Preliminary study on electrotactile sensitivity of the lips

Area of Science:

• Biomedical Engineering
• Neuroscience
• Human-Computer Interaction

Background:

• The lips possess high tactile sensitivity due to extensive cortical representation.
• Previous research highlights the potential for tactile displays in wearable technology.
• Lips have not been previously explored for tactile display applications.

Purpose of the Study:

• To evaluate the sensitivity and discriminating ability of the lower lip for tactile display applications.
• To establish baseline electrotactile characteristics of the lips.
• To inform the design of novel lip-based wearable haptic interfaces.

Main Methods:

• Conducted a preliminary study on five human subjects.
• Utilized three electrotactile stimulator arrays of varying sizes (75 µm to 1.55 mm diameter).
• Measured sensory thresholds and assessed two-line separation discrimination for electrotactile patterns.

Main Results:

• The lower lip requires low intensities for effective electrotactile stimulation (thresholds decreased from 11.6 V to 6.6 V with increasing stimulator diameter).
• Discrimination of two-line separation improved significantly with larger stimulator diameters (correct ratings increased from 47.3% to 84.8%).
• Demonstrated a clear relationship between stimulator geometry and electrotactile perception on the lips.

Conclusions:

• The lips exhibit significant potential for electrotactile stimulation.
• Optimizing stimulator design, particularly diameter, is crucial for effective lip-based tactile displays.
• This research provides foundational data for developing user-friendly, hands-free wearable haptic devices utilizing lip sensation.