Clinical implications of scalp ictal EEG pattern in patients with temporal lobe epilepsy

Clin Neurophysiol. 2019 Sep;130(9):1604-1610. doi: 10.1016/j.clinph.2019.05.028. Epub 2019 Jun 22.


Objective: To determine the clinical implications of scalp ictal EEG pattern in patients with temporal lobe epilepsy (TLE).

Methods: Scalp EEG ictal patterns were retrospectively determined in 27 consecutive patients with medically refractory temporal lobe epilepsy who underwent phase-1 scalp video-EEG and phase-2 simultaneous scalp and intracranial video-EEG recordings for pre-surgical evaluation.

Results: Of the 192 temporal lobe seizures recorded during phase-1 and phase-2 scalp video-EEG studies, 124 (65%) seizures were associated with theta/alpha (5-9 Hz) ictal onset pattern, and 68 (35%) seizures were associated with delta (2-5 Hz) ictal onset pattern. Fourteen (52%) patients had exclusively theta/alpha ictal onset, 3 (11%) patients had exclusively delta ictal onset, and 10 (37%) patients had mixed theta/alpha and delta ictal onsets. MTLE was observed in 26 patients who had 124 seizures with theta/alpha ictal onset and 59 seizures with delta ictal onset. LTLE was observed in one patient who had 9 seizures with delta ictal onset. Scalp ictal EEG pattern was not significantly correlated with postsurgical seizure outcomes.

Conclusions: Both scalp delta and theta/alpha ictal onset patterns can be commonly found in patients with MTLE.

Significance: Scalp delta ictal onset is not a unique EEG pattern for LTLE as commonly believed.

Keywords: Depth electrode; Mesial temporal sclerosis; Neocortical; Scalp ictal onset; Temporal lobe epilepsy.

MeSH terms

  • Adult
  • Cerebral Cortex / physiopathology
  • Electroencephalography / methods*
  • Epilepsy, Temporal Lobe / diagnosis
  • Epilepsy, Temporal Lobe / physiopathology*
  • Female
  • Humans
  • Male
  • Middle Aged