Some people have an aura at the very beginning of a focal seizure or a generalised seizure. Technically, an aura doesn’t happen “before” the seizure, because it is actually part of the seizure. Some examples of auras are a sudden feeling of fear, an odd smell or taste, or a sudden tingling sensation in part of the body.
An aura can also occur by itself. For example, if the seizure activity causing the aura does not spread to other brain areas, then the seizure may not progress to a loss of awareness or loss of consciousness.
Another type of warning, called a prodrome, can occur minutes, hours, or days before the seizure begins. Some examples are headache, mood changes, or changes in thinking abilities.