| Research Abstract |
In order to determine the dominant hemisphere of language and the effect of the temporal lobectomy (TL), event-related potentials (ERP) were recorded in 36 normal subjects and 12 patients received left or right TL (LTL=7, RTL=5). Visual stimuli of verbal ("Kana") and non-verbal ("Dot" in space and "Face") were presented using a tachistoscope and "oddball" paradigm.
In normal subjects (right handers), the P300 amplitude were higher in verbal stimulation to right-visual field and in non-verbal stimulation to left-visual field. When verbal (or non-verbal) stimulus was presented, reaction time was shortest (or longest) in right-visual field stimulus (RV)-right hand response (RH), followed by RV-LH,LV-RH,and LV-LH.In patients received TL,P300 amplitude were lower than normal subjects, and hemispheric dominance to verbal and non-verbal stimuli were not observed. Both LTL and RTL patients had longer P300 latency than normal subjects, especially in "Kana" stimulus in LTL and "Dot" in RTL patients. Thses findings suggest that P300 and reaction time to the tachistoscopic visual stimuli could determine the hemispheric dominance and effect of TL.
Further study in combination with magnetoencephalography and functional MRI would produce precise localization of cognitive function.
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