Epilepsy Surgery

Poor prognostic features

· MRI negative

· Discordant investigations

· Concurrent, generalised spike wave discharges

· Dual pathology

· Absence of febrile seizures in history

· History of secondary GTCS

TLE

Localisation

Clinical signs	46%
Clinical signs + EEG	95%

Semiology

· Overall clinical signs can lateralise ~50% of seizures

· Dystonic posturing – contralateral focus PPV 86-100%

· Unilateral automatisms – ipsilateral – PPV 80%

· Ictal speech preservation - non-dominant hemisphere – PPV 80%

Ictal EEG

· 30% normal

· If unilateral EEG focus identified this will be correct in 90% (10% are mislocalised due to rapid contralateral spread)

· Lateralized post-ictal delta slowing is highle predictive of focus

· TIRDA is higly predictive of unilateral TLE

Epilepsy monitoring

Number of seizures to be obtained

· Number of seizures needed to ‘prove’ unifocal focus

· Depends on pre-test probability of multifocal epilepsy and level of post-test certainty required.

The number of seizures needed in the EMU Epilepsia 2015