Frontotemporal dementias: Recent advances and current controversies

Abstract

Frontotemporal dementia (FTD) syndromes comprise a heterogeneous group of neurodegenerative conditions characterized by atrophy in the frontal and temporal lobes. Three main clinical variants are recognized: Behavioral variant (bv-FTD), Semantic dementia (SD), and Progressive nonfluent aphasia (PNFA). However, logopenic/phonological (LPA) variant has been recently described, showing a distinctive pattern of brain atrophy and often associated to Alzheimer′s disease pathology. The diagnosis of FTD is challenging, since there is clinical, pathological, and genetic overlap between the variants and other neurodegenerative diseases, such as motoneuron disease (MND) and corticobasal degeneration (CBD). In addition, patients with gene mutations (tau and progranulin) display an inconsistent clinical phenotype and the correspondence between the clinical variant and its pathology is unpredictable. New cognitive tests based on social cognition and emotional recognition together with advances in molecular pathology and genetics have contributed to an improved understanding. There is now a real possibility of accurate biomarkers for early diagnosis. The present review concentrates on new insights and debates in FTD.

Keywords

• Frontotemporal dementia
• progressive nonfluent aphasia
• semantic dementia
• taupathies
• TDP-43