Is the development of late-life cognitive impairment more dynamic than sexy?

As people age, they experience characteristic, generally subtle, changes in almost all bodily functions, including brain function.¹ Psychomotor speed slows detectably across the adult lifespan.² By age 50, many people have noticed that their memory is not as good as it was when they were younger; if it troubles them enough to seek medical evaluation, they are said to have a subjective memory complaint. Many people with a subjective memory complaint have cognitive test score abnormalities, often at a rate higher than those who are not troubled by their memory³; of these, many go on to develop dementia.

The evaluation of people with cognitive impairment who do not meet the criteria for dementia is an area of intense investigation. No group has contributed more than the Mayo Clinic investigators. They have reified criteria for mild cognitive impairment (MCI), and identified subtypes. People with MCI can be found with and without a predominant amnestic component, and further with and without impairment in other cognitive domains. Some subsequent epidemiologic reports appeared to contradict some of the initial estimates of the risk conferred by MCI. As Roberts et al.⁴ point out in this issue of Neurology^®, discrepant estimates could be traced to many causes, epidemiologic studies sampling a different group than did …