For example, a method for detection of pain using electroencephalogram signals may comprise measuring electroencephalogram signals using electrodes attached to a head of a subject and circuitry to convert the electroencephalogram signals to digital data representative of the electroencephalogram signals for processing by a computer to perform bandpass filtering the digital data representative of the electroencephalogram signals to generate digital data representative of frequencies associated with spindles associated with pain, performing a Hilbert transform on the digital data representative of frequencies associated with spindles associated with pain to generate digital data representative of the transformed data, detecting an envelope of the digital data representative of the transformed data to generate envelope data, detecting whether the envelope data exceeds a threshold to generate classification data indicating presence or absence of a spindle associated with pain, and displaying or transmitting the classification data indicating the presence or absence of pain.
