Motor problems in autism: Co-occurrence or feature?

Motor features of autism have long been acknowledged by clinicians, researchers, and community stakeholders. Current DSM-5 and ICD-11 guidelines allow clinicians to assign a co-occurring diagnosis of developmental [motor] coordination disorder (DCD) for autistic individuals with significant motor problems. DCD is characterized by poor motor proficiency with an onset of symptoms in early development. Studies have shown considerable overlap in the behavioral motor features observed in autism and DCD. However, others indicate that motor problems in autism and DCD may stem from different underlying sensorimotor mechanisms. Regardless of whether autism has a unique motor phenotype or an overlap with DCD, changes need to be made in the clinical pipeline to address motor problems in autism at the stages of recognition, assessment, diagnosis, and intervention. Consensus is needed to address unmet needs in research on the etiology of motor problems in autism and their overlap with DCD, to optimize clinical practice guidelines. The development of screening and assessment tools for motor problems that are valid and reliable for use with autistic individuals is essential, and an evidence-based clinical pipeline for motor problems in autism is urgently needed. WHAT THIS PAPER ADDS: Motor problems in autism are highly prevalent, yet underdiagnosed and poorly managed. An evidence-based clinical pipeline for motor problems in autism is urgently needed.

Motor differences in autism during a human-robot imitative gesturing task.

BACKGROUND: Difficulty with imitative gesturing is frequently observed as a clinical feature of autism. Current practices for assessment of imitative gesturing ability-behavioral observation and parent report-do not allow precise measurement of specific components of imitative gesturing performance, instead relying on subjective judgments. Advances in technology allow researchers to objectively quantify the nature of these movement differences, and to use less socially stressful interaction partners (e.g., robots). In this study, we aimed to quantify differences in imitative gesturing between autistic and neurotypical development during human-robot interaction. METHODS: Thirty-five autistic (n = 19) and neurotypical (n = 16) participants imitated social gestures of an interactive robot (e.g., wave). The movements of the participants and the robot were recorded using an infrared motion-capture system with reflective markers on corresponding head and body locations. We used dynamic time warping to quantify the degree to which the participant's and robot's movement were aligned across the movement cycle and work contribution to determine how each joint angle was producing the movements. FINDINGS: Results revealed differences between autistic and neurotypical participants in imitative accuracy and work contribution, primarily in the movements requiring unilateral extension of the arm. Autistic individuals imitated the robot less accurately and used less work at the shoulder compared to neurotypical individuals. INTERPRETATION: These findings indicate differences in autistic participants' ability to imitate an interactive robot. These findings build on our understanding of the underlying motor control and sensorimotor integration mechanisms that support imitative gesturing in autism which may aid in identifying appropriate intervention targets.

Community-based postural control assessment in autistic individuals indicates a similar but delayed trajectory compared to neurotypical individuals.

Autistic individuals exhibit significant sensorimotor differences. Postural stability and control are foundational motor skills for successfully performing many activities of daily living. In neurotypical development, postural stability and control develop throughout childhood and adolescence. In autistic development, previous studies have focused primarily on individual age groups (e.g., childhood, adolescence, adulthood) or only controlled for age using age-matching. Here, we examined the age trajectories of postural stability and control in autism from childhood through adolescents using standardized clinical assessments. In study 1, we tested the postural stability of autistic (n = 27) and neurotypical (n = 41) children, adolescents, and young adults aged 7-20 years during quiet standing on a force plate in three visual conditions: eyes open (EO), eyes closed (EC), and eyes open with the head in a translucent dome (Dome). Postural sway variability decreased as age increased for both groups, but autistic participants showed greater variability than neurotypical participants across age. In study 2, we tested autistic (n = 21) and neurotypical (n = 32) children and adolescents aged 7-16 years during a dynamic postural control task with nine targets. Postural control efficiency increased as age increased for both groups, but autistic participants were less efficient compared to neurotypical participants across age. Together, these results indicate that autistic individuals have a similar age trajectory for postural stability and control compared to neurotypical individuals, but have lower postural stability and control overall.

Distinct mental health profiles in children with Developmental Coordination Disorder: A latent class analysis and associations.

