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Developing a Hardened Portable EEG System for Aircrew Physiological Monitoring in Flight

Description:

OUSD (R&E) MODERNIZATION PRIORITY: General Warfighting Requirements (GWR)

 

TECHNOLOGY AREA(S): Bio Medical

 

OBJECTIVE: Design, build, and demonstrate a portable, dry EEG system that is integrated into the HGU-68/P flight helmet and capable of producing reliable and interpretable data in the flight environment which presents considerable sources of noise such as electronic noise, vibration from mechanical components, acceleration forces, changes in temperature and pressure, and non- neurological signals (e.g., muscle activity).

 

DESCRIPTION: To understand the conditions under which pilots are experiencing Physiological Events, the DoD is seeking technological solutions to measure pilot physiological activity in the cockpit using electroencephalography (EEG). Naval aviation is inherently dangerous, especially in high performance aircraft. Even in the most benign conditions, aviators are loaded with bulky flight gear in cramped cockpits and required to breathe highly concentrated air from a closed-loop system. The flight environment is dynamic and adds additional demands on the aviator through changes in temperature and pressure, exposure to acceleration forces (Gs), and sensory inputs. Repeated exposure to such conditions can result in a Physiological Event (PE). PEs are complex pilot-aircraft interactions that involve two components: 1) a physiological episode (i.e., adverse physiological conditions such as black outs, loss of situational awareness, spatial disorientation, or hypoxia) and 2) an apparent aircraft malfunction.

Recent surges in PEs have resulted in the Navy making PEs the number one safety priority in Naval aviation[8]. After examining tens of thousands of samples from onboard oxygen generating systems and revamping the physiology training given to aviators, there was a drastic decrease in the number of PEs reported since 2017[8]. However, PEs have not been eliminated and still present a health risk to aviators in high performance aircraft. Indeed, the POM-23 Aircrew Systems Enabler, Navy Aviation Requirements/Group (ENARG) Executive Steering Committee has stated that PEs continue to be a top health and safety priority for Naval Aircrew.

 

The etiology of PEs is not well understood. Currently, PEs are assessed through a system of trial and error. Utilizing a reactive, rather than proactive method, aviators report physiological episodes after flight and experts on the ground try to diagnose the cause of the PE. This self-report system is a barrier to understanding why a PE occurred and how it affected the aviator because aviators rely on their subjective memory to attempt to assemble a timeline of events during the flight. Since PEs inherently contain a physiological component, relying on aviator memory to establish a timeline and diagnose an issue is problematic. Even without adverse physiological conditions, human memory is often unreliable[3]. Conversely, a proactive approach gathering physiological data from the aviator in real time affords the opportunity to understand why and when a PE occurs and can inform the design of systems to react accordingly.

 

Research has shown EEG can be used to detect sensory and cognitive deficits that result from PEs. For example, disruption in attentional focus after a novel auditory stimulus is presented can be measured when individuals experience acute hypoxia[6]. In a similar vein, a reduction in the ability to process visual sensory information can be measured under hypoxic conditions[1]. Prior research has also shown that objective markers for vection, or the powerful illusion of self-motion in spatial disorientation, can be determined using EEG[5]. Finally, numerous studies have shown that physiological measures such as EEG can be used to measure mental workload[7]. Therefore, if EEG can be used to gather physiological data from aviators in real time, we can begin to understand why PEs are occurring, refine training for aviators to detect the early signs of a PE, and inform the design of aircraft systems that can potentially take corrective actions if the aviator is unable to so.

 

An important consideration for real time recording is that brain dynamics in the laboratory differ from those in real-world environments[2,4]. In the laboratory, recordings can be made under controlled conditions and represent ideal physiological data. However, the flight environment presents considerable sources of noise such as electronic noise, vibration from mechanical components, acceleration forces, changes in temperature and pressure, and non-neurological signals (e.g., muscle activity) that require substantial filtering to interpret, and in some cases, completely prevent the interpretation of physiological data. Thus, an EEG system in a flight environment must able to endure these sources of external noise while capturing reliable and interpretable data.

 

To address these roadblocks and understand the conditions under which pilots are experiencing PEs, the DoD is calling for technological solutions to implement use of EEG in aviation settings.

Proposed designs should be a portable, dry EEG system that is integrated into the HGU-68/P flight helmet[9] and capable of producing reliable and interpretable data in the flight environment which presents considerable sources of noise such as electronic noise, vibration from mechanical components, acceleration forces, changes in temperature and pressure, and non-neurological signals (e.g., muscle activity). Additional applications for such a device could be with special operations warfighters performing in extreme environments, long-duration en route care monitoring unconscious patients, or civil aviation search and rescue aircrew.

