Implicit memory formation using the word stem completion task during anesthesia in children

Aims: To determine whether there is evidence of implicit memory formation during pediatric anesthesia using the word stem completion task. BackgroundIn adults, there is mixed evidence for implicit memory formation during anesthesia; however, there is no evidence in children. Implicit memory in adults has been detected using the word stem completion task. This test has not been used in a pediatric anesthetic setting. MethodsA total of 200 patients aged 7-12 were randomized to hear one of the two lists of 10 words played continuously while anesthetized. Group 1 heard List A and Group 2 heard List B. Postoperatively, 194 completed a word stem completion task where they were required to complete the stems (the first part of words) corresponding to the words on the two word lists combined, with the first word that came to mind. ResultsGroup 1 completed a mean of 2.78 words correctly from List A and a mean of 2.70 words correctly from List B. Group 2 completed a mean of 3.29 words correctly from List A and a mean of 3.66 words correctly from List B. For List A, there was no evidence (P=0.70) for an association between intraoperative exposure to this list and the odds of successfully completing a stem from this list with the corresponding target word. There was little evidence (P=0.09) for an association with List B. ConclusionThis study found no strong evidence that children form implicit memories for auditory words during anesthesia. Given the difference between lists, future research is warranted using carefully chosen word stems.