Vertigo dizziness

Vertigo dizzinessThe causation of optical vertigo is a prominent factor in the causation of sea-sickness. And inasmuch as this factor is dependent upon motions, either of the person or his environs, it comes properly within the limits of this chapter and accordingly will be here considered. We have seen how wathematically accurate are our intuitions of space as exemplified in the accurate muscular adjustments involving space, even though such space cannot by subject be expressed in conventional terms. And we also know how accurate is the intuition of location in space as exemplified in the ability of the woodchopper to strike his axe in the same place repeatedly; his stroke being swift, strong, and through a distance much greater than the chopper's height. And all with little or no deliberation apparently, and with the unaided eye.

It is easy then to see that one's intuition of distances of walls, ceilings, and floors of his room are accurate. It is one of our habitual expectations that the walls, ceilings, and floors of our rooms remain in invariable positions; that any variations of their distances are due to our own movements. Now any change of a wall's distance, or other variation of its position, not due to our own movements, constitutes a result realized differing from a result habitually expected. It therefore constitutes a disappointment, and serves as a stimulus in response to which some kind of physiological violence takes place. One disturbance institutes another, and somewhere in the series of events occur those of which alone we become conscious. These are the vertigo, nausea, vomiting, and other items in a more or less general illness. Not only does every variation of distance constitute a disappointment, but so does also every observed movement of an object which should according to our habitual expectation, remain immovable. It is scarcely necessary to add that the resulting illness represents an accumulated violence.

Thus we explain optical vertigo as it occurs on the ship at sea. It affects the person in any part of the ship. The effect is exaggerated by movements of fluids in vessels, and the oscillations of clothing suspended from hooks, both being violations of the habitual expectation that such things in rooms remain quiet. In a similar way I would explain the optical vertigo consequent on the observation of unexpected relations, momentary or continued, among our environs and between them and ourselves, whether such relations be real or are made apparent by an unusual modification of our usual means of vision. Thus, I am assured that it is a certainty that violence may result to the person through the sense of sight; that persons often get sick nauseated by putting on ill-suited spectacles for the first time, and by leaving off spectacles when accustomed to them; that in these cases all other sources of physiological violence are certainly excluded.

I have become dizzy by attempting to read the inscriptions on the cars of a passing freight train when I was riding on another train in a contrary direction. In such cases I generally failed to make out what the inscriptions were; so that in the case of a single train I made a series of attempts, and nearly as many failures and experienced an equal number of disappointments, each resulting in violence the sum of which amounted to the conscious illness which caused me to cease the efforts.

It sometimes happens that, when motion is observed in an object which we habitually believe to be fixed, we interpret the phenomenon as due to our own movement, and have, in fact, subjective sensatious of motion same kind. That is to say, there occurs then the appropriate vascular adjustment to that motion. But there being no motion of the person, the vascular adjustment amounts really to a vascular disturbance; and this case of adjustment without motion is equal to the case of motion without adjustment. And the illness, seeming to be optical vertigo, is really due to vascular disturbance complicated with the effect of disappointment incidental to the unexpectedness of the event.