Clusters of Cognitive and Behavioral Disorders Clearly Distinguish Primary Progressive Aphasia from Frontal Lobe Dementia, and Alzheimer’s Disease

Abstract

Background/Aims: Frontal lobe dementia (FLD) and primary nonfluent progressive aphasia (PnPA) are two forms of frontotemporal lobe degeneration. The relationship between these conditions remains unclear. Our study aimed to better define the behavioral and cognitive clusters characterizing PnPA patients. Methods: We cognitively and behaviorally evaluated three groups of newly diagnosed patients affected by Alzheimer’s disease (AD, n = 20), FLD (n = 22) and PnPA (n = 10), in order to assess the cognitive-behavioral pattern of PnPA, compared to both FLD and AD. Results: We found, as expected, worse performances in episodic memory in AD, of both the verbal fluency and naming tasks in PnPA, while FLD mainly showed behavioral disorders associated with an unremarkable deficit in the executive tasks. PnPA was not characterized by any significant behavioral disorders. Factor analysis-extracted three main factors (‘mnesic’, ‘behavioral’ and ‘linguistic’) clearly correlated to each group. A discriminant analysis based on the extracted factors correctly classified 84.6% of all patients. Conclusion: The evidence of a characteristics cognitive profile, without any significant behavioral changes, highlights that PnPA is different from other forms of frontotemporal lobe degeneration regarding both the cognitive and behavioral patterns; thus, it should be considered independently in further studies.

The Relationship between Behavioural Changes, Cognitive Symptoms, and Functional Disability in Primary Progressive Aphasia: A Longitudinal Study

“…The differences in behavioural changes in svPPA and nfvPPA are noteworthy and raise two critical points [27,28,29,30,31,32]. Firstly, people with svPPA have marked behavioural dysfunction, which at present, is overshadowed by the emphasis on the semantic deficits that characterize the syndrome.…”

“…These marked behavioural changes are not part of the current diagnostic criteria but in many instances are of greater concern and distress to families than the well-reported semantic deficits [33]. Secondly, people with nfvPPA also demonstrate mild-moderate degrees of behavioural changes, such as apathy, which are equally underreported [30,34]. A proportion of the nfvPPA group with behavioural changes in the present study later developed an atypical Parkinsonian syndrome (CBS or PSP) as a secondary condition [35,36,37].…”

Clinical, genetic and pathological heterogeneity of frontotemporal dementia: a review

“…Stereotypic behaviour, alterations in eating behaviour and loss of social awareness particularly support a diagnosis of FTD, while more posterior symptoms such as difficulty with spatial orientation and locating objects suggest Alzheimer's disease (AD) 31 39 40. Apathy, mood changes and dysexecutive symptoms occur in both and have not been found to be effective discriminators of FTD from AD 39 41 42…”

Accurate Assessment of Behavioral Variant Frontotemporal Dementia

“…Investigation of this domain using "traditional" tasks of executive function has led to largely con fl icting fi ndings. While some studies fi nd impairments in this domain [ 71,[91][92][93] , others do not [94][95][96] . One reason for this discrepancy likely relates to stage of disease at which patients are assessed.…”

“…Examining errors is also important given that some researchers have found that patients with bvFTD often perform faster on measures of executive function (e.g., Stroop Inhibition) than patients with AD, but also make signi fi cantly more errors, indicating an imbalance in their ability to accurately make speed/error trade-offs [ 95,96 ] .…”