Background/Aims: A timely diagnosis of dementia is important, and the Cognitive FunctionInstrument (CFI) is a newly developed instrument to screen for cognitive decline. The aim ofthis study was to evaluate the validity and internal consistency of the Norwegian version ofthe CFI.

Methods: We included 265 participants with dementia, mild cognitive impairment(MCI), subjective cognitive impairment (SCI), and a reference group without subjective or assessed cognitive decline. The participants and their relatives answered the self- and proxyratedversions of the CFI.

Results: The Norwegian CFI had power to discriminate betweenpeople with dementia and with MCI, SCI, and the reference group. The proxy version had betterpower than the self-rated version in our participants (area under the curve [AUC] proxyratedvarying from 0.79 to 0.99, AUC self-rated varying from 0.56 to 0.85). Conclusion: The Norwegian CFI was found to be a useful, valid, and robust instrument.