Decline in cognitive function can be due to many different causes. As a rule, memory is expected to decline with age as a result of the natural aging process. This age-related cognitive decline is considered normal in most people and typically does not interfere with the person’s function. In some cases, medical and neurological conditions can cause cognitive symptoms, such as stroke, infections, renal failure, liver failure, heart failure, medications, and so forth. More severe cognitive decline is typically caused by neurodegenerative conditions. These are conditions in which there is a rapid loss of brain cells at a rate much faster than expected for age. Neurodegenerative conditions include different types of dementia, such as Alzheimer’s disease, for example. When a patient suffers from dementia, the condition is expected to progress fairly rapidly and this is usually reflected in a rapid decline in the score on cognitive examinations. Finally, there is a condition called mild cognitive impairment (MCI), which is thought to be in between age-related cognitive decline and dementia. Some patients with MCI progress to dementia and others have a stable course with isolated impairment in short-term memory that does not typically affect their function. When MCI progresses into dementia, the score on cognitive examination will decline rapidly and reflect this progression. In contrast, when MCI does not progress to dementia, the score on cognitive examinations either remains stable, or declines very slowly.
Decline in cognitive function