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title: "Primary Progressive Aphasia"
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docid: "5dca11fe-b5ee-404c-b22e-4008b7571844"
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authors:
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- key: "c92844c3-e14c-4eff-a8b8-68c82b8d2795"
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value: "Kyle Atcheson, MD"
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- key: "1f262abe-db83-4f18-99af-00bd3045cd4d"
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value: "Marc Benayoun, MD, PhD"
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breadcrumbs:
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-
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name: "Nuclear Medicine"
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slug: "nuclear-medicine"
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treeNodeId: "2406533f-6523-4211-841e-b92d6f8cf34e"
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-
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name: "Central Nervous System"
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slug: "central-nervous-system"
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treeNodeId: "bd6b5c36-69df-4f18-af9c-96cc24b52d8f"
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-
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name: "Neurodegeneration"
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slug: "neurodegeneration"
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treeNodeId: "f2b87cc7-926d-4915-8ec5-ca61a82e8bc9"
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-
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name: "Primary Progressive Aphasia"
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slug: "primary-progressive-aphasia"
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treeNodeId: null
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category: "Nuclear Medicine"
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cmeTopicId: "1b4c5b28-4036-4fba-8c74-df07f4ca186f"
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documentVersionId: "c4e0325c-afd7-4bb0-849a-fc2c1e12627b"
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imageCount: 8
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lastUpdated: "07/22/25"
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pageDescription: "Primary Progressive Aphasia"
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pageKeywords: "Nuclear Medicine, Central Nervous System, Neurodegeneration, Primary Progressive Aphasia"
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pageTitle: "Primary Progressive Aphasia | STATdx"
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enhancedTitle: "Primary Progressive Aphasia"
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type: "DX"
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references: true
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breadcrumbs:
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- "Nuclear Medicine"
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- "Central Nervous System"
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- "Neurodegeneration"
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- "Primary Progressive Aphasia"
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---
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# KEY FACTS
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- ## Terminology
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- Group of heterogeneous neurodegenerative disorders characterized by prominent language and word-finding difficulties
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- This includes logopenic-variant primary progressive aphasia (lvPPA), semantic-variant primary progressive aphasia (svPPA), and nonfluent/agrammatic-variant primary progressive aphasia (nfvPPA)
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- ## Imaging
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- Hypometabolism within critical brain areas on F-18 FDG PET
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- lvPPA: Left precuneus and temporoparietal region
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- svPPA: Left anterior temporal lobe
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- nfvPPA: Left inferior frontal lobe and insula
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- ## Top Differential Diagnoses
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- Alzheimer disease (AD)
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- Frontotemporal dementia (FTD) (behavioral variant)
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- Vascular dementia
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- ## Pathology
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- lvPPA is within AD spectrum
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- svPPA and nfvPPA are within FTD spectrum
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- ## Clinical Issues
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- Progressive language and word-finding difficulties
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- lvPPA: Impaired single-word retrieval, impaired repetition of sentences/phrases
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- svPPA: Impaired single-word comprehension/naming, object knowledge
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- nfvPPA: Agrammatism in language production, apraxia of speech
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- No cure exists for primary progressive aphasias
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- Patients with lvPPA may be eligible for amyloid-binding therapies
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- Engagement of social services and supportive care can aid with patients, families, and caregivers
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# TERMINOLOGY
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- ## Abbreviations
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- Primary progressive aphasia (PPA)
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- ## Definitions
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- Group of heterogeneous neurodegenerative disorders characterized by prominent language and word-finding difficulties
