Bizarre behavior during intracarotid sodium amytal testing (Wada test): are they predictable?

The intracarotid sodium amytal test (ISAT or Wada Test) is a commonly performed procedure in the evaluation of patients with clinically refractory epilepsy candidates to epilepsy surgery. Its goal is to promote selective and temporary interruption of hemispheric functioning, seeking to define language lateralization and risk for memory compromise following surgery. Behavioral modification is expected during the procedure. Even though it may last several minutes, in most cases it is subtle and easily manageable. We report a series of patients in whom those reactions were unusually bizarre, including agitation and aggression. Apart of the obvious technical difficulties (patients required physical restraining) those behaviors potentially promote testing delay or abortion and more importantly, inaccurate data. We reviewed those cases, seeking for features that might have predicted their occurrence. Overall, reactions are rare, seen in less than 5% of the ISAT procedures. The barbiturate effect, patients' psychiatric profiles, hemisphere dominance or selectiveness of the injection were not validated as predictors. Thorough explanation, repetition and simulation may be of help in lessening the risk of those reactions.