A Spanish Neuropsychological Battery Discriminates Between the Behavioral Variant of Frontotemporal Dementia and Primary Progressive Aphasia in a Colombian Sample.

Lina Velilla,Jonathan Hernández,Yakeel Quiroz,Edmarie Guzmán-Vélez,Margarita Giraldo-Chica,Francisco Lopera

doi:10.3389/fneur.2021.656478

Abstract

The differential diagnosis among the behavioral variant of frontotemporal dementia FTD (bvFTD) and the linguist one primary progressive aphasia (PPA) is challenging. Presentations of dementia type or variants dominated by personality change or aphasia are frequently misinterpreted as psychiatric illness, stroke, or other conditions. Therefore, it is important to identify cognitive tests that can distinguish the distinct FTD variants to reduce misdiagnosis and best tailor interventions. We aim to examine the discriminative capacity of the most frequently used cognitive tests in their Spanish version for the context of dementia evaluation as well as the qualitative aspects of the neuropsychological performance such as the frequency and type of errors, perseverations, and false positives that can best discriminate between bvFTD and PPA. We also described mood and behavioral profiles of participants with mild to moderate probable bvFTD and PPA. A total of 55 subjects were included in this cross-sectional study: 20 with PPA and 35 with bvFTD. All participants underwent standard dementia screening that included a medical history and physical examination, brain MRI, a semistructured caregiver interview, and neuropsychological testing. We found that bvFTD patients had worse performance in executive function tests, and the PPA presented with the lower performance in language tests and the global score of Mini-Mental State Examination (MMSE). After running the linear discriminant model, we found three functions of cognitive test and subtests combination and three functions made by the Montreal Cognitive Assessment (MoCA) language subtest and performance errors that predicted group belonging. Those functions were more capable to classify bvFTD cases rather than PPA. In conclusion, our study supports that the combination of an individual test of executive function and language, MoCA's subtest, and performance errors as well have good accuracy to discriminate between bvFTD and PPA.

Highlights

Frontotemporal dementia (FTD) has been widely described as a syndrome that presents clinically by either behavioral/executive (BvFTD) or language dysfunction [i.e., primary progressive aphasia (PPA)]
Function 3 was composed of incorrect p words and descriptive errors for the naming test and classified correctly 71% cases. This function classified correctly 94% behavioral variant of frontotemporal dementia FTD (bvFTD) cases and 33% PPA cases (Wilks’ ň = 0.802, chi2 = 10,606, P < 0.005) (Figure 3). In this cross-sectional study, we assessed the capability to discriminate between bvFTD and PPA of the Spanish version of a set of cognitive tests set widely used in dementia diagnosis in a sample of Colombian patients
We introduced the cognitive variables that significantly discriminated those with bvFTD from PPA into a linear discriminant function model to establish the discriminant functions that better contribute to predicting whether a patient belongs to the bvFTD or PPA group

Summary

Introduction

Frontotemporal dementia (FTD) has been widely described as a syndrome that presents clinically by either behavioral/executive (BvFTD) or language dysfunction [i.e., primary progressive aphasia (PPA)] These presentations are associated with prominent frontal or anterior temporal lobe degeneration [1] but with slightly different degeneration patterns and clinical profiles that merit distinct interventions. It has been described that, in PPA syndromes, most of the patients may debut with prominent anomia but with no frank semantic memory loss, and, those patients emerge with behavioral symptoms [3] This case evolution involves only minor or mixed linguistic alterations and have a similar profile of behavioral change over time, mainly characterized by apathy [4], hindering differential diagnosis. To the best of our knowledge, there are no studies yet that aimed to assess the discriminative capability of the Spanish version of widely used neuropsychological tests to evaluate cognitive changes between FTD and PPA, making it more needed to count on accurate neuropsychological data for the Latino population, where the access to sophisticated diagnostic technologies such PET-TAU and even to functional MRI (fMRI) is scarce

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