Study on the relationship between EEG and salivary IgE under step-change temperature environments

The salivary immunoglobulin E (IgE) level that usually acts as an indicator of human immunity could change significantly with the air temperature. Electroencephalography (EEG) is a commonly used technique to assess the thermal responses of the human body to the environment. However, the relations between them under step-change temperatures would still need more evidence. Experiments were conducted in this study to explore the EEG–IgE relation. Three step-changed temperature conditions in the controlled environment by a climate chamber were selected in this study, under which the air temperature was suddenly transitioned from a low temperature of 15°C to higher temperatures of 18°C, 24°C and 30°C, respectively, before returning to the initial low-temperature condition. The subjective questionnaires, the EEG signals and the salivary samples from 14 subjects in these three step-changed temperature conditions were collected. Results showed that the thermal comfort voting was significantly correlated with the EEG spectral power and the IgE concentration. In addition, a significant negative correlation between the frontal lobe spectral power and the salivary IgE changes was observed. The spectral power of the frontal lobe could be used as an objective indicator to evaluate the salivary IgE levels under step-change temperature environments. This study has provided some guidance for future studies of the human immunity responses to the indoor environment in different seasons.