Oculomotor apraxia: symptoms, treatment and possible causes
A rare eye movement disorder for which little is known about the causes.
Oculomotor apraxia is the inability to perform horizontal eye movements voluntarily or on verbal command. or on verbal command.
It was described by Cogan in 1952 and its etiology is still unknown. Let's see, in more detail, what this congenital disease consists of.
What is oculomotor apraxia?
Oculomotor apraxia or gaze apraxia can be either acquired or congenital.. This second form is an inherited disorder that affects the eye and is generally present from birth.
It consists of an alteration of brain function characterized by the inability to execute horizontal eye movements voluntarily, or under verbal command from another person.
It is a condition, of as yet unknown causes, generally considered to be a sporadic disorder, although cases have been described with autosomal dominant inheritance (when only one copy of the gene allele is sufficient for the disease to be expressed).
The patient suffering from oculomotor apraxia cannot voluntarily change the direction of gaze to the sides, nor presents the fast phase of the vestibulo-ocular or optokinetic reflexes (responsible for stabilizing the gaze). (responsible for stabilizing the gaze to obtain sharp images).
Causes
Although the causes responsible for the development of a condition such as oculomotor apraxia in newborn infants have not yet been identified, it has been suggested that most of the causes of oculomotor apraxia in newborn infants are due to a lack of vision, it has been suggested that most of them may have developed Joubert's syndrome, a genetically transmitted disorder.Joubert syndrome, a genetically transmitted disorder.
This syndrome would cause partial metabolic disturbances or neurodevelopmental defects, such as hypoplasia (incomplete development) of the cerebellar germ, aplasia (absence of development) of the corpus callosum, heterotopias of the gray matter, Kallman syndrome or chromosomal alterations.
Differential diagnosis
In order to establish an accurate diagnosis of oculomotor apraxia other causes, such as fixation defects and abnormal cephalic movements, should be ruled out.The differential diagnosis is based on the following: visual deficits due to ocular problems, mobility disturbances, spasms or psychomotor retardation.
In addition, the patient vertical saccadic movements (both voluntary and reflexive) should be (both voluntary and in vestibulo-ocular and optokinetic reflexes). However, it should be noted that in acquired oculomotor apraxia, secondary to other central nervous system lesions, vertical movements are also affected.
Main features
Cogan identified several key features characteristic of congenital oculomotor apraxia.
Firstly, he emphasized the abrupt turning of the head in the direction of the object of fixation and deviation of the gaze to the opposite side, followed by a slow movement of the eyes towards the desired location.followed by a slow movement of the eyes towards the desired location.
There are also occasional spasms in the fixation of the gaze, and a movement of the head towards the object of fixationand a movement of the head towards the object of fixation while the gaze remains fixed in the first position, followed by a closing of the eyelids and a subsequent slow movement of the eyes towards the new place of fixation.
On the other hand, there is preservation of spontaneous eye movements and gaze in the vertical plane..
Finally, there is an alteration of the attraction movements and, sometimes, of the gaze following movements.
Oculomotor apraxia type 2
One of the most studied oculomotor apraxias is type 2, caused by a mutation in the SETX gene.. This apraxia is often accompanied by ataxia, which is the lack of Muscle control or coordination of voluntary movements.
This type of apraxia is a characteristic symptom of Gaucher diseaseGaucher disease, a rare, degenerative condition resulting from the accumulation of certain fatty substances in organs such as the spleen or liver.
This disease usually causes early death in children who suffer from it, although in recent years an enzyme treatment that replaces the inactive enzymes with new ones is being carried out to try to slow its progression. In the most severe cases, bone marrow transplantation is usually necessary.
Treatment
Some health professionals recommend vision therapy. to cope with a condition such as oculomotor apraxia and the consequences that derive from it.
In this type of therapy non-surgical visual exercises are performed, personalized and prepared by a behavioral optometrist, always under the supervision of an ophthalmologist specializing in the field of oculomotor apraxia.always under the supervision of an ophthalmologist specialized in the field.
There seems to be evidence that the problem improves over the years if the exercises are performed correctly and for the specified time.
However, it has also been suggested that there is no cure for this disease and that the only solution is to adopt compensatory measures to allow the person to adapt to his or her new disability.
Other types of apraxias
Oculomotor apraxia is a specific type of apraxia involving difficulties in eye movement, but there are other types of apraxias with symptoms that generate a number of other complications of a similar nature. of a similar nature. We will now see what they are:
1. Ideomotor apraxia
Ideomotor apraxia is the most common apraxia of all and is characterized by the fact that people who suffer from this apraxia cannot copy movements or perform everyday gestures, such as waving with the hand.such as shaking hands or nodding their heads.
Patients suffering from ideomotor apraxia are able to describe the steps to follow to perform a specific action, but have severe difficulties in performing that action or in imagining that they are performing it.
2. Construction apraxia
This type of apraxia is the second most common. People who suffer from construction apraxia are incapable of carrying out motor actions involving spatial organization; for example, they cannot make aFor example, they cannot draw a picture, make figures with blocks or make a face grimace.
3. Ideational apraxia
Ideational apraxia is a type of apraxia characterized by difficulty in performing complex actions that require some planning, such as sending an email or making a meal.such as sending an e-mail or cooking a meal.
Patients with ideational apraxia generally produce incoherent, inappropriate and disorganized gestures.
4. Apraxia of speech
Apraxia of speech is characterized by the inability to reproduce necessary motor sequences with the mouth in order to speak intelligibly. This apraxia adults as well as children of learning age can suffer from this apraxia.However, in infantile patients this disorder is often referred to as dyspraxia.
5. Kinetic apraxia of the extremities
People suffering from this type of apraxia have a deficit in the fluid movement of the limbs, both upper and lower. They also suffer a loss of dexterity or ability to perform both fine and precise movements with the hands and fingers (fine motor skills) and movements with the arms and legs (gross motor skills).
6. Buccofacial apraxia
In the buccofacial apraxia there is a manifest incapacity to control correctly the muscles of the face, the tongue and the throat, and therefore, problems to control correctly the muscles of the face, the tongue and the throat.and therefore, problems with chewing, swallowing, sticking out the tongue, etc.
This inability is manifested when the person performs voluntary and on purpose - and not involuntary - movements, i.e., it only occurs when a movement is executed after having been thought out and planned in advance.
Bibliographical references:
- Gulias-Cañizo, R., Sánchez-Huerta, V., Rubio-Lezama, M. (2005). Congenital oculomotor apraxia: a case report. Rev Mex Oftalmol.
(Updated at Apr 13 / 2024)