Anton-Babinski syndrome

Anton-Babinski syndrome, also known as Anton syndrome, is a type of cortical blindness occurring as a result of bilateral occipital lobe lesion. The syndrome consists of blindness, visual anosognosia and confabulation ^1-5. 

Epidemiology

The syndrome is rare with 28 documented cases between 1965 to 2016 ¹.

Clinical presentation 

The vision loss can be complete or, in some cases, partial. The patient may have tunnel vision or fluctuating vision loss in case of partial vision loss ¹. The patient has anosognosia and is blind but pretends to have a normal vision, thus there is confabulation. 

Fundoscopy will reveal no retinal pathology and the patient will have normal pupillary light reflex. Ocular movements will be normal when asked to look in a particular direction, but the patient typically cannot follow a target due to visual loss.

Pathology

Anton syndrome is generally caused by lesions affecting the bilateral primary visual cortex (Brodmann area 17), which is located in the occipital lobe. In rare cases, lesions in optic radiation have also caused Anton syndrome ³. 

Anosognosia and confabulation are due to a disconnection between the visual area and language area. A disconnect between visual area and conscious awareness system is also noted ¹. 

Etiology

It is commonly seen after ischemic strokes affecting the posterior cerebral arteries ³. Some of the other known associations include ^1-5: 

• intracerebral hemorrhage (e.g. due to cerebral amyloid angiopathy)

• traumatic brain injury

• multiple sclerosis

• encephalitis and other infective processes (e.g. progressive multifocal leukoencephalopathy)

• hypertensive encephalopathy

• posterior reversible encephalopathy syndrome

• mitochondrial encephalomyopathy with lactic acidosis, and stroke-like episodes (MELAS)

Treatment and prognosis 

The management of Anton syndrome depends on the underlying cause. Patients who are young and without any comorbidities tend to have their vision restored on initiating treatment ^1,5. 

History and etymology

Cases of the syndrome were described in the Roman era, and later in the Renaissance. The syndrome is named after Gabriel Anton (1858-1933), an Austrian neurologist, and Joseph Babinski (1857-1932), a French-Polish neurologist ¹.