Research Paper: The role of sensory processing in word learning in children at risk of autism By Tatjana Zeljic, MSc Ed. Neuroscience

Autism Spectrum Disorder It is characterized by impairments in communication and social skills, repetitive and obsessive interests and behaviours and atypical sensory processing in terms of hyper and/or hyposensitivity to certain stimuli (DSM-5, APA, 2013). ASD is normally diagnosed around 2 to 3 years of age and the diagnosis is based on behavioural signs and characteristics.

BASIS (British Autism Study of Infant Siblings) Network BASIS is a collaborative research network for the study of infants at-risk of autism. The aim is to identify early emerging symptoms and predictors of autism. It would lead to: -develop better understanding how characteristics of autism change in early years -develop better screening and diagnosis -develop early interventions that may improve some symptoms of autism -help families to better adopt to and nurture their children

Focus of the BASIS research Scientists, who study brain and behaviour in children, are investigating whether there are any differences in development of infants who have siblings with autism and those who do not. Face recognition (differentiation between faces making eye contact and faces looking away-6-10 months, no difference in brain response) Following eye gaze to an object (inability to follow eye gaze correlates to severity of autism diagnosed at 3 years) Difference in brain activity in response to social cues

Language Development and Word Learning According to a social pragmatic approach to language acquisition, attention following represents one of a number of social-cognitive behaviors that children use to understand the referential intentions of conversational partners (Tomasello, 2001). Children with autism spectrum disorder are less responsive to social cues, in particular to referential cues (Fletcher-Watson et al. 2009), and experimental studies have shown that they have difficulties using such cues for word learning (Baron- Cohen, Baldwin & Crowson, 1997).

Previous Research The aim of Preissler and Carey’s (2005) study was to examine whether social cues are necessary for mapping novel words to novel items. They conducted two experiments and found that in the first experiment, children with autism were not able to make inferences about a speaker’s referential intent whereas in the second experiment where it was not necessary to rely on these inferences, children with autism performed better then neurotypical children. Akechi et al (2011) found that children with autism perform better when there is an enhanced saliency of the target object and do not use the speakers gaze as a strategy in learning novel words as most typically developing children do.

Perceptual Sensory Processing One of the main characteristics of autism is atypical and in some features superior perceptual functioning. The large number of studies focused on the domain of visual search where it was found that the individuals with autism have shown a great advantage over neuro-typical individuals (O’Roirdon, 2000; Plaisted, O’Riordan and Baron-Cohen, 1998; O’Riordan, Plaisted and Baron-Cohen, 2001). Mottron and Burack (2001) developed the “Enhanced Perceptual Functioning” model which demonstrates the main difference in auditory and visual perception between individuals with autism and non-autistic population.

Language Processing Pasley and Heaton (2008) They have found that children with autism showed a superior ability to use perceptual information to process speech. Examining audio-visual speech integration with older children and adolescents it was found that individuals with autism show atypical audio-visual integration of speech (Smith and Benneto, 2007; Mongillo et al, 2008). Preissler (2008) found that in children with ASD word learning is solely based around sensory and perceptual association.

Eye Tacking Method One way of studying specific characteristic in children with autism and their siblings is using the eye-tracking method. More recently, Bedford et al. (2012) investigated the ability of three year old siblings of children with autism to follow speaker’s gaze to a labelled object and to word learning of a novel object. Their study indicated that siblings of children with autism are able to follow another person’s gaze.

Research question The present study aims to examine the difference in word learning between 24 month old siblings of children with autism and siblings of neurotypically developing children using an eye-tracking paradigm. This experiment which is based on associative ‘word-object’ learning and involves sensory integration of auditory and visual stimuli and consists of three word learning conditions including same object-same voice condition; same object- different voice and different object-different voice condition.

Methodology Participants were 114 children at risk for ASD, recruited through the British Study of Infant Siblings (BASIS: and 27 low risk children, recruited from a volunteer database at the Birkbeck Centre for Brain and Cognitive Development.

Word Learning Task First task was the ‘teaching-testing equivalent’ test trial in three conditions (Familiziration): same object-same voice (SOSVq); same object -different voice (SODVq) and different object different voice (DODVq). Two generalization test trials: same object-same voice (SOSVg) and same object-different voice (SODVg).

Example Kora Kora Kora Kora

Where is the kora?

Data Extraction and Analysis Two sets of word learning data were extracted and analysed including behavioural, pointing data and looking time data. Behavioural, pointing data that was manually documented was recorded and correct and incorrect responses were identified. Next, the scores for two words for each test trial were averaged for each participant. Tobii Studio software was used for eye-gaze data recording and extraction.

Results Two sets of data, proportion of looking data and proportion of correct pointing was analysed using mixed factorial ANOVA.

Figure 1 shows proportion of looking time in three conditions: SOSV, SODV and DODV for test trials where there is a teaching-testing equivalent present in terms of the object and the voice. The graph shows that control group outperformed At-Risk group in all three conditions and similarly both groups performed better in SOSV condition and worst in SODV condition.

Figure 2 shows looking time in two conditions for two looking time generalization trials: SOSV and SODV and it shows that two groups spent similar amount of looking time in both conditions.

Figure 3 shows proportionate correct pointing performance in tasks where there is ‘teaching-testing equivalent’ in terms of objects and voices for three conditions: SOSVq task, SODVq task and DODVq task for Control and At-Risk groups. It demonstrates that control group has performed better in all three conditions than At-risk group. It is also evident that both group performed better in SOSV and DODV conditions than in SODV condition. Control group also performed better in DODV condition than in other two conditions.

Figure 4 shows proportionate pointing performance in SOSV generalization task test trials and SODV generalization task test trials for Control and At-risk groups. It reveals that Control group performed better in SOSV generalization condition whereas At-Risk group has performed better in SODV generalization condition.

Findings At-risk children spent shorter time looking at the object than the control group. (no group effect) Children At-risk group needed shorter time in order to identify the referred object. This is important findings as it demonstrates that At-risk children are able to identify objects quicker than their neurotypically developing children which is in line with previous studies that examined visual search in children with autism (Morton et al, 2006; Kaldy et al., 2011). (Superior visual perception)

Findings At-Risk children performed better in DODV ‘teaching-testing equivalent’ stimuli input condition than in SODV ‘teaching- testing equivalent stimuli input’ condition in terms of both, looking times and pointing tasks, although the level of visual and auditory variability is higher in DODV than in SODV condition. One possible explanation is the children’s enhanced sensitivity to frequency changes in input. This line of reasoning was supported by Kujala et al. (2007) who found that in speech perception relevant to word learning children with autism are sensitive to frequency changes in input and show enhanced neural responses.

Findings There is a possibility that it is the voice itself in terms of frequency and pitch that is essential for children make a successful association between the object and the word as argued by Bonnel et al. (2003). This position is also supported by the evidence of advanced musical abilities in children with autism, especially in the domain of musical pitch processing (Heaton, 2003).

Conclusion The current results reveal that for siblings of children with autism word learning is affected by the variability of auditory and visual input. This findings is important as it sheds the light on enhanced perceptual processing atypicalities associated with autism and adds to the body of work which suggests that not only children with autism but also their siblings possess enhanced sensory processing abilities.