When we observe the environment, our eyes make a great number of movements to capture each of the details and movements that compose it. Then our brain composes a harmonious picture of everything around us, including moving objects and people.
Our vision works like a video camera that processes thousands of images of its surroundings, while our brain projects the “film” into our mind. However, what happens when this functionality is changed? In these cases, acinetopsia appears, A disorder in which the person has difficulty perceiving movement.
What is acinetopsy?
Acinetopsia, also known as acinetopsia or motion blindnessThis is a disorder of a neurological nature and affects the sense of sight. More specifically, acinetopsia causes in people who suffer from it an inability to perceive movement by sight.
This condition, first described around 1991 by the British neurologist Semir Zeki, makes the affected person unable to perceive movement. The patient cannot even see the movement of his own body, like that of other people or objects.
However, acinetopsy is not an “all or nothing” condition. This condition can have varying degrees of severity. From the lightest, in which the person perceives the movement as their own was a sequence of images or a film in which the images pass in slow motion; most severe, in which the patient experiences a complete inability to perceive movement.
In this disorder, the person can perceive other subjects, objects or themselves only in one particular place and suddenly in another. Or at most, he perceives a kind of fuzzy trail behind the moving object.
While the rest of the sensory functions and capabilities remain intact, people with acinetopsia also have impaired visuomotor abilities. Since he does not perceive his own movements well, tasks such as walking and moving, or obtaining objects can be really complicated.
Types of acinetopsia and symptoms
As mentioned above, acinetopsia can occur to varying degrees. These degrees constitute the different typologies of this disorder, which vary both in the severity of the symptoms and in the level of blindness it causes in the person.
There are two different types of kinetopsy. They are as follows.
1. Fine or discrete acinetopsia
This first type of acinetopsy, called fine or discrete, is the one that presents a milder symptomatology and therefore less disabling for the person. Although similarly, people who suffer from it report experiencing tremendous discomfort.
In mild acinetopsia, the person perceives movement like to visualize a reel in which the frames pass at a much slower speed. Another example would be a multiple exposure photograph, in which the person can perceive the wake of the movement of objects and people, including the patient himself.
At the moment, it is not known what abnormality in the functioning of the body causes this disorder. However, experts emphasize the idea that abnormal functioning of the mechanisms that allow us to maintain the visual stability of eye movements can cause this type of acinetopsia.
2. Macroscopic acinetopsy
Also known as coarse acinetopsy, this type of motion blindness is extremely unusual and very low incidence in the population.
Unlike fine acinetopsy, macroscopically, the person is completely unable to perceive the movement in its entirety. This means that the person can only see a static world in which for a moment the object or the person is in one place and for the moment in another.
The few people who suffer from it, they tend to suffer from many problems in carrying out their daily tasks normally. Daily activities such as having a conversation are very complicated because the patient is unable to perceive the changes in the movement of facial expressions. Likewise, daily routines, like crossing the street, become a very dangerous thing; it is no longer possible to perceive the movement of the cars.
To compensate for these difficulties, people with acinetopsia train their hearing. In this way, by means of the sense of listening, they can, for example, calculate the distance of moving objects.
What are the causes?
The cause of acinetopsia is abnormal functioning or interruption of activity in the area of the cortex that is in the central area of the temporal lobe. Structural alterations in this area of the brain can transform the processes of understanding sensory information. In the case of this strange disorder, it is the processes that process visual information that are compromised.
There are several reasons why this region of the brain can be affected. Head injuries, the consumption of certain antidepressants or hallucinogens, or certain diseases such as Alzheimer’s disease.
1. Brain injuries
One of the causes of this disorder may be an injury to the posterior region of the visual cortex, Although it is really complicated, such an injury is likely to generate much more sensory deficits.
2. Antidepressant drugs
Giving very high doses of some antidepressants can cause visual problems such as acinetopsia. However, this tends to go away when the treatment is withdrawn or the dose is readjusted.
3. Hallucinogenic substances
Regular or recurrent consumption of certain hallucinogenic substances it can cause sensory disturbances of all kinds, Including the milder version of acinetopsia, fine acinetopsia.
4. Migraine aura
The aura is a visual phenomenon that accompanies migraines. This tends to appear moments before the onset of pain and is manifested by visual symptoms such as spots in space, sparks, or fine acinetopsia.
5. Alzheimer’s disease
Although they do not appear very frequently, acinetopsia, present in varying degrees, can accompany memory alterations in patients with Alzheimer’s disease.
Is there a treatment?
Currently, there are no pre-established guidelines for the treatment of acinetopsia. In cases where this is caused by the administration of psychotropic drugs, stopping their consumption should eliminate the symptoms of this disorder.
however, brain surgery, although risky, is an option to try to rule out kinetopsia in cases where there is an underlying brain injury.