Lateralized Rhythmic Delta Activity in Patients With Infectious or Autoimmune Insular Lesions

Khalil S. Husari, Eva K. Ritzl

Research output: Contribution to journalArticlepeer-review


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.

Original languageEnglish (US)
Pages (from-to)61-65
Number of pages5
JournalClinical EEG and Neuroscience
Issue number1
StatePublished - Jan 2021


  • HSV
  • acute seizures
  • continuous EEG
  • insula
  • lateralized rhythmic delta activity

ASJC Scopus subject areas

  • Clinical Neurology
  • Neurology


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