Frontotemporal Lobar Dementia is Easily Mistaken for Alzheimer’s Disease

Reviewing Diagnostic Criteria for Differentiating FTLD from AD

Nadège Chéry, PhD

Frontotemporal lobar dementia (FTLD) is the third most common form of cortical dementia following Alzheimer's disease (AD) and Dementia with Lewy Bodies. It is often mistaken for AD, yet it presents strikingly different clinical and histopathological features and therefore, it must be managed distinctly. Discovered over a century ago by Arnold Pick1, it was only recently identified as a specific type of degenerative illness.

FTLD is comprised of three prototypical clinical syndromes: Frontotemporal dementia (FTD), Primary Progressive Aphasia (PPA), and semantic dementia (SD).3 PPA is a disorder of expressive language, which manifests itself as the laboured production of speech, speech containing phonological and grammatical errors, and difficulties in word retrieval. SD is characterized by a severe impairment in naming and word comprehension during fluent, effortless grammatical speech output, with relative preservation of the ability to repeat, read aloud and write. FTD, on the other hand, is considered to be the most common clinical manifestation of FTLD.2,3 This article will focus on FTD, and compare it with AD.

FTD affects men as frequently as it affects women.1 It has a predominantly early age of onset, and most individuals affected are between 50-60 years of age.