Brainwave Entrainment has been used possibly as far back as 200AD, where Ptolemy of the Ancient Greeks noted the effect of flicking sunlight created by a spinning wheel. The first recorded clinical application was by a French psychologist, who again used a spinning wheel but this time illuminated with a lantern instead of the sun. He noted that his patients appeared calmer when they looked into the flickering light, so he used it as a relaxation technique whenever it was needed.
Newberg found that certain areas of the brain were altered during deep meditation. Predictably, these included areas in the front of the brain that are involved in concentration. But Newberg also found decreased activity in the parietal lobe, one of the parts of the brain that helps orient a person in three-dimensional space. "When people have spiritual experiences they feel they become one with the universe and lose their sense of self," he said. "We think that may be because of what is happening in that area if you block that area you lose that boundary between the self and the rest of the world. In doing so you ultimately wind up in a universal state."
Brain trait changes have also been observed in neuroimaging studies, most often employing fMRI. In a meta-analysis of 21 neuroimaging studies, eight brain regions were found to be consistently altered, including areas key to meta-awareness (frontopolar cortex/Brodmann area 10), exteroceptive and interoceptive body awareness (sensory cortex and insular cortex), memory consolidation and reconsolidation (hippocampus), self and emotion regulation (anterior cingulate cortex and orbitofrontal cortex), and intra- and interhemispheric communication (superior longitudinal fasciculus; corpus callosum) These changes were distinguished by density increases in grey matter regions and white matter pathways in the brains of individuals who meditate in comparison to individuals who do not. Of all areas with reported findings, a greater number of structural changes were found in the left hemisphere.
Binaural beats work by playing a different tone in each ear, and in the process the brain creates a “phantom tone” which is the difference between the two tones (for example if you play a 300 hz tone in one ear and a 310 hz in the other ear the brain will produce a 10 Hz phantom tone.) If this phantom tone is 10 hz the brain will gradually be led to a dominant brainwave frequency of 10 hz (this has been measured by EEG devices). If the tone is 7 hz the brain will gradually be led to a 7 hz dominant frequency, and so on.
There is also evidence to suggest meditation plays a protective role against the natural reduction in grey matter volume associated with aging. One study found evidence that Zen meditators experienced a slower age related decline rate for cerebral gray matter volume in the putamen which plays a role in learning, cognitive flexibility and attentional processing  This could suggest a better attentiveness in aging meditators versus non-meditators.
There isn’t really a one-size-fits-all track or frequency range which is right for all kids while doing homework. So that does make it difficult to recommend one thing in particular, and why I have a number of tracks for studying and focus. If they have already learnt and understood the information, but are just trying to commit it to memory for a test, then I would recommend an alpha track, like the Memorization Study Aid product I have with the 10.4Hz frequency you referred to. If they are still trying to fully understand what is being taught in a workbook, then I would recommend a track that is mainly beta frequencies, like my Study Focus tracks. In the middle, I have a number of tracks which use a combination of beta and alpha wave frequencies, like Study Booster, Study Enhancer and Cognition Enhancer. The last 3 use similar frequencies but deliver the tones and brainwave entrainment effects in different ways. As we are all wired a little differently it does sometimes take a bit of trial and error, to see what method or frequency range works best for the individual. These types of tracks are made for a general audience. In an ideal world, you would hook up to an EEG and see in real time exactly what a person responds to best, depending on the goal and current state of mind.
We practice Kundalini Yoga and Meditation to change our brainwaves so that we can be mentally and emotionally balanced. The meditation below, taken from my book The Power of Neutral, will specifically change your brainwaves. With consistent practice, you will notice that you do not unconsciously react, things in life do not bother you so much and you will feel more stable and neutral in your life situations.
The Frequency following response (FFR), also referred to as Frequency Following Potential (FFP), is a specific response to hearing sound and music, by which neural oscillations adjust their frequency to match the rhythm of auditory stimuli. The use of sound with intent to influence cortical brainwave frequency is called auditory driving, by which frequency of neural oscillation is 'driven' to entrain with that of the rhythm of a sound source.
There’s also some new stuff I’ve certainly never included in tracks before including some gentle pink noise and brown noise blended together in the background with what’s called phase modulation. This is almost outside of awareness as you’re listening to it. This is how your ear tells what direction a sound is coming from. Does it arrive at your left ear slightly before your right ear? You can modulate that. So, again, it has a very gentle, imperceptible rhythmic quality to it.
The binaural-beat appears to be associated with an electroencephalographic (EEG) frequency-following response in the brain (3). Many studies have demonstrated the presence of a frequency-following response to auditory stimuli, recorded at the vertex of the human brain (top of the head). This EEG activity was termed "frequency-following response" because its period corresponds to the fundamental frequency of the stimulus (Smith, Marsh, & Brown, 1975). Binaural-beat stimulation appears to encourage access to altered states of consciousness.
Effects on cortisol: The hormone cortisol is commonly associated with stress, and when levels are higher than usual, it can have a negative impact on the body. High levels of cortisol can lead to a range of conditions, including Cushing syndrome, menstrual cycle and female libido changes, anxiety, and depression. Dr. Giampapa noted a reduction of cortisol of up to 70-80 percent in several study participants.