Brain-Computer Interfaces: Discussion and Future Implications for Human Factors
By: Ryan Bird
Brain-computer InterfacesBrain-computer interfaces (BCI) are devices which allow users to communicate with computers via the electrical signals generated by neuronal firing (i.e., brain cell activity). For example, prosthetic limbs can be connected to the brain’s motor cortex (see Figure 1 below) with implantable electrodes, permitting the user to control the prosthesis just as they would any other limb. Although BCIs have been developed and tested in various forms in both human and non-human models for decades (i.e., cochlear implants), recent advances in artificial intelligence and surgical technology are paving the way for incredible medical breakthroughs once thought to be the stuff of science fiction.
Figure 1: Motor Cortex
Monumental Progress
On December 22, 2021, Philip O’Keefe took over the Twitter account of Synchron¹ CEO Thomas Oxley and posted a very short tweet. “Hello, world! Short tweet. Monumental progress.” It doesn’t appear to be much at first glance, but Philip’s tweet represents a significant advance in BCI technology. About 20 months before the tweet, Philip elected to be implanted with Synchron’s new BCI, the Stentrode, in hopes that he might be able to recover an ability he lost due to amyotrophic lateral sclerosis (ALS), a degenerative disease of the central nervous system. Philip’s disease had unfortunately progressed to the point where it was nearly impossible for him to use his hands to type or text with friends, family, and the outside world through social media.
Synchron’s Stentrode (see Figure 2 below) is an electrode array which is able to more easily be attached to the artery nearest to the brain’s motor cortex through blood vessels instead of through extremely invasive brain surgery. Once attached, the Stentrode transmits signals from the brain to a Bluetooth-enabled antenna implanted in the chest of the patient, allowing the brain data to be sent directly to a computer. With this technology, patients are able to send commands to the computer using their thoughts, opening the door for Philip to share his progress with the world on Twitter.
Figure 2: Synchron’s Stentrode
For Melbourne native Philip, the Stentrode is a remarkable lifeline in the wake of a terrible disease and also a fortunate outcome of a relatively straightforward, risk-based medical device regulatory framework² in Australia.
Hurdles Cleared
After several years of back-and-forth with the Food and Drug Administration (FDA), Synchron’s Stentrode was granted³ “Breakthrough Device” status in 2020; a status given to devices that show potential in improving life-threatening or otherwise debilitating diseases. In May 2021, the FDA issued a Leapfrog Guidance⁴ on BCIs, detailing the process to obtain an Investigational Device Exemption (IDE)⁵ for companies developing products in this space. An IDE allows BCI manufacturers the ability to use their device on real patients to gather data to support clinical trials and provide them with a concrete pathway for regulatory approval. Shortly following the Leapfrog Guidance, Synchron’s device became the first permanently implantable BCI to receive the FDA clearance for human trials in the U.S., which are currently ongoing.
Synchron’s achievement marks a significant milestone in the development of BCI technology and sets them apart from other players in the BCI space. For reference, consider the case of Neuralink—Elon Musk’s venture into BCIs. In early March⁶, the FDA rejected Neuralink’s application to begin human clinical trials with their BCI device. Though Neuralink is a private company and is therefore not required to report the details of the rejection to investors, sources close to the company told Reuters that the FDA’s rejection listed “dozens” of issues, some of which were allegedly minor. One major issue, sources told Reuters, was the possibility that the thread-like electrodes in Neuralink’s device could potentially migrate to other areas of the brain, causing inflammation and damage. Although the exact details of the FDA’s rejection are poised to remain unclear, the roadblock is a signal that the regulatory landscape for BCI technology will be difficult to navigate.
BCI Human Factors Engineering
After several years of back-and-forth with the Food and Drug Administration (FDA), Synchron’s Stentrode was granted³ “Breakthrough Device” status in 2020; a status given to devices that show potential in improving life-threatening or otherwise debilitating diseases. In May 2021, the FDA issued a Leapfrog Guidance⁴ on BCIs, detailing the process to obtain an Investigational Device Exemption (IDE)⁵ for companies developing products in this space. An IDE allows BCI manufacturers the ability to use their device on real patients to gather data to support clinical trials and provide them with a concrete pathway for regulatory approval. Shortly following the Leapfrog Guidance, Synchron’s device became the first permanently implantable BCI to receive the FDA clearance for human trials in the U.S., which are currently ongoing.
