The role of polysemy on metaphor comprehension processing: The example of Parkinson's disease

• The role of polysemy on metaphor comprehension was investigated.
• Non-polysemous metaphors are more difficult to process than polysemous metaphors.
• Polysemy has the same effect on metaphor comprehension in PD patients and controls.
• There are a polysemous and non-polysemous metaphor comprehension deficits in PD.
• Polysemy does not influence the metaphor comprehension deficit observed in PD.

Metaphoric language is used every day. The manner in which a metaphor is understood may depend on different factors such as polysemy (the property of a word to have multiple related meanings). Polysemy may have an impact on metaphor comprehension particularly in individuals with executive impairments such as patients with Parkinson's disease (PD). The goal of this study was to investigate the influence of polysemy on metaphor comprehension processing in PD and healthy matched controls. Twenty individuals with PD and twenty controls completed a metaphor comprehension task including metaphors build with a polysemous (MP) and non-polysemous word (MNP). Both groups made significantly more comprehension errors and took significantly longer to understand MNP than MP, suggesting that polysemy has the same effect on metaphor comprehension regardless of the group. Interestingly, a comprehension impairment was observed in the PD group for both types of metaphors, indicating that polysemy does not seem to influence the metaphor comprehension deficit in PD. Further investigations are needed to better understand this finding.