2019 | Samantha Brown
Samantha Brown of Sacred Heart Girls' College, Hamilton, has been awarded a Gold CREST for her project “Binaural Beats" - investigating repeated exposure to a specific type of sound to maximise its potential effect on our brain.
Mentors: Dr Logan Voss, Waikato Clinical School, Dr Rebecca Pullon,University of Auckland and Professor Jamie Sleigh,University of Auckland.
Supporter: Mr Jonathan Termaat
Supervising teacher: Ms Fiona Murphy
Gold CREST medal presented by: Emeritus Professor Roberta Farrell FRSNZ CNZM
Samantha's Executive Summary states:
“Stress is common in our modern society. Many people have become busier, and wellbeing is currently an important focus. Binaural auditory beats are what the listener hears when tones at two different frequencies are presented to the left and right ear. The listener hears a single tone which equals the frequency difference between the two tones. Anecdotal reports suggest that binaural beats can relieve stress and improve sleep by influencing brainwave patterns, however there is little scientific evidence to support these claims. There are anecdotal links between alpha power and relaxation, where binaural beats containing alpha waves increase relaxation. This study investigated repeated exposure to a binaural beat to maximise the potential effect of the binaural beat, as many studies found acute binaural beats to be ineffective.
The hypothesis was that after four weeks of daily exposure to a binaural beat, there will be an increase in alpha power in the frontal lobe. 32 females between the ages of 15-18 years old were recruited from Sacred Heart Girls’ College. Participants listened to a 15-minute recording with 200Hz in the left ear and 210Hz in the right ear, creating a binaural beat at 10Hz. After an electroencephalogram (EEG) recording, participants listened to this binaural beat every night for four weeks, followed by another EEG recording. EEG was recorded with a BIS monitor and unilateral strips. Participants listened to an identical recording, with two minutes of silence before (to record baseline brainwave activity) and after the binaural beat to create a 19-minute recording for each EEG recording.
Each EEG recording was divided into three segments labelled “baseline”, “early” and “last” where baseline referred to the first 2 minutes of recording alpha power without the binaural beat. The early section referred to the first 3 minutes of the 15-minute binaural beat recording, and the last section referred to the last 3 minutes of the 15-minute binaural beat recording. From each EEG section, three 30 second windows were chosen for analysis. A single alpha power value was obtained for each segment by taking the median of the three maximum alpha power values from each 30 second window in that segment. The mean alpha power was compared between segments using ANOVA. Post-hoc analyses determined which subgroups were different.
The results of the first EEG recording showed that the alpha power stayed the same from baseline to the early segment, and decreased in the last segment. Alpha power was a mean of 4.0dB in the baseline segment, and decreased to 2.7dB for the last segment of the recording. In the second EEG recording, there was no effect on alpha power due to repeated exposure to a binaural beat over four weeks. The results suggest that after 15 minutes of continuous listening to the binaural beat, there is a decrease in alpha power, and this trend does not change with daily exposure to the binaural beat. This does not agree with the hypothesis that there would be an increase in alpha power in the frontal lobe after four weeks of daily exposure to a binaural beat. The anecdotal reports which claim binaural beats have an increased alpha power in the brain are not supported by this study."