Topographic Brain Mapping and Conventional Evoked Potential to Checkerboard Reversal and Semantic Visual Stimulation in a Dyslexic Boy with Amblyopia

Abstract

Amblyopia is defined as a loss of visual acuity caused by visual form deprivation and/or abnormal binocular interaction, for which no organic cause can be detected by the physical examination of the eye. As pointed out previously (Kraus-Mackiw etal. 1980), poor sensory binocularity with intermittent alternating central scotoma, as for example in amblyopia, can produce dyslexia, especially when the whole-word method is applied in learning to read and write. It is generally accepted that the end of the sensitive period for orthoptic management in amblyopia is about 8 years of age (von Noorden 1977), a time when dyslexia normally first becomes evident. Evoked potential (EP) measurement together with brain mapping is one direct method of studying cortical responses to different visual stimuli in amblyopia as well as in dyslexia and may help as a diagnostic tool in children to localize function and monitor therapy (Levi and Harwerth 1978, Duffy 1980).