Comparison of Cognitive Impairment Diagnosis Criteria in Clinical Settings: Conventional vs. Neuropsychological.

Background: Theories on Alzheimer disease pathogenesis propose a gap between pathological changes and the onset of clinical symptoms. The early detection of cognitive decline is crucial for the implementation of preventive strategies. Mild cognitive impairment is a transitional stage and an accurate diagnosis is vital. However, the diagnosis of mild cognitive impairment varies due to inconsistent diagnostic criteria. This study aims to explore the effectiveness of comprehensive neuropsychological criteria, including all cognitive domains, for diagnosing cognitive impairment in clinical settings.

Methods: The study included 509 subjects with subjective cognitive complaints between 2017 and 2021. They were diagnosed using the conventional and neuropsychological criteria, and the results were named the complex criteria (conventional criteria-neuropsychological criteria).

Results: Concordance between the conventional and neuropsychological diagnostic criteria diagnoses was 87.82%. Some participants diagnosed with mild cognitive impairment or dementia using the conventional criteria were classified as normal according to the neuropsychological criteria. Notably, the mild cognitive impairment - normal cognition (MCI-NC) and dementia (DEM)-NC (normal cognition) groups exhibited distinct characteristics. The MCI-NC group had higher depression scores ( = .008) and better memory performance ( = .026) and executive function ( = .020) than the MCI-MCI group. The DEM-NC group had better instrumental activities of daily living ( < .001) than the DEM-DEM group.

Conclusion: This study highlights the complexity of diagnosing cognitive impairment and the importance of comprehensive criteria. Relying solely on conventional criteria may lead to overdiagnosis. The neuropsychological criteria consider various cognitive domains and better discriminate between individuals with MCIs or other factors that contribute to cognitive difficulties.