Anton-Babinski syndrome or Anton syndrome is a rare condition where people with cortical blindness deny they are blind. They continue to pretend they are not experiencing vision loss, and it may be difficult to tell that the person has, in fact, become blind. Other people may begin to suspect a problem when the person starts bumping into things and making odd excuses about why they’ve done so.
This condition is exceptionally rare. There were only 28 published cases of Anton-Babinski syndrome between 1965 and 2016.
Anton-Babinski syndrome is a rare form of anosogosia, a neurological symptom where people are in denial about or unaware of their disease. Gabriel Anton, a French neurologist and psychiatrist, explained this phenomenon in 1895 in patients with cortical blindness. Then, in 1914, French neurologist Joseph Babinski first used the term anosognosia to explain why patients with left-sided paralysis seemed oblivious to their disability.
Anton-Babinski syndrome occurs in people with cortical blindness, which is caused by damage to the occipital cortex — the visual processing center in the back of the head. There are five criteria for a diagnosis of cortical blindness:
- loss of blink reflex in response to a threat
- loss of all visual impulses, including the ability to distinguish between dark and light
- loss of a pupillary reaction to changing light
- preservation of extraocular movement, or the ability to move the eyes up/down and left/right
- continued normal appearance of the retina
History of Visual Anosognosia
Although Anton-Babinski syndrome did not have a name until the 1900s, the first recorded description of the condition goes back to Roman times when a slave named Harpaste become blind and denied it. A case was also recorded during the French Renaissance of a nobleman who would not admit he was blind.
Cortical blindness can be caused by many things, including pre-eclampsia, stroke, dangerously low blood sugar, swelling in the brain, head trauma, autoimmune diseases that affect the central nervous system, and hypoxia or severe lack of oxygen.
In general, cortical blindness is caused by a neurological problem in the brain and not a defect in the eyes.
It is important to note that very few people with cortical blindness have developed Anton-Babinski syndrome. Why some do is not yet understood. One hypothesis is that the visual association cortex, the part of the brain that processes visual information and may have a role in memory formation, is damaged along with the occipital cortex. Damage to both of these areas can result in a disconnection between the language and visual parts of the brain, leading to the memory errors present in Anton-Babinski syndrome.
Symptoms of Anton-Babinski syndrome are sometimes difficult to pick up on. Although the person is blind, they will act as if they are not. Others may observe them walking into walls, furniture, or a closed door. They may then begin to describe people and things in the room around them that are not really there.
People with Anton-Babinski syndrome may seem confused, or they may make up excuses for their blindness or attempt to prove that they are not blind, which can be dangerous.
To diagnose Anton-Babinski syndrome, the doctor must first diagnose the patient with cortical blindness; in other words, they must meet the five diagnostic criteria. Once this diagnosis is confirmed, doctors will try to locate the cause of the damage in the occipital cortex with an MRI of the brain or a doppler of the carotid artery to rule out stroke.
Though cases are extremely rare, some risk factors have been identified In older people, the damage that causes Anton-Babinski syndrome usually results from a stroke, while younger people are more likely to develop it from a non-vascular cause. Three cases have been reported in young women between 19 and 36 resulting from a hemorrhage following an abortion with complications, trauma, and a multiple sclerosis exacerbation.
Treatment for Anton-Babinski syndrome depends on the cause of the damage to the occipital cortex. When the damage is not vascular — not from a stroke — treatment centers on resolving the underlying cause. Doctors may manage the head trauma or treat multiple sclerosis exacerbation. Stroke prevention is key to stopping Anton-Babinski syndrome before it starts and includes managing blood pressure, smoking cessation, and controlling cholesterol.
Some people can recover from cortical blindness, depending on their age and the severity and duration of the condition. As for the secondary Anton-Babinski syndrome, when the person is young and has no history of diabetes, hypertension, or cognitive impairment, the odds of recovery are good. In older people who have Anton syndrome as a result of a stroke, the prognosis is not as good, and most are unlikely to recover.