Absolute Detection Threshold of Vibrotactile Stimulation Pulse Width and Inter-Pulse Gap.

Vibrotactile stimulation is often used in sensory substitution systems and brain-machine interfaces for presenting information to the skin. This paper identifies the temporal resolution required to achieve the absolute detection threshold of vibrotactile stimulation. A custom vibrotactile sleeve was designed to conduct two experiments with multiple trials on seven subjects. The results show that the absolute (50%) detection threshold for a single vibrotactile stimulus is 15ms pulse width with a proposed adequate (90%) detection threshold of at least 25ms pulse width for the average user. Furthermore, the absolute detection threshold for an inter-pulse gap between two vibrotactile stimuli is 15ms, with a proposed adequate detection threshold of at least 20ms inter-pulse gap. This work concludes that a single vibrotactile message should have a temporal resolution of at least 25ms pulse width in addition to 20ms inter-pulse gap. Hence, a single vibrotactile message requires a total of 45ms.