Ranasinghe KG, Rankin KP, Loach IV et al. Neurology, 2016; 86: 600-610.
authors examined a cohort of 204 patients with clinical dementia rating.
Early stages of the disease were characterized by profound neuropsychiatric symptoms, insensitivity to errors, slower response times and poor naming.
Stepwise declines that occurred in later stages included free recall, visuoconstruction, set shifting, error insensitivity, semantic and design fluency, emotion naming, calculations, syntax comprehension and verbal agility.
Error insensitivity is called a highly sensitive index of early bv FTD and is likely attributed to the right lateral prefrontal cortex which is responsible for response inhibition and sensitivity to rule violations (esp IFG). Early patients show impaired processing speed and fluency tasks, but are adequate on attention and working memory, and visuoperceptual processing.
bvFTD patients get "denkfaulheit" or an early amotivational syndrome sometimes called emotional laziness. They may score poorly due to noncooperation and disruption of the "ventral salience network stuctures" to identify pedrsonally salient stimuli.