Medical apparatus for assessing, measuring, monitoring, analyzing, grading, identifying and providing feedback on the levels of pain/nociception, using multiple physiological parameters; medical device enabling objective assessment of nociception/pain; medical apparatus and instruments for pain/nociception; medical apparatus and instruments for pain/nociception assessment and monitoring; apparatus for management and control of analgesia; medical apparatus intended to receive an electronic circuit allowing the measurement of the pain/nociception; pain monitoring system for anesthetized patients; wearable medical device enabling objective assessment of pain; medical apparatus for assessing and monitoring analgesia levels