Brainwaves are the patterns of electric pulses made by brain cells (neurons) when they communicate with each other. These pulses are the vibrations made by particles bumping into each other creating a disturbance and transferring energy. All forms of energy, such as light and sound, are transferred in this way. One pulse is measured as a single positive - negative - vibration called a cycle. The frequency of the cycles within one second is measured in Hertz (Hz). The wave pattern of positive-negative-neutral is represented as a line with peaks and valleys of different heights. The height is called amplitude and represents the strength of the wave. Therefore, when you see a brainwave plotted on a screen, you are seeing the frequency and amplitude of brainwaves. Brainwave types are categorized by frequency and associated with different types of activity - described below.
Multiple frequencies can be present in the same brain region at the same time. Think of large sound speaker at a concert. When you look at it closely, or touch it, it is vibrating intensely. Is it producing one sound? No, of course not. There are several sounds coming through the same medium at the same time. Your brain works in the same way - multiple brainwaves are present at the same location at the same time. With neurofeedback, we are training your brain to amplify different brainwave frequencies relative to others to create a dominant frequency and type of brain activity.
The ability to train to specific frequencies is heavily reliant on the quality of the signal that the electroencephalogram (EEG) can detect. There are many factors that impact quality including muscle movement, electrode placement, and digital signal processing algorithms. So, a device can produce a graph or number and label it a brainwave measurement without the quality being good enough for training purposes. You can spend your time training “noise” and get sub-optimal results. Sens.ai has gone to great lengths to address these and other factors. This includes a signal quality test at the beginning of every session to ensure your experience is optimal.
Having too much or too little of power in each waveband can be a problem, and depends on the situation and task. You want lots of delta while in deep sleep, but not that much delta while awake and tasking. So the ability of the brain to be flexible and produce more or less of each band depending the requirements of the moment is key. That is why each band is associated with both negative and positive characteristics. If you are stuck in high theta, then that can be great for access during creative problem solving or therapy but not so great in getting something done.