Semantic variant primary progressive aphasia

Diagnosis (Gorno-Tempini 2011)

1) Must have both:

a. Impaired confrontation naming

b. Impaired single-word comprehension

2) And must have at least three of the following:

a. Impaired object knowledge, particularly for low-frequency or low-familiarity items (i.e. “What is

a screwdriver?”)

b. Surface dyslexia or dysgraphia

c. Spared repetition

d. Spared speech production (grammar and motor speech – though may use increasing number of filler words)

3) Imaging-supported semantic variant diagnosis requires clinical diagnosis above plus imaging with at least one of:

a. Predominant anterior temporal lobe atrophy

b. Predominant anterior temporal hypoperfusion or hypometabolism on SPECT or PET

4) Semantic variant PPA with definite pathology diagnosis requires clinical diagnosis above plus either of the following:

a. Histopathologic evidence of a specific neurodegenerative pathology (e.g., FTLD-tau, FTLD-TDP, AD, other)

b. Presence of a known pathogenic mutation

- patients with svPPA frequently have behavioral symptoms that overlap with bvFTD (Finger 2016)

- as the disease progresses to involve more posterior brain regions (posterior temporal regions, visual temporal association areas), patients may develop prosopagnosia and visual agnosia (Finger 2016)

- elemental neurological examination is generally normal, including frontal release signs (Finger 2016)

- neuropsychological testing: predominant semantic language deficits (tests may include semantically categorized word generation or pyramid and palm tree test); episodic memory may better preservation of recent events than remote memories (opposite pattern to AD) (Finger 2016)

Imaging

- MRI axial view shows asymmetric L>R anterior temporal lobe atrophy (Ljubenkov and Miller 2016)

Pathology

- pathology is typically TDP-43 type C > 3R tau (Ljubenkov and Miller 2016)

References

Finger, E. C. Frontotemporal Dementias. Contin. Minneap. Minn 22, 464–489 (2016). https://pubmed.ncbi.nlm.nih.gov/27042904/

Gorno-Tempini, M. L. et al. Classification of primary progressive aphasia and its variants. Neurology 76, 1006–1014 (2011). https://pubmed.ncbi.nlm.nih.gov/21325651/

Ljubenkov, P. A. & Miller, B. L. A Clinical Guide to Frontotemporal Dementias. FOCUS 14, 448–464 (2016). https://pubmed.ncbi.nlm.nih.gov/31975825/