Oculomotor apraxia is also called Cogan II syndrome and is an extremely rare eye disorder that makes it impossible for affected individuals to perform eye movements for fixation. Most often, the syndrome is congenital, but acquired variants also occur. The movement disorder in this form is usually related to another disease, such as a stroke. Acquired oculomotor apraxias usually resolve on their own by adulthood and are thus no longer a particular limitation for those affected after the age of about 20.
What is oculomotor apraxia?
By oculomotor apraxia, the medical profession means the inability to perform eye movements that serve fixation. These eye movements are also known as gaze target movements, and the totality of all eye movements is synonymous with the medical term oculomotor. In this respect, the term oculomotor apraxia is a confusing one, because the movement disorder in this condition need not refer to the entire oculomotor system, but may in fact be limited to the fixation movements mentioned. The phenomenon is sometimes called Cogan II syndrome or COMA. The phenomenon was first documented in 1952 by U.S. ophthalmologist David G. Cogan.
Causes
Oculomotor apraxia can be congenital, but acquired forms are also within the realm of possibility, although they are much less common. For the congenital form, the cause is as yet unclear, but most often the phenomenon manifests on imaging as a lack of connectivity in the corresponding eye movement centers of the brain or as a movement disorder of the third cranial nerves. If acquired Cogan II syndrome is present, the phenomenon is likely due to neurologic disease or damage. For example, the phenomenon may occur in supranuclear lesions, usually bilateral, that is, lesions of the supranuclear gaze centers in the brain, sometimes accompanied by paralysis, and usually located in the frontoparietal cortex.
Symptoms, complaints, and signs
Congenital Cogan II syndrome particularly affects horizontal eye movements. In acquired Cogan II syndrome, on the other hand, vertical gaze fixation movements are often also affected by the disorder. Often, especially in early life, the disorder manifests itself in the form of a fixed gaze, although affected individuals usually find it easier to move their eyes together with a head movement. In adulthood, this often results in a horizontal and vertical whirling of the head, which jerkily and abruptly turns the entire head over in one direction. The so-called vestibulo-ocular reflex forces the eyes to each other’s stop, so that they are mechanically carried along with the whirling movement of the head. Those affected by oculomotor apraxia usually move their head back a little after the centrifugal movement, whereby their eyes remain fixed in the direction of gaze they have just aimed at. In young children, cerebellar ataxias and delayed motor development are among the most common accompanying symptoms of oculomotor apraxia. In addition, however, balance problems and difficulties with eye-hand coordination may also occur.
Diagnosis and course of the disease
Because of the characteristic head movements that affected individuals with Cogan II syndrome require for gaze control, the diagnosis can usually be made by observation alone. However, especially in cases of acquired oculomotor apraxia, physicians will initialize imaging to help with differential dignostics as well as localization of possible lesions and assessment of their cause. Cogan II syndrome usually regresses over the course of life. This means that in adulthood, affected individuals with a congenital variant often require only a minute and barely noticeable head movement to perform fixational movements with their eyes. Especially by the age of 20, drastic improvements often occur. In acquired forms, spontaneous improvement is less likely, since the phenomenon in this case is often related to another disease. For example, a tumor may also cause such symptoms under certain circumstances, which an experienced physician recognizes by its typical shape in imaging.
Complications
Oculomotor apraxias, which are very rare overall and usually congenital, involve a restriction or complete inability to follow a moving target with the eyes. Affected individuals tend to compensate for oculomotor apraxia by making appropriate head movements. If the condition is congenital, there are usually no further complications to worry about because the inability to follow a moving object with the eyes usually improves as the person grows up. Causal treatment is not (yet) possible for genetic disorders. However, special exercises and physiotherapy can further mitigate the effects of the condition associated with some degree of gaze rigidity. If oculomotor apraxia is caused by an accident, stroke or tumor, serious complications may develop if the cause is not found or treated. For example, in the event of a stroke or hemorrhage in the CNS, the location of the clot or hemorrhage should be diagnosed by imaging to initiate appropriate treatment that can prevent major complications. Similar procedures are indicated when apraxia is caused by a tumor that exerts compression of certain oculomotor nerves by displacing space. In this case, serious complications can be expected if left untreated if the tumor is malignant and may continue to grow or metastasize, depending on the tumor type.
When should you go to the doctor?
