Electrical status epilepticus in sleep (ESES) is a pattern of continuous spikes seen in electroencephalography (EEG) and may be associated with neuropsychological deficits in children. This EEG pattern has not previously been reported in older adults. In this case report, a 66-year-old woman with post-traumatic epilepsy presented to the emergency department following a breakthrough seizure. Her EEG exhibited a striking pattern of continuous spikes during sleep that stopped abruptly with wakefulness, which is characteristic of the ESES phenomenon. This patient had triggers for a breakthrough seizure including subtherapeutic seizure medication levels, exposure to flashing lights, and iatrogenic hyperthyroidism, but none of these triggers have been known to cause selectively continuous spikes during sleep on EEG. This finding suggests that the phenomenon of ESES may persist into older adulthood.