1. A method for detecting epileptiform activity with an epileptiform activity analysis apparatus, the epileptiform activity analysis apparatus including brain wave measurement sensors, an amplifier stage, an A/D converter, a control unit and a monitor screen, the control unit including a microprocessor, memory, a subband-specific transfer means and a calculating means, the method comprising: obtaining brain wave signal data from sensors applied to a subject, and transmitting the brain wave signal data from the brain wave measurement sensors to the amplifier stage; amplifying the brain wave signal data using the amplifier stage to form amplified brain wave signal data; transmitting the amplified brain wave signal data from the amplifier stage to the A/D converter; converting the amplified brain wave signal data using the A/D converter to digitized amplified brain wave signal data; transmitting the digitized amplified brain wave signal data from the A/D converter to the control unit; decomposing, using the subband-specific transfer means, the digitized amplified brain wave signal data into at least one predetermined subband, wherein each subband includes at least one waveform indicative of a specific type of epileptiform activity, and to provide subband-specific time-series data for each of the at least one predetermined subband; determining, using the calculating means, at least one measure for each of the at least one predetermined subband, the at least one measure belonging to a measure set comprising a first measure indicative of the entropy of the subband-specific time-series data of the respective subband and a second measure indicative of a normalized form of k:th order central moment of the subband-specific time-series data of the respective subband, where k is an integer higher than three; indicating the presence of a specific type of epileptiform activity in the brain wave signal data based on the at least one measure of the respective subband regardless of the subject's level of consciousness; and displaying on the monitor screen the presence of the specific type of epileptiform activity in the brain wave signal data of the subject in order to monitor for possible epileptic symptoms.