脑电图在大脑半球切除术前后表现及临床意义

目的:探讨半球综合征(Hemispheric syndromes,HS)患者病变半球切除术前后发作间期与发作期的脑电图(EEG)表现特点及其临床意义。方法:总结自2001年4月至2004年4月行大脑半球切除手术的4例患者的临床资料并结合脑磁共振成像(MRI),对其发作间期、发作期以及病损大脑半球切除术半年后复查EEG结果进行分析总结。结果:4例患者MRI均显示为一侧半球广泛病变,对侧正常。EEG均表现为两侧不对称,患侧波幅明显减低。其中3例EEG表现出背景抑制。发作间期癫 癎异常波表现:1例癎样放电出现的侧别与影像学检查结果相反,2例患者出现了双侧同步癎样放电,1 例无明显异常波。发作期EEG表现:1例患者癎样放电起源与病灶侧别相符,其余3例出现在病灶的对侧。所有患者均接受了病灶侧大脑半球切除术,术后随访最短1例为12个月,4例均没有癫癎发作。手术半年后复查EEG,2例患者对侧发作间期癎样放电未消失,2例对侧EEG正常。结论:EEG对HS患者手术前定位诊断及预后判断都有一定的价值。分析HS头皮EEG时,要考虑到两侧大脑结构的绝对不对称性;当出现双侧癫癎异常放电时,不排除手术可以获得良好预后的可能性,可考虑对患侧半球行切除术治疗。EEG发作期单侧起源,在HS患者癫癎灶定位方面,与MRI结果相比,价值有限。HS患者,如明确患侧已不存在重要功能,应尽早手术治疗。

The characteristics and clinical significance of the scalp electroencephalogram before and after hemispherectomy

Objective:To discuss about the characteristics and clinical significance of the scalp elec-troencephalogrm (EEG) before and after hemispberectomy. Methods: Scalp EEGs were studied in 4 patients with hemispheric syndromes(HS) who admitted and underwent hemispherectomy in our institute from April 2001 to April 2004. The characteristics of pre-and post-surgical interictal and ictal EEGs were analysed and the possible underlying reasons were discussed. Results: All seizures occurred in 4 patients, along with the least follow-up time of 12 months. For pre-surgical EEG, the non-epileptiform activities showed bilateral asymmetric patterns with prominent high voltage on the contralateral to side of surgeries in the 4 patients. Three patients had background activities supressions in the side of surgery. One patient had his interictal epileptiform discharges (IED) ipsilateral to the side of surgery. Two patients had bilateral synchronous IED. The ictal EEGs showed two patterns, one patient having ictal onset ipsilateral to the side of surgery and the others with contralateral patterns. Two patients had their IEDs remaining unchanged for 6 months postoperatively. Conclusions:For patients with HS, the scalp EEGs is valuable in term of presurgical evaluation and outcome prediction. However, the EEGs must be interpretered with caution because there is a remarkable asymmetry between the two hemispheres. Although bilateral IEDs do not exclude the possibility of successful surgery, surgery only on the illed hemisphere is recommend. Ictal EEGs have less localizing valuable in HS group as compared with the result of MRI. For HS patients with intractable epilepsy, early surgery is recommended