Using a customized Brite during diving - a blogpost interview with Triton Systems, Inc.
Due to its technological advantages, such as portability and ease of use, Functional Near-Infrared Spectroscopy (fNIRS) is a neuroimaging modality that allows measuring brain activity in various settings, even outside of the lab. Our (f)NIRS devices are additionally highly customizable, which can increase application possibilities of fNIRS to measure brain activity even in extreme situations. To measure brain activity during deep-water diving, Triton Systems, Inc. modified the Brite device to be waterproofed, and named their system DOLFN (Dive Optimized Localizing fNIRS). In this blogpost interview, they describe their process of modification, discuss challenges, and share insights into results that could be achieved during first validation measurements.
Can you introduce the company Triton, explaining what your aim / vision is and what the company does?
Triton Systems, Inc. is a high-technology development small business firm founded in 1992 that develops advanced technologies for commercial, industrial, and Government use. Our newly renovated 50,000 square foot facility, located in Chelmsford, MA, comprises dedicated offices and state-of-the-art laboratories in chemistry, molecular biology, tissue culture, sensors, robotics, acoustics, electronics, ocean engineering, composites, additive manufacturing, and general machining. These laboratory facilities support several on-going research programs varying across human systems research, wearable sensor development, advanced software applications, simulation analyses, materials processing and manufacturing development for coatings, metal matrix and ceramic matrix composites, polymer synthesis, laser materials development, and thin film deposition techniques among others
Triton Systems, Inc., Chelmsford, MA
Triton has an exceptional track-record of developing deep science/technology-based innovations and translating them from the laboratory to the marketplace. Specifically, Triton has a successful history of leveraging SBIR/STTR funding with private equity investments to develop, manufacture, and commercialize new technologies and products. Commercialization pathways have included technology licensing, joint ventures, and spin-off companies.
Triton has an unusually broad dynamic, multidisciplinary team of scientists and engineers, each carefully selected for their complementary, yet distinct skill sets and domains of expertise that include biomedical and life sciences, advanced materials, electrochemistry, biomechanics, microfluidics, metabolic engineering, microbiology, and applications engineers among others. Together with quality system experts, manufacturing professionals, marketing, and serial entrepreneurs with a track record of multiple startups and exits, Triton has established a critical mass of experience that together give rise to a rich intellectual environment that will enable research breakthroughs and commercialization successes. We also work collaboratively with external academic/company partners to build teams around targeted technology development and commercialization initiatives to enable cross-fertilization of ideas and productive collaboration.
You used a modified version of the Brite to make it waterproof. Can you elaborate on your purpose / research goal of using the Brite?
In response to a Defense Health Agency solicitation entitled fNIRS performance monitor in Navy Divers at Depth (SBIR DHA193-002), Triton proposed to design and fabricate a multichannel fNIRS-based device to provide neurocognitive performance monitoring for deep water diver safety research. The device was required to flexibly provide data from multiple cortical regions which could be used to identify activity indicative of adverse physiological response, perhaps allowing early detection of cognitive deterioration and changes in cognitive loading during diver missions.
The resulting device was required to be compatible with diver equipment, especially for rebreather diving, and able to withstand relatively harsh conditions including 100-300 FSW at temperatures between 32 and 95 degF (0 to 35 degC).
What modifications were needed to make the device waterproof?
There were several modifications required to transform the Brite system to permit safe underwater and hyperbaric operation. First, the Brite user interface and associated circuitry and battery were packaged for submerged use while still allowing the user to actuate the Brite system functions. Second, communication, fNIRS data, and charging cables required waterproof pass throughs. To simplify things for water tight connection and to reduce cable tangles, we modified the Brite two trunk cable with two splitter approach to a more streamline version for divers. Our unique approach also required that the Brite optodes be made pressure and water proof during assembly via a meticulous multi-step assembly and potting process.
Example of an unmodified Brite MKIII
Which challenges did you face during conducting these modifications?
Waterproofing electronics, especially for use under pressure, is extremely challenging. Our system required many quality control steps to verify functionality after each component modification. Small/delicate conductors, shielding, and waterproof connection attachment required patient, careful focus to maintain a functioning unit. We used a pressure vessel to confirm that components had been appropriately waterproofed and to test the full system prior to fielded use.
