A Mind-Bending VR Experience

From Meta’s range of virtual reality (VR) headsets to Apple’s recently released Vision Pro, a lot of effort is being focused on developing immersive computing experiences these days. But while these devices offer ultra-high resolution displays for a highly immersive visual experience, that alone is not enough to simulate reality. Even if a virtual object is perfectly convincing by sight, the illusion will break the moment a user’s hand passes through it without the slightest sensation.

To be fully immersive, VR systems also need to account for our other senses — especially touch. Many advancements have been made in this area, with a variety of haptic interfaces now being available to simulate the sensation of touch. Unfortunately, these systems typically work by placing some type of device at the site of stimulation. For example, vibration motors may need to be individually placed on each fingertip to simulate the feeling of touching an object with one’s fingers. Clearly this approach quickly becomes impractical when fully-body haptic interfaces are needed for an application.

Before this field can move beyond its infancy, radically different solutions are needed. The creative geniuses in Pedro Lopes’ lab at the University of Chicago have once again created a mind-blowing (hopefully not literally!) haptic interface that may ultimately move the field forward. Called the Haptic Source-effector, their wearable system is composed of a single haptic device that directly stimulates the user’s brain to produce haptic sensations anywhere in their body. It does this via magnetic stimulation, which is noninvasive, and according to the researchers, safe for human use.

The key technology that enables the Haptic Source-effector is transcranial magnetic stimulation (TMS), which is used in medicine to stimulate the brain, primarily for the treatment of certain neurological and psychiatric conditions like major depressive disorder. But in this case, the team used TMS to elicit specific haptic sensations. This was achieved by positioning a single medical-grade magnetic coil over the head, which is mechanically moved on tracks to move it to the desired position. By stimulating specific regions of the user’s sensorimotor cortex with electromagnetic pulses, it was demonstrated that at least 15 sensations could be produced throughout the body, from the jaw down to the hands and feet.

To evaluate the Haptic Source-effector, a group of 12 participants were outfitted with the device in addition to a Meta Quest 2 VR headset. They played the role of a cyborg trying to escape a malfunctioning robotics factory. As they progressed through the simulation, the visual effects were paired with sensations around the entire body. In general, the participants were surprised by how realistic the sensations were, and they noted that they felt like the experience was really happening. Some also commented that they could feel the TMS coil moving around on their head, which is not entirely surprising given how large and cumbersome this early prototype headset is.

While TMS is generally considered to be safe, there are a few risks. In most cases, it causes nothing more than localized tingling, but for those with medical implants, it could cause dangerous interference. It is unclear, however, what percentage of the population would find magnetic brain stimulation acceptable for entertainment purposes, even if the risk level is generally considered to be quite low. This could certainly be a factor that prevents widespread adoption of the technology.

Looking ahead, the team is planning to improve the mechanics of their system and reduce both the size and weight to make it more practical. They are also considering ways that they might be able to focus the haptic effects on smaller areas of the body.