Alteraciones de la memoria episódica verbal en fases preclínica y temprana de la enfermedad de Alzheimer familiar precoz por mutaciónE280A en PS1 Translated title: Verbal episodic memory at the preclinical and early phases of familiar early - onset Alzheimer disease caused by E280A mutation at PS1

Abstract

INTRODUCCION. Obtener un diagnóstico temprano o preclínico es uno de los mayores retos en la investigación de demencias. Hasta el momento se han descrito varios marcadores cognitivos; sin embargo, la memoria episódica verbal (MEV), no ha sido ampliamente estudiada en poblaciones con marcadores biológicos. OBJETIVO. Determinar si existen alteraciones tempranas en la MEV, en una muestra de participantes con riesgo de desarrollar Enfermedad de Alzheimer familiar precoz, al ser comparados con un grupo control en dos pruebas de MEV, el MIS (Memory Impairment Screen) y el MCT (Memory capacity test). MATERIALES Y MÉTODOS. La muestra estuvo conformada por 14 portadores asintomáticos, 11 portadores con deterioro cognitivo leve (DCL) y 23 sujetos sanos no portadores. Para la selección, se utilizó el Minimental, las escalas: EDG (Escala de Deterioro Global de Reisberg), FAST (Functional Assessment Staging de Reisberg) y la escala de quejas subjetivas de memoria. Posteriormente, se administraron el MIS y el MCT. Se analizaron las variables de recuerdo libre y facilitado. RESULTADOS. Se encontraron diferencias significativas entre los grupos de portadores, evidenciando que el grupo con DCL tiene una alteración en la MEV, originada en la fase de codificación. Sin embargo, en el grupo portador asintomático se observó, que dicha alteración yace en la fase de evocación. CONCLUSIONES. El MIS y MCT fueron de utilidad para discriminar entre portadores con DCL y portadores sanos. Estos test se caracterizan por ser breves, fáciles de administrar y de bajo costo. Se sugiere que sean empleados en protocolos de evaluación neuropsicológica, destinados a evaluar demencias y fase preclínica. Finalmente, se sugiere validar los test al contexto colombiano, y aumentar el tamaño de la muestra.

Translated abstract

INTRODUCTION. Early pre-clinical diagnosis is the greatest challenge faced by researchers into dementia. Despite several reported cognitive markers, the episodic verbal memory has not been widely studied in populations with biological markers. OBJETIVE. The aim of this study was determine the possible alterations in early episodic verbal memory in a two groups of participants at the risks of developing Early Familial Alzheimer's disease, when was compared with a control group in two test: the MIS (Memory Impairment Screen) and the MCT (Memory capacity test). MATERIALS AND METHODS. The sample group consisted of 48 participants who were genotyped for the E280A PS1 mutations. They were further divided into three groups: 14 asymptomatic carriers, 11 carriers subjects with MCI (Minimal cognitive impairment) and 23 healthy non-carriers. The selection process was performed using the Minimental and the GDS (Global deterioration scale), FAST(Functional Assessment Staging de Reisberg) scales and scale subjective memory complaints. The samples were subsequently administered the MIS and the MCT and variables such as free recall were recorded. RESULTS. Significant differences between groups of carriers, obtaining evidence MCI group that has an alteration in the episodic verbal memory, originated in the encoding phase. However, in asymptomatic carrier group it was observed that the alteration is in the evocation phase. CONCLUTION. The MIS and MCT were useful to discriminate between carriers with MCI and healthy carriers. These tests are characterized by short, easy administer ability, and low cost. It is proposed that this method is used in neuropsychological assessments protocols, in order to effectively assess pre-clinical dementia. It is also suggested to use a larger sample group, to validate the test applied to the Colombian context.