 

PHASE I: The Phase I effort should focus on designing and or developing an innovative solution for a portable EEG system that integrates into the HGU-68/P flight helmet[9]. The in-helmet portion shall be as light weight as possible and shall not exceed 1 lb. The system shall capture reliable and interpretable EEG data, transmit the data wirelessly to a receiver located in the cockpit (e.g., electronic kneeboard, tablet, or other receiver in the cockpit), but not in the helmet, and be able to distinguish genuine EEG signals from sources of external noise (e.g., electronic noise, vibration from mechanical components, acceleration forces, changes in temperature and pressure, and non- neurological signals) - this will be a key factor. EEG data output should include a graphical user interface for “real time” monitoring by the user via the electronic kneeboard or tablet, and be exportable for analysis and integration into other injury and/or human performance algorithms. It is intended that this prototype may be one device of many to monitor operator performance.

 

Integration with other physiological devices will be a key performance parameter. Further, considerations should be made of integration with inflight safety equipment such as vests, night vision systems, and helmet mounted displays. The desired cockpit configurations will be primarily fixed-wing ejection seat aircraft, with secondary considerations for rotary-wing cockpits. Provide detailed Phase I final report that includes a) concepts and plans to develop and test for fixed-wing platforms in stationary and 6DOF simulators and b) development of a pathway to FDA clearance/approval. The Phase I effort will include prototype plans to be developed under Phase II. Provide a plan for practical deployment of the proposed.

 

PHASE II: Develop a working prototype that captures reliable and interpretable data in a powered- on stationary fixed-wing aircraft, and 6DOF simulator. Be advised that effectively filtering out “noise” in an operational environment will be a key factor. The performer should produce a prototype that meets the requirements listed above as well as begin to validate the use of the prototype using human participants. As part of the validation process, user comfort should be evaluated and prioritized especially during long duration wear/use (e.g., a minimum of 2 hours of wear). Testing should ensure the prototype integrates with aircrew survival and safety equipment (i.e., night vision systems or helmet mounted displays), does not impede aircraft egress (i.e., snag hazards), or diminish the survival characteristics of the HGU-68/P flight helmet (i.e., impact protection, visibility, and buoyancy). Through this testing and evaluation process, the performer should make iterative refinements to the prototype to ensure that it meets all of the requirements listed above. In addition, the performer should begin communication with the FDA to ensure that regulatory clearance can be obtained during Phase III. Required Phase II deliverables will include a working prototype, and a report about the overall project progress including all data that demonstrate the ability to measure reliable and interpretable data in the flight environment, and all data that support its potential to meet any parameters that aren’t already met.

 

PHASE III DUAL USE APPLICATIONS: Using the results and progress made during Phase II, a Phase III effort will complete all required flight worthiness approvals in accordance with the Naval Air Systems Command’s (NAVAIR) requirements. This phase will include any remaining work necessary to have the proposed solution meet performance parameters described in this topic, demonstrate its performance in a military-relevant environment, and become production ready.

 

Unlike the military, PEs are not a common factor that degrades the overall safety of the flight environment. However, there are other prevalent factors, such as physiological states of reduced mental or physical performance that result from sleep loss or extended wakefulness that impair a pilot’s ability to safely operate an aircraft. In the civilian market this system will provide an innovative way to use EEG to monitor pilots’ performance in the aircraft to detect physiological states of reduced mental or physical performance before the overall safety of the flight is compromised.

 

REFERENCES:

  1. Blacker, K. J., Seech, T. R., Funke, M. E., & Kinney, M. J. (2021). Deficits in Visual Processing During Hypoxia as Evidenced by Visual Mismatch Negativity. Aerospace Medicine and Human Performance, 92(5), 326-332.
  2. Lin, Y. P., Wang, Y., Wei, C. S., & Jung, T. P. (2014). Assessing the quality of steady-state visual-evoked potentials for moving humans using a mobile electroencephalogram headset. Frontiers in human neuroscience, 8, 182.
  3. Loftus, E. F. (2005). Planting misinformation in the human mind: A 30-year investigation of the malleability of memory. Learning & memory, 12(4), 361-366.
  4. McDowell, K., Lin, C. T., Oie, K. S., Jung, T. P., Gordon, S., Whitaker, K. W., ... & Hairston,

W. D. (2013). Real-world neuroimaging technologies. IEEE Access, 1, 131-149.

  1. Palmisano, S., Barry, R. J., De Blasio, F. M., & Fogarty, J. S. (2016). Identifying objective EEG based markers of linear vection in depth. Frontiers in psychology, 7, 1205.
  2. Seech, T. R., Funke, M. E., Sharp, R. F., Light, G. A., & Blacker, K. J. (2020). Impaired sensory processing during low-oxygen exposure: a noninvasive approach to detecting changes in cognitive states. Frontiers in psychiatry, 11, 12.
  3. Tao, D., Tan, H., Wang, H., Zhang, X., Qu, X., & Zhang, T. (2019). A systematic review of physiological measures of mental workload. International journal of environmental research and public health, 16(15), 2716.
  4. U.S. Department of Defense. Inspector General. (2020). Audit of the Department of the Navy Actions Taken to Improve Safety to Reduce Physiological Events. (Report No. DODIG-2021-004). Office of Inspector General.
  5. Gentex. (2005). HGU-68/P Helmet Assembly. https://shop.gentexcorp.com/content/TP0126- HGU-68P.pdf

 

KEYWORDS: EEG, ruggedized, physiological monitoring, physiological episode, aircrew, human performance

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