC oxygen saturation measurement system using dual-wavelength functional near-infrared spectroscopy. The system is well designed for user-friendly donning and has the advantages of comfort, convenience, portability, and affordability. The performance of the proposed system is investigated by the calibration and experimental results. The wearable system has demonstrated great potential to conduct the physiological monitoring of PFC, and it can be widely deployed in daily life.

**Keywords:** near infrared spectroscopy; wearable; portable; prefrontal cortex oxygen saturation
