Focal seizures without impairment of awareness (previously referred to as simple partial seizures) are seizures that originate from one cerebral hemisphere and do not cause alterations in awareness or responsiveness. Symptoms typically depend on the location of abnormal brain activity and can present as motor symptoms (eg, shaking of one limb), sensory symptoms (eg, paresthesias, olfactory symptoms, flashing lights), autonomic symptoms (eg, sweating, piloerection), or psychic symptoms / auras (eg, fear, epigastric discomfort, déjà vu). Postictal weakness or aphasia may occur. This type of seizure can precede larger seizures that result in impaired consciousness. Events are usually stereotyped and last seconds to minutes. Rarely, seizures can persist, causing status epilepticus or epilepsia partialis continua.

Etiology is variable and includes mesial temporal sclerosis, congenital anomalies, stroke, intracerebral hemorrhage, tumor, infection, post-surgical changes, trauma, etc. While uncommon in infancy, this type of seizure can start in childhood or adulthood with highest incidence in older adults (older than 60 years). Prognosis is variable and may depend on the underlying etiology.