Introduction Lateralized rhythmic delta activity (LRDA) is a rare pattern on the ictal-interictal continuum (IIC) encountered in critically ill patients. Its association with acute seizures is yet to be fully explored. Insular involvement is a common finding in patients with infectious and autoimmune encephalitis. The association between acute insular lesions and the ictal-interictal continuum, particularly LRDA, has not been explored before. Methods A case series of 4 patients with either herpetic or autoimmune encephalitis and prominent insular cortex involvement who had LRDA when monitored on continuous EEG is being presented. Results Two patients had herpetic encephalitis and 2 patients had autoimmune encephalitis. All patients had either clinical or electrographic seizures with 1 patient progressing into new-onset refractory status epilepticus. Conclusion LRDA can be seen in patients with insular cortex acute inflammation. In this group of patients, LRDA may be associated with a higher risk of acute seizures. The presence of this otherwise not clearly epileptiform pattern should raise the clinical suspicion for the development of acute seizures. Patients with LRDA and ipsilateral insular lesions should be carefully monitored for the development of recurrent electrographic or electroclinical seizures and status epilepticus.

中文翻译：

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感染性或自身免疫性岛叶病变患者的侧向节律性 Delta 活动

简介 侧向节律性 delta 活动 (LRDA) 是危重患者中发生的发作间期连续体 (IIC) 上的一种罕见模式。它与急性癫痫发作的关系尚未得到充分探索。岛叶受累是感染性和自身免疫性脑炎患者的常见表现。急性岛叶病变与发作间期连续性，特别是 LRDA 之间的关联，以前尚未探索过。方法 4 例带状疱疹或自身免疫性脑炎和突出的岛叶皮层受累患者在连续 EEG 监测时有 LRDA 的病例系列正在呈现。结果疱疹性脑炎2例，自身免疫性脑炎2例。所有患者都有临床或电图癫痫发作，其中 1 名患者进展为新发难治性癫痫持续状态。结论 岛叶皮质急性炎症患者可见LRDA。在这组患者中，LRDA 可能与较高的急性癫痫发作风险相关。这种原本不明显的癫痫样模式的存在应该引起临床对急性癫痫发作的怀疑。LRDA 和同侧岛叶病变的患者应仔细监测复发性电图或电临床癫痫发作和癫痫持续状态的发展。这种原本不明显的癫痫样模式的存在应该引起临床对急性癫痫发作的怀疑。LRDA 和同侧岛叶病变的患者应仔细监测复发性电图或电临床癫痫发作和癫痫持续状态的发展。这种原本不明显的癫痫样模式的存在应该引起临床对急性癫痫发作的怀疑。LRDA 和同侧岛叶病变的患者应仔细监测复发性电图或电临床癫痫发作和癫痫持续状态的发展。