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Stereoelectroencefalography (iSEEG) signal during altered consciousness (AOC) in epilepsy

Nuria Campora

  • Florencio Varela,
  • Argentina
  • Nuria Campora ¹
  • , Brenda Giagante ¹
  • , Silvia Oddo ¹
  • , Carolina Lomlomjian ¹
  • , Alejandro Nasimbera ¹
  • , Anilu Daza Restrepo ¹
  • , Silvia Kochen ¹
  • 2 Hospital El Cruce Nestor Kirchner

The alteration of consciousness (AOC) during seizures is one of the most striking features. The neuronal network that must be altered for the AOC in focal seizures is not well known. We characterized the epileptic discharge in focal seizures with different grades of AOC. The consciousness Scale (CSS) was proposed to quantify the degree of loss of consciousness, summarizing the response of a patient to 8 behavioural items performed by a clinical practitioner during and after a seizure. We analysed the physiological correlates of the CSS by studying the epileptic discharge recorded with intracranial electrodes in patients requiring an exploratory study before epilepsy surgery (12 patients, 53 seizures). In mesial temporal epilepsy (n=14 seizures), profound AOC was associated with hippocampal compromised and longer seizure. There was a trend of greater left compromised. Meanwhile in frontal epilepsy (n=39 seizures), profound AOC was associated with pre-frontal compromised, bigger size of cortical cortex with epileptic activity and longer seizures, without hippocampus compromised. We concluded that iEEG signal characteristics during AOC were different according epilepsy zone. In frontal seizures, the surface affected by epileptic discharge was related to AOC, while it was not seen in temporal seizures. It would be related to the wide neural network that is necessary to maintain consciousness, which can be affected in different ways at different points in it to produce AOC.