Effects of preoperative binaural beats on the propofol dose for induction of general anesthesia: a randomized...

Brainwave entrainment with low-frequency binaural beats has shown sedative-sparing and anxiolytic effects. We sought to investigate whether the preoperative use of binaural beats could reduce the propofol dose for the induction of general anesthesia.

We enrolled patients scheduled for elective surgery under general anesthesia in a randomized controlled trial. In the preoperative waiting area, we randomized patients to hear the binaural beats with frequencies of 432 and 431 Hz in the binaural-beats group (N = 34) or silent sound in the control group (N = 35) for 20 min via stereo headphones. For the induction of general anesthesia, we administered 10 mg of propofol every 15 sec until we observed three clinical signs: the loss of response to verbal commands of "open your eyes" (primary outcome), loss of eyelash reflex, and a patient state index of ≤ 50. We collected processed frontal electroencephalography data during the intervention and assessed anxiety scores before and after the intervention.

The propofol dose for the loss of response to verbal commands was lower in the binaural-beats group than in the control group (mean [standard deviation], 87 [24] mg vs 105 [32] mg; difference in means, -18 mg; 95% confidence interval, -32 to -5; P = 0.009). There were no significant differences in the delta (P = 0.63), theta (P = 0.28), alpha (P = 0.24), and beta (P = 0.85) bands of the processed frontal electroencephalograms and the anxiety scores (P = 0.50).

Binaural beats with a frequency of 1 Hz modestly reduced the propofol dose for the induction of general anesthesia, but we observed no significant differences in the processed frontal electroencephalograms and preoperative anxiety levels.

ClinicalTrials.gov ( NCT05431881 ); first submitted 9 June 2022.