Nystagmus

“ Now if the rotary movement of the head is prolonged, the eyes lag for a while on their first fixation-point, and then dart suddenly forward to a new fixation-point on which they rest for a while as before, until they dart forward again. Therefore if the head continues to rotate, the eyes fall into a regular and well-marked nystagmus. ”

“ A third peculiarity which sometimes occurs in extreme degrees of congenital amblyopia, is monocular nystagmus of the weak eye. This trembling may be so slight that it is only observable during investigation with the ophthalmoscope; in other cases it is most marked as soon as the weak eye is put into fixation by exclusion of the sound one. ”

“ When the nystagmic motions have ceased, they may often be called into activity by placing the patient in a dark room and getting him to direct his eyes to a candle held above the horizontal line of the field of vision. The motions are usually lateral, or in some cases the centre of the cornea describes an ellipse or circle which causes the patient to see a ring of light. It has been observed to occur much more frequently in those working in shafts where there is a good deal of fire-damp; which has caused some writers to assert that the nystagmus has been dependent upon the action of the gas. ”

“ Inco-ordination of movement is rendered most obvious during active movement of the limb, decreasing towards the termination of that movement, and ceasing so soon as the object is attained. This is most readily demonstrated by the well-known ‘finger-to-nose’ test.
Nystagmus is one of the most frequent symptoms of cerebellar tumour, usually lateral, the movements coarse or fine, and most marked when the eyes are directed towards the side of the lesion. ”

“ Syringing with hot water causes a nystagmus directed towards the ear syringed; syringing with cold water, away from the ear.
(b) If there be a localized labyrinthine lesion, and the function of the labyrinth is still maintained, the same results will be obtained on syringing. Care, however, must be taken that the syringing is not forcible, otherwise the caloric tests will be unreliable, as in these cases nystagmus may be produced on even slight increase of pressure within the external auditory canal, and with this there may be a sensation of giddiness and nausea. ”

“ Later in the disease, usually after a few years, a peculiar speech-disturbance is noticed, which resembles the scanning of disseminated sclerosis. It depends on ataxia of the tongue and lips. This is usually associated with nystagmus. About this time the patient develops a different set of motor symptoms from those characterizing the onset of the disease; contractures, paralysis, and atrophy are found in the affected extremities; sometimes the patients cannot ascend a stair, owing to their inability to lift the feet high enough. ”

“ These movements are often so extensive as to be manifest by ordinary inspection, and are sometimes sufficiently marked to resemble nystagmus.2 Nervous movements of the eyelids may also be noted, either by ordinary inspection, or by lightly touching the lid of one eye while the other regards an object either at the near-point or the distance. The visual axes are never parallel, and the deviation from the normal may become so marked as to constitute the condition of squint. ”

“ Certain convulsive affections—for instance, the spasmus nutans of young children, the salaam tic, and what are known as "baboon movements"—are still rather obscure and in many cases seemingly not equivalent to tics. Their occasional association with strabismus or nystagmus constitutes a plea for their possible dependence on some encephalic lesion. In two cases under Oppenheim's observation the nodding spasm appeared solely in the hours of the night and during sleep. ”

“ Between the attacks the equilibrium may be disturbed, there being marked nystagmus and unsteadiness of gait. The attacks of vertigo tend to become less frequent and may entirely pass away, but the deafness may remain permanent ”

“ There may be an alternation of periods of crying and laughing which with the occasional exhibition of intention tremor and rarely nystagmus may make one think of multiple sclerosis. The patient tends to sleep even when lying in a bright sunlight. ”

“ Fibrillary twitching is rare, and in our tabulated cases was observed only in one instance, a glioma of the filum terminale. General convulsions with unconsciousness are exceedingly uncommon. In one case, however, a round-celled sarcoma at the level of the seventh, eighth, ninth, and tenth cervical vertebræ, the patient is recorded as having died in a fit. Nystagmus was observed once, but probably had no significance so far as the spinal affection was concerned, as the cerebral dura mater exhibited evidences of inflammation. ”

“ The symptoms usually begin with headache and dizziness, feeling of fatigue and muscular weakness. One of the early symptoms is a disturbance of vision which may progress until the patient is blind. Both the extrinsic and intrinsic muscles of the eye become involved. There is blepharoptosis and the pupils become dilated. There is diplopia and the loss of adaptative response of the eye to the light. There is soon complete loss of accommodation, opthalmoplegia, nystagmus, strabismus and in some cases photophobia. ”

“ The speech-defects present in a number of cases were rather due to the change in mental condition than to any involvement of speech-centres. Under Symptomatology has been given in some detail a study of the psychical condition in one case of antero-frontal tumor. The absence of true paralysis and of anæsthesia is characteristic. Nystagmus and spasm in the muscles of the neck and forearm were present in one instance, but usually marked spasm is not to be expected. Vomiting is less frequent than in tumors situated farther back. ”

“ In patients who cannot walk, ataxia may be tested by ordering repeated pronation and supination of the forearm. Paresis or asthenia may be found in the trunk muscles, or evidenced by weakness of the grip, or drooping of the head to one side. Changes in muscle tone may arise and lead to exaggerated or decreased reflexes, often varying from day to day. Vertigo and nystagmus may also be present, in addition to occipital headache and tenderness on percussion. When one lateral lobe is implicated, the symptoms are referred to the same side ”

“ There may be a contraction of the field of vision or disturbance of color sense, tactile sensation, smell and taste, with muscular weakness, Babinski reflexes, speech defects, dizziness, uncertain gait, nystagmus, etc. Somnambulism is sometimes encountered in epilepsy, although it is strongly suggestive of hysteria. The great majority of cases present the picture of a simple dreamy stuporous [483] condition. Apprehension is clouded, the patients become confused, cannot control their thoughts, mistake the persons around them, lose themselves on the street, and wander away. ”

