OBJECTIVE: To identify the most accurate
cognitive measures in discriminating between
individuals with presymptomatic AD and individuals who
remained nondemented.
METHODS: During a 10-year
prospective community study, 120 nondemented subjects
completed a battery of standard cognitive tests and
clinically manifested AD 1.5 years later. Performance
on each of 16 cognitive tests was compared between
these 120 presymptomatic cases and 483 controls who
remained nondemented over the 10-year follow-up
period. The area under the receiver operating
characteristic (AUC) curve for each test was used to
measure its accuracy of discrimination between cases
and controls.
RESULTS: Among the 16
neuropsychological tests, Word List Delayed Recall
discriminated best between cases and controls (AUC =
0.806), followed by the Word List 3rd Learning Trial
(0.787), Word List 1st Learning Trial (0.774), and
Trail-making Test B (0.773), compared to the
Mini-Mental State Examination (MMSE) (0.726). Both
Word List Delayed Recall and Word List 3rd Learning
Trial were significantly more accurate than the MMSE.
The combination of Word List Delayed Recall and
Trail-making Test B comprised the optimal set of
cognitive measures, with the highest AUC (0.852).
CONCLUSION: Measures of delayed recall and
executive functions were the best discriminators
between those who would manifest AD 1.5 years later
and those who would remain nondemented. These findings
are relevant for the early detection of AD and,
therefore, for prevention and early intervention
trials. Executive dysfunction may be a subtle
manifestation of incipient AD, along with memory
dysfunction.