NEW PUBLISHED ARTICLE
Utility of the Addenbrooke’s Cognitive Examination-III online calculator to differentiate the primary progressive aphasia variants
David Foxe†, Anne Hu†, Sau Chi Cheung, Rebekah M. Ahmed, Nicholas J. Cordato, Emma Devenney, Yun Tae Hwang, Glenda M. Halliday, Nicole Mueller, Cristian E. Leyton, John R. Hodges, James R. Burrell, Muireann Irish, Olivier Piguet
Brain Communications https://doi.org/10.1093/braincomms/fcac161 Abstract video: https://youtu.be/RRAMxKJ6A4E
† These authors contributed equally to the work.
What the study is about
Primary progressive aphasias (PPA) are rare younger-onset dementias that primarily affect speech and language functions. Recent findings suggest that the three variants of PPA (logopenic: lv-PPA; non-fluent: nfv-PPA; semantic variant: sv-PPA) can be distinguished based on their distinct profiles on the subdomain scores of a widely used general cognitive screening test, the Addenbrooke’s Cognitive Examination-III (ACE-III) (Foxe et al. 2021; Leyton et al. 2013). In this study, we investigated the utility of the ACE-III to differentiate the PPA variants based on their item-by-item performance profiles on this test. From these results, we created an interactive ACE-III PPA online calculator which predicts the variant based on a patient’s unique ACE-III item-by-item profile.
What we did
We conducted multinomial regression analyses to establish performance profiles among groups, and R Shiny from RStudio was used to create the interactive ACE-III PPA diagnostic calculator. To verify its accuracy, probability values of the regression model were derived based on a 5-fold cross validation of cases. The calculator’s accuracy was then verified in an independent sample of PPA patients who had completed the ACE-Revised (ACE-R: an older version of this test) and had in vivo amyloid-PET imaging and/or brain autopsy pathological confirmation.
What we found
Our ACE-III PPA diagnostic calculator demonstrates sound accuracy in differentiating the variants based on an item-by-item ACE-III profile. The calculator is freely for clinicians and is suitable for most clinical settings http://shiny.maths.usyd.edu.au/PPA_diagnostic_calc/