Recent increase in both the elderly population and associated incidence of dementia are of critical importance to patient care in ICUs in the United States. Identification of pre-existing cognitive impairment, such as mild cognitive impairment and dementia, could prevent delirium and associated morbidity and mortality in the ICU. Additionally, noncognitive behavioral symptoms, such as depression, psychosis, agitation, and catastrophic reactions, are common in patients with pre-existing cognitive impairment. Detection and management of noncognitive behavioral symptoms associated with MRI and dementia in ICU leads to improved delivery of life-saving critical care.