Atypical processing of prosodic changes in natural speech stimuli in school-age children with Asperger syndrome Riikka Lindström, PhD student Cognitive Brain Research Unit University of Helsinki 31.8.2012 1
Autism spectrum disorders Neurodevelopmental disorders characterized by: deficient social and communication skills repetitive patterns of behavior Main diagnostic groups: Childhood autism and Asperger syndrome (AS) Individuals with AS have normal development of formal speech and normal verbal intelligence 75% individuals diagnosed with childhood autism are also diagnosed with intellectual disability 31.8.2012 2
Language abnormalities in AS Impaired semantics and pragmatics Problems with reading the mind in the voice : Rutherford et al. (2002) Abnormal prosody common feature: monotonic speech pitch / volume control deficits deficits in vocal quality inappropriate use of stress Laugh one s head off 31.8.2012 3
Autism research with EEG Electroencephalography (EEG) = measuring the electrical activity of the brain from the surface of the scalp Non-invasive High temporal resolution Event-related potentials (ERPs) reflect neural activity related to sensory or cognitive events Recordings can be done even in absence of participants attention and task performance 31.8.2012 4
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Mismatch negativity MMN) Reflects automatic, pre-conscious detection of violations of auditory regularities Elicited by any discriminable change in auditory flow Can be elicited in the absence of the participants attention Large MMN amplitude = accurate auditory discrimination Small MMN amplitude = poor discrimination accuracy Used with many clinical groups (e.g. coma, dyslexia, autism) 31.8.2012 6
P3a Reflects further attentive discrimination of stimulus deviation Diminished P3a amplitude: abnormal attention switch Enhanced P3a amplitude: distractibility Here will be a picture of MMN and P3a 31.8.2012 7
Abnormal cortical speech-sound processing in children with AS Impaired low level speech-sound feature encoding (Jansson- Verkasalo et al., 2003; Lepistö et al., 2006; Kujala et al., 2010) Impaired duration, vowel and consonant change detection (Jansson-Verkasalo et al., 2003; Lepistö et al. 2006; Kujala et al. 2010) Impaired pitch discrimination in Kujala et al. (2010) but hypersensitive pitch change detection in Lepistö et al. (2006) Hypersensitive reactions to the intensity changes (Kujala et al., 2010) Less efficient auditory stream segregation ability (Lepistö et al., 2009) 31.8.2012 8
Processing of prosodic changes in natural speech in children with AS Subjects: 10 healthy children and 13 children with AS (mean age 10 years). Data collection continues Measurements: non-attentive ERP recordings (children were watching a silent movie) and behavioural discrimination test Stimuli: a Finnish word Saara uttered by a female speaker with four different emotional connotations. The stimuli were previously used by Kujala et al. (2005) and developed by Leinonen et al. (1997). 31.8.2012 9
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Preliminary behavioural results No significant group differences were found for the hit rates or reaction times However, the majority of children with AS tended to show prolonged reaction times for the deviant stimuli. 31.8.2012 12
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Preliminary ERP results Children with AS showed atypically large MMN amplitudes for the sad prosodic deviant, indicating hyperactive neural responsiveness for prosodic changes No group differences were found for the amplitude of the positive deflection Korpilahti et al. (2007) showed enhanced MMNs to commanding prosodic change Kujala et al. (2005) showed diminished MMN amplitudes to the same prosodic changes in adults with AS. In future studies our aim is to further explore, which specific prosodic features are processed atypically in children with AS 31.8.2012 14
References Lepistö, T., Silokallio, S., Nieminen-von Wendt, T., Alku, P., Näätänen, R. & Kujala, T. (2006). Auditory perception and attention as reflected by the brain event related potentials in children with Asperger syndrome. Clin Neurophysiol, 117, 2162-2171. Lepistö, T., Kuitunen, A., Sussman, E., Saalasti, S., Jansson-Verkasalo, E., Nieminen-von Went, T. & Kujala, S. (2009). Auditory stream segregation in children with Asperger syndrome. Biol Psychol, 82, 301-307. Korpilahti, P., Jansson-Verkasalo, E., Mattila, M.L., Kuusikko, S., Suominen, K., Rytky, S., Pauls, D. & Moilanen, I. (2007). Processing of Affective Speech Prosody is Impaired in Asperger Syndrome. J Autism Dev Disord, 37, 1539-1549. Jansson-Verkasalo, E., Ceponiené, R., Kielinen, M., Suominen, K., Jäntti, V., Linna, SL., et al. (2003). Deficient auditory processing in children with Asperger syndrome, as indexed by eventrelated potentials. Neurosci Lett, 338, 197 200. Kujala, T., Lepistö, T., Nieminen-von Wendt, T., Näätänen, P., Näätänen, R. (2005). Neurophysiological evidence for cortical discrimination impairment of prosody in Asperger syndrome. Neurosci Lett, 383, 260-265. Kujala, T., Kuuluvainen, S., Saalasti, S., Jansson-Verkasalo, E., von Wendt, L. & Lepistö, T. (2010). Speech-sound discrimination in children with Asperger syndrome as determined with the multi-feature mismatch paradigm. Clin Neurophysiol, 121, 1410-1419. 31.8.2012 15
Thank you! 31.8.2012 16