The logopenic variant of
primary progressive aphasia is a syndrome with neuropsychological and linguistic specificities, including phonological loop impairment for which diagnosis is currently mainly based on the exclusion of the two other variants, semantic and nonfluent/agrammatic
primary progressive aphasia. The syndrome may be underdiagnosed due (1) to mild language difficulties during the early stages of the disease or (2) to being mistaken for
mild cognitive impairment or
Alzheimer's disease when the evaluation of episodic memory is based on verbal material and (3) finally, it is not uncommon that the disorders are attributed to psychiatric co-morbidities such as, for example, anxiety. Moreover, compared to other variants of
primary progressive aphasia, brain abnormalities are different. The left temporoparietal junction is initially affected. Neuropathology and
biomarkers (cerebrospinal fluid, molecular
amyloid nuclear imaging) frequently reveal
Alzheimer's disease. Consequently this variant of
primary progressive aphasia does not fall under the traditional concept of
frontotemporal lobar degeneration. These distinctive features highlight the utility of correct diagnosis, classification, and use of
biomarkers to show the neuropathological processes underlying logopenic
primary progressive aphasia. The logopenic variant of
primary progressive aphasia is a specific form of
Alzheimer's disease frequently presenting a rapid decline; specific linguistic
therapies are needed. Further investigation of this syndrome is needed to refine screening, improve diagnostic criteria and better understand the epidemiology and the
biological mechanisms involved.