The relationship between thermal comfort, performance, and electroencephalogram during cognitive tests at normal indoor temperatures in summer

Abstract

Electroencephalograms have been proposed as potential physiological indicators to gauge the thermal comfort and cognitive performance of individuals in indoor environments, yet further experimental validation is required. In this study, a simulated experiment was conducted in a climatic room during summer, with temperatures set at 24 °C, 26 °C, 28 °C, 30 °C, and 32 °C. Twenty participants, attired in typical summer clothing (short sleeves and long pants totaling 0.39 clo), undertook cognitive tests assessing short-term memory and concentration while seated, alongside providing thermal comfort ratings. Electroencephalogram signals were continuously recorded from 14 electrode channels across the brain during the second cognitive test unit, spanning the 70th to 90th minute of experimental exposure. The relative power of electroencephalogram signals was computed and analyzed in conjunction with thermal comfort voting, revealing a significant impact of indoor temperature variations on α-band activity in the occipital lobe, with peak α-band relative power observed at 26 °C. Moreover, the whole-brain α-band relative power was significantly higher in states of thermal comfort compared to discomfort, particularly concentrated in the occipital lobe. Linear correlation analysis between cognitive test results and electroencephalogram signals indicated significant associations between the relative power of whole-brain β, δ, and θ bands and scores from the concentration-focused Flanker test. Channels O1 and P8 emerged as potential candidates for single-channel electroencephalogram signals, offering insights into thermal comfort status and cognitive performance related to concentration.