The present invention relates to a biological signal display apparatus which displays an evoked response that is elicited by stimulating a living body, in an easily understandable and adequate manner. A situation where an evoked response has an abnormal value or the waveform is not reproducible indicates that a change or abnormality occurs in the living body, and hence it is possible to know the state of the living body rapidly and easily.
In a related-art apparatus, it is usual that a waveform obtained by a measurement is displayed as it is, or that the amplitude, latency, and the like, which are feature amounts of the waveform, are displayed as numerical values.
When such a related-art display is performed, the doctor performing surgery is apart from the related-art apparatus, and cannot operate the apparatus. Therefore, the doctor must approach the vicinity of the apparatus to gaze the waveform on the display, or ask a medical staff to read out the values of the latency, the amplitude, etc on the display. In order to enable the usefulness of an evoked response to be exerted during surgery, consequently, considerable effort is required. In an evoked response, particularly, its change must be recognized at each time of stimulation. Therefore, such a related-art display is not adequate for monitoring a patient during surgery.
In the viewpoint of intuitive grasping of the state of a biological signal, there are an electrocardiograph in which the local maximum value of an electrocardiographic signal is displayed in bar graph form (see JP-A-10-057331), and a sphygmomanometer in which the blood pressure is displayed in the form of a bar (see JP-A-2007-135716). However, the apparatus disclosed in JP-A-10-057331 is intended to check the connection state of electrodes, and the apparatus disclosed in JP-A-2007-135716 simulates the display of a cuff pressure in blood pressure measurement by a mercury column. Even when these techniques are applied as they are to a display of an evoked response obtained by stimulation, therefore, they are not useful.