R4Alz-Revised: A Tool Able to Strongly Discriminate 'Subjective Cognitive Decline' from Healthy Cognition and 'Minor Neurocognitive Disorder'

Background: The diagnosis of the minor neurocognitive diseases in the clinical course of dementia before the clinical symptoms' appearance is the holy grail of neuropsychological research. The R4Alz battery is a novel and valid tool that was designed to assess cognitive control in people with minor cognitive disorders. The aim of the current study is the R4Alz battery's extension (namely R4Alz-R), enhanced by the design and administration of extra episodic memory tasks, as well as extra cognitive control tasks, towards improving the overall R4Alz discriminant validity. Methods: The study comprised 80 people: (a) 20 Healthy adults (HC), (b) 29 people with Subjective Cognitive Decline (SCD), and (c) 31 people with Mild Cognitive Impairment (MCI). The groups differed in age and educational level. Results: Updating, inhibition, attention switching, and cognitive flexibility tasks discriminated SCD from HC (p <= 0.003). Updating, switching, cognitive flexibility, and episodic memory tasks discriminated SCD from MCI (p <= 0.001). All the R4Alz-R's tasks discriminated HC from MCI (p <= 0.001). The R4Alz-R was free of age and educational level effects. The battery discriminated perfectly SCD from HC and HC from MCI (100% sensitivity-95% specificity and 100% sensitivity-90% specificity, respectively), whilst it discriminated excellently SCD from MCI (90.3% sensitivity-82.8% specificity). Conclusion: SCD seems to be stage a of neurodegeneration since it can be objectively evaluated via the R4Alz-R battery, which seems to be a useful tool for early diagnosis.

Automated summary

The aim of this study was to extend the R4Alz battery by adding extra episodic memory tasks and cognitive control tasks, in order to improve its discriminant validity. The results showed that the tasks in the R4Alz-R battery were able to effectively discriminate between healthy adults, subjective cognitive decline, and mild cognitive impairment patients. Therefore, the R4Alz-R battery appears to be a useful tool for early diagnosis, as it can objectively evaluate the condition of minor neurocognitive diseases.