Date Published: January 28, 2019
Publisher: Public Library of Science
Author(s): Fei Chen, Lan Wang, Gang Peng, Nan Yan, Xiaojie Pan, Simone Sulpizio.
The deficit in speech sound production in some children with autism spectrum disorder (ASD) adds to their communication barriers. The 3-D virtual environments have been implemented to improve their communication abilities. However, there were no previous studies on the use of a 3-D virtual pronunciation tutor designed specifically to train pronunciation for children with ASD. To fill this research gap, the current study developed and evaluated a 3-D virtual tutor which served as a multimodal and real-data-driven speech production tutor to present both places and manners of Mandarin articulation. Using an eye-tracking technique (RED 5 Eye Tracker), Experiment 1 objectively investigated children’s gauged attention distribution online while learning with our computer-assisted 3-D virtual tutor in comparison to a real human face (HF) tutor. Eye-tracking results indicated most participants showed more interests in the visual speech cues of the 3-D tutor, and paid some degree of absolute attention to the additional visual speech information of both articulatory movements and airflow changes. To further compare treatment outcomes, training performance was evaluated in Experiment 2 with the ASD learners divided into two groups, with one group learning from the HF tutor and the other from the 3-D tutor (HF group vs. 3-D group). Both groups showed improvement with the help of computer-based training in the post-intervention test based on the calculation of a 5-point Likert scale. However, the 3-D group showed much higher gains in producing Mandarin stop and affricate consonants, and apical vowels. We conclude that our 3-D virtual imitation intervention system provides an effective approach of audiovisual pronunciation training for children with ASD.
Given the high incidence of autism spectrum disorder (ASD), at close to 1% worldwide , there is an urgent need to improve our understanding of ASD and to refine our treatment strategies. Besides the social communication deficits and repetitive sensory-motor behaviors, speech and language disorders tend to be a hallmark of ASD. Among the communicative characteristics of children in the second and third year of life who are identified with ASD, delayed onset and development of the spoken language tends to be one of the key signs and symptoms. Approximately 10–25% of all children with ASD fail to develop speech to communicate with others . Due to the known deficits that characterize ASD in the theory of mind , researchers have identified that pragmatic skill is the most seriously impaired in terms of language deficits in ASD [4,5]. In contrast, less attention has been paid to the articulatory and phonological deficits among this population.
The main goal of our investigation was to compare the treatment efficacy of a HF tutor and our 3-D virtual pronunciation tutor for pronunciation intervention in low-functioning children with ASD. These two types of tutors (HF tutor and 3-D tutor) were widely used in various computer-assisted pronunciation training systems [33,58,60]. The results of the first eye-tracking study implied that, during the learning process, ASD learners showed more interests in the AOIs of 3-D virtual tutor and paid some degree of absolute attention to the additional visual speech cues of articulatory and airflow models in our 3-D virtual tutor. The learners’ visual attention to visual speech cues was important for language learning as the ‘noticing hypothesis’  indicates that noticing itself does not result in acquisition, but is an essential first step in acquiring a speech item. In experiment 2, a treatment outcome study was further conducted and showed that, compared with those learning from HF tutors, the 3-D group showed a much higher increase in scores while uttering Mandarin stops, affricates, and two Mandarin apical vowels (-i[ɿ], -i[ʅ]). Based on these findings, we could conclude that relative to the HF tutor, children with ASD benefited more from noticing the visual speech cues in our multimodal 3-D pronunciation tutor. Furthermore, the user experience was evaluated by conducting a short oral interview with parents or caregivers after pronunciation training, which included three aspects: enjoyment, motivation, and acceptability. Although the enjoyment level was medium with some degree of concerns about the uncommon internal articulators in daily life, most of the parents or caregivers showed a strong motivation and a high acceptability towards our computer-assisted 3-D virtual pronunciation tutor, and even wanted to make a copy of the 3-D videos. To conclude, the above quantitative and qualitative results showed the benefit and usability of the implementation of 3-D virtual tutor for the pronunciation training in children with ASD.
A subgroup of children with ASD, especially those with more severe global language impairment, may exhibit more severe speech sound production difficulties. Clinicians and SLPs should be aware that children with more severely impaired language and behavior, may exhibit more severe speech production difficulties. Recently, two studies [37,78] have emphasized the critical need for both researchers and clinicians to address pronunciation problems and to focus on speech sound behavior in individuals with ASD. However, available interventions that aim to improve pronunciation ability in children with ASD are extremely limited.