Evaluating language comprehension in Alzheimer's disease: the use of the Token test.

OBJECTIVE To analyze the psychometric properties of the Token test (TT), a verbal comprehension test, and its applicability to the diagnosis of mild Alzheimer's disease (AD). METHODS One hundred and sixty participants (80 AD and 80 controls) performed the TT and a short battery of neuropsychological tests designed to evaluate general cognitive status, working memory and executive functions. Internal consistency, factor structure, correlation with other measures and group comparisons were evaluated. RESULTS The test evinced good internal consistency and a bi-factorial structure (related to comprehension and attention). Differences between AD and controls were significant, however the TT presented only moderate sensitivity and specificity for the AD diagnosis. CONCLUSION The TT showed evidence of good psychometric properties and adequacy for characterizing comprehension deficits in AD, but it was not an appropriate test for the AD detection and diagnosis.