Hemi-Sync® Journal 2004-3&4 (Summer/Fall)

child. Culturally, two participants were Asian, one was Filipino, three were Middle Easterners, and five were Caucasian. Materials Binaural-Beat Stimulation Two compact discs (CDs), each entitled Einstein's Dream, were specially produced for this project by The Monroe Institute. The control-phase CD contained no binaural-beat stimulation, and the CD for the experimental phase did. The beta tones were presented with 16 and 24 Hz binaural beats. Subjectively, the two CDs sounded identical and were present- ed to the participants through battery-operated stereo head- phones. Attentional Task A modified version of the Conners’ Continuous Performance Test 3.0 (CPT) was used during each “music” phase as a behavioral assessment of improvement in task com- pletion while listening to music containing binaural beats. The attentiveness scores for this behavioral task were analyzed by the program and included measures for correct responses measuring sustained attention (pressing the mouse button each time any letter but an “X” appeared on the screen), errors of omission measuring selective attention (not pressing the mouse button when required), and errors of commission measuring impulse control (pressing the mouse button when not required). During an initial practice phase, each participant was seat- ed in a clinical counseling chair with the mouse on a shelf in front of him or her. The CPT was presented on a high-resolu- tion seventeen-inch computer monitor and was programmed to administer a four-minute segment of stimuli per phase. Stimuli letters of the alphabet were shown, and the person practiced clicking the mouse each time any letter but an “X” appeared on the screen. Electroencepbalography EEG recording was accomplished using a BIOPAC Systems, Inc., Data Acquisition Unit, along with electrode lead sets, disposable vinyl electrodes, electrode gel, adhesive electrode holders, and abrading paste. This system uses a non- invasive method of recording bioelectric activity of the brain at the scalp. The BIOPAC equipment is widely used in research laboratories to acquire measures of instantaneous activity within the cerebral hemispheres at the cortical level. EEG translates electrical activity from neurons, and during this study the electrical activity was collected through a monopolar electrode placed at the International 10-20 System of Electrode Placement scalp location of Cz with electrodes attached to each earlobe, one acting as a reference and the other as a ground. Impedance levels were checked for each electrode and were kept below 10 kilo-ohms. The key EEG power that correlates with most cognitive tasks is the 12-24 Hz beta frequency band, whose power is “maximal at the central electrode sites.” The theta/beta ratio recorded at the Cz electrode placement has been shown to be 93 percent accurate for predicting ADHD in children. BIOPAC AcqKnowledge® software was used to record the EEG data, filter the data into the specific bandwidths for alpha, theta, beta, and delta, and display the results on-screen in real time. The software includes procedures for analyzing EEG signals and quantifying the relative and total power in each band. Additionally, the fluorescent lights in the laboratory were --- PAGE 4 (OCR) --- HEMI-SYNC® JOURNAL turned off during all EEG recording phases to avoid the 60 Hz spikes they cause during recording. Only illumination from the incandescent ceiling fixtures was utilized. Procedure This study was conducted at CSUN’s Computerized Attention and Speech Center for Individuals with ADHD laboratory. Children were accompanied by at least one parent at all times while on campus. After the consent and screening forms were completed, the participant was familiarized with the CPT program. Each person practiced the CPT for three to five minutes until he/she was comfortable with the protocol required to respond to the appearance of letters on the monitor. Participants (and their parents, in the case of child partic- ipants) were kept blind to the true purpose of the project. When recruited, they were told that the project was being undertaken to rate a new computerized attentional task designed for individuals with ADHD and that the consisten- cy of their scores across two different sections of the task would be measured. During each session, participants were told that the CDs they were listening to were meant to block out any distracting external noise. The deception was essential to prevent any expectation bias, and participants (and their parents) were debriefed and thanked at the conclusion of their session. After the child participants had been familiarized with the CPT, they chose a new small toy from the researcher's toy chest, which they were allowed to keep. The toy was placed on the floor in front of the child to facilitate his/her fixating on one visual point (looking down eliminates many artifacts of muscle movement). The adult participants were asked to pick and concentrate on a focal point on the floor. The EEG electrodes were fitted to each participant according to the international 10-20 electrode-placement system. Five EEG recording phases were designed for this project (see Figure 1), During the first two-minute baseline- recording phase, each person was asked to look down at the floor, focus his/her eyes on the small toy or focal point, remain as still as possible, and refrain from blinking. During the second recording phase, stereo headphones (powered by batteries) were placed over the participant's ears and he/she listened to a CD playing soft music containing no binaural beats (while continuing to focus his/her eyes on the small toy or the focal point). Two more minutes of EEG were record- ed. Third, while still listening to non-binaural-beat music, the person completed four minutes of the CPT. Fourth, the participant listened to a CD playing soft music containing binaural beats, and