Smith Elizabeth, Zhang Shouling, Bennetto Loisa
Department of Clinical and Social Sciences in Psychology, University of Rochester, Rochester, NY USA.
Res Autism Spectr Disord. 2017 Jul;39:11-19. doi: 10.1016/j.rasd.2017.04.001. Epub 2017 Apr 15.
Individuals with Autism Spectrum Disorders (ASD) have been shown to have multisensory integration deficits, which may lead to problems perceiving complex, multisensory environments. For example, understanding audiovisual speech requires integration of visual information from the lips and face with auditory information from the voice, and audiovisual speech integration deficits can lead to impaired understanding and comprehension. While there is strong evidence for an audiovisual speech integration impairment in ASD, it is unclear whether this impairment is due to low level perceptual processes that affect all types of audiovisual integration or if it is specific to speech processing.
Here, we measure audiovisual integration of basic speech (i.e., consonant-vowel utterances) and object stimuli (i.e., a bouncing ball) in adolescents with ASD and well-matched controls. We calculate a temporal window of integration (TWI) using each individual's ability to identify which of two videos (one temporally aligned and one misaligned) matches auditory stimuli. The TWI measures tolerance for temporal asynchrony between the auditory and visual streams, and is an important feature of audiovisual perception.
While controls showed similar tolerance of asynchrony for the simple speech and object stimuli, individuals with ASD did not. Specifically, individuals with ASD showed less tolerance of asynchrony for speech stimuli compared to object stimuli. In individuals with ASD, decreased tolerance for asynchrony in speech stimuli was associated with higher ratings of autism symptom severity.
These results suggest that audiovisual perception in ASD may vary for speech and object stimuli beyond what can be accounted for by stimulus complexity.
自闭症谱系障碍（ASD）患者已被证明存在多感官整合缺陷，这可能导致他们在感知复杂的多感官环境时出现问题。例如，理解视听言语需要将来自嘴唇和面部的视觉信息与来自声音的听觉信息进行整合，而视听言语整合缺陷可能导致理解受损。虽然有强有力的证据表明ASD患者存在视听言语整合障碍，但尚不清楚这种障碍是由于影响所有类型视听整合的低水平感知过程，还是特定于言语处理。
在这里，我们测量了患有ASD的青少年和匹配良好的对照组对基本言语（即辅音-元音发音）和物体刺激（即一个弹跳球）的视听整合情况。我们使用每个人识别两个视频（一个时间对齐，一个未对齐）中哪一个与听觉刺激匹配的能力来计算整合的时间窗口（TWI）。TWI测量听觉和视觉流之间时间异步的容忍度，是视听感知的一个重要特征。
虽然对照组对简单言语和物体刺激表现出相似的异步容忍度，但患有ASD的个体却没有。具体而言，与物体刺激相比，患有ASD的个体对言语刺激的异步容忍度较低。在患有ASD的个体中，言语刺激异步容忍度的降低与自闭症症状严重程度的较高评分相关。
这些结果表明，ASD患者对言语和物体刺激的视听感知可能因刺激复杂性之外的因素而有所不同。
