Biomarcadores no convencionales en demencia a través del examen neurológico: una revisión de la literatura

Introduction: Blood and cerebrospinal fluid biomarkers have gained prominence in dementia diagnosis; however, they are not always available. Objectives: To describe unconventional biomarkers identifiable during neurological examination. Methods: A narrative review was conducted, searching for cognitive impairment in relation to unconventional biomarkers in PubMed, EMBASE, and SciELO databases. Original and secondary studies describing this relationship were included, along with tools for clinical evaluation. Results: Neuropsychiatric symptoms are among the earliest manifestations and a marker of progression, present in approximately 97% of patients. Depression, anxiety, and apathy are three potential indicators, assessable through clinical expertise, scales, or new technologies. Other markers include bradyphrenia and executive function impairment, which affects motor function parameters in 8-13% of cases. Regarding cranial nerves, alterations in the optic nerve and retina, changes in eye movements, and hearing loss may occur. Motor examination is one of the most promising areas, focusing on dual-task performance, gait speed, and grip strength. It has been estimated that these factors may influence the occurrence of dementia by more than 50%. Sensory alterations in pain perception may also be observed. Lastly, the appearance of two or more frontal release reflexes is a marker of cognitive decline. Conclusions: Evidence supporting the use of unconventional biomarkers was found, which may serve as an alternative for early detection of cognitive impairment.