EEG after brexu-cel treatment. (A) Study characteristics from 13 total EEG recordings after CAR T-cell therapy. In total, 11 patients were studied. EEG characteristics broken down by occurrence. Characteristics found include: generalized rhythmic delta activity (GRDA); generalized periodic discharges (GPD); stimulus-induced rhythmic, periodic, or ictal discharges (SIRPIDs); and normal. Seizure and status epilepticus were found in 1 patient with HHV-6 encephalitis. (B) and (C) are representative EEG tracings of GPDs and GRDAs from patients with ICANS. In contrast, (D) and (E) show bilateral seizure activity found in 1 patient with HHV-6 encephalitis at >1 month after CAR T-cell therapy. Asterisks (∗) in panel A indicate the EEG data from this patients with HHV-6 encephalitis, with EEG recording performed outside of typical ICANS presentation.