婴幼儿脑电图λ波的产生机制及其临床意义

Mechanism and Clinical Significance of Lambda Wave in Electroencephalogram of Infants

目的以在婴幼儿脑电图监测中遇到的高大枕区"棘慢波样"λ波为切入点,探讨λ波的产生机制及其临床意义。方法收集5例具有高大的枕区"棘慢波样"λ波的5个月~1岁11个月患儿的脑电图,该图形在低频间断闪光刺激(intermittent photic stimulation,IPS)下频繁出现。以IPS作为诱发事件,参考诱发电位的叠加平均处理方式对5例患儿的脑电图进行处理。结果该λ波具有诱发电位性质,即同一患者在不同频率的闪光刺激下得到的叠加平均图形具有潜伏期一致、波幅不同、且与刺激具有锁时关系的特点。结论低频率的闪光刺激是鉴别该λ波的方法之一。该λ波的产生机制是枕叶皮层的视觉诱发电位未经叠加即显示出自发或诱发λ波,可能反映了部分婴幼儿枕叶皮层的高兴奋性。

Objective In order to explore the mechanism and clinical significance of lambda wave in the occipital region of infants and young children.Methods In this study,the electroencephalogram(EEG)was collected from 5 infants aged 5 months,5 months,6 months,11 months and 1 year 11 months respectively.The EEG in the 5 cases featured uncertain"spike slow wave pattern".This pattern was characterized by frequent occurrence under IPS(intermittent photostimulation).With IPS serving as the evoked event,the EEG of 5 infants was processed with superposed average method.Results The lambda wave had the property of evoked potential,that is,the superposition average pattern obtained by the same patient under different frequency of flash stimulation had the same latency,different amplitude and time-locked relationship with stimulation.Conclusion Low frequency flash stimulation is one of the identification methods of this kind of lambda wave.The mechanism of this wave is visual evoked potential in occipital cortex.The spontaneous or induced lambda wave without superposition may reflect the excitability of occipital cortex in some infants.