Are object naming capacities affected in Parkinson's Disease? Exploration of picture naming abilities and associated cognitive deficits

Background: The presence of naming difficulties in Parkinson's Disease (PD), especially object naming difficulties, as well as the associated cognitive difficulties, remains a controversial topic. Aims: This study assesses object naming capacities in PD patients and the cognitive impairment related to the patients,' word naming difficulties, whether linguistic, executive or associated to slower cognitive processing speed. Methods and Procedures: To that aim, 46 PD patients and 48 control participants were presented with a picture naming task of objects. Specific language difficulties were examined by analysing the naming errors, the effects of word frequency and length on naming performances, as well as the patients' semantic performances in semantic matching and synonym judgment tasks. The executive assessment consisted of working memory, inhibition, flexibility and updating tasks, and cognitive processing speed was explored through an odd/even judgment task. Outcomes and Results:The results show that PD patients have lower object naming scores. Regarding the associate cognitive impairment, the outcomes reveal that naming difficulties are related to updating difficulties and slower cognitive processing speed. Conclusions: This study confirms the presence of object naming difficulties in PD. Moreover, the relationships between naming difficulties and executive deficits as well as slower processing speed are in line with many studies that also indicate relationships between executive dysfunction or slower processing speed and language difficulties in PD, but for other tasks.