Stability of different subtypes of mild cognitive impairment among the elderly over a 2- to 3-year follow-up period.
OBJECTIVE
To investigate the longitudinal stability and progression of different subtypes of mild cognitive impairment (MCI) in older adults.


METHODS
We classified 217 individuals with no cognitive impairment (NCI), amnestic MCI (aMCI) based on a single test (aMCI-1) or multiple tests (aMCI-2+), nonamnestic MCI (naMCI) based on a single test (naMCI-1) or multiple tests (naMCI-2+), or amnestic + nonamnestic MCI (a+naMCI), using their baseline neuropsychological test scores, and performed annual follow-up evaluations for up to 3 years.


RESULTS
None of the subjects with aMCI-2+ reverted to normal during follow-up, with 50% of these subjects remaining stable and 50% worsening over time. Similarly, less than 20% of subjects with aMCI-2+ and a+naMCI reverted to NCI during the follow-up period, whereas 50% of aMCI-1 and 37% with naMCI-1 reverted to NCI during this same period.


CONCLUSIONS
Reversion to NCI occurs much more frequently when the diagnosis of MCI is based on the results of a single neuropsychological test than when it is based on the results of more memory tests. In epidemiological studies and clinical trials the diagnosis of MCI will likely be more stable if impairment on more than one test is required for amnestic and/or nonamnestic domains.
Wein Center for Alzheimer's Disease and Memory Disorders, Mount Sinai Medical Center, Miami Beach, Fla., USA. dloewenstein@att.net
David A
DA
Loewenstein
Amarilis
A
Acevedo
Brent J
BJ
Small
Joscelyn
J
Agron
Elizabeth
E
Crocco
Ranjan
R
Duara
D000368:Aged; D000704:Analysis of Variance; D003072:Cognition Disorders / Q000523:psychology*; D018450:Disease Progression; D005260:Female; D006801:Humans; D007802:Language; D008137:Longitudinal Studies; D008297:Male; D008568:Memory / Q000502:physiology; D008875:Middle Aged; D009483:Neuropsychological Tests; D011597:Psychomotor Performance / Q000502:physiology; D012959:Socioeconomic Factors; D013028:Space Perception / Q000502:physiology; D014888:Wechsler Scales