Balint's syndrome

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Revision as of 00:32, 24 April 2008

What is Balint’s Syndrome?

Rezso (Rudolf) Balint identified Balint’s syndrome in 1909 as a disjointed and paralysis

of gazing ability with haphazard scanning skills. Balint’s syndrome is characterized by

optic ataxia (uncoordinated hand and eye movement) and optic apraxia (inability to

voluntarily guide eye movements and change locations of visual fixations). Due to the

combination of optic ataxia and optic apraxia, patients with Balint’s syndrome also

display simultanagnosia or the inability to perceive more then one object at a time even

when the objects are taking up the same area of the visual field. In some cases, the patient

may behave as if they are blind.

Simultanagnosia in Balint's Syndrome

What is really interesting about Balint’s syndrome is that the simultanagnosia involved

with Balint’s syndrome is not specific to one object or spatial location. For example, the

tester could hold up two objects that intersect each other on the patient’s visual field and

ask the patient what he sees. The patient is just as likely to pick one item over the other,

while being completely blind to the second object.

Jackson et al (2006) conducted a perceptual priming task with a Balint's patient where 2

pictures were shown (either the same or different semantic categories), and the participant was

asked to either classify one of the pictures or name both pictures. The results indicate that

there was a significant decrease in classification performance when the 2 pictures were different

in semantic category. The surprising aspect of this result is that the patient rarely indicated

that he saw more than one object. Thus, Jackson et al (2006) found results pointing to a

theory that Balint’s patients do not have a difficulty in seeing more than one item at a

time, but they have a deficit in explicitly identifying one item at any given time.

Brain Areas Involved and Coping Stratigies

Balint’s syndrome has been associated with bilateral damage to the posterior parietal

cortex with a primary cause of the syndrome being multiple strokes, Alzheimer’s,

intracranial tumors or brain injury. Only recently has Balint’s syndrome been associated

with damage to the parietal-occipital vascular boarder zone and in children.

While the brain damage is irreversible in most cases, there are adaptation strategies

involving a functional approach. In this approach, the individual’s abilities are accounted

for and are utilized to address the difficulties.