Accession Number:

ADP013887

Title:

Almost Loss of Consciousness: A Factor in Spatial Disorientation?

Descriptive Note:

Corporate Author:

NAVAL AIR SYSTEMS COMMAND PATUXENT RIVER MD CREW SYSTEMS DEPT

Report Date:

2003-02-01

Pagination or Media Count:

13.0

Abstract:

During high-performance flight, air crew exposed to Gz-stress may exhibit symptoms ranging from light loss LL to Gz-induced Loss Of Consciousness GLOC. If the stress is insufficient to cause GLOC, a syndrome called Almost Loss Of Consciousness ALOC can occur, which features deficits in motor and cognitive function. It is possible that these types of deficits may influence the nature or extent of spatial disorientation symptoms. In order to produce a definitive description of ALOC symptoms, nine subjects one female Ss were exposed to a series of repeated short 6, 8, and 1O Gz pulses at the NAVAIR Warminster centrifuge facility, which were lengthened in 0.25s increments until they experienced GLOC. Of a total of 161 Gz pulses, 66 episodes of ALOC were identified. A math task before and during each pulse was used to determine short-term memory loss. Ss were required to press and hold a button spanning the time from initial LL symptoms to full recovery of vision. ECG and near infrared spectroscopy NIRS of relative cerebral tissue oxygenation rSO2 were also recorded. Data analysis included a description of physical, cognitive, and emotional signs and the timing of their occurrence and resolution, and the timing of the LL from its onset to full recovery. The primary manifestation of ALOC symptoms was a disconnection between the desire to do something and the actual ability to act upon it. This could linger well beyond the end of the Gz exposure. Physical symptoms included tingling, twitching, uncontrollable hand movements, hearing loss and transient paralysis. Cognitive deficits included confusion, amnesia, delayed recovery, a vacant feeling and difficulty in forming words. Surprise, concern and pleasant feelings were some of the emotional signs.

Subject Categories:

  • Psychology
  • Stress Physiology

Distribution Statement:

APPROVED FOR PUBLIC RELEASE