DEFINITION

• Frontotemporal dementia (FTD) encompasses a group of neurodegenerative diseases characterized by progressive impairments in temperament, conduct, executive functions, and language.
• Three canonical syndromes are recognized:
  • Behavior variant FTD (bvFTD)
    • The most common variant, it is characterized by a progressive deterioration of conduct and cognition, in association with radiological evidence of frontal and/or anterior temporal atrophy or hypometabolism.[1]
  • Two primary progressive aphasia (PPA)/language variants
    • Primary non-fluent aphasia (PNFA)
      • Presents with labored and agrammatic speech alongside impaired sentence comprehension, with sparing of word and object knowledge, in association with radiological evidence of left posterior fronto-insular atrophy or hypometabolism[2]
    • Semantic dementia(SD)
      • Manifests as fluent and vacuous speech, featuring dysnomia and agnosia for words and objects, in association with radiological evidence of focal anterior temporal atrophy or hypometabolism[2]
• Eventually all phenotypes converge on a global dementia state, in which severe disability is observed in every cognitive and functional domain.[3]
• Frontotemporal lobar degeneration (FTLD) refers to the histopathological state that underlies the clinical syndromes.
• Cognitive impairment due to frontotemporal dementia is classified under the neurocognitive disorders (NCDs) section of the Diagnostic and Statistical Manual of Mental Disorders, 5th Edition (DSM-5).[4]