BACKGROUND: Children with Developmental Coordination Disorder (DCD) show indications for mental health problems. However, these problems are poorly understood. AIMS: To identify patterns (profiles) of mental health in this population and to analyze the associations between profiles and child characteristics. METHODS AND PROCEDURES: Parents of 119 children with DCD completed the Strengths and Difficulties Questionnaire. OUTCOMES AND RESULTS: Results indicated that a four latent class was the best model. Profile 1 was defined as "no" mental health problems (n = 28; 24 %), Profile 2 was defined as "hyperactivity" problems (n = 53; 43.3 %), for clinical indications for hyperactivity, Profile 3 was defined as "internalizing" problems (n = 8; 7.3 %), for clinical indications for emotional symptoms and peer problems, and Profile 4 was defined as "internalizing and externalizing problems" (n = 30; 25.4 %), for clinical indications for problems in both areas. In addition, having a co-occurring disorder, accommodation plans, and using medications were associated with the profiles. CONCLUSIONS AND IMPLICATIONS: There are distinct and unique profiles that children with DCD exhibit. Clinicians can use these profiles to better understand the presentation of mental health symptoms in this population and provide adequate services or support if mental health difficulties are present.

Movement smoothness during dynamic postural control to a static target differs between autistic and neurotypical children.

BACKGROUND: Autistic children and adults have known differences in motor performance, including postural instability and atypical gross motor control. Few studies have specifically tested dynamic postural control. This is the first study to quantify movement smoothness and its relationship to task performance during lateral dynamic postural control tasks in autism. RESEARCH QUESTION: We sought to test the hypothesis that autistic children would have less smooth movements to lateral static targets compared to neurotypical children, and that this difference would relate to specific movement strategies. METHODS: We used camera-based motion-capture to measure spatiotemporal characteristics of lateral movement of a marker placed on the C7 vertebrae, and of markers comprising trunk and pelvis segments during a dynamic postural movements to near and far targets administered in an immersive virtual environment. We tested a sample of 15 autistic children and 11 age-matched neurotypical children. We quantified movement smoothness using log dimensionless jerk. RESULTS: Autistic children exhibited more medial-lateral pelvic position range of motion compared to neurotypical children, and used a stepping strategy more often compared to neurotypical children. Autistic children also had higher log dimensionless jerk than neurotypical children for motion of the C7 marker. All participants had higher log dimensionless jerk for far targets than for near targets. Autistic children had longer trial durations than neurotypical children, and younger children had longer trial durations than older children across diagnostic groups. SIGNIFICANCE: The stepping strategy observed more often in the autistic group likely contributed to log dimensionless jerk and reduced movement smoothness. This strategy is indicative of either an attempt to prevent an impending loss of balance, or an attempt to compensate for and recover from a loss of balance once it is detected.

Autistic Children Use Less Efficient Goal-Directed Whole Body Movements Compared to Neurotypical Development.

Autistic children have differences in their movements which impact their functional performance. Virtual-reality enables researchers to study movement in safe, engaging environments. We used motion-capture to measure how 7-13-year-old autistic and neurotypical children make whole-body movements in a virtual-reality task. Although children in both groups were successful, we observed differences in their movements. Autistic children were less efficient moving to the target. Autistic children did not appear to use a movement strategy. While neurotypical children were more likely to overshoot near targets and undershoot far targets, autistic children did not modulate their strategy. Using kinematic data from tasks in virtual-reality, we can begin to understand the pattern of movement challenges experienced by autistic children.

Harvesting Twitter Data for Studying Motor Behavior in Disabled Populations: An Introduction and Tutorial in Python.

Social media platforms are rich and dynamic spaces where individuals communicate on a person-to-person level and to broader audiences. These platforms provide a wealth of publicly available data that can shed light on the lived experiences of people from numerous clinical populations. Twitter can be used to examine individual expressions and community discussions about specific characteristics (e.g., motor skills, burnout) associated with a diagnostic group. These data are useful for understanding the perspectives of a diverse, international group of self-advocates representing a wide range of clinical populations. Here, we provide a framework for how to harvest data from Twitter through their free, academic researcher application programming interface access using Python, a free, open-source programming language. We also provide a sample data set harvested using this framework and a set of analyses on these data specifically related to motor differences in neurodevelopmental conditions. This framework offers a cost-effective and flexible means of harvesting and analyzing Twitter data. Researchers should utilize these resources to advance our understanding of the lived experiences of clinical populations through social media platforms and to determine the critical questions that are of most importance to improving quality of life.

Identity and Discourse Among #ActuallyAutistic Twitter Users With Motor Differences.

