Agreement among neuropsychological and behavioral data and PiB findings in diagnosing Frontotemporal Dementia

Abstract

Diagnostic inaccuracies have been reported in Alzheimer’s disease (AD) and Frontotemporal dementia (FTD) using clinical data alone. The [11C]-PiB PET scan offers a new method of identifying AD based on the detection of amyloid deposits. Our study investigated whether there was an agreement between neuropsychological and behavioral data and PiB findings in the diagnosis of FTD. Participants were 32 patients diagnosed with suspected FTD by clinical consensus. All participants underwent neuropsychological testing and PiB imaging. In addition, caregivers completed behavioral ratings of participants’ memory, frontal behaviors, and mood. Seventeen participants were classified as PiB positive (+). Results of MANOVA and subsequent ANOVA analyses showed a significant difference on memory performance between the PiB− and PiB+ groups, with the PiB− group performing better than the PiB+ group. There were no significant differences between the groups on cognitive or behavioral measures of executive/frontal impairment, mood. Both groups showed similar severity of dementia. These findings provide evidence for the utility of the [11C]-PiB PET scan in distinguishing between AD and FTD, with evaluation of memory at clinical diagnosis serving as a valuable indicator of the absence of FTD and consideration for an AD diagnosis. Our results would support the concern that patients who may present with primary behavioral or executive dysfunction may not necessarily have FTD, particularly if memory deficits are evident.

Papez Circuit Gray Matter and Episodic Memory in Amyotrophic Lateral Sclerosis and Behavioural Variant Frontotemporal Dementia

“…Furthermore, memory findings are in accordance with imaging studies showing significant MTL changes (Hornberger et al, 2012;Papma et al, 2013;Irish et al, 2014;Ryan et al, 2017;Wong et al, 2016).…”

FTD spectrum: Neuroimaging across the FTD spectrum

“…Furthermore, the tau isoforms present in bvFTD patients with genetic mutations can vary and hence influence tau-PET findings (see pathological section below) and many of these bvFTD studies have not screened cases for genetic mutations 124,125,127 . In addition, approximately 50% of bvFTD cases can show amyloid deposition on PET scanning 129 suggesting the possibility of underlying AD pathology which may influence tau-PET findings in bvFTD 126 . The value of tau-PET in bvFTD is therefore currently low until we have a better understand of the biological underpinnings of ligand binding.…”

Diagnostic imaging of dementia with Lewy bodies, frontotemporal lobar degeneration, and normal pressure hydrocephalus

“…In general, amyloid deposits are uncommon in most FTLD patients. Thus, amyloid PET is an important potential biomarker for differential diagnosis of AD from FTLD [49], and for studying the clinicopathological correlation of amyloid pathology in FTLD [50]. Since recent tau PET tracers have off-target problems involving binding to non-specific tau molecules, tau PET does not indicate pure tau deposition, but rather is used to show non-tau associated with neurodegeneration pathology [51,52] and the correlation of FTLD pathology with function [53].…”