Serial recovery of language during the intracarotid amobarbital procedure

There is considerable variability among epilepsy centers in the methods and interpretations of the intracarotid amobarbital procedure. Prominent among these differences is the determination of language representation and assessment of language functions. Some centers rely on speech arrest following amobarbital injection as a marker for language representation, whereas other centers examine verbal output for the presence of aphasic errors. The present study assessed the pattern of language recovery following amobarbital injection in epilepsy patients who were candidates for temporal lobectomy. Language recovery from dominant hemisphere injection (left or right) followed a stereotypical progression, with 71.8% of patients showing return of vocalization followed by return of naming and comprehension. Repetition deficits with paraphasic errors persisted the longest (mean = 12'30"), with a conduction aphasia persisting after the acute global aphasia resolved. Although two patients interpreted as left hemisphere language dominant were mute following right hemisphere injection, all language functions were intact immediately upon resumption of vocalization and they showed no other signs of aphasia such as paraphasias or anomia. Possible explanations for serial language recovery and persistent conduction aphasia are discussed. These findings have significant implications for the determination of cerebral language dominance.