Deterioro cognitivo leve y enfermedad de Alzheimer: Revisión de conceptos.

Abstract

Alzheimer’s Disease (AD) is a neurological degenerative condition that affects over 46 million people
around the world. It is the most common cause of dementia in the elderly and is characterized by a
major memory impairment affecting a person’s ability to perform everyday activities. AD impacts the
person, their family/caregiver and society causing a great burden on health, social and economic systems.
In recent years, early detection of AD has become the main focus in aging research. Diagnosing
AD in its prodromal stage, where brain pathology is present but dementia still has not appeared, is
key to improving intervention mechanisms and to delay the expression of symptoms. As a result, it is
crucial to study Mild Cognitive Impairment (MCI), the symptomatic pre-dementia phase. Defining
MCI´s clinical manifestations, diagnostic criteria and its relation with AD is critical to the development
of methods that aid in identifying individuals who are at risk of developing dementia. The study of
cognitive impairment and biomarkers allows early and differential diagnosis of AD. Neuropsychological
evaluation is essential to determine different cognitive profiles and to assess the progression of
MCI to AD. Impairment in episodic memory, the first neuropsychological symptom of amnestic MCI,
deteriorates severely if the person develops AD, affecting long term memory. Other cognitive functions
such as attention, language, visuospatial abilities, reasoning and mental flexibility can be affected
in MCI and deteriorate even further in AD interfering with the person´s independence and functional
integrity. Likewise, the study of biomarkers in cerebrospinal fluid (CSF), neuroimaging and blood
biomarkers has permitted the identification of neuropathological signs of the disease. Together with
neuropsychological assessment, biomarkers constitute the most effective diagnostic approach for early
detection of AD.