Dyslexia

Dyslexia: A specific reading disability due to a defect in the brain's processing of graphic symbols.

Dyslexias are characterized by their characteristic hemishperic deficit.
Pirozzolo (1979) and Pirozzolo and Hess (1976) suggest that there are two fundamental types of dyslexia: auditory-linguistic dyslexia and visual-spatial dyslexia. Persons with the former exhibit difficulties in the verbal and language area, have naming problems, and are slow in carrying out any types of verbal tasks. The persons with the former struggle with visual perceptual difficulties. Bakker (1973; 1979; 1982; 1983) thinks about different approaches to reading. The linguistic-auditory group uses their left type hemishphere hence called L-type dyslexics. The visual dyslexics have a difficulty with perceptual requirements in word representation and use the disorder stems from right hemisphere, hence the term P-called dyslexics. The same kind of differentiation is meant by the the words dysphonetic(auditory problems) and dyeidetic dyslexics (visual problems). Hemishpheric EEGs also show preferential brain activation with the different types of dyslexics.