Given considerable variation in diagnostic and therapeutic practice, there is a need for national
guidance on the use of neuroimaging, fluid biomarkers, cognitive testing, follow-up and diagnostic
terminology in Mild Cognitive Impairment (MCI). MCI is a heterogenous clinical syndrome
reflecting a change in cognitive function and ...
Given considerable variation in diagnostic and therapeutic practice, there is a need for national
guidance on the use of neuroimaging, fluid biomarkers, cognitive testing, follow-up and diagnostic
terminology in Mild Cognitive Impairment (MCI). MCI is a heterogenous clinical syndrome
reflecting a change in cognitive function and deficits on neuropsychological testing but relatively
intact activities of daily living. MCI is a risk state for further cognitive and functional decline with
5-15% of people developing dementia per year. However, ~50% remain stable at 5 years and in
a minority, symptoms resolve over time. There is considerable debate about whether MCI is a
useful clinical diagnosis, or whether use of the term prevents proper inquiry (by history,
examination and investigations) into underlying causes of cognitive symptoms, which can include
prodromal neurodegenerative disease, other physical or psychiatric illness, or combinations
thereof. Cognitive testing, neuroimaging and fluid biomarkers can improve the sensitivity and
specificity of aetiological diagnosis, with growing evidence that these may also help guide
prognosis. Diagnostic criteria allow for a diagnosis of Alzheimer’s disease to be made where MCI
is accompanied by appropriate biomarker changes; but in practice such biomarkers are not
available in routine clinical practice in the UK. This would change if disease-modifying therapies
became available and required a definitive diagnosis but would present major challenges to the
NHS and similar health systems. Significantly increased investment would be required in training,
infrastructure and provision of fluid biomarkers and neuroimaging. Statistical techniques
combining markers may provide greater sensitivity and specificity than any single disease marker
but their practical usefulness will depend on large-scale studies to ensure ecological validity, and
that multiple measures, e.g. both cognitive tests and biomarkers, are widely available for clinical
use. To perform such large studies, we must increase research participation amongst those with
MCI.