Pain has been defined as a subjective experience. Various pain assessment tools, (such as NRS) have been developed and validated to objectively monitor and treat pain. There are certain patient populations, in whom, the current pain assessment tools cannot be used effectively due to communication problems such as cognitively impaired patients. In the US, the Joint Commission on Accreditation of Healthcare Organizations (JCAHO) has made it mandatory to monitor and treat pain. In the absence of reliable pain assessment tools that would objectively measure pain, there is also risk of under treatment and overtreatment of pain that may lead to negative outcomes. Therefore, a monitor that is able to predict pain levels objectively, will help to achieve above goals. The investigators are using Skin Conductance Algesimeter (SCA) to measure pain by analyzing changes in skin conductance.