Tsoures Elene, Lewerenz Jan, Pinkhardt Elmar, Ludolph Albert C, Fauser Susanne
Department of Neurology, University Hospital Ulm, Oberer Eselsberg 45, 89081 Ulm, Germany.
Department of Neurology, University Hospital Ulm, Oberer Eselsberg 45, 89081 Ulm, Germany; Epilepsy Center Bethel, Mara Hospital, Maraweg 21, 33617 Bielefeld, Germany.
Epilepsy Res. 2017 Sep;135:115-122. doi: 10.1016/j.eplepsyres.2017.06.009. Epub 2017 Jun 15.
Thalamo-cortical networks have mainly been studied in the generation of idiopathic (genetic) epilepsies. The purpose of this study was to analyze EEG patterns and the occurrence of focal (symptomatic) epileptic seizures in patients with acquired circumscribed thalamic lesions.
Among 596 patients with thalamic lesions, we identified 47 patients in whom circumscribed thalamic lesions were detected by MRI and who underwent an EEG examination at the same stay at hospital. EEG findings were divided into normal findings, unspecific pathological changes and epileptiform discharges. The EEG findings were correlated to the localisation of the lesion within the thalamus and to the patientś symptoms.
In 32 patients (68%) pathological EEG findings were observed. They were heterogeneous and comprised regional and generalized slowing, triphasic waves, generalized periodic and regional epileptiform discharges. However, some characteristic findings were seen: Regional slowing was associated with ipsilateral thalamic lesions independent of the thalamic subarea, epileptiform discharges were related to lesions in the ipsilateral medial thalamus and periodic generalized discharges/triphasic waves with lesions in the anterior-ventromedial thalamus. Epileptic seizures were also more common in patients with medial thalamic lesions. Patients with regional epileptiform discharges responded to antiepileptic treatment whereas patients with triphasic waves and generalized periodic patterns did not. In some cases, it remained difficult to decide whether the thalamic lesion was the cause or consequence of epileptic activity.
Pathological EEG findings are common in patients with acute and chronic thalamic lesions. EEG patterns associated with circumscribed thalamic lesions were influenced by the affected thalamic subregion. As in idiopathic generalized epilepsy, also in symptomatic epilepsy, the medial thalamus revealed to play a role in the generation of epileptiform discharges. In the patients with generalized periodic discharges and acute lesions in the ventral-anterior-medial thalamus, however, EEG changes were more likely caused by a disinhibition of cortico-thalamic networks than by a status epilepticus and thus risks and benefits of an aggressive antiepileptic treatment must be thoroughly balanced.
丘脑 - 皮质网络主要在特发性（遗传性）癫痫的发生过程中得到研究。本研究的目的是分析获得性局限性丘脑病变患者的脑电图模式和局灶性（症状性）癫痫发作的发生情况。
在596例丘脑病变患者中，我们确定了47例通过MRI检测出局限性丘脑病变且在住院期间同时接受脑电图检查的患者。脑电图结果分为正常结果、非特异性病理改变和癫痫样放电。脑电图结果与丘脑内病变的定位以及患者症状相关。
32例患者（68%）观察到病理性脑电图结果。它们具有异质性，包括局部和全身性慢波、三相波、全身性周期性和局部癫痫样放电。然而，也观察到一些特征性结果：局部慢波与同侧丘脑病变相关，与丘脑亚区域无关；癫痫样放电与同侧内侧丘脑病变有关；周期性全身性放电/三相波与前腹内侧丘脑病变有关。内侧丘脑病变的患者癫痫发作也更常见。有局部癫痫样放电的患者对抗癫痫治疗有反应，而有三相波和全身性周期性模式的患者则无反应。在某些情况下，如果丘脑病变是癫痫活动的原因还是结果仍难以确定。
病理性脑电图结果在急性和慢性丘脑病变患者中很常见。与局限性丘脑病变相关的脑电图模式受受累丘脑亚区域的影响。与特发性全身性癫痫一样，在症状性癫痫中，内侧丘脑在癫痫样放电的产生中也起作用。然而，在全身性周期性放电且腹侧前内侧丘脑有急性病变的患者中，脑电图变化更可能是由皮质 - 丘脑网络的去抑制引起的，而不是癫痫持续状态，因此积极抗癫痫治疗的风险和益处必须仔细权衡。
