Exploring virtual worlds through the sense of touch.

• Author: Jean, Grace V.
• Position: INSIDE SCIENCE + TECHNOLOGY

* Millions of receptors and sensory cells lie beneath the skin to help us discern the physical world that we live in. Of our five senses, only the sense of touch extends throughout our bodies and allows us to detect the temperature, pressure, movement and texture of objects in our surroundings. Is it any wonder then that digital gizmos are catering more and more to this essential sensor?

Chances are you already own a gadget that incorporates some form of haptics, or tactile feedback technology. Pick up your cell phone, or that PlayStation game controller. Both will vibrate to let you know that you're missing a call or that you're going out of bounds in a video game.

The iPhone and the Nintendo Wii have taken the technology another step further. Now we can swipe our fingers across a glossy surface to expand or contract web browsing screens or cast virtual fishing lines and feel the fish nibbling at the bait.

Some cell phone manufacturers have followed Apple's lead by eliminating their keypads and substituting touch screens as the primary user interface. These devices incorporate vibration-feedback to let users know they have "pressed" a button.

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Until recent years, technologies employing haptics were found mostly in niche applications, such as the automotive and aerospace industries where computer simulations help engineers design vehicles and aircraft. But the concept of tactile feedback has gained so much popularity that it's becoming pervasive in numerous areas.

In the medical realm, computer simulations increasingly are being embraced as useful training tools for surgeons. Researchers are beginning to fuse haptics into these virtual trainers. Using hands-on tools that simulate the appropriate levels of resistance, doctors can "operate" on patients and receive realistic tactile feedback.

One such trainer can be found at Walter Reed Army Medical Center, Md., where scientists at the National Capital Area Medical Simulation Center are developing a computer-based simulator to help medics learn how to do a cricothyroidotomy, or surgical airway in the throat. The simulation blends haptics and stereographic technologies to create a realistic experience for medics. Trainees wear special glasses to see the patient on the computer screen pop out in 3D. Grasping two stylus "pens" that are mechanically connected to motors, trainees can "touch" the patient and feel the bumps and ridges of his throat. When making the incision, the...