AUTHOR=Isella Valeria , Licciardo Daniele , Ferri Francesca , Crivellaro Cinzia , Morzenti Sabrina , Appollonio Ildebrando , Ferrarese Carlo 

TITLE=Reduced phonemic fluency in progressive supranuclear palsy is due to dysfunction of dominant BA6

JOURNAL=Frontiers in Aging Neuroscience

VOLUME=Volume 14 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/aging-neuroscience/articles/10.3389/fnagi.2022.969875

DOI=10.3389/fnagi.2022.969875

ISSN=1663-4365

ABSTRACT=Background: Reduced phonemic fluency is extremely frequent in Progressive Supranuclear Palsy (PSP), but its neural correlate is yet to be defined. 
Objective: We explored the hypothesis that poor fluency in PSP might be due to neurodegeneration within a dominant frontal circuit known to be involved in speech fluency, including the opercular area, the superior frontal cortex (BA6), and the frontal aslant tract connecting these two regions. 
Methods: We correlated performance on a letter fluency task (F, A, S, 60 sec for each letter) with brain metabolism as measured with Fluoro-deoxy-glucose Positron Emission Tomography, using Statistical Parametric Mapping, in 31 patients with PSP.
Results: Reduced letter fluency was associated with significant hypometabolism at the level of left BA6. 
Conclusion: Our finding is the first evidence that in PSP, as in other neurogical disorders, poor self-initiated, effortful verbal retrieval appears to be linked to dysfunction of the dominant opercular-aslant-BA6 circuit.