Entrainment devices designed to stimulate the brain to enter a specific state using a pulsating sound, light or electromagnetic field…
Entrainment devices designed to stimulate the brain to enter a specific state using a pulsating sound, light or electromagnetic field – has long been claimed to increase memory performance and improve theta wave activity.
A team of researchers from the University of California Davis set out to see if this is correct.
Electrical activity in the brain causes different types of brainwaves that can be measured from the outside of the head. Theta waves, occurring about five or six cycles per second, are usually associated with a brain that actively monitors something.
The researchers previously found that high levels of theta wave activity immediately prior to a memory task resulted in a better
Commercial entrainment devices using a combination of sound and light to stimulate brainwave activity with oscillatory patterns in sensory inputs that will be reflected in measured brain activity. While these devices are designed to address a range of problems, including anxiety, sleep problems, low mood and learning, there are very little published scientific evidence confirming these statements.
The researchers were able to test a theta wave limiter with 50 volunteers who had the task of either using the device for 36 minutes or listening for 36 minutes of white noise before performing simple memory tasks.
The participants who used the device showed improved memory performance and improved thetaw activity. The researchers then repeated the experiment with another 40 participants, but instead of just listening to white noise, the control group received beta-wave stimulation ̵
1; another type of brainwave pattern that occurs at about 12 to 30 cycles per second that has
Similar to the first experiment , those who had the Tetraway impact improved improved surfactant activity and better memory performances.
To prove that these devices actually worked, researchers conducted a separate study of electrical stimulation to improve theta waves. On the other hand, this had the opposite effect.
The participants experienced interfering thetaw activity and temporarily weakened memory features, which shows that entrainment devices actually work to increase memory performance.
“What astonishing is that the device has a lasting effect on theta activity and memory performance for over half an hour after it was turned off,” said Professor of Psychology Charan Ranganath and colleagues at the Center for Neuroscience.  The function and role of theta brainwaves remains a hot topic in the science community with some argue that they are simple a product of normal brain function without role, while others, including Ranganath, believe that they play a role in coordinating brain regions.
“The neurons are more eccentric at the peak of the wave, so when the waves in two brain regions are synchronized with each other, they can talk to each other,” he says.
The study was published in  04] Cognitive Neuroscience .