Psychophysiological Responses of Cut Flower Fragrances as an Olfactory Stimulation by Measurement of Electroencephalogram in Adults.

Horticultural therapy (HT) is green care that can help improve and recover the health of modern people living in cities through natural experiences. Many studies have been conducted to determine HT's therapeutic effects and underlying mechanisms, but investigation for developing readily applicable clinical techniques is insufficient. We aimed to investigate adults' brain activity and emotional state during flower arrangement (FA) with different flowers in an HT program. We recruited thirty adults and used a randomized cross-over study method to set them to participate in five FA tasks at 90-s intervals. While performing FA tasks, the participants' prefrontal cortex brain waves were measured by a wireless electroencephalography device and their emotional states between FA tasks were measured by questionnaires. Results showed that each FA task resulted in a different attention level of the participants. The participants showed the highest attention level during FA with stocks and carnations, while FA with lilies showed the lowest attention level among the five FA tasks. Instead, the participants showed the highest arousal, tension, and anxiety for emotional states during FA with lilies. Therefore, this study confirmed the differences in attention level and emotional changes according to flower types for using clinical techniques of HT for various clients.