Track: 3. Neurophysiology / 3C. Other Clinical EEG
University of Michigan
There have been few studies to date characterizing the neurologic sequelae of COVID-19 and minimal description of EEG findings.
We performed a prospective observational study of COVID-19 patients who underwent long-term EEG monitoring at the University of Michigan Hospital from March 15 to May 8, 2020. All EEGs were performed for standard indications (e.g., altered mental status, suspected seizures). All EEGs were reviewed by fellowship-trained epileptologists.
Twenty-two patients with confirmed COVID-19 underwent EEG monitoring, representing 4% of ~580 COVID-19 patients hospitalized through May 8. Of patients monitored, 16 were men and 13 were African American. The mean age was 60 years (range 20-80; SD 14.4). The majority of patients (19) were comatose; the rest of the patients had altered mental status or lethargy. Twenty patients had a metabolic derangement at some point during their hospitalization. Sixteen patients had no seizure history, five had well-controlled epilepsy, and one had poorly-controlled epilepsy.
EEG showed background slowing or attenuation for all patients and ten patients also had superimposed focal slowing/attenuation. Eleven patients had rhythmic or periodic discharges of which four had lateralized periodic discharges (LPDs) or lateralized rhythmic delta activity (LRDA), four had generalized periodic discharges (GPDs) or rhythmic delta activity (RDA), and six had triphasic waves. Interictal epileptiform discharges were observed in eight patients, seven of whom had a prior history of epilepsy and one with anoxic brain injury. Three patients had nonconvulsive status epilepticus-one with prior history of epilepsy and two with acute intracranial pathology appreciable on brain imaging. The patient with anoxic brain injury had convulsive seizures. One patient with a history of epilepsy had focal seizures. In total, eight patients died, 12 were still hospitalized at the time of data analysis, and two were discharged.
The most common EEG findings for COVID-19 patients were background slowing and periodic discharges, consistent with nonspecific encephalopathy. Seizures were only observed in patients with a history of epilepsy or with acute intracranial imaging abnormalities.