“ Case 440. (Roussy and Boisseau, May, 1917.)
A soldier in the engineers, 29, entered the neuropsychiatric center at Scey-sur-Saône, August 23, 1916. His diagnosis was: organic shock syndrome with right-side deafness and tremors. He carried a ticket showing an otological examination: tympanum normal; Rombergism absent; walks with eyes closed swerving to right; tends to fall, eyes closed, on standing on one foot; vertigo produced by rotation in either direction; no nystagmus either spontaneous or by test; deafness especially on the right side; equilibrium function insufficient. ”

“ Merkel's case, occurring in a patient with embolism of the artery of the fissure of Sylvius, would also point to lesion near the angular gyrus. Stintzing223 gives a case where there was thrombosis of the basilar and Sylvian arteries. Oglesby224 relates two cases where nystagmus came on suddenly with dilatation of the pupils, the autopsies showing a clot which pressed on the medulla. Fienzal225 also gives a case where there was a tumor in the left peduncle of the brain. It is often seen during epileptic convulsions. ”

“ The next of the series of bad results of eyestrain are cerebral. The brain comes out to see, but owing to the enormous difficulty of the task, it sees poorly and with exhausting or irritating labor. As its every process and act is bound up with and the product of vision, visual disorders by reflex and passed-on malfunction induce cerebral affections, evidenced primarily by headache, migraine, etc. Although the medical text-books give little or no hint of this, it is true, as thousands of good physicians and patients well know, that headaches, ninety per cent, at least, are due to eyestrain. ”

“ The nerve centers, which animate and control the nerves supplying the eye muscles to which we have just alluded, are in close proximity to other most important nerve centers in the brain, so irritation of the eye centers will produce sympathetic irritation of these other centers, leading to manifold and complex symptoms which we will describe under this head. But these symptoms do not necessarily develop in everyone having farsightedness or astigmatism, since both are often present at birth. ”

“ The nerves which move the eyes in various directions lie next to the pituitary. If, in its expansion, it moves sufficiently outward, it may press upon, irritate them or paralyze, and so evolve various eye disturbances in association with the headache. No one can overrate this conception of migraine, for a number of men of genius have suffered from sick-headache and eye symptoms.
As for epilepsy, the problem is more complex. One has to rule out first those who have organic destructive disease of the brain. But they are out of our field: genius predicates at least an intact brain. ”

“ Destruction of the visual cortex of one hemisphere alone produces in the dog impairment of vision, not as in the bird practically exclusively in the opposite eye, but in one lateral half of each eye, and that half the half opposite the hemisphere injured. Thus when the cortex destroyed is of the right cerebral hemisphere, the resultant visual defect is in the left half of the field of vision of both eyes. And this is so in man also.
In man disturbances of sensation can be better studied because it is possible to obtain from him his description of his condition. ”

“ Hemianopsic phenomena may be functional and transient, as witnessed just before attacks of migraine or sick headache.
Attempts recently made, from purely theoretical considerations, to locate centres in the occipital cortex for perception of light, form, and color separately, are wholly unjustified or at least premature.
Loss of reflex pupillary movements is a symptom of much importance. It occurs chiefly under these conditions: (1) with paralysis of the iris due to lesion of the third cerebral nerve; (2) with amaurosis or anæsthesia of the retina; (3) with posterior spinal sclerosis. ”

“ Its sensory nerves with their protopathic constituents have been drawn backwards into the great bundle of the fifth nerve, which joins the hind-brain, whilst the nerve from the retina has established a secondary connection with the mid-brain. The mid-brain receives in consequence the protopathic nerves of the eye. But the nose being the real tip of the body and anterior to the eye the sensory fibers of the skin which lines it although bound up with the fifth nerve, extend forwards within the cerebrospinal axis to the very front of the mid-brain. ”

“ We need only suppose that when the head turns in the plane of any one of them, the relative inertia of the endolymph momentarily increases its pressure on the nerve-termini in the appropriate ampulla, which pressure starts a current towards the central organ for feeling vertigo. This organ seems to be{76} the cerebellum, and the teleology of the whole business would appear to be the maintenance of the upright position. If a man stand with shut eyes and attend to his body, he will find that he is hardly for a moment in equilibrium. ”

“ At this point he stopped the treatment against my advice, and I have not seen him since. He was greatly helped by the universal swing, which he practiced all day. The truth about glaucoma is that it is a functional neurosis caused by strain, and as such is curable. You can produce hardness in a normal eye by having the patient strain to see (see page 2) , and you can soften a glaucomatous eyeball by relief of strain. These changes are so rapid that no change in the contents of the eyeball could account for them. ”

“ The symptoms caused by pressure of cerebellar tumors upon adjacent organs are of importance, because in conjunction with the special symptoms they acquire unusual significance. Sight and hearing are the two special senses apt to be affected, because of pressure upon the geniculate bodies and upon the auditory nerve or its nucleus. Descending optic neuritis, progressing to total blindness, and varied forms of oculo-motor paralysis may be present. Strabismus convergens has been said to be a symptom, caused by the paralysis of the sixth nerve. ”

“ Bright light striking our eye makes the pupil narrower by a contraction of the iris, and in the same way our eyelids close if a finger be thrust suddenly towards them. We know, too, the principle of these reflex mechanisms; they depend on nerve connexions. Sensory nerves are so connected in the nerve-centres with motor nerves, that a stimulus affecting the former at the periphery of the body, as at the eye, is carried to certain nerve-cells of the brain, and from these it excites to activity certain motor centres, so that definite movements are set up. ”