Introduction :
First cause of dementia, Alzheimer’s disease (AD) is a neurodegenerative pathology that causes progressive loss of neurons, first located in medial temporal lobe and then extent to other areas of the brain, creating an impairment in cognitive functions such as memory, language, judgement etc.
Recently, social cognition assessment (especially theory of mind) in neurodegenerative diseases become an interesting topic for researchers. Indeed, deficit in theory of mind (ToM) in Alzheimer’s disease can contribute to inappropriate social behaviour we can observe in patients. Moreover, patients who suffers from AD also have deficits in pragmatic abilities which can hinder their communication with other people. As an example, non-literal language such as metaphors or sarcasm are forms of language which are use in everyday life. However, their comprehension can be altered in patients and interfere with socials interactions. Some research found a link between theory of mind and pragmatic, especially in non-literal language comprehension.
Our work’s goal is to investigate about cognitive theory of mind abilities and also non-literal language comprehension (metaphors and sarcasm) in Alzheimer’s disease. We’ll also try to find a link between these two functions.
Hypothesis :
- We expect to find a difference between AD patients and healthy elderly people in theory of mind abilities.
- We also postulated that AD patients will be impaired in non-literal language comprehension.
- More specifically, some authors underlined that sarcasm comprehension requires higher cognitive resources than comprehension of metaphors. Then, we hypothesized that performance on sarcasm comprehension task will be more difficult than metaphor comprehension task for both of our groups.
- Finally, we postulated the existence of a correlation between theory of mind and pragmatics abilities in AD patients.
Methods :
In this study, we compared 10 moderate AD patients with 10 healthy subjects. Both groups were matched in age and sociocultural level.
As we use verbal tasks, we choose to ensure that all the participants have preserved verbal comprehension skills, so we propose to all of them a writing comprehension tasks from MT-86 battery (Nespoulous, 1992).
In order to assess theory of mind abilities, we used the TOM-15 (Desganges et al., 2012). This test is based on false-belief tasks. Each story is presented as a cartoon with 3 images and a text legend that explain the situation. All stories follows the same kind of scenario: In the first part, a situation is described where one of the character is learning a new information. Then, the situation changes but the character is not aware of this change. In the last part, the character’s belief is now incorrect because he has not all the element of the real situation. We ask participants to answer about the character’s false-belief and to choose between two propositions.
We choose an experimental task to assess comprehension of non-literal language. We created 10 very shorts stories including 5 stories with a metaphoric statement and 5 stories with a sarcasm statement. Each stories shows two friends having a conversation. One of them say a last sentence to his/her friend, which is either a metaphor or a sarcastic statement. We asked participants to explain the real signification of this last sentence.
Results:
Our results didn’t show a significant difference but we can see that AD patients had inferior performances than control group in TOM-15 task. Regarding non-literal comprehension task, our hypothesis is confirmed because patients are impaired in pragmatic abilities compared to healthy elderly people.
Moreover, we find a significant difference between metaphor comprehension and sarcasm. Indeed, comprehension of sarcasm is more impaired that comprehension of metaphor, but only in AD patients.
Unfortunately, we were not able to find any correlation between theory of mind and pragmatic abilities in this study.
Conclusion:
Although all our hypothesis were not completely confirmed, it remains important to keep on exploring the link between theory and mind and pragmatics abilities in order to provide a better understanding about problematic behavioural or social interaction in AD.
Key words :Alzheimer’s disease, theory of mind, pragmatic, non-literal language, metaphors, sarcasm, social cognition, communication.
Words I have learned : statement : une assertion ; to ensure : s’assurer de ;
References :
Desgranges, B., Laisney, M., Bon, L., Duval, C., Mondou, A., Bejanin, A., … Eustache, F. (2012). TOM-15 : Une épreuve de fausses croyances pour évaluer la théorie de l’esprit cognitive. Revue de Neuropsychologie, 4(3), 216‑220.
Barbara DANIEL, M2 PPCECC