Previous studies have demonstrated asymmetric hemispheric contributions to deficit awareness during hemisphere inactivation with intracarotid barbiturate infusion (Wada studies). These observations provide insight into the neuropsychological basis of anosognosia for hemiparesis (AHP),arguing against earlier explanations based upon psychologicaldenial, global cognitive disturbance, or emotional indifference. Although prior Wada studies equated AHP T="I"afterthe procedure with AHP T="I"during the period of deficit, a selective memory failure could also account for these findings. We, therefore, assessed the occurrence of AHP during and after right-hemisphere inactivation in a group of epilepsy patients undergoing preoperative Wada testing. Because aphasia obscures assessment of deficit awareness duringleftcarotid studies, we compared the frequency of AHP between right- and left-hemisphere inactivation only after recovery.As noted in earlier reports, AHP was present significantly more often after right- than left-hemisphere inactivation.The proportions of subjects with AHP during right-hemisphere anesthesia compared with the proportion of subjectswith AHP after the procedure were statistically equivalent, suggesting that the AHP observed after right-hemisphereanesthesiaresults from true failure of deficit awareness rather than inability to recall the deficit. © 1995 American Academy of Neurology.