Introduction and Objectives: Although new complementary tests have emerged for the diagnosis of cognitive impairment and dementia, due to their high costs and limited availability, it is crucial to find low-cost, simple, and quick tools during the clinical examination that allow the physician to correctly diagnose these diseases. The study aims to evaluate the predictive value of mentioning the year 1900 during temporal orientation in patients presenting with cognitive disorders. No similar studies to the one proposed have beenreported.

Materials and Methods: A prospective cross-sectional observational study was conducted on patients who underwent cognitive evaluation between April and October 2019 and were being followed up in a cognitive neurology service. Within the administration of the Mini-Mental State Examination (MMSE) by Folstein, the reported year during temporal orientation was recorded, considering it positive if the response was between 1900 and 1999. The presence of dementia was determined according to the NIA-AA clinical criteria. Epi Info 7.2.1 was used for statistical analysis.

Results: A total of 192 patients with a mean age of 68.5 ± 13.97 years were included (65.10% women and 34.90% men). 20.31% had dementia (51.28% non-Alzheimer’s dementia and 48.72% Alzheimer’s-type dementia), while 79.69% had other diagnoses (73.6% non-amnestic mild cognitive impairment, 8% subjective complaint, 4% psychiatric disease, 14.4% amnestic mild cognitive impairment). Mentioning the 1900s had a specificity of 95% and a sensitivity of 58% for diagnosing Alzheimer’s-type dementia versus other dementia types (positive and negative predictive values of 92% and 70% respectively). A positive response in the 1900s was associated with a lower MMSE score (Mean 20.5 SD 5.38 vs. Mean 27.1 SD 3.19 in patients with a negative response (p < 0.0001). Additionally, patients without a 1900s response had a higher number of years of education 14.03 SD 4.2 vs. 10 SD 5.3 (p 0.0001).

Conclusions: While this is a preliminary result and a larger sample would be needed, thinking you are in the 1900s seems to be a good dementia indicator, although it remains to be determined if it could be specific to a particular type.