Based on some painful lessons learned, human error can and does occur. Specifically, we developed checklists to confirm that lids had been closed, caps had been secured, and o’ ring seals had been properly greased and secured using required torque settings. Even with such care, redundant safety systems were fabricated and integrated to protect the most critical components. Those safety systems included leak detection sensing with audible/visual alarms to limit the potential for water damage.
Having created custom optodes, methods for functional checks were required. We developed custom calibration jigs with optical phantoms that can be used while submerged and under pressure to confirm that optode function remained consistent.
You recently finished a first round of test measurements with the Brite under water. What were the results?
Modified Brite used in divers. Courtesy of Divers Alert Network (DAN)
The data is still being analyzed; however, preliminary results indicate that our modified device, which we called DOLFN (Dive Optimized Localizing fNIRS), functioned as expected in both hyperbaric chamber studies at Duke University, including while submerged. Data from our device clearly indicates regional brain activation changes in response to breathing gas mixture variations. Similarly, cognitive load, depth, and breathing gas mixture variation resulted in cortical brain activity changes when used by Divers Alert Network (DAN) researchers at Deep Dive Dubai.
Did you expect these outcomes?
Yes, we had hoped that fNIRS would be a useful tool for detection of brain activity associated with health challenges. Whether we can use measured signals to predict symptom onset remains an open question. We are hopeful that, now that a device exists for this purpose, additional research will be performed to better understand brain responses for divers.
How was the signal quality? Did you achieve good signal quality?
Similar to clinical applications of fNIRS, hair and skin pigment are a challenge for our device. In addition, real-world measurement of fNIRS signals (as opposed to clinical applications) can be difficult due to optode perpendicular alignment and movement artifact. For our use case, coupling the device with facemask straps made alignment of optodes a little challenging with the cap. Motion of the optodes on the head was somewhat controlled using a neoprene cap with punched hole locations; however, cap movement on the head, especially during facemask placement may have been an issue. Finally, motion of the head and movement of the whole body while swimming introduces entirely new challenges to signal quality that we need to study and learn how to mitigate.
Did you face any issues during the study? If so, how did you overcome them?
In response to usability and technical challenges experienced during hyperbaric chamber research, we learned and iterated our prototype to fabricate a second version for diver use in a second study. The resulting second device included an electrically independent system for logging environmental variables (e.g., external temperature and pressure) and included additional safety features (e.g., better leak detection) while also enhancing usability.
Waterproofing electrical connections to protect expensive system elements was one of the biggest challenges. Finally, interpreting and analyzing the volume of resulting data required expertise that pushed our team’s capabilities, ultimately necessitating collaboration with specialized experts.
How did your participants feel using the Brite during diving?
One of the researchers from the DAN, Dr. Frauke Tillmans would be better to answer that question. Her portion of this research included some survey questions related to that question but that data has not yet been published. Sixteen respondents answered questions regarding comfort, willingness to wear over a longer duration, how much the device interferes with diving, how distracting was the device, etc. Most of their responses have more to do with the optode-to-cap interface than anything specifically related to the Brite system. Without analysis of statistical significance, no respondents indicated discomfort or a tendency to dislike wearing the device. The most interesting scores include distraction (average of 3.4/10) – which indicates not distracting - and ease of taking the device off (8.3/10) – which indicates very easy.
Perhaps more interesting is that our researchers, who had to place the device on the participants and activate on-board data logging using a modified Brite UI, were able to confidently utilize the device after only limited training.
Do you have any future plans? What will be your next steps?
Yes. Analysis of our collected data will hopefully lead to academic publications. In addition, the two prototypes that we fabricated have been delivered to Navy researchers who intend to use the device to explore cognitive loading. The plan is to accumulate data indicating device utility to support further development and to leverage what we have learned to potentially develop products for diver safety.
This material is based upon work supported by the Department of Defense (DoD) Small Business Innovation Research (SBIR) Program under Contract No. W81XWH21C0061.
Any opinions, findings and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the DoD SBIR Program or the US Army Medical Research (USAMRDC).
“Special thanks to Triton Systems, Inc., especially Brian Moyer, for sharing their insights into the customization process of the DOLFN and first results of measuring with this device, and to the Divers Alert Network (DAN) for sharing visuals of the DOLFN device during diving.”