Alexia (from the Greek α, privative, expressing negation, and λέξη = "word") is an acquired type of sensory aphasia where damage to the brain causes a patient to lose the ability to read. It is also called word blindness, text blindness, or visual aphasia.

Causes

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Alexia is often the result of damage to the left brain's parietal-temporal-occipital (PTO) association area. This area of the cortex lies between the processing centers for auditory, visual, and somatosensory processing. It coordinates the information that is gathered from all three processing centers and assigns meaning to the stimulus. In the left brain, the PTO is primarily responsible for language recognition. In the right brain, the PTO mainly handles recognition of an object and its spatial characteristics.

Presentation

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Alexia may or may not be accompanied by expressive aphasia (the inability to produce language) such as agraphia, the loss of one's ability to write. If damage to the brain is exclusively to the PTO (an exclusively input-based locus), then output ability may not be lost. In this scenario, an individual's ability to create language may exist without the ability to understand it.

• Neuron Learning Fast ForWord Reading Programmes

See also

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• Visual agnosia
• Dyslexia

Aphasia