Dr. Patrick Ganzer speaks to News-Medical about his groundbreaking research into restoring the sense of touch using brain-computer interfaces.
What provoked your research into the sense of touch?
I have been studying neural systems that process touch for several years, especially following nervous system damage.
In the past, my teams have focused on developing therapies that can restore upper limb function following damage, such as a spinal cord injury or stroke.
The sense of touch is critical for overall movement control. Specifically, this was an unmet need for the current brain-computer interface (BCI) system our group is developing at Battelle.
How can the sense of touch become damaged?
Specific pathways in the nervous system transmit touch information from your skin to the spinal cord, and eventually to the brain.
The participant in our BCI clinical trial, unfortunately, has a severe spinal cord injury. His paralyzed hand also has a significantly impaired sense of touch, and almost completely lacks meaningful sensation. This is a major functional deficit that impairs his ability to function normally.
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Why is the sense of touch essential in humans?
Many of us have experienced an impaired sense of touch, maybe when our limb has fallen asleep or we have been outside in the cold for too long.
Even a small disruption in touch capability can have a major impact on resulting movement capability. Touch and movement circuits in the nervous system interact as well. We use sensory and touch signals all of the time to stand up straight, grip objects with the correct force, and so on.
How did you implement a Brain-Computer Interface system into your research? How does this system work?
Our team’s past studies have used the participant’s ‘thoughts’ to restore movement alone to his paralyzed hand.
Using a small chip implanted in the participant’s brain, the brain-computer interface (BCI) would record the participant’s thoughts related to an intended hand movement (e.g., I want to grab that bottle), use a computer to detect that specific brain activity, and then stimulate his muscles to make his hand move in the desired way.
Using the BCI system, the participant can once again move his paralyzed hand, to swipe a credit card, pick up an array of objects, and many other motor functions.
Using this system, you managed to restore the sense of touch. How did you do this?
Unfortunately, the participant’s hand is not only completely paralyzed, but it is also almost completely lacking sensation. This a major problem, as the sense of touch is critical for appropriate movement control.
The participant has trouble detecting general touch, and essentially cannot even feel small objects. Because of this lack of sensation, at times the participant’s hand also feels foreign.
In our current study, we address many of these problems and restore the participant’s sense of touch. We first discovered that when the participant touches objects, a very small ‘subperceptual touch signal’ is generated in the brain.
Said differently, we began recording faint touch activity in the brain, even though the participant cannot detect the touch events. We then taught a computer how to detect these subperceptual touch signals. Lastly, we ‘boosted’ this subperceptual touch signal into conscious perception, using vibration-based feedback on the skin the participant can feel.
Enhancing subperceptual touch into conscious perception led to an array of benefits for the participant. His ability to detect touch was almost completely restored. When he uses the system in real-time, his movements speed up and he is able to manipulate and transfer objects faster.
The participant’s perception that he is controlling his own hand is also enhanced, due to the artificial sensory feedback.
What is haptic feedback?
Haptic feedback is any technology that can be used to convey a sense of touch – like the vibration from a cell phone or video game controller.
How will the research benefit people suffering from spinal cord injuries?
A BCI can be used to restore significant function in individuals living with paralysis and sensory dysfunction following spinal cord injury. Our hope is that these findings further demonstrate the number of functions that can be restored in patients using this technology – not just movement but also the sense of touch.
The field of neurotechnology has a bright future, and we hope that these types of systems can be used in a home environment soon.
What further research needs to be carried out before this can be used in homes?
There are a number of challenges in creating a take-home version of a BCI system. The NeuroLife group at Battelle is tackling many of these.
We have recently made the ‘muscle stimulation system’ miniaturized and portable. It is now a more aesthetically pleasing ‘sleeve’ that can be zipped up around the arm to enable hand movement.
Another exciting milestone we have accomplished recently is using a ‘computer tablet-controlled muscle stimulation system’ in the participant’s home. He has used this to perform a number of actions, importantly outside of the laboratory.
Many other challenges remain, such as ensuring device security, device safety, and device longevity.
What are the next steps in your research?
We are very excited about the future of neurotechnology broadly, and especially BCIs. Some of our upcoming goals are focused on further developing the system for use in the home and also applying the muscle stimulation technology to other impairments, such as paralysis following a stroke.
Where can readers find more information?
Read more about his research at Battelle here!
About Dr. Patrick Ganzer
Dr. Ganzer received his BS in Neuroscience from King’s College in 2008, completed his Ph.D. in Biomedical Engineering and Science from Drexel University in 2013, and finished his post-doctoral fellowship at the University of Texas at Dallas in 2017.
He is now a Principal Research Scientist at Battelle Memorial Institute, the world’s largest non-profit research organization located in Columbus, Ohio.
Dr. Ganzer works on several neurotechnologies at Battelle, including brain-computer interfaces and non-surgical neurotechnologies. He is currently the Principal Investigator for Battelle’s Bioelectronic Medicine program – a research and development initiative focusing on developing bioelectronic medicine therapies for treating disease.
His previous research at the University of Texas at Dallas utilized targeted vagus nerve stimulation to boost the effects of rehab and restore connections to paralyzed muscles in preclinical models of spinal cord injury, stroke, and peripheral nerve injury.
Dr. Ganzer’s work is now being translated to multiple clinical trial applications and has been enabled by over $4 million dollars in funding from agencies such as the Defense Advanced Research Projects Agency (DARPA), the Wing’s for Life Foundation, and the W.W. Caruth Jr. Foundation.
With his talented teammates, Patrick is developing new neurotechnologies and bioelectronic medicines to treat patients suffering from dysfunction and disease.
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