Developmental change of hemispheric dominance using visual event-related potentials (ERPs)

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In order to determine the dominant hemisphere of visual recognition and examine the developmental changes of the hemispheric dominance, event-related potentials (ERPs) were recorded in 20 normal adlescence (21-45 years of age) and 40 normal children (6-12 years of age). Visual stimuli of verbal ("Kana") and non-verbal ("Dot" in space and "Face") were presented using a tachistoscope and "oddball" paradigm.In normal adlescence (right handers), the P300 amplitude in verbal stimulation to right-visual field were higher than those to left-visual field. On the other hand, the P300 amplitude in non-verbal stimulation to left-visual field were higher than those to right-visual field. These findings suggest that P300 to the tachistoscopic visual stimuli could determine the hemispheric dominance. In normal right-handed adlescence, dominant hemisphere of verbal recognition present in the left and that of nonverbal recognition in the right.In normal right-handed children elder than 6 years of age, the P300 amplitude in verbal stimulation to right-visual field were also higher than those to left-visual field. The P300 amplitude in non-verbal stimulation "Dot" to left-visual field were higher than those to right-visual field in the children elder than 8 years of age. These findings suggest that hemispheric dominance of verbal recognition had already presented in the left in the children elder than 6 years of age and that of non-verbal recognition presented in the right in the children elder than 8 years of age.Further study in the children younger than 6 years of age would give the precise observation of the developmental change of hemispheric dominance of visual recognition.