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Differential levels of automaticity for processing information from tachistoscopic displays were studied using three variations of the partial report procedure. Processing of both spatial and identity information in letter displays was assessed simultaneously and then independently. Analyses indicated feature extraction is a highly automated process while spatial information extraction is a controlled process. Implications for separate processing pathways in the visual system are discussed

This study compared two computerized cognitive performance assessment systems: a typical laboratory desktop computer system and a ruggedized, hand- held field-portable system. Identical cognitive performance assessment software was installed on the two devices in order to determine whether differences in the hardware configurations of the two devices influenced measures of cognitive performance. Data were collected on 24 subjects over a period of 1 week during which subjects performed six cognitive tasks twice a day on each of the computer systems. Results indicated a high degree of sensitivity of the cognitive tests to day and session effects. Also, there were tasks in which the type of device used to present stimuli and record data influenced the results obtained. Differences between the two devices in terms of their display characteristics seem to account for the influences.

Adequate nutrition and hydration can be crucial to the survival of downed aircrews. To determine the nutritional adequacy and palatability of an improved, all-purpose, all-environment survival packet (GP-I) compared to the old survival packet (GP), a field test was conducted using combat survival school students. During a five day survival exercise, 41 aircrew member's ate the GP-l and 57 ate the GP. Nutrition/hydration status were assessed from food/fluid intake records as well as changes in body weight. Water turnover was measured in a subset of subjects (n=30) using deuterium oxide. Pre- and posttest hemoglobin, hematocrit plasma osmolality, urine specific gravity (SG) and ketones were also measured. Acceptability of the two rations was evaluated. Subjects eating the GP-l consumed more Calories; GP-l 774+/-436 vs GP 642+/-408 kcal/d. Carbohydrate and protein consumption were similar but the GP-l group ate significantly more fat, 35+/-21 vs 24+/-18 g/d. Mean fluid intake was similar for both groups (GP-l 4.3+/-1.7, GP 4.4+/-1.9 L/d). Sodium intakes were 1.6 g/d. Weight decreased significantly for the GP-l and GP groups (2.9+/-1.4, 3.4+/-1.7 kg, respectively); changes were similar between groups. Water turnover data indicated subjects maintained adequate hydration as did hemoglobin, hematocrit, and plasma osmolality. Mean posttest urine SG was 1.024-/+0.007 and moderate amounts of ketones were detected. Both rations received favorable ratings, but the greater variety of the GP-l ration resulted in higher acceptability ratings for this ration. We conclude from these results that either ration is adequate, however, the variety and palatability of the GP-l is more desirable than He GP.

Army aviation personnel often encounter work schedules which require the transition from daytime to nighttime duty hours without the benefit of an adaptation period. Rotations from daytime and nighttime duty hours, particularly those that occur within a 24-hour period, usually result in loss of sleep, fatigue, and cognitive degradation (Comperatore and Krueger, 1990). Strategies in the scheduling of sleep, meals, work, and exercise are currently under study with the purpose of identifying patterns that assist in the physiological adaptation to nighttime duty hours. These coping strategies are composed of countermeasures designed to prevent the sleep loss and chronic fatigue usually associated with rapid transitions from daytime to nighttime duty hours. The study of shiftwork coping strategies requires the empirical characterization of effective countermeasures which prevent chronic fatigue and preserve normal cognitive function. In the laboratory, the study of variables such as alertness, sensory processing, reaction time, and cognitive processing assessment approach requires the use of multidesciplinary test batteries that not only challenge cognitive processes, but also document the functional status of brain regions associated with sensory processing and alertness.

In response to a request from the Aviation Life Support Equipment Product Manager (ALSE-PM) of the Aviation Systems Command (AVSCOM), the U.S. Army Aeromedical Research Laboratory (USAARL) conducted an investigation and evaluation of the Prebreather/Portable Oxygen System (P/POS) manufactured by American Safety Flight Systems, Inc. A test of the P/POS was conducted in the hypobaric chamber at the U.S. Army School of Aviation Medicine. Four crews of four subjects each and one crew of three (the last crew had only three because one subject had a middle ear infection) prebreathed 100 percent chamber oxygen for 30 minutes. Then they switched to the P/POS while the chamber was depressurized to 18,000 feet MSL at a rate of 500 fpm. They remained at this altitude pressure until they reduced the P/POS pressure from 1800 psi to 200 psi. Following this, the chamber was repressurized to sea level at a rate of 4000 fpm. Mission durations, percent oxygen saturation and cognitive performance were measured for each subject. The average mission duration was 2 hr 28 min with a standard deviation of 13.9 min. The study indicated the P/POS will meet the needs of all helicopter missions for the Army that do not require prebreathing.

The effect of 2 mg and 4 mg injections of atropine sulfate on helicopter pilots was investigated using a specially instrumented UH-1H helicopter and several laboratory tests. A counterbalanced, within-subjects design was employed in which flight performance, vision, electroencephalographic activity, cognitive skill, and tracking performance were assessed on each of three different drug administration days (placebo, 2 mg, and 4 mg) separated by control days. Results indicated numerous atropine-related difficulties, seen most often with the 4 mg dose. Measurements of flight performance revealed decrements on at least one measure (i.e., heading, air speed, vertical speed) in both visual- and instrument-referenced straight and level flight, standard-rate turns, a straight climb and descent, steep turns, a climbing turn, and an instrument landing system (ILS) approach. Also, there were degradations in performance of a confined area approach and an out-of-ground-effect hover maneuver. Vision tests showed atropine-related increases in pupil diameter and double vision, concurrent with decreases in accommodation and depth perception. Cognitive tests revealed decrements in visual search, logical reasoning, quantitative ability, short-term memory, and response times. Psychomotor tracking tasks indicated atropine-induced increases in tracking errors across three levels of tracking complexity, and these sometimes were accompanied by deficits in responding to a secondary task. Electrophysiological data revealed a number of effects on both evoked potentials and resting EEGs which were consistent with the observed atropine-related performance problems.

A study was conducted to compare the performance of AH-64 (Apache) pilots to other Army pilots on visual tasks. Each pilot was given a task presented monocularly to the right eye, a task presented monocularly to the left eye, and a task presented to both eyes simultaneously in a dichotic task. Results indicated no performance difference between the groups of pilots on the dichotic task, but indicated better performance on the left monocular task for the AH-64 pilots. These results indicate that AH-64 pilots who are required to switch their attention from their left eyes to their right eyes in order to obtain needed information are capable of processing information efficiently and effectively using only one eye. The implications of these results for the Integrated Helmet and Display Sighting System (IHADSS) are discussed. Keywords: Dual processing; Helmet mounted displays; Monocular tasks.