Severity of medial temporal atrophy and amnestic mild cognitive impairment: selecting type and number of memory tests.

OBJECTIVE: Medial temporal lobe atrophy (MTA) can be used as a biomarker of pathology that affects mechanisms of episodic memory. The authors compared the strength of this biomarker with performance on four memory measures and examined the influence of demographic factors including age, level of education, and primary language (English or Spanish).

METHODS: The Hopkins Verbal Learning Test-revised, Fuld Object Memory Evaluation (FOME), delayed memory for a story passage, and delayed visual reproduction of the Wechsler Memory Scale-revised tests were administered to 281 subjects who were diagnosed as having no cognitive impairment, mild cognitive impairment (MCI), impaired non-MCI, or dementia. MTA scores were obtained from visual ratings of the hippocampus, entorhinal cortex, and perirhinal cortex on coronal magnetic resonance imaging scans using a magnetization-prepared rapid gradient echo protocol.

RESULTS: Age was associated with scores on all memory measures and MTA. Level of educational attainment had no influence on FOME performance but had greater associations with scores on other memory measures. In regression models, FOME scores had the strongest relationship with MTA scores, accounting for 31% of the explained variability. Among subjects with MCI, an index representing the total number of memory tests that were impaired was also predictive of the severity of MTA scores.

CONCLUSION: Among four common tests of memory, the FOME was highly associated with MTA, and it exhibited minimal influences of education. Impairment on more than one memory test was more predictive of MTA than impairment on a single memory test.