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- Classically grouped, given their language-predominant symptoms, though they are separate pathologic processes
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# IMAGING
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- ## General Features
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- ### Best diagnostic clue
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- Hypometabolism within critical brain areas on F-18 FDG PET
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- Classically involves left cerebral hemisphere, given majority of people are left language dominant
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- MR will demonstrate volume loss in affected areas in late-stage disease
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- ### Location
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- Logopenic-variant PPA (lvPPA): Involves left precuneus and left temporoparietal region
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- Semantic-variant PPA (svPPA): Involves left anterior temporal lobe
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- Nonfluent/agrammatic PPA (nfvPPA): Involves left inferior frontal lobe and left insula
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- ## Imaging Recommendations
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- ### Best imaging tool
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- F-18 FDG PET
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- Prominent, asymmetric hypometabolism within affected left cerebral hemispheric structures
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- MR
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- Initially used to assess for alternative etiologies that could cause symptoms (i.e., neoplasm, infarct, infection, trauma)
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- Qualitative and quantitative volume assessment can be performed to identify areas of neurodegeneration in late-stage disease
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- Amyloid PET
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- Positive in majority of lvPPA cases
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- Negative in svPPA and nfvPPA
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- Interpreted as "scant to few" (negative) or "moderate to frequent" (positive) β-amyloid neuritic plaques (Aβs)
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- ### Protocol advice
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- MR
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- DWI/ADC, T2/FLAIR, and SWI/GRE performed to assess for alternative etiologies (vascular insults, neoplasms, infection)
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- 3D T1 MR to assess for subtle volume loss; can perform quantitative volumetric analysis
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- F-18 FDG PET
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- Patient preparation
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- Patient should fast, stop IV fluids containing dextrose, and stop parenteral feeding for 4-6 hours; blood sugar should be < 150 mg/dL
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- Place patient in quiet, dimly lit room for 30 minutes prior to examination
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- Radiopharmaceutical: F-18 FDG
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- Dose: 7-10 mCi (260-370 MBq)
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- Dosimetry: Bladder is critical organ
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- Image acquisition: 45-60 minutes post injection
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- Amyloid PET
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- No patient preparation necessary
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- Radiopharmaceutical: F-18 florbetapir (or other amyloid-based tracers)
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- Dose: ~ 10 mCi (370 MBq) for F-18 florbetapir
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- Dosimetry: Gallbladder, bowel, intestines are critical organs
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- Image acquisition: 30-50 minutes post injection for F-18 florbetapir
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# DIFFERENTIAL DIAGNOSIS
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- [Alzheimer Disease (Classic Type)](/document/alzheimer-disease/2aad3ac4-44fd-43e5-8e50-a86987483af3)
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- Most common dementia
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- Memory impairment is prominent symptom
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- Language difficulties typically reserved for advanced disease
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- F-18 FDG PET demonstrates more symmetric temporoparietal hypometabolism
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- Positive on amyloid PET
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- [Frontotemporal Dementia (Behavioral Variant)](/document/frontotemporal-dementia/9f9eda8c-7e3c-4292-9861-4b8abc2c6474)
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- Classically presents with behavioral and personality changes
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- F-18 FDG PET demonstrates symmetric anterior frontal and temporal hypometabolism
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- MR demonstrates corresponding atrophy in frontotemporal lobes
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- [Vascular Dementia](/document/multiinfarct-dementia/3823c4d4-5e98-46da-a717-892fef54b382)
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- 2nd most common cause of dementia
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- MR shows scattered infarcts of varying ages, typically in deep gray nuclei or within vascular territory
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- Left middle cerebral artery (MCA) territory infarcts can affect areas involved in language and communication
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- ## Limbic-Predominant Age-Related TDP-43 Encephalopathy (LATE)
