A nystagmus is generally understood to be a jerky eye movement that is carried out at very short intervals from left to right or from right to left. On the one hand, nystagmus has very biological tasks, but under certain circumstances it can also be a sign of an illness.
Nature established nystagmus to improve the way in which the brain absorbs and processes visual effects. This mechanism can be illustrated particularly well using the example of the view from a moving train. If you look out of the window of a moving train and look at the landscape that passes you, you get the impression of a whole picture. In reality, however, this image consists of many individual images that the brain collects through the return movement of the eye and then combines to form an overall image (in this case the landscape image).
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If you look outside from a moving train, the eye fixes a certain point. This happens unconsciously. The eye now follows this point until it disappears from the field of view. Then it chooses a new point. To do this, the eye quickly returns to the starting position. This rapid, involuntary movement is known as nystagmus.
One distinguishes two forms of nystagmus: the physiological nystagmus or normal, innate and den pathological nystagmus or pathological nystagmus.
Of the physiological Nystagmus is by nature Stabilization of image perception been established. Quick, trembling eye movements create a landscape that e.g. quickly passes by, perceived as a whole, stable image. The eye collects different fixed points of view. It sticks to one point until it disappears from the field of vision and then immediately looks for a new point. As a result, the eye quickly returns to the starting position. This eye reset movement is not actively perceived. An observer who looks at him, however, does. The quick retraction movement is made by the Cerebellum and parts of the Brain stem coordinated and controlled. With the so-called Jerk nystagmus the eye slowly follows a certain object and then makes a quick jerky movement in the opposite direction. The direction of the nystagmus is indicated by the rapid phase.
$config[ads_text2] not foundAt the PendelnystagmuThe adjusting movements of the eye are the same in both directions. The nystagmus, which is used to stabilize the Retinal image occurs (moving train and looking outside) is also called optokinetic nystagmus (OKN). The so-called vestibulo-ocular reflex enables a stabilization of the retinal image with own head movement, i.e. if someone turns their head in a certain direction, their eyes are automatically moved in the opposite direction and then jump to the center of the eye with a jerk. This measure is also required to stabilize the image. Disturbances of this vestibulo-ocular reflex indicate damage to the Balance nerves (Vestibular nerve).
To the pathological nystagmas count the suddenly occurring, undirected Nystagmus. It occurs suddenly without the need for point tracking. Another pathological form of nystagmus describes the congenital nystagmus. This is a congenital eye flicker that increases when certain points are fixed. It has an irregular shape that is weakened when looking at certain directions, but can also be reinforced by others. Congenital nystagmus is a sign of a congenital disorder of the Eye muscle motor skills. Another possible cause can be a severe congenital visual disorder. A central nervous system disorder or a tumor are practically never available.
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The linactive nystagmus occurs when one eye is covered and disappears when both eyes are uncovered. He is a sign of early childhood squint syndrome. The so-called nystagma is also one of the pathological nystagmas vestibular nystagmus.
In the event of a failure of an organ of equilibrium, such as in Meniere's diseasesudden eye tremors occur, which the patient reports from severe dizziness perceives. The vertigo attacks, which are usually vertigo attacks, are sometimes so severe that the patient is under Balance disorders, stronger nausea and even Vomit suffers. If the patient fixes a certain point, the nystagmus is usually inhibited. Severe dizziness after a change in position (e.g. from lying down to a seat or from sitting to standing) is sometimes also associated with nystagmus. The reasons for this are probably in one calcification and in an increasing immobility, the small spheres, also known as otoliths, which are responsible for the balance in the equilibrium organ of the Ear available.
Possible causes of a pathological nystagmus are a failure of the equilibrium organ and calcification of the otoliths as well as injuries or damage to the brain stem. Here could e.g. a bleeding or a tumor trigger this disorder. Appropriate imaging, such as CT or MRI should definitely be performed if the nystagmus is unclear.
To check the nystagmus there are some tests that the ENT doctor usually carries out. First, the patient is placed on a swivel chair and this is then accelerated. A slowly beating eye nystagmus occurs, initially against the direction of rotation, followed by a quick return movement in the direction of rotation.With this measure, the body tries to reproduce as complete an image as possible on the retina, as when fixing the surroundings from a moving train. If the swivel chair is now stopped, the direction of the nystagmus changes. This is mainly due to the inertia, which is decisive for equilibrium Endolymph in the organ of equilibrium. This nystagmus can also be observed in healthy people and can be made visible with the so-called Frenzel glasses. These special glasses, which are put on the patient, enable an accurate representation of the eye movements through a very strong refraction of the eyes. So even a very fine beating nystagmus will be well represented through these glasses. So that the examinee cannot fix a point through the glasses, he is prevented from doing so by a glare lamp.
