Evaluation of Fatigue Based on Reaction Time and fNIRS of RSVP Small Target Detection

Abstract

Fatigue has an impact on the target recognition accuracy in small target detection task based on the rapid serial visual presentation (RSVP) paradigm. It is necessary to evaluate brain fatigue objectively to adjust RSVP parameters, so as to prolong the effective task execution time. This paper proposes a method to evaluate the degree of brain fatigue based on reaction time and Oxyhemoglobin (HBO) index of functional near-infrared spectroscopy (fNIRS). A 100-min RSVP task was designed to induce the fatigue state. The fNIRS data of 17 channels in the prefrontal cortex (PFC) region and 440 groups of auditory key reaction time data of 11 subjects were collected and analyzed. The degree of brain fatigue can be divided into conscious state and fatigue state by combining the subjective evaluation scale, probability density distribution and cumulative distribution of reaction time, and the concentration change of HBO. The results show that, in the RSVP task, with the increase of brain fatigue, the reaction time of human gradually increases and the overall distribution is lognormal, the reaction time of HBO reduces and the concentration increases in PFC at the same time. Therefore, the reaction time index and fNIRS index can be used as potential indicators to evaluate the brain fatigue model in RSVP small target detection task, and provide the basis for the later research on the monitoring and regulation of brain fatigue.