Evaluation of Environmental Sensors in Training: Performance Outcomes and Symptoms during Airborne and Combatives Training

Investigating the feasibility and potential validity of using biomechanical environmental sensor technologies to improve the detection of potentially concussive events that could lead to mild traumatic brain injury (mTBI).

Traumatic brain injury (TBI) has been labeled as the “signature injury” of Operation Iraqi Freedom and Operation Enduring Freedom (OIF and OEF). More than 20% of service members deployed to Iraq or Afghanistan are estimated to have sustained at least one TBI. Depending on the severity of the TBI, symptoms may last from a few days to several years following the injurious event. Moreover, repeated TBIs may result in more severe and longterm consequences.

DETECT (Display Enhanced Testing for Cognitive Impairment and mTBI) is a rugged, portable assessment tool designed for use in field and triage settings for the evaluation of functional neurologic impairment after a potential concussive injury.

The Defense and Veterans Brain Injury Center (DVBIC), in conjunction with the Armed Forces Health Surveillance Center, track TBI diagnoses for all U.S. military personnel (deployed and non-deployed). DVBIC reported that 383,947 TBI diagnoses of all severities were made between 2000 and 2018-Q1. Of the diagnosed TBI cases, 82.3% (315,897) were classified as mild in severity (also referred to as concussion). In 2013, it was recognized that at least 80% of TBI diagnoses were made in a non-deployed (garrison) setting. TBI diagnoses in the non-deployed setting may be the result of vehicle crashes (private or military-owned), falls, sports and recreational activities, or military training.

A mild TBI (mTBI) is generally characterized by less than one hour loss of consciousness (LOC), less than 24 hours of a confused or disoriented state and memory loss, and normal results from structural brain imaging. Due to mTBI prevalence and difficulty in the identification/diagnosis, a high priority has been placed on an objective method for the accurate and timely identification of a potentially injurious exposure and subsequent diagnoses.

The current process for diagnosing mTBI begins following an exposure to a concussive event. Within 12 hours of the event, the soldier may be ordered by a medic or supervisor to have an assessment due to loss of consciousness (LOC), an obvious alteration of consciousness (memory loss, confusion, dizziness, etc.), or based on specified criteria (e.g., the soldier was within 15 meters of the blast). In addition to being ordered to have an assessment, a soldier may self-report due to symptoms and/or involvement in a possible TBI-causing incident.

After a soldier reports for an assessment, a combat medic or clinician will administer the Military Acute Concussion Evaluation (MACE) or other comparable medical evaluation. The MACE consists of several screening questions (incident description, any LOC or alterations in consciousness, whether a head impact was sustained, and concussion history), a cognitive exam (memory and concentration tests), and a neurological exam (balance, eye, speech, and motor tests). The updated MACE 2 also includes vestibular-ocular-motor assessment. The evaluation is heavily reliant on self-reporting for initiation and completion. The difficulties in administering the MACE exam in an operational/training environment often result in a clinician or combat medic having to make a determination of whether a soldier has suffered an mTBI either at the time of the event (rapid evaluation) or at some point following medical evacuation (full evaluation).

Both situations are not ideal for diagnosing an mTBI and may result in undiagnosed or misdiagnosed mTBIs due to omission of important symptoms or allowing symptoms to change over a prolonged period of time before diagnosis. Without an accurate diagnosis of mTBI, soldiers may go untreated and be allowed to return-to-duty while still affected and vulnerable to damaging secondary effects.

Using environmental sensors capable of detecting impact exposure from potentially concussive events offers one avenue for additional data to be used in diagnosing mTBI. Biomechanical data from potentially concussive events could provide objective information for combat medics or supervisors to direct the course of action for a soldier exposed to a potentially concussive event. However, there are still several challenges with using environmental sensors including ease-of-use in the field and validity in terms of relating to mTBI sequela. Additionally, a “threshold” has yet to be identified that provides a reliable indication of mTBI. Thus, environmental sensors may be an aid in diagnosing mTBI when paired with sensitive performance measures, such as neuropsychological or vestibular functioning tests.

This work was done by Kyle A. Bernhardt; Amanda M. Kelley; Colby Mathews; Brian Novotny; and Tyler F. Rooks of the Army Aeromedical Research Laboratory for the Army Medical Research and Development Command. For more information, download the Technical Support Package (free white paper) here  under the DAQ, Testing & Sensors category. ARL-0246

This Brief includes a Technical Support Package (TSP).
Document cover
Evaluation of Environmental Sensors in Training: Performance Outcomes and Symptoms during Airborne and Combatives Training

(reference ARL-0246) is currently available for download from the TSP library.

Don't have an account? Sign up here.