FTD spectrum: Neuroimaging across the FTD spectrum

Whitwell, Jennifer L.

doi:10.1016/bs.pmbts.2019.05.009

Cited by 40 publications

(47 citation statements)

References 269 publications

(414 reference statements)

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“…Hypometabolism on FDG-PET is shown for individual patients, represented as Z score maps depicting abnormalities compared to controls. Adapted with permission from Whitwell 2019 [ 258 ] …”

Section: Neuroimaging Of Frontotemporal Dementia Syndromesmentioning

confidence: 99%

“…Hypometabolism on FDG-PET is shown for individual patients, represented as Z score maps depicting abnormalities compared to controls. Adapted with permission from Whitwell 2019 [258] effect sizes [143]. Hypometabolism can often be found impacting the frontal lobes, particularly in the medial PFC, dorsolateral PFC, ventrolateral PFC, orbitofrontal cortex, and anterior cingulate cortex [138,144,145].…”

Section: Behavioral Variant Frontotemporal Dementiamentioning

confidence: 99%

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Neuroimaging in Frontotemporal Dementia: Heterogeneity and Relationships with Underlying Neuropathology

et al. 2021

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Frontotemporal dementia encompasses a group of clinical syndromes defined pathologically by degeneration of the frontal and temporal lobes. Historically, these syndromes have been challenging to diagnose, with an average of about three years between the time of symptom onset and the initial evaluation and diagnosis. Research in the field of neuroimaging has revealed numerous biomarkers of the various frontotemporal dementia syndromes, which has provided clinicians with a method of narrowing the differential diagnosis and improving diagnostic accuracy. As such, neuroimaging is considered a core investigative tool in the evaluation of neurodegenerative disorders. Furthermore, patterns of neurodegeneration correlate with the underlying neuropathological substrates of the frontotemporal dementia syndromes, which can aid clinicians in determining the underlying etiology and improve prognostication. This review explores the advancements in neuroimaging and discusses the phenotypic and pathologic features of behavioral variant frontotemporal dementia, semantic variant primary progressive aphasia, and nonfluent variant primary progressive aphasia, as seen on structural magnetic resonance imaging and positron emission tomography.

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“…Hypometabolism on FDG-PET is shown for individual patients, represented as Z score maps depicting abnormalities compared to controls. Adapted with permission from Whitwell 2019 [ 258 ] …”

Section: Neuroimaging Of Frontotemporal Dementia Syndromesmentioning

confidence: 99%

Section: Behavioral Variant Frontotemporal Dementiamentioning

confidence: 99%

Neuroimaging in Frontotemporal Dementia: Heterogeneity and Relationships with Underlying Neuropathology

et al. 2021

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“…Classically, FTD cases show frontotemporal and insular atrophy in structural neuroimaging, with Magnetic Resonance Imaging (MRI) ( 104 ). In functional neuroimaging including positron emission tomography (PET) or single-photon emission computed tomography (SPECT), hypometabolism and hypoperfusion have been described ( 105 ), suggesting the involvement of either structural and/or functional impairment of the frontal lobe in the pathogenesis of FTD ( 19 ).…”

Section: Resultsmentioning

confidence: 99%

“…Nevertheless, several other biomarkers are being used around the world, including functional imaging allowing in vivo imaging of proteins, DTI allowing to evaluate the connection between lobes, among others ( 105 ). They have provided important insights into FTD pathology, especially in HIC ( 104 , 129 ), therefore an effort should also be done to increase the access to those resources for special cases.…”

Section: Resultsmentioning

confidence: 99%

Systematic Review: Genetic, Neuroimaging, and Fluids Biomarkers for Frontotemporal Dementia Across Latin America Countries

