Use of graphical markers for the differential diagnosis of primary progressive aphasia subtypes

Abstract

AbstractBackgroundPrimary Progressive Aphasia (PPA) brings together a group of neurodegenerative pathologies whose principal characteristic is to start with a progressive language disorder. Three main PPA subtypes were established, depending on the affected brain regions and the type of language disorder: the logopenic subtype (lvPPA), the non‐fluent/agrammatic subtype (nfavPPA) and the semantic subtype (svPPA) (Gorno‐Tempini et al., 2011). PPA diagnosis is often delayed in non‐specialised clinical settings. With the development of technologies, new diagnostic tools can be used, such as writing on a touch pad (Plonka et al., 2020). We have already highlighted differences between patients with typical Alzheimer's Disease (AD) and healthy controls (Gros et al., 2019), but the kinematic writing parameters are still understudied in the differential diagnosis of PPA subtypes.Method29 subjects with Primary Progressive Aphasia (lvPPA N= 18; nfavPPA N=6; svPPA N=5) were included in this study. They performed ten graphical markers tasks (2 non‐cognitive and non‐linguistic tasks, 4 cognitive and non‐linguistic tasks and 4 linguistic tasks) on an I‐Pad® tablet. Different writing parameters were extracted: writing pressure, velocity, jerk and stroke.ResultPreliminary results revealed a main effect of diagnosis in linguistic tasks on average velocity (p= 0,041) and on average stroke (p= 0,029). The two‐by‐two comparison of different variants of PPA also showed significative differences: 1) lvPPA vs nfavPPA: significant differences in the average velocity, jerk and stroke were found, with lvPPA participants showing a higher velocity (p= 0,037), jerk (p= 0,046) and stroke (p= 0,014) than nfavPPA participants in linguistic tasks. 2) lvPPA vs svPPA: significant difference in velocity was found in linguistic task (p=0,037). 3) nfavPPA vs svPPA: significant difference in maximum pressure was found in linguistic task (p= 0,044), with nfavPPA participants showing a lower maximum pressure than svPPA participants.ConclusionThese preliminary results suggest that the use of graphical markers can be helpful in the differential diagnosis of PPA subtypes. A longitudinal study is ongoing to collect a bigger and more balanced PPA sample by including these markers within an already existing screening test battery.