Background Previous studies have found that exploring and evaluating the mental fatigue state on medical staff is of great significance to improve productivity in the workplace. However, the physiological markers for exploring and evaluating the mental fatigue state on medical staff have not yet been identified. As a non-invasive, portable and simple brain functional imaging technology, near-infrared spectroscopy (NIRS) can monitor the blood oxygen reaction in prefrontal lobe in real time, which may provide evidences for identifying and evaluating the mental fatigue state.
Objective To detect the variation of blood oxygen reaction in the prefrontal cortex of medical staff under different fatigue levels based on logical operation tasks by near-infrared spectroscopy.
Methods From February to March in 2016, 74 medical workers were randomly selected from a hospital, including 22 males (29.73%) and 52 females (70.27%), aged from 19 to 40 (28.97±1.82) years. The participants were divided into mild, moderate, and severe groups by the visual simulation score method according to the subjective fatigue degree. The near-infrared spectroscopy was used to detect the transition of oxyhemoglobin and deoxyhemoglobin in the frontal lobe region while completing the logical operation task, and the differences in oxidized hemoglobin and deoxyhemoglobin in frontal lobe of patients in the three groups were compared.
Results During baseline, there were no statistically significant differences in oxy-Hb content and Deoxy-Hb content at any channel (P＜0.05). In different fatigue states, oxy-Hb content was compared during logic operation task. Compared with severe fatigue, the oxy-Hb content decreased significantly in CH14, CH15 and CH16 channels during moderate fatigue (P＜0.05), and it increased significantly in CH13 during mild fatigue when compared with moderate fatigue (P＜0.05, respectively). The Deoxy-Hb content in CH4 channel decreased significantly during mild fatigue when compared with moderate fatigue, and in CH9, CH12, CH13, CH15 and CH16 channels when compared with severe fatigue (all P＜0.05).
Conclusion NIRS can detect the activation state of frontal lobe under logic operation task. Under different fatigue states, there are significant differences in cerebral blood oxygen content when dealing with complex tasks. The cerebral oxygen content decreases in some brain regions while increases significantly in other brain regions, indicating that the brain activity increases and the body compensation mechanism appears in the subjects.
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