Methods and apparatus are provided to format a probability index that reflects where an electroencephalogram (EEG) pattern lies within the spectrum of wakefulness to deep sleep, which employs a computer/microprocessor that performs frequency domain analysis of one or more discrete sections of the EEG to determine the EEG power or amplitude at specified frequencies, optionally calculates the total power or amplitude over specified frequency ranges, assigns a rank to the power or amplitude at each frequency, or frequency range, assigns a code that reflects the ranking of the different frequencies or frequency ranges, and determines an index that reflects where the EEG pattern within the section(s) lies within the spectrum of wakefulness to deep sleep by use of a reference source, such as a look-up table or other suitable decoding instrument. The reference source is obtained by calculating the probability of different codes occurring in epochs scored as awake or asleep in reference files scored by one or more expert technologists or by an automatic scoring software.
METHOD AND SOFTWARE TO DETERMINE PROBABILITY OF SLEEP/WAKE STATES AND QUALITY OF SLEEP AND WAKEFULNESS FROM AN ELECTROENCEPHALOGRAM