If irregularities in eye movements are noted in newborn infants, action is needed. In most cases, obstetricians take over the initial examinations of the infant in a routine procedure and notice the abnormalities of the eyes. Therefore, there is no need for the parents to initiate further steps. The nurses, midwives or doctors present coordinate the further examinations to enable a diagnosis to be made. A treatment plan is then drawn up so that adequate medical care can be provided. If sudden abnormalities of eye positions as well as eye movements occur in adulthood, a doctor must be consulted. If the irregularities occur after a jerky head movement, a fall or accident, a doctor must be consulted. If there are disturbances in balance, pain in the head or swelling, medical advice should be sought. Restrictions in vision, sleep disturbances or a decrease in physical or mental performance should be professionally examined. If behavioral peculiarities become apparent or if severe emotional distress is present, a physician is also needed. Dizziness, unsteadiness of gait as well as a general feeling of malaise must be presented to a physician. If there are changes in memory, impaired consciousness or attention deficits, a visit to the doctor is necessary. In the event of an acute health-threatening condition, an ambulance service must be alerted. To ensure survival, first aid must be initiated according to first aid guidelines.
Treatment and therapy
Oculomotor apraxias are not causally treatable as such. However, physiotherapy, occupational therapy, remedial early intervention, optometry, and mothopaedics can be used to treat associated symptoms as well as to learn compensatory mechanisms. In addition, individual symptoms can possibly be alleviated with medication. As a rule, affected persons visit a specialist once a year, who documents their current condition in a videolog in order to keep an overview of the course of the disease. In the case of acquired oculomotor apraxia, the method of treatment depends on the cause. If a tumor is associated with the condition, the physician will likely surgically remove it as much as possible. In the case of lesions of the visual centers due to inflammation, the inflammation will likely be addressed via medication. However, intensive inpatient treatment may also be required for infections of the brain.
Outlook and prognosis
The prognosis of oculomotor apraxia is unfavorable in most cases. In a congenital disorder, a genetic defect is present. Because human genetics cannot be altered for legal reasons, treatment of the cause cannot occur.Overall, changes are achieved through early intervention programs. However, freedom from symptoms is not achieved. The further course of acquired oculomotor apraxia is similarly unfavorable. The disturbances of the eye movements are consequences of a serious disease. In most patients, there is an emergency situation that has led to the development of the health abnormalities. An accident, cancer or stroke are the most common acquired causes of apraxia. Therefore, the general health condition is already weakened. The concentration of a medical care is normally on the relief of the symptoms of the underlying disease. The overall quality of life should be improved and the patient’s remaining life should be prolonged. Nevertheless, the prognosis may improve if the underlying disease at hand is cured. In addition, individual complaints can be alleviated or completely reversed by the administration of drugs. For this purpose, the affected person must undergo long-term therapy. In order to achieve a health stabilization and improvement he needs a regular control of a treating physician.
Prevention
Because oculomotor apraxia is congenital and the cause of the defect has not yet been determined, the phenomenon cannot be prevented. However, the condition is of enormous rarity, so expectant parents should not live in fear of the disorder. Phenomena such as strokes, which in the rarest cases can be the cause of acquired Cogan II syndrome, can be prevented by various measures. For example, prevention may include regular checking of the arteries and taking special medications.
Follow-up care
In oculomotor apraxia, the main thing to avoid is any overexertion of the affected eye. Glaring sunlight and bright lights from lamps should be avoided, and lighting conditions should be adjusted by affected individuals to suit the condition. If, for example, there is a desire to read a book, then sufferers must ensure that they are provided with sufficient light. If sufferers do not do this, they accept a worsening of the oculomotor apraxia and the symptoms. The disease usually also brings with it disturbances of balance. In this case, affected persons should ensure sufficient safety during movement. For example, help and support can be sought from family or relatives for everyday tasks. If this is not an option for sufferers, there are special walking aids that can help them move around safely and provide sufficient support. The shoes of the patient should be tightly laced and as stable as possible in order to provide sufficient support. Shoes with high heels should not be worn. These do not provide sufficient security and can lead to a loss of balance. The reduction of vision triggers a high emotional burden for many affected persons. Therefore, treatment by a psychologist should be considered.
What you can do yourself
In everyday life, the possibilities for self-help in oculomotor apraxia are extremely limited. In many cases, the eye movement disorder is just a complaint that the affected person has. In everyday life, excessive efforts of the eye should be avoided. Under no circumstances should the eye be directed into bright light sources. This includes sunlight as well as bright spotlights built into lamps. Although no change of the movement possibilities is obtained, it is nevertheless important that the environment is supplied with sufficient light conditions with the desire of reading or writing. Otherwise, the eye is subjected to further strain and already existing complaints increase in scope or intensity. Since the disease is often accompanied by disturbances of balance, care must be taken to ensure adequate safety when moving around. If necessary, walking aids should be used, as they can provide necessary support in uncertain situations. The footwear worn should be closed and stable. High heels should be avoided as they promote gait insecurity. A reduction in vision causes anxiety in many affected individuals. It should be examined whether psychotherapeutic support should be sought.The patient should be informed in advance about the optimal behavioral guidelines in anxiety-provoking situations to avoid panic.