Objectifying Subjective Cognitive Decline

Abstract

Subjective cognitive decline (SCD) refers to the self-reported experience of reduced cognitive function in individuals who perform within normal limits on objective cognitive testing.1 A growing public awareness about dementia and the prospect of disease-modifying drugs and multidomain intervention programs to improve brain health, both of which may be most effective in early or even presymptomatic disease, leads to an increasing number of individuals to seek medical advice because of concerns about cognitive functioning. SCD, most often reflecting concerns about memory and/or reduced processing speed, is common—between 50% and 80% of cognitively normal older individuals report some decline in cognitive function when specifically questioned.2 Although most individuals with SCD will not develop progressive cognitive decline, in some, the perceived dysfunction may be the first sign of a neurodegenerative dementia. It is a difficult clinical challenge to determine those individuals who have underlying brain disease and those who will have alternative explanation, for example, a functional cognitive disorder.3 This distinction is already important, allowing for different treatments and predicting different outcomes, and will become even more pressing when disease-modifying treatments for neurodegeneration become available.