Phd in CLINICAL EXPERIMENTAL NEUROSCIENCE AND PSYCHIATRY

Thesis title: Spontaneous Imitation and Affective Modulation in Minimally Speaking Autistic Preschoolers

Background Autistic children present distinct imitation patterns compared to neurotypical children, with differences in frequency, accuracy, and the degree to which imitation is modulated by the demonstrator’s behavior. However, little is known about minimally speaking autistic children's imitative abilities. Objectives To investigate imitation abilities in minimally speaking autistic preschoolers compared to speaking autistic and neurotypical peers. Methods Participants were 79 preschoolers (age M=34.7 months, SD=11), including 32 speaking and 31 minimally speaking autistic children, and 16 neurotypical children. Minimally speaking status was operationalized as expressive language age equivalent scores in the Mullen Scales of Early Learning ≤ 14 months. Participants watched videorecorded stimuli displaying an unfamiliar demonstrator performing actions on objects under two conditions: 1) Playful, whereby the demonstrator showed positive affect during the demonstration; 2) Neutral, whereby his facial expression was neutral. After each video-demonstration, participants were provided with the same materials used in the video-demonstrations and encouraged to play, with no specific prompts to imitate. Participants’ eye movements were recorded with an eye-tracking system to measure their visual attention during the demonstration. Their spontaneous imitation (or lack of thereof) in response to the demonstration was coded to determine the frequency and accuracy of their imitation (see Table 1), and how these parameters were modulated by the condition. Two independent raters scored imitation accuracy, with high inter-rater reliability (>.98). Results A binary logistic regression focused on the frequency (presence or absence) of imitation, showed that minimally speaking autistic children were approximately 5 times less likely to imitate compared to speaking autistic participants across conditions [Neutral: (95% CI [1.58–15.50], p = .006); Playful: (95% CI [1.64-17.80], p = .006)], and approximately 4 times less likely than typical children, although this difference did not reach significance [Neutral condition: (95% CI [0.87-16.67], p = .08); Playful:(95% CI [0.85-15.84], p = .08)]. A repeated measure GLM fitted to examine differences in imitation accuracy showed a main effect of condition F(1,71)=4.45, p=.04, η²ₚ=.06) and main effect of group F(2,71)=4.49, p=.01, η²ₚ=.11), but no interaction between condition and group, indicating that while across groups actions were imitated more accurately in the playful condition, minimally speaking autistic children imitated less accurately than speaking autistic children across conditions (p=.03). Eye-tracking analyses revealed a main effect of group (F(2,75=6.96, p=.002, η²ₚ=.15) on duration of attention towards the demonstration, indicating lower attention in minimally speaking autistic children across conditions. Across groups, children who look longer at the demonstration had higher expressive language scores (p-values ranging from .003-.045 across conditions). Conclusions Rather than being atypical across all autistic participants, spontaneous imitation appeared to be distinctively impaired in minimally speaking children, who imitated less frequently and less accurately than their speaking autistic and neurotypical peers alike, and paid less attention to the demonstration. However, their imitative performance was modulated by the demonstrator’s affect, as observed in the other groups. These findings suggest that interventions for minimally speaking autistic children should capitalize on their responsivity to affective facial expressions and be tailored to increase attention and response to demonstrated actions.