Clinical Research, Observation, Diagnostic Tools

Investigations of bodily expressions will enrich basic clinical research and lead to the development of new observational and diagnostic tools. Many studies of emotional communication disorders have reported deficits in face recognition in clinical populations as well as in patients with psychiatric disorders. These include autism spectrum subjects, people with schizophrenia and individuals with mood disorders like depression and high anxiety or social anxiety. Lets briefly consider the research on people with autism. Autism spectrum disorder (ASD) is usually defined by mild-to-severe impairments in communication and reciprocal social interaction and by repetitive and stereotyped behaviors.

To date, research on emotional and social communication disorders has focused primarily on impairments in the neurofunctional processes associated with viewing facial expressions. In view of reports that patients with ASD may actually systematically avoid attending to the face, investigations of other channels of communication look particularly needed and promising. Two studies were recently performed on bodily expression processing—one using still images (Hadjikhani et al., 2009) and another video clips (Grezes et al., 2009). The main finding of the first study (using still bodies) is that brain activation patterns in individuals with ASD show no evidence of differentiation between bodily expressions of fear and bodies engaged in neutral actions. This finding suggests an abnormality in the brain areas that are normally engaged in the perception of bodily expressed emotions and is consistent with recent behavioral findings of Hubert et al. (2007), who reported normal perception of point-light displays of neutral actions in ASD but abnormal perception of emotions.

In the study using video clips of neutral- and fear-expressing whole-body actions, normal perception of dynamic actions in ASD was also observed. Yet there were clear anomalies linked to a failure to grasp the emotional dimension of the actions. Brain activity was measured using fMRI during perception of fearful or neutral actions, and the results suggested that, whereas similar activation of brain regions known to play a role in action perception was revealed in both autistics and controls, ASD subjects failed to activate the AMG, inferior frontal gyrus, and premotor cortex when viewing gestures expressing fear. The results support the notion that dysfunctions in this network may contribute significantly to the characteristic communicative impairments present in autism. It was observed that ASD subjects failed to engage cerebral regions involved in grasping the emotional meaning of the actions they view. The suggestion was made that this deficit might reflect an important failure of the mechanisms that control normal behavioral responses to emotional signals. The ensuing deficiency in the appraisal of emotional cues could lead to the inappropriate behavioral responses and social difficulties that are characteristic of this population. This suggestion takes us well beyond the conclusions reached in studies about communication deficits using only facial expressions. In fact, it now allows us to generate specific hypotheses about the social interactive impairments that are so clearly present in many ASD individuals and that clearly involve much more than an unwillingness to attend to the face.

 
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