the next two minutes of EEG activity were recorded. Two minutes of recording was considered adequate since the onset of binaural beat oscillation is imme- diate. Finally, while still listening to the music containing binaural beats, the person completed four more minutes of the CPT. Project protocol included EEG recording during all five phases of the experiment. As expected, the Phase I baseline recording appeared to be very similar to the Phase II (non- binaural-beat music) recording, and Phase IIT and Phase V (during which the participant worked on the CPT) were not analyzed since they were comprised mainly of movement arti- facts. The protocol design was successful, however, since the fact of the two “music” recordings being the focal phases was concealed from the participant. After each phase of EEG recording, the children placed a sticker next to that phase number on a one-page checklist, personalized for each child. Since the frequency effects of binaural beats have been found to last from twenty minutes to one hour or more, any influ- ence of order effect in this study was sacrificed to avoid carry- over effects. Figure 1: Five Experimental Phases Phase I Two-minute baseline recording Phase II | Two-minute non-binaural-beat recording Phase III] Four minutes of CPT while still listening to non-binaural-beat music Phase IV] Two-minute binaural-beat recording Phase V | Four minutes of CPT while still listening to binaural-beat music Results Electroencephalography The EEG software package utilized in this study pro- vided a composite of spectral outputs by which to observe recorded brain waves. All wave-recorded formats were downloaded into files that were opened and analyzed in the computer program SPSS. The analog EEG waves (amplitude measured as voltage over time) were sampled at a rate of 200 samples per second and were translated by the software into digital values accounting for the voltage of each three-second epoch. Fast Fourier transformation was used to process the voltage over time into voltage over frequency to display the level of elec- trical energy (power) of the beta, and mean power was cal- culated for each epoch. A paired-samples ¢ test analysis was used to compare any change in power between Phase II and Phase IV. Absolute beta frequency power was found to be significantly higher during Phase IV, recorded while participants were listening to music containing binaural beats (M = 66.544), than dur- ing the non-binaural-beat music presented during Phase II (M = 60.670), 410) = -8.362, p <.001 (see Figure 2). --- PAGE 5 (OCR) --- Summer/Fall 2004 Figure 2: SPSS Bar Chart of Beta Brain-Wave Activity EEG Measured Absolute Beta Power 67. 665 65-4 64 634 624 614 “| | | 59. Mean Phase 2 EEG Mean Phase 4 EEG Mean Attentional Performance The CPT was scored using the program's attentiveness analysis for the task completed during each phase. In accor- dance with signal detection theory, the attentiveness score was analyzed by calculation of d’. The sensitivity measure of d’ is the distance along the X-axis between the noise distribution and the signal distribution in standard-score units. A paired-samples t test was used again to maximize statis- tical: power in comparing the attentiveness scores during Phase II and Phase IV. Participants exhibited a significantly higher attentiveness level during the binaural-beat phase (/ = 2.946) than during the non-binaural-beat phase (M = 1.783), (10) = -5.773, p <.001 (see Figure 3). Figure 3: SPSS Bar Chart of CPT Attentiveness Measure CPT Behavioral Measures of Attentiveness 3.2. 2.84 26 2.44 2.24 a _ 2.04 134 16 |_—__ Phase 2 Attentvenass Discussion Mean Phase 4 Attentiveness Support of Previous Studies It is expected that the improvements in attention found in this study were a result of improved levels of electrical arousal within the brain elicited by the auditory binaural beats. The observed effects were consistent with the hypothesis regarding the enhancing effects of binaural beats in the beta frequency range on absolute power of beta brain waves as measured in individuals with ADHD. Binaural beats in the EEG beta fre- quency range were associated with significantly higher levels of attentiveness during the binaural-beat condition compared to attentiveness results during the non-binaural-beat condi- tion. These findings lend empirical support to studies showing that auditory binaural beats have a positive effect on vigilance, on memory, and on other measures of attention. The attentional improvement was recorded in the absence of participant or parental expectations, and precise experimen- tal design ruled out other confounding effects. All listening phases of this study maintained the explanation that head- phones and music were utilized to eliminate external auditory distractions, and the CDs were placed in the player out of the participant’s view so that they would remain unaware that dif- ferent treatments were being presented. It is expected that the improvements in the attentional task were influenced by changes in the levels of absolute beta frequency electrical activity resultant from binaural-beat stim- ulation. Moreover, it would normally be expected that scores on the final CPT measure would be considerably lower due to performance decline as a result of working with the same bor- ing task for the third time. According to Conners,’ “In a bor- ing task children become less efficient as they become less strict in deciding whether a signal is a target or not.” The results of this study showed.a significant increase in CPT attentiveness scores for the final phase and suggest support of the positive effect of the binaural-beat recording. This expla- nation coincides with prior studies that support the finding of changes in EEG in response to presentation of binaural beats. The evidence of improvement in beta-wave activity when pre- sented with binaural beats deserves further study using brain-