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- Recently described neurodegenerative disease that classically occurs in older adult patients (> 80 years old)
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- Typically does not present with language difficulties
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- F-18 FDG PET demonstrates hypometabolism within anterior temporal lobes and insula, usually bilateral
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# PATHOLOGY
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- ## General Features
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- Undetermined cause, likely secondary to combination of genetic, lifestyle, and environmental factors
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- ## Staging, Grading, & Classification
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- Diagnostic criteria
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- lvPPA
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- Core criteria: Impaired single-word retrieval, impaired repetition of sentences/phrases
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- Other features: Speech errors in spontaneous speech, spared single-word comprehension and object knowledge, spared motor speech, absence of frank agrammatism
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- svPPA
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- Core criteria: Impaired confrontation naming, impaired single-word comprehension
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- Other features: Impaired object knowledge, surface dyslexia/dysgraphia, spared repetition, spared speech production
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- nfvPPA
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- Core criteria: Agrammatism in language production, effortful/halting speech with speech sound errors and distortions (apraxia)
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- Other features: Impaired comprehension of syntactically complex sentences, spared single-word comprehension, spared object knowledge
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- ## Gross Pathologic & Surgical Features
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- Late-stage disease demonstrates prominent volume loss within affected regions
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- Increased sulcal volume within left cerebral hemisphere
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- lvPPA is believed to be within Alzheimer disease (AD) spectrum
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- Associated with Aβ and τ neurofibrillary tangles (τ-NFT) (80% of cases)
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- svPPA and nfvPPA are believed to be within frontotemporal dementia spectrum
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- svPPA is associated with TDP-43
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- nfvPPA is associated with 4-repeat τ isoform (4R-τ)
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# CLINICAL ISSUES
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- ## Presentation
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- ### Most common signs/symptoms
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- Progressive word-finding and language difficulties
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- lvPPA: Impaired single-word retrieval, impaired repetition of sentences/phrases
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- svPPA: Impaired single-word comprehension/naming, object knowledge
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- nfvPPA: Agrammatism in language production, apraxia of speech
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- Delayed diagnosis can occur given lack of apparent memory loss or behavioral symptoms
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- ### Other signs/symptoms
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- Late-stage disease will have memory loss/dementia
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- Psychiatric issues (i.e., depression, anxiety) may be present
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- ## Natural History & Prognosis
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- Progressive language and word-finding difficulties
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- End-stage disease presents with near-complete inability to communicate
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- Memory loss is less evident in early disease and can present later in disease course
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- Significant distinction from AD, where memory loss is primary symptom and language difficulties are seen later in disease course
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- No prominent behavioral, anger, or dysexecutive symptoms
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- Distinct from behavioral-variant frontotemporal dementia, where behavioral issues are evident early in disease course
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- ## Treatment
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- No cure exists for PPAs
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- lvPPA patients may be eligible for amyloid-targeting therapy
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- No disease-modifying therapies exist for svPPA or nfvPPA
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- Speech therapy and rehabilitation can aid in improving communication with caregivers/family
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- Engagement of social services and supportive care can aid with patients, families, and caregivers
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# DIAGNOSTIC CHECKLIST
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- ## Image Interpretation Pearls
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- F-18 FDG PET
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- Asymmetric hypometabolism within left temporoparietal region (lvPPA), left temporal pole (svPPA), or left inferior frontal lobe and insula (nfvPPA)
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- MR
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- Asymmetric left cerebral hemispheric volume loss within affected areas
