Cognition is the term used to describe our ability to think. As humans, we are continually receiving input from the world around us and making decisions about how to respond. Some of these decisions are made with awareness, while others are reflexive responses. For example, cognitive development in infants is based on their experiences with their environment. Cognitive processes continue to develop throughout childhood, adolescence, and adulthood as we learn how to adapt and use knowledge to solve problems and reach desired outcomes.

Many factors can influence an individual’s continuously evolving cognitive function from fetal development through adulthood. For example, diseases and health conditions can impair a person’s cognitive development and functioning during childhood and beyond. Impaired ability to think and make decisions can be temporarily affected by things such as infection, alcohol, drugs and medications, poor oxygenation, stress, or grief. Sensory deprivation and sensory overload can also affect an individual’s ability to process information. (See the “Sensory Impairments” chapter for more information on this topic.)

Nurses monitor for changes in mental status and report them to health care providers to assist in the diagnosis and treatment for underlying causes of impairment. This chapter will review cognitive development, as well as common acute and chronic cognitive impairments in adults.