Facial responsiveness to odours in normal and pervasively developmentally disordered children

Area of Science:

• Neuroscience
• Psychology
• Developmental Disorders

Background:

• Pervasive developmental disorder (PDD) is characterized by social and communication deficits.
• Understanding facial responsiveness in PDD is crucial for assessing sensory processing and social interaction.
• Olfactory stimuli provide a unique modality to investigate emotional and facial responses.

Purpose of the Study:

• To compare facial responsiveness to odors of varying hedonic valence in children with PDD and neurotypical (N) children.
• To investigate the accuracy of facial response classification in PDD subjects.
• To explore potential deficits in the socialization of hedonic facial displays in PDD.

Main Methods:

• Covert videotaping of facial responses in 10 PDD and 10 N children exposed to odors.
• Analysis of facial movements using the Facial Action Coding System (FACS).
• Observer ratings of facial behavior to classify odor pleasantness.

Main Results:

• PDD and N subjects exhibited distinct facial action units in response to unpleasant odors.
• PDD subjects showed more muscular actions indicating negative experiences, while N subjects displayed more smiles.
• Facial responses to unpleasant odors were classified more accurately in PDD than in N subjects.

Conclusions:

• Children with PDD possess a functional ability to sense odor hedonics.
• A deficit in the socialization of hedonic facial displays is suggested in individuals with PDD.
• Facial coding systems and observer ratings reveal differences in emotional expression related to olfactory stimuli.