title: Contralateral EEG slowing and amobarbital distribution in Wada test: an intracarotid SPECT study.
abstract: OBJECTIVE
  To relate the occurrence of contralateral electroencephalogram slowing (CES) to amobarbital distribution, we performed electroencephalogram (EEG) monitoring and intracarotid single photon emission computed tomography (SPECT) during an intracarotid amobarbital procedure (IAP).
  
  
  METHODS
  IAP was performed on 22 patients with temporal lobe epilepsy. CES was defined as the occurrence of significant EEG slowing on the contralateral hemisphere (>50% of the ipsilateral hemisphere slowing) after amobarbital injection. To map the distribution of the amobarbital, we injected a mixture of amobarbital and (99m)technetium-ethylcysteinate dimer (99mTc-ECD) into the internal carotid artery and performed a brain SPECT 2 h later. In the SPECT images, regions of interest were determined by ipsilateral and contralateral anterior cerebral artery territories (iACA, cACA), ipsilateral and contralateral middle cerebral artery territories (iMCA, cMCA), and ipsilateral and contralateral posterior cerebral artery territories (iPCA, cPCA), as well as ipsilateral and contralateral anterior and posterior mesial temporal regions (iAMT, cAMT, iPMT, cPMT). The perfusion of amobarbital was interpreted visually in each region.
  
  
  RESULTS
  Amobarbital was distributed in the iMCA in all the patients; in the iACA in 20 (90.9%) patients; in the iAMT in 14 (63.5%); and in the iPCA and iPMT in only two (9.1%). CES was observed in 13 (59.1%) patients. Cross-perfusion of amobarbital in limited areas of the cACA were observed in only four of 13 patients. Wada retention memory scores (WRMS) showed no significant difference between the CES- (n = 9) and CES+ (n = 13) groups.
  
  
  CONCLUSIONS
  Amobarbital rarely perfused the iPCA territory and the iPMT region and was rarely delivered to the contralateral hemisphere. The occurrence of CES was not related to the cross-perfusion of amobarbital. CES appears to be produced by a transient functional disconnection from the ipsilateral hemisphere.
authors.affiliation: Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea. sbhong@smc.samsung.co.kr
authors.forename: S B
authors.initials: SB
authors.lastname: Hong
authors.forename: K W
authors.initials: KW
authors.lastname: Kim
authors.forename: D W
authors.initials: DW
authors.lastname: Seo
authors.forename: S E
authors.initials: SE
authors.lastname: Kim
authors.forename: D G
authors.initials: DG
authors.lastname: Na
authors.forename: H S
authors.initials: HS
authors.lastname: Byun
mesh_terms: D000293:Adolescent; D000328:Adult; D000654:Amobarbital / Q000378:metabolism / Q000494:pharmacology; D001921:Brain / Q000098:blood supply* / Q000000981:diagnostic imaging* / Q000378:metabolism; D002343:Carotid Artery, Internal; D002648:Child; D003545:Cysteine / Q000031:analogs & derivatives / Q000378:metabolism; D004569:Electroencephalography / Q000187:drug effects* / Q000706:statistics & numerical data; D004833:Epilepsy, Temporal Lobe / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000378:metabolism; D005260:Female; D007839:Functional Laterality / Q000187:drug effects / Q000502:physiology*; D006801:Humans; D008297:Male; D008568:Memory / Q000187:drug effects / Q000502:physiology; D008875:Middle Aged; D015609:Organotechnetium Compounds / Q000378:metabolism; D019275:Radiopharmaceuticals / Q000378:metabolism; D012039:Regional Blood Flow; D015899:Tomography, Emission-Computed, Single-Photon
chemical_list: D015609:Organotechnetium Compounds; D019275:Radiopharmaceuticals; D000654:Amobarbital; C059659:technetium Tc 99m bicisate; D003545:Cysteine