scholarly journals Perturbations of language network connectivity in primary progressive aphasia

Cortex ◽  
2019 ◽  
Vol 121 ◽  
pp. 468-480
Author(s):  
Borna Bonakdarpour ◽  
Robert S. Hurley ◽  
Allan R. Wang ◽  
Hernando R. Fereira ◽  
Anisha Basu ◽  
...  
2017 ◽  
Vol 13 (7) ◽  
pp. P1544-P1545
Author(s):  
Borna Bonakdarpour ◽  
Robert Hurley ◽  
Allan Wang ◽  
Hernando Fereira ◽  
Arjuna Chatrathi ◽  
...  

Cortex ◽  
2021 ◽  
Author(s):  
M.-Marsel Mesulam ◽  
Christina A. Coventry ◽  
Benjamin M. Rader ◽  
Alan Kuang ◽  
Jaiashre Sridhar ◽  
...  

2014 ◽  
Vol 10 (10) ◽  
pp. 554-569 ◽  
Author(s):  
M.-Marsel Mesulam ◽  
Emily J. Rogalski ◽  
Christina Wieneke ◽  
Robert S. Hurley ◽  
Changiz Geula ◽  
...  

2013 ◽  
Vol 7 (1) ◽  
pp. 2-9 ◽  
Author(s):  
Marsel Mesulam

ABSTRACT Primary progressive aphasia (PPA) is a clinical syndrome diagnosed when three core criteria are met. First, there should be a language impairment (i.e., aphasia) that interferes with the usage or comprehension of words. Second, the neurological work-up should determine that the disease is neurodegenerative, and therefore progressive. Third, the aphasia should arise in relative isolation, without equivalent deficits of comportment or episodic memory. The language impairment can be fluent or non-fluent and may or may not interfere with word comprehension. Memory for recent events is preserved although memory scores obtained in verbally mediated tests may be abnormal. Minor changes in personality and behavior may be present but are not the leading factors that bring the patient to medical attention or that limit daily living activities. This distinctive clinical pattern is most conspicuous in the initial stages of the disease, and reflects a relatively selective atrophy of the language network, usually located in the left hemisphere. There are different clinical variants of PPA, each with a characteristic pattern of atrophy. The underlying neuropathological diseases are heterogeneous and can include Alzheimer's disease as well as frontotemporal lobar degeneration. The clinician's task is to recognize PPA and differentiate it from other neurodegenerative phenotypes, use biomarkers to surmise the nature of the underlying neuropathology, and institute the most fitting multimodal interventions.


2020 ◽  
Author(s):  
Haroon Popal ◽  
Megan Quimby ◽  
Daisy Hochberg ◽  
Bradford C. Dickerson ◽  
Jessica A. Collins

AbstractAs their illness progresses, patients with the semantic variant of Primary Progressive Aphasia (svPPA) frequently exhibit peculiar behaviors indicative of altered visual attention or an increased interest in artistic endeavors. In the present study, we examined changes within and between large-scale functional brain networks that may explain this altered visual behavior. We first examined the connectivity of the visual association network, the dorsal attention network, and the default mode network in healthy young adults (n=89) to understand the typical architecture of these networks in the healthy brain. We then compared the large-scale functional connectivity of these networks in a group of svPPA patients (n=12) to a group of age-matched cognitively normal controls (n=30). Our results showed that the between-network connectivity of the dorsal attention and visual association networks was elevated in svPPA patients relative to controls. We further showed that this heightened between-network connectivity was associated with a decrease in the within-network connectivity of the default mode network, possibly due to progressive degeneration of the anterior temporal lobes in svPPA. These results suggest that focal neurodegeneration can lead to the reorganization of large-scale cognitive networks beyond the primarily affected network(s), possibly contributing to cognitive or behavioral changes that are commonly present as part of the clinical phenotype of svPPA.


Author(s):  
Borna Bonakdarpour

Neuroimaging is a standard part of a primary progressive aphasia (PPA) diagnostic work-up and an important component of research investigating changes in the speech-language network in patients with PPA. In this paper, structural neuroimaging, including computed tomography (CT), magnetic resonance imaging (MRI), and diffusion tensor imaging (DTI), as well as functional neuroimaging, including single photon emission computed tomography (SPECT), positron emission tomography (PET), and functional MRI (fMRI), are discussed. Neuroimaging, in conjunction with meticulous clinical and neuropsychological evaluation, can increase diagnostic certainty for PPA subtyping and identification of underlying pathology, which is important for justification of potential pharmacological treatments, such as cholinesterase inhibitors. MRI and, more recently, DTI, have expanded our knowledge of structural brain changes in PPA, including gray matter abnormalities as well as alterations in neuronal tracts. SPECT and PET provide information regarding brain regional blood perfusion (SPECT) or metabolism (PET). Recently, thanks to PET ligands that bind to amyloid protein, it has become possible to diagnose or rule out Alzheimer pathology as a cause for PPA and tau imaging may be forthcoming. Finally, fMRI provides a unique window into brain-behavior relations for language as well as reorganization of the language network in disease. fMRI has also been used to gauge the effects of therapeutic interventions, including language treatment, and can be used for implementation of neuromodulatory mediations, such as repetitive transcranial magnetic stimulation (TMS).


2003 ◽  
Vol 53 (2) ◽  
pp. 242-247 ◽  
Author(s):  
Marco Catani ◽  
Massimo Piccirilli ◽  
Antonio Cherubini ◽  
Roberto Tarducci ◽  
Tiziana Sciarma ◽  
...  

Neurology ◽  
2020 ◽  
Vol 95 (7) ◽  
pp. e847-e855 ◽  
Author(s):  
Sandra Weintraub ◽  
Benjamin Rader ◽  
Christina Coventry ◽  
Jaiashre Sridhar ◽  
Jessica Wood ◽  
...  

ObjectiveTo investigate evidence of the potential role of early cortical vulnerability in the development of primary progressive aphasia (PPA).MethodA woman with a diagnosis of PPA and her 9 adult siblings, 7 with developmental language disabilities, underwent neuropsychological testing, structural MRI, and resting-state fMRI. Whole-exome sequencing was conducted for genes associated with dyslexia or with neurodegenerative dementia.ResultsThe siblings demonstrated lower verbal than nonverbal cognitive test scores in a developmental dyslexia pattern. On structural MRI, although the siblings did not differ from controls in total brain volume, the left hemisphere language area volume was significantly smaller than the right. Furthermore, cortical connectivity between the left superior temporal area, previously identified as the region of peak atrophy in the proband early in the course of illness, and adjacent language network components, including the planum temporale, was decreased in the siblings. No distinctive genetic signatures were identified.ConclusionThis report further supports the hypothesis that at least some cases of PPA may be based on a familial language network vulnerability that interferes with the acquisition of language in some members and that makes the language network a locus of least resistance to the effects of an independently late-arising neurodegenerative disease in others. This association offers a conceptual model to explain why identical neurodegenerative diseases may selectively target the language network in some individuals while targeting networks that regulate memory or behavior in others. The genetic basis for this vulnerability remains to be determined.


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