Temporal lobe seizures may arise from mesial and lateral temporal regions. This distinction is important in the surgical evaluation of refractory epilepsy. Mesial temporal lobe seizures will often be abolished after standard temporal lobectomy or selective amygdalohippocampectomy, while lateral temporal lobe seizures will often require invasive video-EEG monitoring in order to map eloquent cortex and tailor a surgical resection. The clinical features favoring mesial temporal lobe epilepsy include early age of onset, history of complex febrile seizures, congenital brain malformations, CNS infections, tumors, head trauma, perinatal injury, stuttering course of seizure control, and typically with well-controlled seizures in early childhood but re-emergence of refractory epilepsy in adolescence or early adulthood and infrequent or rare secondarily generalized seizures. In contrast, lateral temporal lobe epilepsy is typically characterized by later age of onset of seizures, absence of early risk factors, absence of hippocampal atrophy, and more common negative structural or functional brain imaging.

Mesial temporal lobe seizures often have an aura—with rising epigastric discomfort or inappropriate fear or olfactory feeling and or autonomic signs like; pallor, flushing, mydriasis, irregular respiration or respiratory arrest, abdominal borborygmi, and eructation. These seizures often exhibit contralateral dystonic posturing of the hand (and ipsilateral hand automatisms), preserved ictal language if the focus is in nondominant temporal lobe, ictal speech arrest if the focus is in dominant temporal lobe, postictal nose wiping with ipsilateral hand, ictal vomiting or retching behavior, and head version in transition to secondary generalization.

Mesial temporal lobe seizures are often associated with a rhythmic theta-range ictal discharge on scalp EEG [4]. Typically, an initial focal temporal rhythmic activity of <5 Hz frequency is followed within 30 s by 5–7 Hz sphenoidal maximum theta activity [5]. At times, sudden generalized or lateralized suppression or attenuation is also seen [6]. Interictal EEG abnormalities consist of frequent spikes or sharp waves predominantly in the inferomesial (sphenoidal electrodes) and anterior temporal regions.

Lateral temporal lobe seizures are relatively less common than mesial temporal lobe seizures. However, these seizures may be associated with an aura of vertigo, or with auditory or visual hallucinations. These seizures often evolve early to a unilateral clonic activity and early head turning. On scalp EEG, lateral temporal lobe seizures have a high incidence of repetitive epileptiform discharges at ictal onset [6]. Also if present, a transitional sharp wave at ictal onset favors a neocortical rather than hippocampal seizure onset [7]. Neocortical seizures often start with higher frequency activity (alpha or beta range) on scalp EEG, but may also be associated with irregular, polymorphic, 2–5 Hz lateralized activity [4]. Interictal EEG abnormalities in neocortical temporal epilepsy may be absent or consist of occasional spikes or sharp waves predominantly in the anterior or mid-temporal regions [8].

While certain semiological features can help lateralize the seizure onset zone and, further, localize it to the temporal lobe, they cannot discriminate between mesial and lateral temporal onsets. These include ictal emeticus, ictal urinary urge, and ictal spitting, which often localize to the right temporal lobe, and piloerection, which localizes to the left temporal lobe.

Extratemporal lobe seizures can mimic temporal lobe seizures semiologically and electrographically (1). These are often referred to as temporal plus epilepsies (TPE) (2). They are often difficult to differentiate simply by using general clinical features. However, early ictal signs and symptoms that suggest involvement of the perisylvian region, the orbitofrontal cortex, or the temporo-parieto-occipital junction should heighten the suspicion of temporal plus epilepsies (2). This is of clinical importance since misdiagnosis as temporal lobe epilepsy and recommending temporal lobectomy will result in surgical failure and persistence of seizures.