Assessment of cognition in older people

A simple and systematic approach

Cognitive impairment is a reduced ability to think, focus, or remember, and it is the most feared aspect of growing old.1 It is common2 and important,3 but underdiagnosed4 and undertaught. You will meet people with cognitive impairment daily in your clinical practice, but you may not detect it if cognitive assessment is not part of your routine clinical examination. This article provides a simple and systematic approach to its assessment in people aged 65 or older.

Cognitive impairment can be caused by any damage to the brain, such as head injury, stroke, infection, learning disability, or some mental illnesses. The commonest causes by far in older people are dementia and delirium. Dementia is progressive chronic cognitive impairment affecting daily functioning. In 2010 an estimated 35.6 million people have dementia worldwide, with the prevalence expected to double every 20 years.5 Sixty percent of dementia cases are in low and middle income countries.2 The risk of dementia increases worldwide with age: 0.3-1.2% of people aged 60-64,2 9.7-33.2% aged ≥85,2 and up to 48.8% of women aged ≥95.6

Chronic cognitive impairment without impact on daily activities is called mild cognitive impairment. Acute cognitive impairment associated with altered consciousness is likely to be delirium. Delirium is also a common and serious diagnosis, affecting around one third of general medical inpatients. It is linked to increased mortality both during admission (about one third will die) and after …