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- ## Reporting Tips
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- Identify asymmetric hypometabolism if present
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- Describe key brain areas that are affected to convey specificity of underlying disease process
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- Exclude alternative etiologies and identify normal areas of metabolism on F-18 FDG PET
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- Consider additional imaging, such as amyloid PET, for suspected lvPPA, which would be beneficial for assessing candidacy for amyloid-targeting therapies
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92b83333-bc7b-40b2-b629-dd77297359fc
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## References
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# Selected References
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1. [Minoshima S et al: (18)F-FDG PET imaging in neurodegenerative dementing disorders: insights into subtype classification, emerging disease categories, and mixed dementia with copathologies. J Nucl Med. 63(Suppl 1):2S-12S, 2022](http://www.ncbi.nlm.nih.gov/pubmed/?term=35649653%5Bpmid%5D)
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1. [Minoshima S et al: Brain [F-18]FDG PET for clinical dementia workup: differential diagnosis of Alzheimer's disease and other types of dementing disorders. Semin Nucl Med. 51(3):230-40, 2021](http://www.ncbi.nlm.nih.gov/pubmed/?term=33546814%5Bpmid%5D)
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1. [Europa E et al: Diagnostic assessment in primary progressive aphasia: an illustrative case example. Am J Speech Lang Pathol. 29(4):1833-49, 2020](http://www.ncbi.nlm.nih.gov/pubmed/?term=32910678%5Bpmid%5D)
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1. [Marshall CR et al: Primary progressive aphasia: a clinical approach. J Neurol. 265(6):1474-90, 2018](http://www.ncbi.nlm.nih.gov/pubmed/?term=29392464%5Bpmid%5D)
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1. [Gorno-Tempini ML et al: Classification of primary progressive aphasia and its variants. Neurology. 76(11):1006-14, 2011](http://www.ncbi.nlm.nih.gov/pubmed/?term=21325651%5Bpmid%5D)
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## Images
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### Selected Images
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*A diagnostic decision tree for clinical diagnosis of primary progressive aphasia (PPA) subtypes is shown along with a 3D surface rendering of an FDG brain PET, indicating key areas of involvement in each PPA subtype: Nonfluent-variant PPA (nfvPPA), logopenic-variant PPA (lvPPA), semantic-variant PPA (svPPA).*
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*A diagnostic decision tree for clinical diagnosis of primary progressive aphasia (PPA) subtypes is shown along with a 3D surface rendering of an FDG brain PET, indicating key areas of involvement in each PPA subtype: Nonfluent-variant PPA (nfvPPA), logopenic-variant PPA (lvPPA), semantic-variant PPA (svPPA).*
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*A diagnostic decision tree for clinical diagnosis of primary progressive aphasia (PPA) subtypes is shown along with a 3D surface rendering of an FDG brain PET, indicating key areas of involvement in each PPA subtype: Nonfluent-variant PPA (nfvPPA), logopenic-variant PPA (lvPPA), semantic-variant PPA (svPPA).*
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*A diagnostic decision tree for clinical diagnosis of primary progressive aphasia (PPA) subtypes is shown along with a 3D surface rendering of an FDG brain PET, indicating key areas of involvement in each PPA subtype: Nonfluent-variant PPA (nfvPPA), logopenic-variant PPA (lvPPA), semantic-variant PPA (svPPA).*
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*Brain surface map of F-18 FDG PET in a patient with lvPPA demonstrates hypometabolism <img src='img/arrows/CC.png'/> throughout the left temporoparietal region. Notice the asymmetry compared to the contralateral temporal lobe <img src='img/arrows/WC.png'/>.*
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*Axial F-18 florbetapir at the level of the lateral ventricles in a patient with lvPPA demonstrates diffuse radiotracer uptake throughout the supratentorial gray matter <img src='img/arrows/WO.png'/>, consistent with moderate to frequent amyloid neuritic plaques.*
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*Brain surface map of F-18 FDG PET in a patient with svPPA demonstrates focal hypometabolism <img src='img/arrows/CS.png'/> in the anterior left temporal lobe. Notice how it is fairly localized to the anterior pole and asymmetric when compared to the contralateral side <img src='img/arrows/WS.png'/>.*
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*Brain surface map of F-18 FDG PET in a patient with nfvPPA demonstrates focal hypometabolism <img src='img/arrows/WO.png'/> in the inferior left frontal lobe. This may be underrepresented on the surface map due to its location immediately adjacent to the mesial temporal lobe <img src='img/arrows/CO.png'/>, so make sure to attend to this region on cross-sectional reformats.*
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### Additional Images
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*Brain surface rendering of F-18 FDG PET of the brain in a patient with lvPPA demonstrates statistically significant areas of hypometabolism <img src='img/arrows/WC.png'/> in the left temporoparietal region relative to an age-matched database.*
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*Brain surface rendering of F-18 FDG PET of the brain in a patient with nfvPPA demonstrates statistically significant areas of hypometabolism <img src='img/arrows/BS.png'/> within the left inferior frontal lobe relative to an age-matched database.*
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*Brain surface rendering of F-18 FDG PET of the brain in a patient with svPPA demonstrates statistically significant areas of hypometabolism <img src='img/arrows/CS.png'/> within the left anterior temporal lobe relative to an age-matched database.*
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