An ultrasound probe is placed on the head of a patient, and is used to
generate an ultrasound pulse which propagates through the skull and brain
of the patient, and is reflected off of the skull and soft tissue lying in
a path perpendicular to the ultrasound probe. A portion of a generated
Echo EG signal is then selected, and the Echo EG signal is integrated over
the selected portion to generate an echo pulsograph (EPG) signal. Using an
ECG signal as a reference, the EPG signal is used to provide information
regarding the physiological state of the tissue at a depth from the
ultrasound probe corresponding to the selected portion of the Echo EG
signal.
