D. E. Johnson

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INTRODUCTION: Performance data from a visual perception task, complex motor flight task, and psychomotor vigilance task were evaluated in U.S. Air Force Pilots navigating a high-fidelity fixed-wing jet simulator over 26.5 hours of continuous wakefulness.
BACKGROUND High-frequency EEG (HFE) as a potential predictor of alertness/drowsiness was first proposed by Kaplan and Loparo. Sampling EEG at 950 Hz, they established an HFE bandwidth of interest ranging from 100-475 Hz. We extend their work by applying discrete Fourier transform (DFT) of HFE signals sampled at 1000 Hz and partitioned into spectral bands(More)
INTRODUCTION Visual perception task, complex motor flight task, and psychomotor vigilance task performances were evaluated in U.S. Air Force pilots navigating a high-fidelity fixed wing jet simulator over 26.5 h of continuous wakefulness. METHODS Eight military pilots on flight status performed the primary task of flying a simulated 12.5-h overnight(More)
Changes in maximal saccadic velocity (SV), initial pupil diameter (IPD), constriction latency (CL) and constriction amplitude (CA) determined by the pupillary light reflex have been found to be sensitive indicators of impairment as a result of drugs, sleepiness, and/or fatigue. Ambient illuminance and time of day are controlled when these indices are(More)
The IBM eServere BladeCentert system allows compute, network, and storage components to operate under a common chassis management scheme. It offers a new approach to solving many systems management issues surrounding the integration of power, packaging, cooling, media peripherals, and cabling of multiple compute servers, network switches, and storage into(More)
A VLSI implementation of an artificial neural network using a single n-channel MOS (metal-oxide semiconductor) transistor per synapse is investigated. The simplicity of the design is achieved by using pulse width modulation to represent neural activity and by using a novel technique to manipulate negative weights. A simple multilayer perceptron (MLP)(More)
INTRODUCTION Visual neglect is the unconscious inability to recognize or acknowledge some visual information in the presence of a structurally intact visual system, and was hypothesized to occur with less than 24 h of continuous wakefulness. Visual perception was evaluated in military pilots during a simulated overnight flight to explore for the possible(More)
BACKGROUND Computerized neurocognitive testing (NCAT) has been proposed to be useful as a screening tool for post-deployment cognitive deficits in the setting of mild traumatic brain injury (mTBI). We assessed the clinical utility of post-injury/post-deployment Automated Neurocognitive Assessment Metric (ANAM) testing, using a longitudinal design to compare(More)
PRIMARY OBJECTIVE To examine differences between the baseline-referenced and norm-referenced approaches for determining decrements in Automated Neuropsychological Assessment Metrics Version 4 TBI-MIL (ANAM) performance following mild traumatic brain injury (mTBI). RESEARCH DESIGN ANAM data were reviewed for 616 US Service members, with 528 of this sample(More)
Background. If operational requirements prevent or restrict sleep then other intervention strategies may be necessary to prolong the period before cognitive and physical impairments affect the success of the mission. The focus of this research was to examine the effects of caffeine on vigilance, marksmanship and physical performance during field trials with(More)