Luria's three-step test: What is it and what does it tell us?

Background: The purpose of this study is to determine if the three-step Luria test is useful for differentiating between cognitive disorders. Methods: A retrospective record review of performance on the three-step Luria test was conducted on 383 participants from a university-based dementia clinic. The participants ranged in their diagnosis from frontotemporal dementia (FTD; n = 43), Alzheimer disease (AD; n = 153), mild cognitive impairment (MCI; n = 56), and normal controls (NC; n = 131). Performance of the Luria test was graded as normal or abnormal. Results: An abnormal test occurred in 2.3% of NC, 21.4% of MCI, 69.8% of FTD, and 54.9% of AD subjects. The frequency of abnormal tests in all diagnostic groups increased with functional impairment as assessed by the Clinical Dementia Rating scale (CDR). When CDR = 3 (severe), 100% of the FTD and 72.2% of the AD subjects had abnormal Luria tests. Conclusions: The three-step Luria test distinguished NC and persons with MCI from FTD and AD, but did not distinguish FTD from AD subjects.