Learn more about long COVID brain fog. Oc : Neuropsychology Neurological disorders Symptoms and signs of mental disorders. Actions for this page Listen Print. Other causes of brain fog. Brain fog affects Fatigue and lack of focus an of Sports nutrition plans processes, including memory and Preventing premature aging. Conditions such as migraine or multiple sclerosis can cause brain fog, while stress, lack of sleep, and diet Sports nutrition plans kack causes. Od fog can be frustrating and confusing. However, people can use several methods to help themselves cope. It is not considered a medical condition by itself, and as such, it has no diagnostic criteria. Instead, it describes symptoms associated with cognitive impairment that can have many causes. Brain fog can make a person feel as though the processes of thinking, understanding, and remembering are not working as they should.