Her charge was to keep it moving. The 1 to 4 hertz range, called Delta, occurs during sleep and sometimes during comas. The 4 to 8 hertz range is called Theta. Also known as a hypnogogic state, it falls between a deeply relaxed state and sleep. A relaxed but alert state of mind occurs in the 8 to 12 hertz range and is known as Alpha.
Most neurofeedback practitioners concentrate on two types of training.
Beta, which focuses on the left side of the brain in the 15 to 18 hertz range, makes people feel more alert. Typically a hyperactive child will respond best to SMR training. The video games are designed to encourage people to produce and maintain brainwaves within a certain desired frequency, using visual aids such as colored rocket ships that speed up when the person achieves the right frequency. Initially, Silverberg says, playing the game for 40 minutes left her mentally exhausted. It immediately made me feel better.