Objective: To identify clinical factors contributing to the lateralization of mesiotemporal memory functions in epilepsy by using memory- activated fMRI. Methods: Sixty patients aged 16 to 63 years with mesial tempora...Objective: To identify clinical factors contributing to the lateralization of mesiotemporal memory functions in epilepsy by using memory- activated fMRI. Methods: Sixty patients aged 16 to 63 years with mesial temporal lobe epilepsy (MTLE)and 20 patients aged 16 to 60 years with extratemporal epilepsy (ETE) due to circumscribed epileptogenic lesions who cnsecutively underwent presurgical evaluation including continuous video- EEG monitoring and structural MRI examinations were examined. During memory fMRI, the activation condition consisted of retrieval from long- term memory induced by selfpaced performance of an imaginative walk through the patient’ s hometown. On the basis of a previous study, memory lateralization was defined as typical if larger fMRI activation was in the mesiotemporal structures contralateral to the epileptic focus. Results: There were 45 patients with MTLE who had typical memory lateralization (75% ), whereas only 9 patients (45% ) with ETE exhibited typical memory lateralization (p = 0.013). In MTLE patients, bilateral independent epileptiform discharges occurred more often in the atypical group than in patients with typical memory lateralization (p = 0.015). Conclusions: The fMRI lateralization of mesiotemporal visuospatial memory functions in patients with mesiotemporal lobe epilepsy (MTLE) is asymmetric: The larger activation usually appears contralateral to the side of the epileptogenic region. These findings occur more often in MTLE; in patients with extratemporal epilepsy, such type of asymmetry is not characteristic. In MTLE patients with bilateral independent epileptiform discharges, this type of asymmetry is also less frequent.展开更多
Objective: To test pathophysiologic hypotheses regarding the occurrence of a splenial lesion in patients with epilepsy. Methods: The authors studied 16 patients with a splenial lesion and 32 control patients, all of w...Objective: To test pathophysiologic hypotheses regarding the occurrence of a splenial lesion in patients with epilepsy. Methods: The authors studied 16 patients with a splenial lesion and 32 control patients, all of whom had MRI examination immediately after presurgical EEG long-term monitoring (LTM). The authors compared the number of generalized tonic-clonic and partial seizures during LTM, antiepileptic drug (AED) withdrawal, and laboratory results, Results: All of the patients with a splenial lesion had their AEDs stopped completely,vs 47%of the controls (p = 0.001). Patients with SCC lesion had a longer duration of complete withdrawal (median 3.5vs 2 days, p = 0.03). There was no correlation with seiz ure frequency or the introduction of new AEDs. Conclusion: Alesion of the splenium of the corpus callosum in patients with epilepsy is not associated with toxic drug effects or high seizure frequency, but might be induced by a rapid and relatively long-lasting reduction of antiepileptic drugs. Its frequency might be underestimated as MRI after long-term monitoring is rarely done.展开更多
文摘Objective: To identify clinical factors contributing to the lateralization of mesiotemporal memory functions in epilepsy by using memory- activated fMRI. Methods: Sixty patients aged 16 to 63 years with mesial temporal lobe epilepsy (MTLE)and 20 patients aged 16 to 60 years with extratemporal epilepsy (ETE) due to circumscribed epileptogenic lesions who cnsecutively underwent presurgical evaluation including continuous video- EEG monitoring and structural MRI examinations were examined. During memory fMRI, the activation condition consisted of retrieval from long- term memory induced by selfpaced performance of an imaginative walk through the patient’ s hometown. On the basis of a previous study, memory lateralization was defined as typical if larger fMRI activation was in the mesiotemporal structures contralateral to the epileptic focus. Results: There were 45 patients with MTLE who had typical memory lateralization (75% ), whereas only 9 patients (45% ) with ETE exhibited typical memory lateralization (p = 0.013). In MTLE patients, bilateral independent epileptiform discharges occurred more often in the atypical group than in patients with typical memory lateralization (p = 0.015). Conclusions: The fMRI lateralization of mesiotemporal visuospatial memory functions in patients with mesiotemporal lobe epilepsy (MTLE) is asymmetric: The larger activation usually appears contralateral to the side of the epileptogenic region. These findings occur more often in MTLE; in patients with extratemporal epilepsy, such type of asymmetry is not characteristic. In MTLE patients with bilateral independent epileptiform discharges, this type of asymmetry is also less frequent.
文摘Objective: To test pathophysiologic hypotheses regarding the occurrence of a splenial lesion in patients with epilepsy. Methods: The authors studied 16 patients with a splenial lesion and 32 control patients, all of whom had MRI examination immediately after presurgical EEG long-term monitoring (LTM). The authors compared the number of generalized tonic-clonic and partial seizures during LTM, antiepileptic drug (AED) withdrawal, and laboratory results, Results: All of the patients with a splenial lesion had their AEDs stopped completely,vs 47%of the controls (p = 0.001). Patients with SCC lesion had a longer duration of complete withdrawal (median 3.5vs 2 days, p = 0.03). There was no correlation with seiz ure frequency or the introduction of new AEDs. Conclusion: Alesion of the splenium of the corpus callosum in patients with epilepsy is not associated with toxic drug effects or high seizure frequency, but might be induced by a rapid and relatively long-lasting reduction of antiepileptic drugs. Its frequency might be underestimated as MRI after long-term monitoring is rarely done.
