TEMPORAL LOBE SEIZURE

Overview

Temporal lobe seizures are characterized by behavioral arrest and impaired awareness. Automatisms are common during the seizure, and include oral and/or manual automatisms. There may sensory (auditory), emotional (fear), cognitive (deja vu) or autonomic features (epigastric sensation, tachycardia, colour change) prior to onset of impaired awareness. Postictal confusion typically occurs.

Specific features suggest seizure onset in the dominant or non-dominant temporal lobe (see hemispheric lateralization). Ictal speech, spitting, vomiting, drinking, urge to urinate and automatisms with preserved consciousness suggest seizure onset in the non-dominant temporal lobe. Postictal speech disturbance suggests a dominant temporal lobe seizure. Upper limb dystonia is a useful lateralizing feature, lateralizing the seizure to the contralateral hemisphere. Conversely, manual automatisms usually occur on the ipsilateral side.

In infants, temporal seizures may be subtle and manifest with pallor, apnoea and behavioral arrest. There may be earlier and more marked motor manifestations including tonic seizures and epileptic spasms, which may reflect different patterns of spread in the developing brain.

CAUTION Temporal focal impaired awareness seizures can have similar features to frontal focal impaired awareness seizures, however impaired awareness seizures of temporal origin tend to have a slower onset and progression, and postictal confusion is more pronounced.

CAUTION Temporal focal impaired awareness seizures need to be distinguished from absence seizures. While both may have automatisms, temporal lobe seizures are typically longer (> 30 seconds), associated with pallor, and followed by postictal confusion.

Subtypes of temporal lobe seizures

Mesial temporal lobe including hippocampus
Seizures that arise in the mesial temporal lobe may be characterized by distinctive seizure onset features such as an autonomic seizure with rising epigastric sensation or abdominal discomfort, or cognitive seizure with deja vu/jamais vu, or emotional seizure with fear. Unpleasant olfactory and gustatory sensory seizures may also occur. These focal seizure types may occur in isolation or may be followed by the onset of behavioral arrest with slowly progressive impairment of awareness and oral (chewing, lip-smacking, swallowing, tongue movements) and manual automatisms. Autonomic phenomena (pallor, flushing, tachycardia) are common. Upper limb automatisms may be unilateral and may lateralize the seizure to the ipsilateral hemisphere. Unilateral pupillary dilatation can occur, and can also lateralize the seizure to the ipsilateral hemisphere. Contralateral upper limb dystonia may develop and head and eye version to the contralateral side can occur. Whilst seizures tend to have a longer duration than for lateral temporal lobe seizures, evolution to a focal to bilateral tonic-clonic seizure is uncommon.
Lateral / neocortical temporal lobe
Lateral temporal lobe seizures may have an initial focal seizure with auditory or vertiginous features. The focal sensory auditory seizure is usually a basic sound such as buzzing or ringing (rather than formed speech). If the sound is heard in only one ear it suggests the seizure is in the contralateral hemisphere. In comparison to mesial temporal lobe seizures, lateral temporal seizures are of shorter duration, and the onset of impaired awareness is an earlier feature (the initial aware phase is not as prolonged). Lateral temporal lobe seizures may spread and motor features such as contralateral upper limb dystonia, facial twitching or grimacing, and head and eye version may occur. Evolution to a focal to bilateral tonic-clonic seizure is more common than in mesial temporal lobe seizures.