Using different memory cutoffs to assess mild cognitive impairment.
OBJECTIVE
Although mild cognitive impairment (MCI) is characterized by performance on memory and other measures below expected normative values, neither a scientific rationale nor a consensus exists regarding which measures have the most use or the optimal cutoffs to use to establish impairment.


METHODS
Different memory measures were administered to 80 normal community-dwelling subjects divided into two age groups. This provided conormed data on eight different memory indices by which to compare 23 nondemented clinically diagnosed patients with MCI who met all other criteria for Alzheimer disease (AD).


RESULTS
On immediate memory for passages, delayed visual reproduction, object memory, and a measure sensitive to semantic interference, 70%-78% of patients with MCI were identified as impaired at 1.5 standard deviations or greater below expected levels. Conditional logistical regression for age-matched samples indicated that consideration of raw scores for these neuropsychologic tests in combination did not significantly change the odds of MCI diagnosis. When impairment relative to the total normal elderly sample was calculated based on one or more impairments at a 1.5 or greater cutoff, specificity fell below acceptable levels when more than three memory measures were considered.


CONCLUSIONS
An array of widely used neuropsychologic measures demonstrated utility in distinguishing patients with MCI-AD from cognitively normal community-dwelling elders. The appropriateness of more or less stringent cutoffs was highly influenced by the number of measures considered. These findings have important implications regarding the choice of cut points for impairment used for the diagnosis of MCI in both research and clinical settings.
Loewenstein
David A
DA
Wien Center for Alzheimer's Disease and Memory Disorders, Mount Sinai Medical Center, Miami Beach, FL 33140, USA. dloewenstein@worldnet.att.net
Acevedo
Amarilis
A
Ownby
Raymond
R
Agron
Joscelyn
J
Barker
Warren W
WW
Isaacson
Richard
R
Strauman
Silvia
S
Duara
Ranjan
R
D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000175:diagnosis* / Q000523:psychology; D000647:Amnesia / Q000175:diagnosis* / Q000523:psychology; D003072:Cognition Disorders / Q000175:diagnosis* / Q000523:psychology; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D009483:Neuropsychological Tests / Q000706:statistics & numerical data*; D011594:Psychometrics / Q000706:statistics & numerical data; D012372:ROC Curve; D012016:Reference Values; D015203:Reproducibility of Results