Magnetoencephalography(MEG)is a novle noninvasive method of human brain research developing from 1960,and is apllied widely in diagnosis of neural disease and function of language or recgnization.This paper introduced separatethe role of MEG in neurosurgery,neural medicine and research about function of language.

Objective To explore the common causes of epilepsy and the etiologic characteristics in different age groups of patients with epilepsy.Methods A retrospective survey was made in 5572 epilepsy patients in Epileptic Center of Guangdong 999 Brain Hospital from January 2003 to December 2009.According to the diagnostic criteria published in 2005 from ILAE,all the diagnoses of 5572 cases were made by epileptic specialists.Based on history,cranial MRI or CT and pathologic data,causes of epilepsy were classified into idiopathic,symptomatic and cryptogenic epilepsy.The cases of symptomatic epilepsy were further arranged into different categories in different age grades,such as head trauma,perinatal injuries,infection in central nervous system, cerebral vascular disease, brain tumor, disorders of cortical development,neurocutaneous syndrome and others.The cases with febrile seizures and family history were collected,and positive ratio of febrile seizures and family history were contrasted in different categories of cases by Kruskal-Wallis test ( nonparametric test ).Results In 5572 cases,66 were idiopathic,2834 symptomatic,2672 cryptogenic,and the ratio of these causes was 1％,51％,48％ respectively.Among 2834 cases of symptomatic epilepsy,822 were head trauma,497 were perinatal injuries,360 were infection in central nervous system,249 were brain tumor,150 were cerebral vascular disease,135 were disorders of cortical development,62 were neurocutaneous syndrome and 559 were others. In brief,head trauma,perinatal injuries,infection in central nervous system,brain tumor and cerebral vascular disease were top 5 causes of symptomatic epilepsy. Hippocampal sclerosis was found in 744 cases in those of eryptogenic epilepsy.The importance of febrile seizures( idiopathic:15.2％ ( 10/66 ),symptomatic:6.5％ ( 185/2834 ),cryptogenic:9.4％ ( 250/2672 ) ; x2 =181.393,P =0.000 ) and family history ( idiopathic:83.3％ ( 55/66 ),symptomatic:1.1％ (31/2834),cryptogenic:0.4％ (12/2672) ; x2 =68.354,P =0.000) was statistically different in different causes of epilepsy.Febrile seizures was the most frequent in cases with hippocampal sclerosis than those with other causes,and family history was the most frequent in neurocutaneous syndrome in symptomatic cases.Perinatal injurics was thc first causc in cases of infancy and childhood,head trauma was the top one in those of juvenile and adulthood,and cerebral vascular disease was the main cause in senile cases. Conclusions In the whole epileptic cases of 5572, 1％ was idiopathic,51％ was symptomatic,and 48％ cryptogenic. The main causes of them were head trauma,perinatal injuries,infection in central nervous system,brain tumor,and cerebral vascular disease.