1. A method comprising: transforming a EEG signal to the frequency domain with a Discrete Fourier Transform using a processor, obtaining an amplitude of each frequency component using the processor, summing all of the amplitudes of frequencies in the range of 201-500 Hz to obtain a high frequency amplitude using the processor, summing all of the amplitudes of frequencies in the range of 1 to at least 15 Hz to obtain a low frequency amplitude using the processor, and calculating an Index based on a ratio of the high frequency amplitude to the low frequency amplitude using the processor.