Emotion Processing in Autism Spectrum Disorder Ruth Clare Margaret Philip PhD Thesis 2009 Division of Psychiatry University of Edinburgh Emotion Processing in Autism Spectrum Disorder 2 Emotion Processing in Autism Spectrum Disorder Table of contents Acknowledgements....................................................................................................................................... 7 Declaration.................................................................................................................................................... 9 Publications................................................................................................................................................. 11 Abstract....................................................................................................................................................... 13 Chapter 1 - An Introduction to Autistic Spectrum Disorder.................................................................. 15 1.1 Introduction ...................................................................................................................................... 16 1.2 Historical background of autism...................................................................................................... 16 1.3 Clinical definition of autism............................................................................................................. 19 1.3.1 Impairments in language ........................................................................................................... 20 1.3.2 Impairments in social interaction .............................................................................................. 20 1.3.3 Restricted and repetitive behaviour ........................................................................................... 21 1.4 Autism as a neurodevelopmental disorder ....................................................................................... 21 1.4.1 Genetics ..................................................................................................................................... 21 1.4.2 Brain structure........................................................................................................................... 24 1.4.3 Functional neuroanatomy.......................................................................................................... 25 1.5 Psychological theories of autism ...................................................................................................... 26 1.5.1 Executive Dysfunction Theory.................................................................................................... 26 1.5.2 Weak Central Coherence ........................................................................................................... 28 1.5.3 Theories of social impairment.................................................................................................... 31 1.5.4 Emotion processing.................................................................................................................... 33 1.5.4.1 Face emotion processing .................................................................................................... 33 1.5.4.2 Processing emotion from body movement ......................................................................... 34 1.5.4.3 Emotion in the auditory modality....................................................................................... 34 1.6 Conclusions....................................................................................................................................... 36 Chapter 2 - A Systematic Review of the Investigation of ASD with Functional Magnetic Resonance Imaging........................................................................................................................................................ 37 2.1 Introduction ...................................................................................................................................... 38 2.1.1 fMRI methodology...................................................................................................................... 38 2.1.2 Limitations of the method........................................................................................................... 39 2.1.3 Application to ASD .................................................................................................................... 41 2.2 Methods............................................................................................................................................. 41 2.2.1 Literature search methods ......................................................................................................... 41 2.2.2 Inclusion criteria........................................................................................................................ 42 2.2.3 Data extraction .......................................................................................................................... 42 2.3 Results ............................................................................................................................................... 42 2.3.1 Included papers.......................................................................................................................... 42 2.3.2 ASD participant demographics.................................................................................................. 43 2.3.3 Summaries of fMRI findings....................................................................................................... 44 2.3.3.1 Perceptual processing and executive function tasks........................................................... 44 2.3.3.2 Face processing .................................................................................................................. 60 2.3.3.3 Emotional face processing.................................................................................................. 64 2.3.3.4 Motion in relation to social stimuli .................................................................................... 67 2.3.3.5 Eye gaze ............................................................................................................................. 68 3 Emotion Processing in Autism Spectrum Disorder 2.3.3.6 Social cognition.................................................................................................................. 69 2.3.3.7 Imitation ............................................................................................................................. 72 2.4 Discussion ......................................................................................................................................... 73 2.4.1 Limitation of literature review methods..................................................................................... 73 2.4.2 ASD study participants............................................................................................................... 74 2.4.3 The influence of specific task demands ...................................................................................... 75 2.4.4 Are there differential social deficits?......................................................................................... 75 2.4.5 Is it a modulation problem?....................................................................................................... 77 2.4.6 A Region Of Interest approach .................................................................................................. 78 2.5 Conclusion ........................................................................................................................................ 78 2.5.1 Conclusions drawn from the review........................................................................................... 78 2.5.2 Implications for future studies ................................................................................................... 79 Chapter 3 - Behavioural Investigation of Emotion Processing in ASD.................................................. 81 3.1 Introduction ...................................................................................................................................... 82 3.2 Methods............................................................................................................................................. 83 3.2.1 Recruitment of ASD participants ............................................................................................... 83 3.2.2 Participant details...................................................................................................................... 83 3.2.3 Test Procedures ......................................................................................................................... 84 3.2.3.1 Diagnostic measures of ASD ............................................................................................. 84 3.2.3.2 Background measures of cognitive ability ......................................................................... 84 3.2.3.3 Emotion recognition........................................................................................................... 85 a) Face tasks .............................................................................................................................. 85 b) Body movement task............................................................................................................