Abstract:

Autism spectrum disorder (ASD) is a kind of neurodevelopmental disorder that presents in childhood. Attentional disengagement is an essential part of the attentional orientation network. It refers to the process of disengaging attention from the original object to another one during an attention shift. In early childhood, the ability to engage and disengage attention is necessary for the development of social communication. Atypical patterns of disengagement may have adverse implications for emotional regulation, orienting, joint attention, and other abilities directly associated with socio-emotional functioning. The attentional disengagement suggests holds that early impairment of the attentional disengagement in ASD could substantially affect the development of the perception and cognitive capacity, which could then ultimately escalate into a number of impairments within the core clinical symptoms of ASD.
Many studies have shown that high-risk infants (high-risk by virtue of having an older sibling diagnosed with ASD) who are later diagnosed with ASD have impairments in attentional disengagement at an early age, and some researchers believe that attentional disengagement deficits are an early behavioral marker for the diagnosis of autism in the future. Therefore, investigating the developmental characteristics and cognitive neural mechanisms of attentional disengagement in ASD individuals has practical significance for exploring the etiology, early diagnosis, and intervention of ASD. However, studies using the gap-overlap paradigm resulted in controversial findings regarding the abnormal attentional disengagement ability in individuals with ASD. Longitudinal studies of early high-risk infants had shown that individuals with ASD exhibited difficulty in attentional disengagement before being diagnosed. The ability of attentional disengagement in infancy could predict the development of ASD later in life. The more difficult the attentional disengagement, the more likely the development of ASD. Studies of older children, adolescents, and adults with ASD had yielded mixed results. Studies found slower, faster, and no group differences in the latency of attentional disengagement in individuals with ASD compared to those in the control groups. These inconsistent results may indicate that the attentional disengagement hypothesis cannot fully explain the development of attentional disengagement in ASD. Impairments in attentional disengagement for individuals with ASD may not emerge in the first year of life and may not continue into adulthood.
This review summarizes the controversial research on the attentional disengagement of individuals with ASD in gap-overlap tasks and its relationship with the clinical symptoms of ASD. It is possible that the participants’ characteristics, the research methods, and the stimulus properties are the main factors affecting attentional disengagement. This neural mechanism may involve the oculomotor nervous system, the frontal lobe, the parietal lobe, the cerebellum, and the corpus callosum. Additionally, based on previous studies, this paper proposes several possible trajectories for the development of attentional disengagement in individuals with ASD, that enrich the theoretical research in ASD. Finally, the future research directions of attentional disengagement in ASD are prospected.
The evidence of inconsistent results in attentional disengagement in ASD individuals also underscores the importance of future research aimed at establishing whether there is an ASD-specific disengagement impairment. Future research should focus on research of brain mechanisms to map the trajectory of attentional disengagement in ASD over time. It is not only necessary to conduct a prospective longitudinal study on high-risk infants with ASD but also to consider the effects of participant characteristics, the heterogeneity of ASD, stimulus properties, and variability of measurement indexes and research methods on the results of attentional disengagement comprehensively, as well as further clarify its role in the early prediction and recognition of autism. Furthermore, other behavioral manifestations or early risk markers should be combined for comprehensive diagnosis and identification, so as to develop targeted early intervention strategies and programs for high-risk infants.

Key words: attentional disengagement, autism, gap-overlap paradigm, neural mechanisms