Synchron’s achievement marks a significant milestone in the development of BCI technology and sets them apart from other players in the BCI space. For reference, consider the case of Neuralink—Elon Musk’s venture into BCIs. In early March⁶, the FDA rejected Neuralink’s application to begin human clinical trials with their BCI device. Though Neuralink is a private company and is therefore not required to report the details of the rejection to investors, sources close to the company told Reuters that the FDA’s rejection listed “dozens” of issues, some of which were allegedly minor. One major issue, sources told Reuters, was the possibility that the thread-like electrodes in Neuralink’s device could potentially migrate to other areas of the brain, causing inflammation and damage. Although the exact details of the FDA’s rejection are poised to remain unclear, the roadblock is a signal that the regulatory landscape for BCI technology will be difficult to navigate.
BCI Human Factors Engineering
Despite the flashy headlines and general buzz around BCI technology, the pathway to FDA and other regulatory approval for BCIs is largely unknown. At the same time, BCI technological advancements are happening at a rapid rate, and much of the attention appears to be centered on pure technical aspects of the design (e.g., the efficiency of electrode arrays, wireless transmission of information, battery life). However, the development and implementation of BCIs must also involve careful, human-centered design focused specifically on the safety, usability, wearability, and overall ergonomics of the devices if they are to make it to market. In other words, the success of these new technologies will hinge on proper Human Factors Engineering (HFE).
Although there is little publicly available information on the HFE-related processes currently underway at the leading BCI tech companies mentioned above, recent scholarly work by Lu and colleagues (2021)7 discusses the importance of HFE in design and development of future BCI technologies and offers some relevant recommendations for future BCI-Human Factors engineers to consider. Based on the Human-Centered Design approach8 detailed by the International Organization for Standardization (ISO) in 2010, the authors recommend the following approach for BCI-Human Factors iterative design:
- Step 1: Understand and clarify usage scenarios. BCI has broad application prospects in neurorehabilitation, auxiliary equipment control, education, military, entertainment, smart home, and other use cases. Before product design, it is necessary to collect and analyze relevant product information, understand the BCI market demand, determine the application direction of the product, and conduct interviews and investigations on relevant users to locate the target group.
- Step 2: Analyze user needs. Use the obtained user needs to define the function of the product and explore the shape of the product, which is of guiding significance for the later product development. User needs can be achieved through questionnaires and semi-standardized interviews, asking the end users how satisfied they are with the actual brain-controlled equipment in various aspects. If the application of BCI control is for communication, effectiveness and efficiency are of paramount importance, while when it is for entertainment, there may be more focus on design and other gadgets, as users have a higher tolerance for them.
- Step 3: Provide design solutions for users. Start off with designing a model based on the requirements obtained in Step 2, and then select healthy subjects to test and evaluate the preliminary model. Finally, by iteratively improving the previous model version, the final prototype is expected to become a universal device that can be personalized to the patient's needs.
References
- https://synchron.com
- https://www.tga.gov.au/news/news/answering-your-questions-how-tga-regulates-medical-devices-australia
- https://www.businesswire.com/news/home/20200827005748/en/Synchron%E2%80%99s-Stentrode-Brain-Computer-Interface-Receives-Breakthrough-Device-Designation-from-FDA
- https://www.fda.gov/regulatory-information/search-fda-guidance-documents/implanted-brain-computer-interface-bci-devices-patients-paralysis-or-amputation-non-clinical-testing
- https://www.fda.gov/medical-devices/premarket-submissions-selecting-and-preparing-correct-submission/investigational-device-exemption-ide
- https://www.reuters.com/investigates/special-report/neuralink-musk-fda/
- Lu, X., Ding, P., Li, S., Gong, A., Zhao, L., Qian, Q., Su, L., & Fu, Y. (2021). Sheng wu yi xue gong cheng xue za zhi = Journal of biomedical engineering = Shengwu yixue gongchengxue zazhi, 38(2), 210–223. https://doi.org/10.7507/1001-5515.202101093 https://www.iso.org/standard/52075.html