Reorganisation of the language system in epilepsy

点击翻译按钮获取中文摘要

Brain surgery for the treatment of epilepsy is associated with a risk of cognitive impairment. Avoidance of disabling post-operative impairments depends in large measure on our ability to predict and measure individual patterns of language lateralization prior to neurosurgical intervention. Typical patterns of lateralisation cannot be assumed in patients with epileptogenic lesions. There appears to be a consensus that atypical representation is more frequent in patients with epilepsy than it is in the normal population, and values above 20% are not unrepresentative Partial epilepsy arises from a region in the brain and spreads to involve other areas. This is contrasted with generalised epilepsy, which appears to arise all over the brain simultaneously. Partial epilepsy is often associated with lesions such as tumors or hippocampal sclerosis, and often seizures are intractable. Patients with partial epilepsy have a number of sources of brain damage in the language areas. Primary brain changes may be pre-existing, which means they pre-date the onset of habitual seizures. They may consist of a focal developmental abnormality (a malformation of cortical development) or may represent a general genetic predisposition to seizures. Therefore, partial epilepsy is not only associated with severe abnormalities in epileptogenic region but also with additional widespread abnormalities in both hemispheres. There is also evidence for a correlation of abnormalities with seizure frequency with some suggestion that the duration of epilepsy may also increase the degree of abnormality in the hemisphere. The neuronal conditions in language cortex that give rise to altered lateralisation in function are currently not known. The primary aim of this study is to understand reorganisation of the language system in epilepsy by using the current most sensitive non-invasive methods of assessing brain damage and brain function, using magnetic resonance imaging.