Subcortical atrophy in frontotemporal dementia and Alzheimer's disease: Significance for differential diagnosis and correlation with clinical manifestations

Abstract

Cerebral subcortical atrophy occurs in both Alzheimer’s disease (AD) and frontotemporal dementia (FTD) but its significance for clinical manifestations and differential diagnosis between these common types of dementia has not been extensively investigated.ObjectivesTo compare the severity of cerebral subcortical atrophy in FTD and AD and to analyze the correlations between cerebral subcortical atrophy and demographics and clinical characteristics.MethodsTwenty three patients with FTD and 21 with AD formed the sample, which comprised 22 men and 22 women, aged 33 to 89, with mean age (±SD) of 68.52±12.08 years, with schooling ranging from 1 to 20 years, with a mean (±SD) of 7.35±5.54 years, and disease duration with a mean (±SD) of 3.66±3.44 years. The degree of cerebral subcortical atrophy was measured indirectly with a linear measurement of subcortical atrophy, the Bifrontal Index (BFI), using magnetic resonance imaging. We evaluated cognition, activities of daily living and dementia severity with the Mini-Mental State Examination, Functional Activities Questionnaire and the Clinical Dementia Rating, respectively.ResultsThere was no significant difference (p>0.05) in BFI between FTD and AD. The severity of cognitive deficits (for both FTD and AD groups) and level of daily living activities (only for AD group) were correlated with BFI.ConclusionsA linear measurement of cerebral subcortical atrophy did not differentiate AD from FTD in this sample. Cognitive function (in both FTD and AD groups) and capacity for independent living (only in AD group) were inversely correlated with cerebral subcortical atrophy.

Comparative Study of Subcortical Atrophy in Patients with Frontotemporal Dementia and Dementia with Extrapyramidal Signs

“…A significant negative correlation was found between BFI scores and cognitive performance in MMSE in both groups. A previous study conducted by our group found a very similar association studying comparatively FTD and AD [ 6 ]. Several other studies have reported that subcortical structures are associated with deficits of language and cognitive functions [ 8 , 33 , 34 ].…”

“…Subcortical grey matter atrophy may contribute as significantly to symptoms of FTD as cortical atrophy [ 9 ]. The subcortical and deep cortical structures may provide important clues on the clinical expression of this disorder, including also cognitive and behavioral abnormalities, given the growing consensus on the involvement of the basal ganglia in non-motor functions such as language, executive functions, memory, and learning [ 6 ].…”

“…BFI appears unsatisfactory for the differential diagnosis between FTD and dementia with EPS. Vieira and Caixeta [ 6 ] also found BFI unsatisfactory for the differential diagnosis between FTD and AD. Chaves et al [ 32 ] also found that BFI from Alzheimer and vascular patients were not significantly different.…”

“…One of the earliest changes seen in brain atrophy is the dilatation of the frontal horns of the lateral ventricle, BFI is one of the most consistent and practical linear measurement, when compared withother indexes, to estimate early brain atrophy [ 23 ]. The rate of cerebral atrophy has been studied as a biomarker for some neurodegenerative disorders, however its clinical importance and its relationship with extrapyramidal signs (EPS) has not been examined widely [ 6 ].…”