Anesthesiology is the practice of medicine dedicated to the relief of pain and total care of the surgical patient before, during and after surgery. Anaesthesia by definition is the loss of sensation with or without the loss of consciousness. The American Society of Anesthesiologists define anaesthesiology as "the practice of medicine dedicated to the relief of pain and total care of the surgical patient before, during and after surgery." Anaesthesia or anaesthesia is a state of temporary induced loss of sensation or awareness. It may include analgesia (relief from or prevention of pain), paralysis (muscle relaxation), amnesia (loss of memory), or unconsciousness. A patient under the effects of anaesthetic drugs is referred to as being anesthetized. The practice of anaesthesiology is broad and transcends the operating room as well. Anaesthesiologists are experts in pain medicine. They help patients with chronic disease live better lives through pain management treatments for every day. General anaesthesia suppresses central nervous system activity and results in unconsciousness and total lack of sensation. Sedation suppresses the central nervous system to a lesser degree, inhibiting both anxiety and creation of long-term memories without resulting in unconsciousness. Regional anaesthesia and local anaesthesia, which block transmission of nerve impulses between a targeted part of the body and the central nervous system, causing loss of sensation in the targeted body part. Anaesthesiologists frequently relieve pain for patients before, during and after surgery. However, some specialized anaesthesiologists specifically treat chronic pain unrelated to surgery. These anaesthesiologists have the education and training to accurately diagnose, evaluate and treat chronic pain patients through a comprehensive approach including medication and pain procedures. The treatment of chronic pain can be complex, due to the strength of pain medication and the anatomy and delicate structure of the spine and nerves upon which chronic pain interventions are performed.