Evaluation of vigilance in subjects exposed to complete seated inversion body posture

Smith, Deanne M. (2013) Evaluation of vigilance in subjects exposed to complete seated inversion body posture. Masters thesis, Memorial University of Newfoundland.

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Abstract

The seated inversion posture is reported as being useful in evaluating potential effects of gravitational force on the upper body versus that of the lower body. The seated inversion posture is useful in simulating the environments that astronauts are exposed to in microgravity conditions as well as environments that humans may be exposed to during normal daily routines. Many recreational and labor related inverted positions occur in the air, outer space, as well as on or under water. Vigilance is required to complete activities of daily living, extra-curricular activities as in avoidance of and escape from life threatening conditions. Vigilance encompasses the functions of cognition, attention, alertness, and decision making skills that a re required to maintain upright posture and balance as well as required to ensure proper accuracy and perception when solving problems. The purpose of this study was to understand the effects of an inverted posture on variables of vigilance, heart rate and blood pressure. Eight males completed 5 sessions of assessment. Heart rate (HR), and blood pressure (BP), as well as vigilance tasks and reaction time were assessed first in a seated upright posture, followed by the seated inverted postures, and again a seated upright posture. Intraclass correlation coefficients for Tower of London (ToL), Selective Attention and Response Competition (SARC), anxiety, Heart Rate (HR), Systolic Blood Pressure (SBP) and Diastolic Blood Pressure (DBP) were excellent (R>0.95). The inverted condition produced significant (p<0.0001) decrements in performance on The Tower of London (ToL) tests and Selective Attention and Response Competition test. Time to completion was significantly slower in (63.4% and 40.7%) the ToL during the inverted condition as compared to the pre and post upright assessments. Reaction time was slower (10.4% and 11.7%) during the SARC tests during the inverted condition as compared to the pre and post upright assessments. o significant change (p<0.537) were found in the Attention Networks Test. SBP (p<0.0001), DBP (p=0.0003), and HR (p<0.001) demonstrated significant decreases during the inverted condition as compared to that of the pre and pot conditions for the ToL. Similar results for SBP, DBP and HR were observed in all tests of vigilance (SARC and AT) in the inverted condition. During the inverted condition participants reported a feeling of anxiety 25% higher than the pre-inversion condition and 51% higher than the post-inversion condition.

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