The attack in the gravest forms is often abrupt, and, according to Charcot, is always preceded by a sudden loud noise in the affected ear. I have, however, notes of many cases in which this was not present. The patient reels, staggers, or falls, usually forward or to one side, loss of consciousness being very rare. The sensory hallucinations are remarkable. If at rest or after his fall he seems to himself to sway, and tends to pitch or roll over; the bed rocks, the room and its contents reel. The patient's terror is intense; he clutches the bed; seeks relief in fixing his eyes on an object, which in slight attacks is competent to relieve, or else he closes them. The least motion starts the vertigo afresh. In some cases turning the head or looking up will bring it back, or the patient may remain for days or weeks in this condition, with continuous dizziness and frequent recurrences of severe vertigo, while there is more or less constant nausea and sometimes vomiting.
There should be no trouble in distinguishing the cases in which deafness exists, but the nausea is apt to direct attention to the stomach. Tinnitus is common in vertigo, however arising; and when, as I am sure does chance, there is for years now and then a slight and transient deafness with vertigo, or a permanent deafness in one ear, and therefore not noticed, the inner ear is apt to be overlooked as a source of trouble.
Vertigo from growths on the auditory nerve before it enters the inner ear is rare in my experience. It is described as slow in its progress, the deafness and tinnitus being at first slight, but increasing steadily, while there is tendency to fall toward the side affected.7 In the cases of disease attacking the seventh nerve within the cranium there is usually so much involvement of other and important nerve-tissues as makes the disorder of audition and equilibration comparatively unimportant.
7 Burnett.
Vertigo from coarse organic lesion of brain, such as a tumor, is common, and is, indeed, rarely absent in such cases. The cases in which it is lacking or least remarkable are, I think, to be found in the anterior and middle cerebral lobes, while it is almost sure to exist at some time when the tumor is in or near the cerebellum.
Growths or other causes of irritation in the crura of the cerebrum or cerebellum, or on the pons, are sure to give rise to disturbed equipoise or to methodical involuntary actions; but these are not always, though often, accompanied with delusive impressions as to exterior objects, or with the other symptoms found in typical vertigo. I recall one remarkable case where a blow on the left side of the occiput resulted in a tendency to roll to the left which finally triumphed over volitional control, so that the patient would at times roll over on the floor until arrested by a wall. After the rotation had lasted for a minute there was, when it ceased, a false sense of movement of objects to the left, but at the outset there were no sensory illusions, and at no time any mental disorder. The patient recovered, and is now in good health; but it is interesting to learn that while, during the time of these attacks, he had normal hearing, he has gradually lost hearing in the left ear and acquired permanent tinnitus. I have reached the conclusion that there is a group of functional vertigoes, and that in some of them the trouble lies in the semicircular canals; that is to say, the lesion is slight or transient, but in rare cases recurs until a more distinct and permanent result justifies the original diagnosis.
OCULAR CAUSES OF VERTIGO.—For the most part, the eyes as a source of vertiginous impressions are neglected in the textbooks; but as the cause of certain of the slighter vertigoes, and as a fertile agent in emphasizing or recalling vertigoes due to the stomach or inner ear, they are well worthy of careful study, nor is it ever wise to neglect these organs in cases either of headache or of vertigo.
A number of eye conditions cause giddiness or increase it or reproduce it. Thus, sudden loss of accommodation in one eye or in both may occasion it, and perhaps the enlarged pupil may have its share, since even in healthy people, and surely in all habitually vertiginous patients, sudden exposure to brilliant light gives rise to sense of instability.
Abrupt change in intraocular pressure is another cause, as in acute glaucoma or in sudden partial collapse of the eye from discharge of the aqueous humor.
Permanent vertigo of quite severe character may arise from astigmatic defects, and from almost any form of disorder affecting steadily the power of the eye to accommodate itself to distances; but simple myopia of moderate grades, excessive one-sided myopia, or presbyopia is unlikely to do so. Oculo-motor troubles, paralytic or spastic, are very effective causes of vertigo, which is sometimes quite promptly producible by the wearing of a prism on one eye or by the use of glasses which over-correct, or if exact are for some reason badly borne. This latter is apt to be the case, I think, in accurate corrections of long-standing hypermetropic astigmatisms. There is one point on which, in this connection, I have again and again insisted: Optically defective eyes may exist through life without notable brain disturbance, unless, from over-use with worry, work under pressure, the strain of prolonged or of brief and intense emotion, or any cause of ill-health, the centres become sensitive, as they are then apt to do. When this occurs defective eyes, and in fact many other sources of irritation, grow at once into competence for mischief, and occasion vertigo or headache or other cerebral disorders.