Although pain must be assessed to be treated, it has been challenging to obtain consistent, objective, and quantifiable measurements. The best methods currently available are subjective scales communicated by the patient such as standardized sentences, visual analog scales (VAS), or plain numeric scales. When a patient is unable to communicate, methods used to monitor pain are inadequate. A device that provides an objective assessment of pain in these patients would alert the patient's caregivers that the patient may be in pain and analgesic treatment is indicated.