Abstracts

Rationale: The novel SARS coronavirus of 2019 has presented a new challenge in the field of neurology, producing various neurological symptoms ranging from encephalopathy to stroke. Our center, in Phoenix, Arizona, treated a significant portion of COVID-19 patients during the pandemic within our region, and we evaluated possible correlation between EEG patterns and radiographic findings in confirmed COVID-19 patients.

Methods: We performed a retrospective chart review on patients who tested positive for COVID-19 and had inpatient EEG between March 2020 and February 2021. Information collected included the patient's age, indication for EEG, type of EEG (trend versus routine EEG), history of prior seizures, neuroradiologic findings, presenting history of cardiac arrest, as well as the incidence and location of EEG findings in respect to the background, epileptiform discharges, and seizures.

Results: We identified 91 patients who had EEG and neuroimaging tests among confirmed COVID-19 patients in the hospital during the study period. 45% (n=41/91) had normal imaging with the EEG findings of diffuse slowing without clear localization in 37% (n=34/91) and normal in 7% (n=7/91). Diffuse anoxic injury was present in 7% (n=6/91) with EEG showing severe diffuse background slowing or suppression: One patient also had generalized epileptiform discharges and seizures and another one with generalized periodic discharges. Microhemorrhages were present in 3% (n=3/91) of patients: Two patients with diffuse or multifocal microhemorrhages had EEG which showed diffuse moderate to severe slowing, while the third showed parietal interictal epileptiform discharges when MRI showed ipsilateral thalamic microhemorrhage. Focal intracranial hemorrhage was seen in 7% (n=6/91) of patients but only 4 of these had a focal EEG abnormality. Nonspecific focal T2 hyperintensities/hypodensities were present in 5% (n=5/91) of patients and only one of these had correlating focal EEG abnormality. 10% (n=9/91) of patients had strokes, but only 3 of these showed corresponding focal EEG abnormalities. Other imaging findings were considered chronic or remote and EEG did not show clear focal abnormalities. In total, of the 23% (n=21/91) of patients with acute focal neuroradiologic findings, only 23% (n=5/21) had correlated EEG abnormalities within the same region.

Of note, frontal imaging abnormalities were seen on 13% patients (n=12/91), of which only one showed corresponding frontal EEG abnormalities (right frontal slowing in the setting of a right frontal hematoma).

Conclusions: Acute neuroimaging findings included abnormalities, acute strokes, hemorrhages, and white matter lesions. In these cases only 25% showed clear anatomical correlation between imaging and EEG findings. Our study suggests that COVID-19 patients may have more diffuse cerebral disturbance even when imaging findings showed focal abnormalities only. This is particularly illustrated the lack of correlation between the higher than average frontal findings on EEG in COVID-19 patients, despite a low correlation between frontal EEG findings and frontal imaging abnormalities in our study. This may provide some prognostic value for their neurocognitive recovery.

Funding: Please list any funding that was received in support of this abstract.: None.