Risk factors for unsuccessful testing during the intracarotid amobarbital procedure in preadolescent children.
OBJECTIVE
Identification of risk factors for unsuccessful testing during intracarotid amobarbital procedure (IAP) in preadolescent children.


METHODS
A pediatric IAP protocol was attempted in 42 candidates for epilepsy surgery (5-12 years old; mean, 10 years) based on the ability to pass a practice test. Language dominance was defined by marked asymmetry until first verbal response and paraphasic errors. Intact hemispheric memory was defined by recall of >/=60% of test items. The odds ratios of baseline variables (age at IAP, Full-Scale IQ, side of disease, age at seizure onset, amobarbital dose) were calculated for various IAP outcomes.


RESULTS
IAPs were accomplished in 40 children. Language dominance was established in 25 (62.5%) of 40 patients: all 21 focal resection candidates were left language dominant; four hemispherectomy candidates had intact language after injection of the damaged hemisphere. In 12 (30%) of 40 patients, language testing failed because of agitation or obtundation. Compared with the 21 children with language dominance established by bilateral IAP, these 12 children had lower mean Full-Scale IQ (66.4 vs. 87.9; p = 0.014), and more frequently, the epileptogenic lesion in the left hemisphere (presumed dominant by right-handedness; 78 vs. 33%; p = 0.04). Excluding hemispherectomy candidates (intentionally only one injection), memory testing could not be completed in 13 (36%) of 36 children because of obtundation or agitation. These children were significantly younger than the 23 (64%) of 36 with successful bilateral memory testing (mean age, 107.6 vs. 128.7 months; p = 0. 006). The eight (25%) of 32 children with failing retention scores after ipsilateral injection had lower Full-Scale IQ than did the 24 (75%) patients who passed (mean, 59.6 vs. 81.7 months; p = 0.03).


CONCLUSIONS
The IAP successfully established hemispheric language dominance and memory representation for just under two thirds of the preselected preadolescent children. Risk factors for unsuccessful testing included low Full-Scale IQ (especially <80), young age (especially <10 years), and seizures arising from the left hemisphere presumed dominant by right-handedness.
Hamer
H M
HM
Department of Neurology, The Cleveland Clinic Foundation, Cleveland, Ohio 44195, USA.
Wyllie
E
E
Stanford
L
L
Mascha
E
E
Kotagal
P
P
Wolgamuth
B
B
D000367:Age Factors; D000654:Amobarbital / Q000008:administration & dosage*; D002343:Carotid Artery, Internal; D002540:Cerebral Cortex / Q000503:physiopathology* / Q000601:surgery; D002648:Child; D002675:Child, Preschool; D004827:Epilepsy / Q000175:diagnosis* / Q000503:physiopathology / Q000601:surgery*; D004833:Epilepsy, Temporal Lobe / Q000175:diagnosis / Q000503:physiopathology / Q000601:surgery; D005260:Female; D007839:Functional Laterality / Q000502:physiology*; D006801:Humans; D007361:Intelligence Tests / Q000706:statistics & numerical data; D007802:Language; D007807:Language Tests / Q000706:statistics & numerical data; D008297:Male; D008568:Memory / Q000502:physiology; D016017:Odds Ratio; D013702:Temporal Lobe / Q000503:physiopathology / Q000601:surgery; D016896:Treatment Outcome
D000654:Amobarbital