title: Ictal unilateral eye blinking and contralateral blink inhibition - A video-EEG study and review of the literature.
abstract: BACKGROUND
  There is limited information on ictal unilateral eye blinking (UEB) as a lateralizing sign in focal seizures. We identified two patients with UEB and propose a novel mechanism of UEB based on a review of the literature.
  
  
  METHODS
  We report on two patients with intractable focal epilepsy showing UEB among 269 consecutive patients undergoing noninvasive video-EEG monitoring from October 2011 to May 2013.
  
  
  RESULTS
  Unilateral eye blinking was observed in 0.7% (two of 269) of our patients. Patient one had four focal seizures. Semiological signs in all of her seizures were impaired consciousness, bilateral eye blinking (BEB), and UEB on the right. During one seizure, BEB recurred after UEB with a higher blink frequency on the right. Patient two had ten focal seizures. Among them were one electrographic seizure and nine focal seizures with BEB (in 3/10) and UEB on the left (in 1/10 seizures, respectively). Both patients did not display any clonic activity of the face. In seizures with UEB, ictal EEG onset was observed over the ipsilateral frontotemporal region in both of the patients (over F8 in 2/4, Fp2-F8 in 1/4, Sp2-T2 in 1/4, and F7 in 1/1 seizures, respectively). Ictal pattern during UEB showed bilateral ictal activity (in 4/4) and ictal discharges over the ipsilateral frontal region (maximum over F3 in 1/1 seizure). Interictal EEG showed sharp waves over the same regions.
  
  
  CONCLUSIONS
  Unilateral eye blinking was ipsilateral to the frontotemporal ictal EEG pattern in both patients. The asymmetric blink frequency during BEB in patient one leads to the hypothesis that ictal UEB is caused by contralateral blink inhibition due to activation in frontotemporal cortical areas and mediated by trigeminal fibers.
authors: Department of Neurology, Christian Doppler Klinik, Paracelsus Medical University Salzburg, Ignaz Harrer Straße 79, 5020 Salzburg, Austria.
authors: Gudrun
authors: G
authors: Kalss
authors: Department of Neurology, Christian Doppler Klinik, Paracelsus Medical University Salzburg, Ignaz Harrer Straße 79, 5020 Salzburg, Austria.
authors: Markus
authors: M
authors: Leitinger
authors: Department of Neurology, Christian Doppler Klinik, Paracelsus Medical University Salzburg, Ignaz Harrer Straße 79, 5020 Salzburg, Austria.
authors: Judith
authors: J
authors: Dobesberger
authors: Department of Neurology, Christian Doppler Klinik, Paracelsus Medical University Salzburg, Ignaz Harrer Straße 79, 5020 Salzburg, Austria.
authors: Claudia A
authors: CA
authors: Granbichler
authors: Department of Neurology, Christian Doppler Klinik, Paracelsus Medical University Salzburg, Ignaz Harrer Straße 79, 5020 Salzburg, Austria ; Department of Neurology, Medical University of Innsbruck, Innrain 52, Christoph-Probst-Platz, 6020 Innsbruck, Austria.
authors: Giorgi
authors: G
authors: Kuchukhidze
authors: Department of Neurology, Christian Doppler Klinik, Paracelsus Medical University Salzburg, Ignaz Harrer Straße 79, 5020 Salzburg, Austria.
authors: Eugen
authors: E
authors: Trinka
keywords: Blink inhibition; Focal epilepsy; Ictal unilateral eye blinking; Lateralization; Trigeminal nerve