A growing number of research groups are now including older minimally verbal individuals with autism spectrum disorder in their studies to encompass the full range of heterogeneity in the population. There are numerous barriers that prevent researchers from collecting high-quality data from these individuals, in part because of the challenging behaviors with which they present alongside their very limited means for communication. In this article, we summarize the practices that we have developed, based on applied behavioral analysis techniques, and have used in our ongoing research on behavioral, eye-tracking, and electrophysiological studies of minimally verbal children and adolescents with autism spectrum disorder. Our goal is to provide the field with useful guidelines that will promote the inclusion of the entire spectrum of individuals with autism spectrum disorder in future research investigations.

The intricate relationship between multisensory integration and attention has been extensively researched in the multisensory field; however, the necessity of attention for the binding of multisensory stimuli remains contested. In the current study, we investigated whether diverting attention from well-known multisensory tasks would disrupt integration and whether the complexity of the stimulus and task modulated this interaction. A secondary objective of this study was to investigate individual differences in the interaction of attention and multisensory integration. Participants completed a simple audiovisual speeded detection task and McGurk task under various perceptual load conditions: no load (multisensory task while visual distractors present), low load (multisensory task while detecting the presence of a yellow letter in the visual distractors), and high load (multisensory task while detecting the presence of a number in the visual distractors). Consistent with prior studies, we found that increased perceptual load led to decreased reports of the McGurk illusion, thus confirming the necessity of attention for the integration of speech stimuli. Although increased perceptual load led to longer response times for all stimuli in the speeded detection task, participants responded faster on multisensory trials than unisensory trials. However, the increase in multisensory response times violated the race model for no and low perceptual load conditions only. Additionally, a geometric measure of Miller’s inequality showed a decrease in multisensory integration for the speeded detection task with increasing perceptual load. Surprisingly, we found diverging changes in multisensory integration with increasing load for participants who did not show integration for the no load condition: no changes in integration for the McGurk task with increasing load but increases in integration for the detection task. The results of this study indicate that attention plays a crucial role in multisensory integration for both highly complex and simple multisensory tasks and that attention may interact differently with multisensory processing in individuals who do not strongly integrate multisensory information.

Despite many studies documenting the prevalence of various co-occurring psychiatric symptoms in children and adults with ASD, less is known about how these symptoms relate to subtypes defined by particular phenotypic features within the ASD population. We examined the severity and prevalence of comorbid symptoms of psychopathology, emotion dysregulation, and maladaptive behaviors, as well as adaptive functioning, in a group of 65 minimally verbal children ( n = 33) and adolescents ( n = 32) with ASD. On the Child and Adolescent Symptom Inventory (CASI-5), for all the symptom classifications except oppositional defiant disorder and conduct disorder, more participants in our sample showed elevated or clinically concerning severity scores relative to the general population. On the Emotion Dysregulation Inventory (EDI) , the mean scores for Reactivity and Dysphoria factors in our sample were lower than in the autism calibration sample, which included a large number of inpatient youth with ASD. Overall, few differences were found between the children and adolescents within this severely impaired group of ASD individuals based on clinical cutoff scores on the CASI-5 and EDI factor scores. Psychiatric comorbidities and emotion dysregulation measures were not correlated with autism symptom severity or with measures of adaptive functioning, and were largely unrelated to IQ in our sample. The number of clinically significant psychiatric symptoms on the CASI-5 emerged as the main predictor of maladaptive behaviors. Findings suggest a wide range of co-occurring psychopathology and high degree of maladaptive behavior among minimally verbal children and adolescents with ASD, which are not directly attributable to autism symptom severity, intellectual disability or limitations in adaptive functioning.

Numerous studies have investigated the predictors of language in pre-verbal toddlers and verbally fluent children with autism spectrum disorder (ASD). The present study investigated the concurrent relations among expressive language and a set of empirically-selected social communication variables-joint attention, imitation, and play-in a unique sample of 37 minimally verbal (MV) children and adolescents with ASD. Results revealed that imitation and play were significantly correlated with expressive language, even when controlling for non-verbal IQ, but joint attention was not. Imitation was the only predictor variable to reach significance within the regression model. Findings demonstrate that predictors of expressive language vary for subpopulations of the autism spectrum, and have broader implications for intervention design for older, MV individuals with ASD.

Attending preferentially to social information in the environment is important in developing socio-communicative skills and language. Research using eye tracking to explore how individuals with autism spectrum disorder deploy visual attention has increased exponentially in the past decade; however, studies have typically not included minimally verbal participants. In this study, we compared 37 minimally verbal children and adolescents with autism spectrum disorder with 34 age-matched verbally fluent individuals with autism spectrum disorder in how they viewed a brief video in which a young woman, surrounded by interesting objects, engages the viewer, and later reacts with expected or unexpected gaze-shifts toward the objects. While both groups spent comparable amounts of time looking at different parts of the scene and looked longer at the person than at the objects, the minimally verbal autism spectrum disorder group spent significantly less time looking at the person’s face during the episodes where gaze following—a precursor of joint attention—was critical for interpreting her behavior. Proportional looking-time toward key areas of interest in some episodes correlated with receptive language measures. These findings underscore the connections between social attention and the development of communicative abilities in autism spectrum disorder.