Cognitive decline refers to a gradual decrease in mental abilities, such as memory, reasoning, and problem-solving skills. It can occur due to aging, medical conditions, or lifestyle factors. Common signs include forgetfulness, difficulty concentrating, and challenges in completing everyday tasks. This decline can affect daily life and may lead to conditions like Alzheimer's disease or other forms of dementia. Early detection and intervention are important for managing symptoms and maintaining quality of life. Engaging in mental exercises, physical activity, and social interactions can help slow down the progression of cognitive decline.