Mild Cognitive Impairment, the hidden enemy

Recently at the National Congress of the Spanish Society of Geriatrics and Gerontology held in San Sebastian, I carried out a review of mild cognitive impairment (MCI) in a paper by the Dementia Group, which I think could be interesting to disseminate.

Mild cognitive impairment affects as many as 14-18% of people over 70 years of age, with highly variable rates in relation to the diagnostic criteria used and the type of population studied (community, memory units). Following the 2011 consensus of the American National Institute on Aging, the presence of a subjective memory impairment, together with the involvement of other cognitive domains, without functional impairment or meeting criteria for dementia, is defined as nuclear symptoms. Behavioural disorders in the form of depression, irritability, anxiety or apathy are common. Although there is a percentage of patients who can refer to normal cognitive functioning, which indicates the dynamic changes that can occur, what is especially relevant is that the risk of progression to dementia is 10% per year (patients without MCI is 1-2% per year), mainly in the first years; increasing the probability age, diabetes mellitus, at a neuropsychological level the assessment of deferred free memory and visual recognition memory tasks, affective disorders, cardiovascular disease and certain walking patterns. It is especially relevant, apart from the overall impact on patient functioning and their environment, which increases mortality, especially in males, and the presence of cardiovascular disease.

Once the presence of a subjective memory disorder is known, a screening for possible systemic causes must be performed, mainly thyroid, B12 deficit, folate, secondary effects of anticholinergic drugs or neuropsychiatric ones. Specific screening tests such as the Addenbroke or Montreal cognitive assessment have been developed to differentiate the presence or not of cognitive impairment, or other tests such as the Memory Alteration test or the short test (QCST) capable of discriminating between MCI and dementia. The use of blood and CSF biomarkers, as well as functional neuroimaging tests that evaluate areas such as the posterior cingulum, hippocampus, middle temporal lobe, has not been demonstrated to be useful in normal clinical practice, due to the great variability that exists.

From a therapeutic point of view, attempts have been made to modify the progression to dementia with different strategies such as the use of acetylcholinesterase inhibitors, anti-inflammatory drugs, nasal insulin, nicotine patches with little effectiveness.

For all these reasons, the concept of mild cognitive impairment is dynamic, heterogeneous, the physiopathology is not completely known, the measuring instruments are varied and the outcome variables are different, so much remains to be done. Perhaps the most important thing is to raise awareness of the concept, so that families, society itself, especially the nearest neighbourhood or social network, are able to recognise early cognitive changes, which can help in decision-making, affecting the patient's own safety. To review this topic I recommend reading the following article.

Langa K et al. JAMA 2014;312 (23):2551-2561