A Subclinical seizure is a type of seizure often experience by people with epilepsy, in which an EEG trace will show abnormal brain activity, usually for a short duration of time but which does not present any noticeable clinical signs or symptoms. This is often manifest as a single spike on the EEG trace or a slowing of brain activity not correlating to their level of consciousness or awareness. Subclinical seizures can be useful to a neurologist when displayed on an EEG in the diagnosis of epilepsy.