Thresholds for the Perception of Angular Acceleration as Indicated by the Oculogyral Illusion,
Abstract
The oculogyral illusion may be perceived by a person passively exposed to angular acceleration as apparent motion (in the direction of turn) of visual objects that are fixed relative to him. The illusion has its genesis in the semicircular canals and a knowledge of cupuloendolymph mechanisms, the role of adaptation effects and the influence of secondary etiological factors are all essential for predicting its behavior under different stimulus conditions. Studies have shown that its perception under ideal test conditions yields lower threshold values than other canal response indicators: the manifestation of nystagmus, and the sensation and aftersensation of rotation. The thresholds of the illusion are so low that their measurement is limited by the precision of the rotating device. A highly sophisticated servo-controlled device, the Rotating Litter Chair (RLC), was developed expressly for determining with this indicator any changes in cupular thresholds of response that might occur during the prolonged weightless Skylab missions. The purpose of the report is to evaluate the RLC and a relatively short method for determining the thresholds of perception of the illusion in a large sample of normal subjects and in four deaf persons with severe bilateral labyrinthine defects.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 11, 1973
- Accession Number
- AD0769268
Entities
People
- Ashton Graybiel
- Earl F. Mille Ii
Organizations
- Naval Aerospace Medical Research Laboratory