2019 年 78 巻 3 号 p. 197-202
Chronic vertiginous conditions worsen the subjects' QOL over the long term. The problem has been brought into acute focus with the recent rapid aging of the society. To quantify this chronic vertiginous status, we have proposed the use of a 3-dimensional eye movement analysis, and also a description of the Listing's plane. In this manuscript, we provide an outline of our previous study and our future view.
We use infrared video-oculographic images and extract numerical data on eye movements along the horizontal, vertical, and torsional components. Then, we obtain rotational vector description, through Euler's angle. Assembly of this rotational vector description allows the Listing's plane to be described. Our previous study about this Listing's plane demonstrated the possibility of quantitative evaluation of the otolith vestibulo-ocular reflex, and also gravitational recognition. Not only some kinds of peripheral vestibular dysfunction and cerebellar ataxia, but also pseudo-inclination of one's head (so-called “vection,” caused by optokinetic stimulation), could thicken the Listing's plane, which implies decrease of the precision of the otolith vestibulo-ocular reflex or gravity recognition.
In the future, we propose to estimate the characteristics changes of the Listing's plane caused by spinocerebellar degeneration, which is a representative disease causing cerebellar ataxia. In addition, to improve the precision of measurement of the rotational eye movements, we are exploring the development of an algorithm, which can detect false measurement of rotational eye movements. On the other hand, we constructed a measurement system for the eye movements of mice, which enables us to study mouse models and also perform fracture experiments, to gain further knowledge on pathophysiological mechanisms. Our goal is to establish a clinical instrument and algorithm to measure the otolith functions and gravitational recognition in order to manage patients with chronic vertiginous conditions.