Frontotemporal Dementias Flashcards
Frontotemporal dementias
group of neurodegenerative disorders that leads to deterioration of the anterior temporal and/or frontal lobes resulting in behavioral changes, language dysfunction, and/or motor deficits.
Biomarkers of frontotemporal dementias
40% caused by an abnormal accumulation of tau protein
BUT more than half of FTDs are tau negative and are caused by an abnormal accumulation of TDP-43 protein
Age of diagnosis of frontotemporal dementias
Known for being a younger-onset dementia syndrome
FTD = onset 40s - 50s
Alzheimer’s = onset after 65
FTDs are commonly divided into three variants according to the symptom pattern, which are?
Behavioral variant
language variant
motor variant
FTD Behavioral Variant
previously referred to as Pick’s disease
progressive, focal degeneration of the bilateral frontal and temporal brain regions, and/or the presence of argyrophilic globular inclusions (Pick bodies; clumps of protein that builds up) and swollen, achromatic neurons (Pick cells).
Pick bodies and Pick cells can be found in frontal/temporal neocortex, amygdala, globes pallidus, etc.
bvFTD of three FTD variants is the most common (about half of all FTD cases) and occurs more frequently in men than women.
Presentation and course of FTD Behavioral Variant
Initial changes in personality and emotion regulation, two subtypes:
apathetic subtype - reduced motivation, lack of interest in prior activities, progressive social isolation, decreased empathy,
disinhibited subtype - disinhibition (e.g., overspending), impulsivity (e.g., inappropriate comments in public), hyperorality (especially for sweet foods), repetitive motor movements, and perseverative behaviors.
rarely results in hallucinations/delusions (compared to schizophrenia)
Executive/generation deficits with relative sparing of memory and visuospatial functions
generally lack awareness of deficits
pathophysiology and incidence of FTD Language Variant
Most cases of PPA have tau-positive, ubiquitin/TDP-43-positive frontotemporal lobar degeneration (FTLD) pathology or AD pathology
The language variant of FTD is commonly referred to as…?
primary progressive aphasia (PPA)
Three subtypes of FTD language variant
nonfluent/agrammatic variant (also called progressive nonfluent aphasia [PNFA]) - syntax difficulties, paraphasic errors, pitch distortions, and flawed grammar in writing and speech. difficulty comprehending complex sentences can also be apparent.
- d/t deterioration in the left posterior frontal and insular regions
semantic dementia (also called temporal variant FTD or semantic variant FTD) - semantic dementia - naming deficits (impaired confrontation naming) with loss of single word knowledge (typically for objects) and eventually progresses to loss of person recognition.
- deterioration in the bilateral anterior temporal region
logopenic variant (also called logopenic progressive aphasia and phonological variant PPA). - logopenic variant - anomia without loss of word knowledge, but there is also difficulty with sentence/phrase repetition and often phonologic errors.
- pathology involving the left temporoparietal regions
FTD language variant/primary progressive aphasia symptoms
characterized by initial and prominent language deterioration with relative preservation of other cognitive abilities until late in the disease process
presents with marked word-finding difficulty, decreased performance on word list generation tasks, problems with verbal comprehension, and dysarthria.
Reading and writing abilities typically remain preserved longer than speech.
distinguishing the logopenic from the semantic variant.
Logopenic has relatively spared grammar, object knowledge, and single word comprehension
distinguishing the logopenic from the progressive nonfluent variant
Logopenic has spared motor speech
Progression of FTD semantic variant in terms of language functions
deficits in object knowledge begin with loss of the ability to finely distinguish between types of objects (e.g., types of animals such as a tiger and a lion)
progresses to a broader difficulty making such distinctions (e.g., the difference between a tiger and an alligator)
progresses to a loss of knowledge of the word and the category (e.g., a loss of knowledge of what tigers are and what animals are).
FTD Motor Variant subtypes
progressive supranuclear palsy (PSP) - most common
corticobasal syndrome (CBS)
FTD with motor neuron disease (FTD-MND)
progressive supranuclear palsy (PSP)
most common FTD Motor Variant subtype d/t astrocytic lesions, tau-positive neurofibrillary tangles, and neuropil threads within the brainstem and basal ganglia.
Supranuclear vertical gaze palsy (impaired downward and upward gaze) which may be perceived as blurred vision
Bradykinesia Rigidity
Swallowing problems
Frequent falls
