Diagnosing and managing mild cognitive impairment.
Behrman S., Valkanova V., Allan CL.
There has been a rapid rise in the number of people diagnosed with dementia in England from 232,000 in 2008 to 850,000 in 2014. Currently, it is estimated that the prevalence of mild cognitive impairment in adults aged 65 and over is 10-20%. It is likely that this figure will increase in line with trends in dementia diagnosis. In some cases, mild cognitive impairment may be a prodrome for dementia, and my be caused by any of the dementia pathology subtypes. The relationship between depression in the elderly and mild cognitive impairment is difficult to tease out as they are frequently comorbid conditions and both have been found to be independent risk factors for subsequent dementia: about 10% convert to dementia each year, compared with 1-2% of the general elderly population. It is important to obtain a history of cognitive changes over time, as well as information about the onset and nature of cognitive symptoms, confirmed by a reliable informant, if available. To confirm the diagnosis objective evidence of cognitive impairment is required. However, there are no specific neuropsychological tests for patients with mild cognitive impairment. On neuropsychological tests, individuals with mild cognitive impairment typically score 1-15 SD below the mean for their age and education, although these ranges are guidelines and not cut-off scores. GPs should consider referring people who signs of mild cognitive impairment for assessment by specialist memory assessment services to aid early identification of dementia, because more than 50% of people with mild cognitive impairment later develop dementia.