Electrical Stimulation Controls Fingers

A new solution from the University of Chicago’s Human Computer Integration Laboratory, combined electrical muscle stimulation (EMS) and mechanical brakes. DextrEMS, a haptic device invented and developed in the Department of Computer Science. As EMS electrodes on the forearm move fingers to their desired position, ratchet brakes at the finger joints lock them in the target gesture and restrict unwanted movement from other fingers.

EMS works by affixing electrodes to the user’s skin, then sending small, painless electrical signals that cause muscles to contract. For controlling the fingers, EMS electrodes are commonly placed on the wrist and forearm, where the finger muscles originate. But because of this distance and the close proximity of muscles for different fingers, it’s hard to control digits independently. Even natural motion, controlled by the brain, struggles to move a single finger without also moving its neighbors.

More information:

https://news.uchicago.edu/story/new-wearable-device-controls-individual-fingers-sign-language-music

BCI Implant Evoke Sense of Touch

Many illnesses and injuries, including stroke, diabetes or spinal cord injury, can produce loss of touch, which makes everyday movements difficult and takes an emotional toll on patients. Imagine not being able to feel a hot cup or the hand holding yours. Previously, through BCI technology, researchers have been able to electrically stimulate certain (gyral) areas of the brain and restore some sensation to the hand. Through this new research, scientists have successfully shown that stimulation of harder to reach (sulcal) areas of the brain using stereoelectroencephalography (SEEG) electrodes can evoke precise sensory percepts in the fingertips.

Through a minimally invasive procedure led by the Institute of Bioelectronic Medicine at the Feinstein Institutes, two patients were implanted with the SEEG electrodes in the sulci (grooves) of the brain. While providing electrical stimulation the study participants reported feelings of tingling or sensation of electricity localized to the hand and fingertips. To research the brain’s response, the same electrodes used for stimulation were also used to record neural signals during mechanical stimulation of the hand. This process has allowed researchers to deepen the current knowledge of neural circuitry involved in processing touch-related sensations in the human brain.

More information:

https://www.technologynetworks.com/tn/news/brain-implant-electrodes-evoke-sense-of-touch-352212

IJHCI 2021 Article

Last week, a co-authored journal paper was published at International Journal of Human-Computer Interaction sponsored by Taylor & Francis. The paper is entitled “Study of Full-body Virtual Embodiment Using noninvasive Brain Stimulation and Imaging” and investigates the influence of anodal transcranial direct current stimulation of the brain area linked to processing of the bodily self (right temporoparietal junction) to the subjective strength of virtual embodiment and its main constituents, using within subject experimental design with sham-controlled stimulation.

The sense of embodiment in virtual reality is a strong case of body ownership illusion, effectively allowing humans to experience the ownership of a modified, or a completely different body. However, little is known about the neural mechanisms behind full-body virtual embodiment. Virtual embodiment was studied using questionnaires, accompanied by brain signals gathered using EEG.  Our results suggest that stimulation did not affect the sense of ownership toward the virtual avatar. Borderline strengthening of the perceived sense of agency toward the avatar’s actions was found in the sessions with stimulation.

More information:

https://www.tandfonline.com/doi/abs/10.1080/10447318.2020.1870827