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The caloric review is another way to test nystagmus. The patient receives either cold water with a temperature of approx. 25 degrees or warm water with a temperature of approx. 40 degrees in the external auditory canal. This leads to irritation of the Vestibular organ and to induce nystagmus. This change in temperature simulates a rotation in the brain, which immediately leads to a jerk nystagmus through the vestibulo-ocular reflex (VOR). Why this temperature difference leads to the triggering of nystagmus is largely unknown to this day. Numerous attempts have been made to do this in space, excluding the force of gravity.
For those in whom nystagmus is triggered, there are initially no symptoms if it is physiological nystagmus. As a rule, there is nystagmus completely unnoticed and is embedded in everyday situations in which certain points are fixed.
As soon as the nystagmus is not physiological but pathological, moderate to severe symptoms can arise. In the case of non-physiological nystagmus, there is a pretense of a rotating movement, which the brain registers. Then will severe dizziness triggered, which can usually be the first symptom of a pathological nystagmus. The dizziness is mostly of a spinning nature. In the case of very strong attacks of dizziness, the patient can also suffer from severe balance disorders, which lead to the fact that he can no longer stand on his own feet. Furthermore, a frequent accompanying symptom of severe dizziness is also severe nausea, which can lead to vomiting. Patients with pathological nystagmus are in very poor health and in urgent need of diagnostic and therapeutic help.
First and foremost, the cause of nystagmus should be determined. At the benign positional vertigowhich causes nystagmus by hardening of the otoliths Fall and throw exercises very helpful and often lead to an improvement in symptoms after just a few applications. If the cause of nystagmus is unclear, imaging by a MRI-, or CT Admission should be carried out to rule out injury or damage to the brain stem. Treatment options are very limited for nystagmas caused by bleeding and / or stroke.
$config[ads_text1] not foundSometimes nystagmas can also go through Ametropia arise. If some points cannot be fixed correctly, the eye tries to collect various different points. This is then reflected in a nystagmus. In the case of ametropia and a developing nystagmus, prism glasses can be used to try to eliminate the nystagmus. Consistent wearing of the glasses is necessary.
There are also some drugs that can be used to treat nystagmus. The drugs should be mentioned Gabapentin and Memantine. Gabapentin is mainly used so far in the treatment of Nerve pain come into use. Memantine is used today in the treatment of Alzheimer's dementia used. Why and to what extent these drugs cause this effect is not entirely clear. In the case of nystagmus that leads to severe nausea and vomiting, the accompanying symptoms should definitely be treated, even if this does not stop the nystagmus. Through medication, like MCP or Vomex the symptoms can be significantly alleviated.
Very often there is also a different degree of nystagmus in the Multiple sclerosis in front. It is very similar to congenital nystagmus. The cause is largely unknown. It is assumed, however, that there is a connection between nystagmus and optic nerve inflammation, which is also very common in MS. The nystagmus in MS can take on different dimensions and if it is mild it can cause no symptoms at all, but it can also be so strong that it can lead to nausea, severe dizziness and vomiting.
When fixing a point while driving, the eye slowly moves in a vertical direction against the direction of travel. The movement is very slow. This eye movement is followed by a quick return nystagmus in the direction of travel. The same sequence of movements is triggered in the swivel chair test. First of all, the eye moves against the direction of rotation, followed by a rapid movement in the direction of rotation. After the chair has stopped, the directions of rotation change for a brief moment, which is attributed to the indolence of the endolymph. After a short time, the eye will be in a state of rest again. During the thermal examination of the nystagmus, the viewing direction depends on the temperature used. For example, irrigation with a cool liquid would direct the nystagmus in the direction of the opposite ear; if a warm solution is used, nystagmus occurs in the direction of the irrigated ear. In the case of pathological nystagmas, due to damage or injuries to the brain stem, both left and right-handed nystagmas, as well as fast but also very slow eye movements can occur.
Caution should be exercised when nystagmus occurs in the newborn. Because there can always be a serious illness behind it. The disease, also known as congenital nystagmus, is a congenital eye tremor that usually increases when a point is fixed. It has a horizontal direction of impact and is mostly irregular. This eye tremor is weakened in certain viewing directions, but intensified in others. The cause of congenital nystagmus can be disorders in the oculomotor system, i.e. disorders in the Coordination of the eye muscles. In addition to this cause, severe ametropia can also trigger congenital nystagmus in newborns. The eye tries to collect many points of view in the environment because it is not able to represent a point more precisely. This results in nystagmus. Tumors or damage to the central nervous system are practically never the cause of congenital nystagmus. Nevertheless, imaging of the head should be carried out, even in newborns, if no other causes of the nystagmus can be found.
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