ComuFaces: The perception of communicative faces by infants with Prader-Willi syndrome (year 2)

Neuropsychological studies have detailed several cognitive deficits in Prader-Willi Syndrome (PWS), among which the observation of altered social interactions, with notable difficulty in interpreting and responding to social information. The integration of the information from the face and the voice is important for our social communication as they are essential for our understanding of the social world and to interact with it. Indeed, faces and voices provide observers rich and complex information about the identity (gender, age, etc), the socio-emotional state (eye-gaze and prosody) and the linguistic message (auditory speech sounds/mouth movements) of our social partners. Our hypothesis is that PWS patients present deficit in processing these important social informations. In complement to our recent observation showing that PWS are unable to discriminate a human voice from environmental sounds, we are proposing to study how PWS are processing human faces. The aim of this research project is to understand, first, how infants with Prader-Willi Syndrome perceive communicative faces from their first months of life. We hypothesize that the general lack of alertness observed at birth might prevent infants with PWS to benefit from communicative faces as much as normal-developing babies. Later on in their life, these early impairments could contribute to their immature social and emotional behaviors. Indeed we will evaluate infants and young adult PWS patients using natural images and videos with a specific analysis of the oculomotor behavior using eye-tracking device. This project will allow us to characterize these abilities and then, more importantly, to develop adapted rehabilitation methods, intervening since the first month of life, to stem the development of further social and cognitive impairments later on. Crucially, this study could not only improve care but could also directly impact the social life of people with Prader-Willi Syndrome.

This project was funded in partnership with FPWR-France

Research Outcomes: Public Summary

With our general and comprehensive approach to social processing in the PWS, we have provided new insights on social deficit in this syndrome. We reported a general deficit in face and voice discrimination with a deficit much more pronounced for faces and emotion processing. The atypical face exploration, and the implication of the contextual social content in dynamic sequences can be similar to conclusions proposed in ASD. We have extended our analysis to cognitive mechanism and revealed that patients with PWS suffer to a global alteration in decision making mechanisms. Indeed, such alteration can explain the deficit in explicit tasks as in implicit tasks we have not observed a specific alteration of patients to discriminate face or voice attributes.
An important point is that our results strongly suggest that the DEL and UPD populations strongly differ in their deficit to process social information such as faces and voices, with UPD patients relatively more impaired than DEL patients. The main difference is on the oculomotor behavior during face exploration, as UPD patients, similarly to ASD patients, ignore the eye regions of a face which is supposed to carry important information of emotion and intention.