Page 81 - JSOM Spring 2026

Night Vision Goggles

Influence on Cognition, Gait, and Tactical Tasks

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Rachel Rauth *; Joshua Thompson, MBA ; Matt Segovia, MS ;
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Owen Salmon, MS ; Cierra Ugale, MS ; Jaeho Shim, PhD ; Cory Smith, PhD 7
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ABSTRACT
Background: Night vision goggles (NVG) grant warfighters a can result in headaches, neck pain, and eye strain, all of which
tactical advantage in low-light environments. However, NVG have been reported by both experienced and inexperienced
use can negatively affect visual acuity, depth perception, and users. For example, a survey of military pilots found 33%
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color discrimination, which impacts warfighter safety and op- of rotary-wing NVG, 66% of fixed-wing NVG, and 14% of
erational performance. Therefore, the purpose of this study AH-64 Pilot Night Vision Sensor (PNVS) users reported de-
was to examine the biomechanical effects in the walking phase graded resolution and insufficient detail during their missions.
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of an obstacle clearance course and prefrontal cortex (PFC) Other reports show slower locomotion, increased metabolic
regional oxygen saturation (rScO ) during embedded marks- demand, and disrupted gait patterns over a hilly forest terrain
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manship and cognitive tasks performed with and without while wearing NVGs. Furthermore, decrements in navigation
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NVGs. Methods: Twelve participants (21 [SD 1] years) com- and wayfinding performance are associated with NVG use.
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pleted an obstacle avoidance course with and without NVGs, In summary, attributes native to NVG compromise biome-
which included pistol marksmanship assessments, cognitive chanical and cognitive functioning of wearers. These intrinsic
assessments, and ground obstacles. Gait pattern, performance factors have the potential to affect mission success by slowing
tasks, and PFC activity were recorded. Results: Marksman- movement and diminishing tactical performance. 9,10
ship performance decreased by 58.2% (P<.01), but cogni-
tive performance was not impacted with NVG use (P=.676). Understanding how image quality, FOV constraints, and fa-
Toe clearance increased by 32.2% (P<.01), toe velocity de- tigue associated with NVG use affect mission success will
creased by 20.5% (P<.01), and ankle dorsiflexion increased enable warfighters to adjust mission and training protocols
by 24.0% (P=.02) with NVG. Significant reductions in rScO for the safest and most successful task execution. Previous
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during Marksmanship 2 (P<.01) and Cognitive Assessment studies have reported tactical performance and biomechan-
Task 1 (P=.01) and 2 (P=.01) were observed. Conclusion: Per- ical deficits when wearing NVGs; 1,4–11 however, no previous
formance decrements with NVG use are hypothesized to be studies have examined the effects of NVG use on cerebral ac-
primarily due to altered vision perception and increased met- tivation patterns over the prefrontal cortex (PFC), a key area
abolic demand affecting marksmanship performance and gait for processing, decision-making, and, consequently, tactical
patterns. NVG training may minimize the risk of musculoskel- performance. 12,13
etal injuries and improve operational performance.
An effective way to quantify PFC activation is with functional
Keywords: tactical performance; cognitive assessment; near-infrared spectroscopy (fNIRS). This emerging technology
functional near-infrared spectroscopy; biomechanics; night is robust to movement artifact and quantifies the hemodynamic
vision goggles responses in the cerebral cortex. 14,15 These hemodynamic re-
sponses include relative regional cerebral oxygen saturation
(rScO ), a measurement derived from the total oxygenated
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and deoxygenated hemoglobin over the region of interest. The
Introduction
use of rScO can provide insights into neurovascular coupling,
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Night operations are integral to modern military missions, a physiological process that represents the hemodynamic re-
which often require performing complex tasks in dark con- sponses associated with neural activation in targeted brain
ditions. Although night vision goggle (NVG) technology has regions. Specifically, as glycolysis and oxidative phosphoryla-
shown great improvements across multiple conflicts, the func- tion are upregulated in the brain, an increase in tissue meta-
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tional mechanism remains the same: ambient light is gathered, bolic activity is observed, which results in heightened oxygen
converted into electrons, intensified thousands of times, then extraction from the blood to fuel increased information pro-
changed back into visible light. This process results in a com- cessing. Thus, within the current study, the use of rScO will
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promised image due to a reduced field of view (FOV), image provide insight into the neural stress associated with NVG use
graininess (amount depends on the type of NVG, user eyesight, while performing cognitive assessments, marksmanship, and
and ambient light levels), and a lack of depth perception. obstacle clearance tasks. Therefore, the aim of this study was
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This altered image and the weight of the NVGs themselves to highlight biomechanics, rScO , marksmanship performance,
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*Correspondence to rachel_rauth1@baylor.edu
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1 Rachel Rauth, Joshua Thompson, Matt Segovia, Owen Salmon, Cierra Ugale, and Dr. Cory Smith are affiliated with the Human & Envi-
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ronmental Physiology Laboratory, Baylor University, Waco, TX. Dr. Jaeho Shim is affiliated with the Robbins College of Health and Human
Sciences, Baylor University, Waco, TX.
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