A focal seizure with impaired awareness (complex partial seizure) is a seizure that originates from one cerebral hemisphere (often the temporal lobe) and causes altered consciousness. 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).

Seizures may be accompanied by automatisms such as repetitive, stereotyped movements of the orofacial or hand muscles. Altered consciousness can manifest in a variety of ways, such as perseveration, daydreaming, a feeling of déjà vu, laughter, or decreased awareness. Patients have no memory of the events that occurred during the seizure. Events typically last 1-3 minutes and may be followed by postictal confusion. Postictal weakness or aphasia may also occur. Seizures can persist and result in status epilepticus.

Causes include tumor, encephalitis or autoimmune encephalitis, vascular malformations or other vascular etiologies, and heterotopias. This type of seizure can start in childhood or adulthood, with a higher incidence in adults over age 60. Prognosis is variable and may depend on the underlying etiology.