We used Pattern visual evoked potential (PVEP) and Electrooculogram (EOG) to clarify the confilicting evidence of neurophysiological abnormalities in dyslexic children.Methods
PVEP and EOG were recorded simultaneously in 72 children including 36 dyslexic and 36 normal children that were matched for age, sex and intelligence. Two check sizes of 60 and 15 min arc were used with temporal frequencies of 1.5 Hz for transient and 6 Hz for steady state methods.Results
Our findings show no differences in VEP components between dyslexia and normal that did not support the magnocellular hypothesis. High contrast EOG stimulus in detection of dyslexia is more reliable than VEPs.Conclusion
The results are not consistent with the evidence of an isolated deficit of the magnocellular function. The high contrast stimulus used in this study is thought to be involved to paravocellular system.