et al. 2021

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Frontotemporal dementia (FTD) includes a group of clinically, genetically, and pathologically heterogeneous neurodegenerative disorders, affecting the fronto-insular-temporal regions of the brain. Clinically, FTD is characterized by progressive deficits in behavior, executive function, and language and its diagnosis relies mainly on the clinical expertise of the physician/consensus group and the use of neuropsychological tests and/or structural/functional neuroimaging, depending on local availability. The modest correlation between clinical findings and FTD neuropathology makes the diagnosis difficult using clinical criteria and often leads to underdiagnosis or misdiagnosis, primarily due to lack of recognition or awareness of FTD as a disease and symptom overlap with psychiatric disorders. Despite advances in understanding the underlying neuropathology of FTD, accurate and sensitive diagnosis for this disease is still lacking. One of the major challenges is to improve diagnosis in FTD patients as early as possible. In this context, biomarkers have emerged as useful methods to provide and/or complement clinical diagnosis for this complex syndrome, although more evidence is needed to incorporate most of them into clinical practice. However, most biomarker studies have been performed using North American or European populations, with little representation of the Latin American and the Caribbean (LAC) region. In the LAC region, there are additional challenges, particularly the lack of awareness and knowledge about FTD, even in specialists. Also, LAC genetic heritage and cultures are complex, and both likely influence clinical presentations and may modify baseline biomarker levels. Even more, due to diagnostic delay, the clinical presentation might be further complicated by both neurological and psychiatric comorbidity, such as vascular brain damage, substance abuse, mood disorders, among others. This systematic review provides a brief update and an overview of the current knowledge on genetic, neuroimaging, and fluid biomarkers for FTD in LAC countries. Our review highlights the need for extensive research on biomarkers in FTD in LAC to contribute to a more comprehensive understanding of the disease and its associated biomarkers. Dementia research is certainly reduced in the LAC region, highlighting an urgent need for harmonized, innovative, and cross-regional studies with a global perspective across multiple areas of dementia knowledge.

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“…Structural MRI studies have revealed the extent of gray matter (GM) atrophy and its impact on the occurrence and development of disease 10‐12 . Moreover, functional connectivity studies using resting‐state functional magnetic resonance imaging (rs‐fMRI) have revealed the changes in brain network 10,13 . However, there are few studies on the changes in local brain activities.…”

Section: Introductionmentioning

confidence: 99%

Changes in local brain function in mild cognitive impairment due to semantic dementia

et al. 2021

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Aims Mild cognitive impairment due to semantic dementia represents the preclinical stage, involving cognitive decline dominated by semantic impairment below the semantic dementia standard. Therefore, studying mild cognitive impairment due to semantic dementia may identify changes in patients before progression to dementia. However, whether changes in local functional activity occur in preclinical stages of semantic dementia remains unknown. Here, we explored local functional changes in patients with mild cognitive impairment due to semantic dementia using resting‐state functional MRI. Methods We administered a battery of neuropsychological tests to twenty‐two patients with mild cognitive impairment due to semantic dementia (MCI‐SD group) and nineteen healthy controls (HC group). We performed structural MRI to compare gray matter volumes, and resting‐state functional MRI with multiple sub‐bands and indicators to evaluate functional activity. Results Neuropsychological tests revealed a significant decline in semantic performance in the MCI‐SD group, but no decline in other cognitive domains. Resting‐state functional MRI revealed local functional changes in multiple brain regions in the MCI‐SD group, distributed in different sub‐bands and indicators. In the normal band, local functional changes were only in the gray matter atrophic area. In the other sub‐bands, more regions with local functional changes outside atrophic areas were found across various indicators. Among these, the degree centrality of the left precuneus in the MCI‐SD group was positively correlated with general semantic tasks (oral sound naming, word‐picture verification). Conclusion Our study revealed local functional changes in mild cognitive impairment due to semantic dementia, some of which were located outside the atrophic gray matter. Driven by functional connectivity changes, the left precuneus might play a role in preclinical semantic dementia. The study proved the value of frequency‐dependent sub‐bands, especially the slow‐2 and slow‐3 sub‐bands.

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FTD spectrum: Neuroimaging across the FTD spectrum

Cited by 40 publications

References 269 publications

Neuroimaging in Frontotemporal Dementia: Heterogeneity and Relationships with Underlying Neuropathology

Neuroimaging in Frontotemporal Dementia: Heterogeneity and Relationships with Underlying Neuropathology

Systematic Review: Genetic, Neuroimaging, and Fluids Biomarkers for Frontotemporal Dementia Across Latin America Countries

Changes in local brain function in mild cognitive impairment due to semantic dementia

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