Comparing two Italian picture naming tasks: insights from an FDG PET study in Primary Progressive Aphasia
Picture naming constitutes one of the most effective
neuropsychological tools to evaluate language impairments. Despite its
apparent simplicity, impairments of various nature can be found in the
clinical population.
The study aims to provide critical considerations for selecting and using
picture naming tests in clinical practice for Primary Progressive
Aphasia (PPA). To achieve the goal, we focused on CaGi and SAND
Italian naming tests. Firstly, we examined the accuracy and the
qualitative errors profile in 52 PPA patients. We evaluated the capacity
of both tests to discriminate patients from healthy controls (HC), and
between PPA variants (semantic sv-PPA; non-fluent nfv-PPA;
logopenic lv-PPA). Secondly, we explored how different
psycholinguistic variables affected performance. Finally, we
investigated brain metabolism with FDG-PET in 6 Regions of Interest.
Behavioural results suggested that SAND and CaGi differed in terms of
accuracy and errors profile, suggesting that SAND is more difficult than
CaGi, as revealed by reduced accuracy. Both tests distinguished
between HC and PPA, nonetheless only SAND was able to discriminate
among variants. Imaging findings revealed a correlation between
hypometabolism in the left anterior fusiform gyrus, naming accuracy,
and semantic errors in both tests, as well as SAND anomic errors, in the
whole sample. Left temporal pole hypometabolism was associated to
accuracy in both tests, and semantic errors in CaGi. Again, accuracy
and semantic errors in CaGi correlated with hypometabolism in the left
posterior fusiform gyrus in the sv-PPA group.
To conclude, in absence of imaging data SAND may be better at
highlighting subtle distinctions between PPA variants, namely to be
suitable in diagnosis, whereas CaGi may be useful for a detailed
characterization on of the nature of the impairments, more suitable
7
possible rehabilitation settings. The theoretical and practical
implications of the empirical findings are discussed.
Keywords: Primary Progressive Aphasia, picture naming, semantic
errors, FDG-PET.
Picture naming constitutes one of the most effective
neuropsychological tools to evaluate language impairments. Despite its
apparent simplicity, impairments of various nature can be found in the
clinical population.
The study aims to provide critical considerations for selecting and using
picture naming tests in clinical practice for Primary Progressive
Aphasia (PPA). To achieve the goal, we focused on CaGi and SAND
Italian naming tests. Firstly, we examined the accuracy and the
qualitative errors profile in 52 PPA patients. We evaluated the capacity
of both tests to discriminate patients from healthy controls (HC), and
between PPA variants (semantic sv-PPA; non-fluent nfv-PPA;
logopenic lv-PPA). Secondly, we explored how different
psycholinguistic variables affected performance. Finally, we
investigated brain metabolism with FDG-PET in 6 Regions of Interest.
Behavioural results suggested that SAND and CaGi differed in terms of
accuracy and errors profile, suggesting that SAND is more difficult than
CaGi, as revealed by reduced accuracy. Both tests distinguished
between HC and PPA, nonetheless only SAND was able to discriminate
among variants. Imaging findings revealed a correlation between
hypometabolism in the left anterior fusiform gyrus, naming accuracy,
and semantic errors in both tests, as well as SAND anomic errors, in the
whole sample. Left temporal pole hypometabolism was associated to
accuracy in both tests, and semantic errors in CaGi. Again, accuracy
and semantic errors in CaGi correlated with hypometabolism in the left
posterior fusiform gyrus in the sv-PPA group.
To conclude, in absence of imaging data SAND may be better at
highlighting subtle distinctions between PPA variants, namely to be
suitable in diagnosis, whereas CaGi may be useful for a detailed
characterization on of the nature of the impairments, more suitable
7
possible rehabilitation settings. The theoretical and practical
implications of the empirical findings are discussed.
Keywords: Primary Progressive Aphasia, picture naming, semantic
errors, FDG-PET.