Tuma and DeAngelis1 report that delirium in patients with cancer may have multiple causes, many of which are reversible and allow a complete recovery of cognitive functions. They underscore the importance of neuroimaging investigations even in the absence of focal neurological signs, but overlook the usefulness of the electroencephalogram (EEG) in such patients. We feel that an EEG should be performed as well, because it can identify patients with nonconvulsive status epilepticus (NCSE), whose mental state may mimic delirium.2,3