Indirect assessment of memory for music during anesthesia

Study Objective: To obtain evidence. for intraoperative registration of auditory information in patients undergoing elective surgery. Design: Within-subject with three levels of frequency of exposure to music. Setting: A university of hospital and a university language laboratory. Patients: Thirty-four patiens sceduled for elective surgery and 20 healthy undergraduate psychology students. Interventions: Selections of instrumental ethnic music were played to patients for 0, 3, or 12 exposures in one experiment and for 0, 6, or 24 exposures in another study. The undergraduates heard 0, 3, or 12 exposures of the music while awake. Measurements and Main Results: Forty-eight hours after hearing the music, all subjects were tested on their preference for the selections they had heard as well as selections they had not heard. For the patients, the mean preference ratings (in millimeters, mm) on a visual analog scale following 0, 3, and 12 exposures were 73.3 mm, 74.0 mm, and 65.1 mm, respectively, a nonsignificant difference. For the patients who were exposed to the music 0, 6, and 24 times, the mean preference ratings were 64.4 mm, 66.1 mm, and 70.6 mm, respectively, a nonsignificant difference. For the waking participants, the mean preference ratings following 0, 3, and 12 exposures were 55 mm, 66.2 mm, and 62.5 mm, respectively, a significant difference ( p < 0.05). Conclusions: The anesthetized patients did not exhibit indirect memory for music played intraoperatively, at least to the extent required to demonstrate an exposure effect.