Tactile phantom sensation for coaching respiration timing.

Respiration coaching is one of the key factors for radiation therapies. However, there are relatively few studies relating to respiration coaching, and most of them use audio or visual cues. In this paper, we show that a tactile phantom sensation moving continuously on the back can be used to adequately coach respiration timing. By using the tactile modality, the device rarely interferes with other communication channels used by therapists. The phantom sensation simplifies the mechanical structure. Several parameters were studied to obtain optimal performance when utilizing the phantom sensation. In a series of experiments, we determined the proper position and duty ratio for the actuators. To evaluate the device performance, we conducted an interference test (Kraepelin test), and the results suggest that the developed device interferes little with cognitive tasks. The experiments suggest that participants can easily understand stimulation on the back in terms of respiration guidance and properly follow changes in the cycle period with changes in respiration activity.