This research aims to estimate the psychometric properties of the neuropsychological assessment instrument - Neuropsi in the Central Hospital of the Peruvian Air Force. The study is of psychometric type, of non-experimental design and in relation to the time it is of transversal type and is oriented through the quantitative paradigm. We worked with a non-probabilistic sample of 432 medical records from 2016 to 2018 of older adult patients who were diagnosed with cognitive impairment or dementia from the FAP Central Hospital and the Geriatric and Gerontological Center of the FAP to whom the brief neuropsychological assessment instrument in Spanish - Neuropsi by Dr. Feggy Ostrosky Solis, Alfredo Ardila and Monica Rosselli was applied. It is concluded that the instrument has a high reliability of 0.86 and a content and construct validity. At the same time, we propose scales for different groups of people by age and educational level and finally we provide percentile scales for people with educational levels between 10 and 24 years old for older adults between men and women.