Cognitive impairment refers to a decline in cognitive abilities, which are mental processes that include memory, attention, perception, problem-solving and language skills. This term is often used interchangeably with terms such as dementia or cognitive decline, but can also refer specifically to conditions like traumatic brain injury, stroke, or neurodegenerative diseases like Alzheimer's disease that affect memory, thinking, and behavior. Cognitive impairment can vary in severity, with some individuals experiencing mild difficulties while others may have more significant problems carrying out daily activities.