Word reading threshold and mild cognitive impairment: a validation study.

BACKGROUND

It was previously found, in a pilot study, that Word Reading Threshold (WRT) test is abnormally prolonged in individuals with Alzheimer's disease (AD) and Mild Cognitive Impairment (MCI), with high sensitivity and specificity. This validation study examines the WRT test as a prognostic tool in MCI individuals. We wish to confirm in a larger group the sensitivity and specificity of the WRT test and determine whether it is influenced by deterioration on other cognitive domains.

METHODS

We measured WRT in 60 MCI individuals, 29 AD patients, and 33 normal elderly control (NE). We followed the MCI individuals over 8 years to monitor who progressed to dementia.

RESULTS

We found a statistically significant difference in WRT scores between the three groups. However, using the same cutoff of 85 milliseconds suggested by Massoud and his colleagues, we found lower diagnostic sensitivity (72%) and specificity (76%) when comparing NC and AD. Furthermore, the test did not clearly differentiate MCI individuals who progressed to dementia from those who did not. WRT was found to correlate to some degree with other cognitive domains, especially attention.

CONCLUSIONS

We conclude that the WRT is insufficient alone as a diagnostic tool for prodromal AD.