The Effect Of Gravitoinertial Force Upon Ocular Counterrolling

The Effect of Gravitoinertial Force Upon Ocular Counterrolling

The effect in terms of magnitude of ocular counterrolling of g- loading at various angles of tilt up to 63 degrees was measured on normal subjects and compared with the effect upon persons with severe or complete loss of otolith function. The group of six normal subjects manifested a compensatory eye roll which increased as a direct and essentially linear function of the component of the gravitoinertial force acting laterally upon the subject. This increase in response was not observed in the five deaf subjects with severe or complete bilateral loss of their vestibular organs. These findings confirmed similar results found by other authors using other measuring techniques which show that the reflex eye movement is dependent upon and limited to the magnitude of the gravitoinertial stimulus (within the range used) when the otolitho-ocular system is functioning normally. However, when this function is impaired or lost, the magnitude of the compensatory eye roll is limited to that manifested at 1 g and possibly to non-otolithic contributions. These findings offer means for differentiation between otolithic defective individuals and 'normal' persons who exhibit little counterrolling.

Ocular Counterrolling Measured During Eight Hours of Sustained Body Tilt

Vestibular System Part 2: Psychophysics, Applied Aspects and General Interpretations

The function of the vestibular system is not as obvious as those of vision, hearing, touch or smell. Vestibular dysfunction, however, is clearly apparent where lesions are present. It is probably for this reason that the vestibular sense was not discovered until the nineteenth century and that clinicians have continued to playa major role in basic vestibular research right up to the present. The relationship between basic and clinical research is certainly stronger in the vesti bular field than in that of tactile sensation, for instance, as testified by the work of clinicians as MENIERE, BREUER, BARANY, DEKLEIJN and FRENZEL. In this respect the situation is similar in vestibular physiology and in endocrinology, and for the same reason. This second part of the vestibular volume of the Handbook of Sensory Physio logy will be of interest to neurologists, otologists, neurosurgeons, ophthalmologists and physiotherapists on the one hand, and psychologists, physiologists, engineers and aviation specialists on the other. For a full understanding of Part 2, it is necessary to have assimilated the basic anatomy, physiology, and biochemistry of Part 1.