NEW YORK (Reuters Health) - People with mild cognitive impairment appear to have a lower risk of future dementia than previously believed, according to UK researchers reporting in the Journal of Neurology, Neurosurgery and Psychiatry.
Lead investigator Dr. Alex J. Mitchell from the University of Leicester told Reuters Health that mild cognitive impairment is a condition often seen in both primary and secondary care. “Although mild cognitive impairment is a high-risk condition, some people remain stable and some actually improve.”
Mitchell, along with Dr. M. Shiri-Feshki of Nottinghamshire Healthcare NHS Trust in Nottingham, analyzed data combined from 15 studies that lasted at least 5 years.
The two researchers determined that the yearly progression rate from mild impairment to dementia was 4.2 percent, much lower than “the widely cited 10 to 15 percent conversion rate.”
Among explanations for their long-term results, the investigators point out that populations studied at specialist centers, such as memory clinics, might have high rates of early progression. “In the first few years of follow-up, many of those with the most adverse risk profile will tend to progress, dropout or die, leaving a (group) of less vulnerable sufferers,” they write.
Altogether, continued Mitchell, “we found the rate of deterioration was about one third of that expected.” The team also found “that over 10 years, most people with the condition do not appear to develop dementia, although the risk is still substantial.”
Because of the possibility of improvement, Mitchell concluded that “health professionals should look for potentially treatable causes of cognitive impairment at the earliest opportunity.”
SOURCE: Journal of Neurology, Neurosurgery and Psychiatry, November 2008.