Despite a growing awareness of the prevalence of motor differences in the autistic community, their functional impact is poorly understood. Social media offers the ideal setting to observe this discourse in a less-contrived setting than lab-based structured interviews. The aims of the present study were (a) to determine the proportion of Twitter users who self-identify as autistic and dyspraxic/having developmental coordination disorder, relative to autistic alone, and (b) to identify common themes emerging from two moderated chat threads with motor-related prompts. Using the Twitter research application programming interface, we harvested data from users' public profiles and tweets containing terms related to autism and developmental coordination disorder within a 1-month time period. We also harvested data from two #AutChat threads related to motor skills, which included 151 tweets from 31 unique autistic users (two with co-occurring developmental coordination disorder). Of these tweets, 44 were explicitly about motor differences, while the remainder consisted of discussion topics more loosely associated with motor skills. The following common themes were quantified: manual dexterity, lower extremity, oral motor, gross motor, posture, balance, stimming, movement pain, and coordination. Together, these findings indicate that motor differences are highly recognized and discussed among autistic individuals but are not overtly integrated into their identities at the same rate.

#DCD/Dyspraxia in Real Life: Twitter Users' Unprompted Expression of Experiences With Motor Differences.

Little is known about adults' experiences with developmental coordination disorder (DCD; sometimes also referred to as dyspraxia). Social media is an accessible opportunity for those who identify as dyspraxic or as having DCD to provide valuable insight into the lifespan impact of this condition on functional ability, participation, compensatory strategies, and well-being. We used the Twitter research application programming interface to identify users who self-identified with the keywords Developmental Coordination Disorder, #DCD, #dyspraxic (or # dyspraxia), or clumsy in their profile descriptions between October 10 and November 10, 2021. During that period, 818 tweets were harvested with 524 remaining after removing duplicates (e.g., multiple promotions of a single resource) and unrelated tweets. They were labeled according to motor differences (general motor, coordination, fine motor skills, oral motor skills, manual dexterity, driving, gross motor skills, movement pain and fatigue, posture and balance, and lower extremity); functional impact (advocacy/awareness, support for others, resources, information, and education, intervention, accommodation, and work); or other related topics (stimming and sensory, co-occurrence and diagnostic overlap, cognitive, social and communication speech, and emotional and mental health). The DCD/dyspraxic community has clearly identified a lifelong impact of motor differences across multiple contexts. DCD/dyspraxic Twitter users shared compensatory strategies that could help others, and offered insight into their experience of co-occurring conditions and cognitive/emotional sequelae of motor challenges.

Motor skills predict adaptive behavior in autistic children and adolescents.

It is well-documented that intelligence quotient (IQ) is a poor predictor of adaptive behavior scores in autism, with autistic children having lower adaptive behavior scores than would be predicted based on their IQ scores. Differences in motor skills may explain the variability in their adaptive behavior scores. The current study examined how motor skills might explain autistic individuals' low adaptive behavior scores and which individual components of IQ (i.e., verbal comprehension and perceptual reasoning) and motor skills (i.e., manual dexterity, aiming and catching, and balance) may drive this effect. We examined the associations between IQ, motor skills, calibrated severity, and adaptive behavior scores in 45 autistic children and adolescents. Using a t-test, we found a significant difference (p <0.001) between full-scale IQ and adaptive behavior scores, indicating that our participants' adaptive behavior scores were lower than would be expected given their full-scale IQ. Using a linear regression, we investigated whether motor skills predicted adaptive behavior in autistic children and adolescents and found that motor skills scores were associated with adaptive behavior scores (p = 0.022). To further investigate these associations, we used another linear regression to examine how individual components of IQ and motor skills predicted adaptive behavior scores in autistic children and adolescents. Our results indicated that manual dexterity scores were associated with adaptive behavior scores (p = 0.036). These findings clearly illustrate the need for further understanding of autistic individuals' difficulties with adaptive behavior and the potential role of motor skill difficulties that may underlie these difficulties. LAY SUMMARY: Autistic children have lower adaptive behavior scores (e.g., daily living skills, social skills, communication) than intelligence scores (e.g., verbal and perceptual skills) along with difficulties with motor skills. Motor skills may explain the gap between adaptive behavior and intelligence. We found motor skills were associated with adaptive behavior in autistic children and adolescents. In particular, hand coordination was associated with adaptive behavior. We need to better understand how autistic individuals' motor skills impact their adaptive behavior to provide effective supports.

Post-processing integration and semi-automated analysis of eye-tracking and motion-capture data obtained in immersive virtual reality environments to measure visuomotor integration.

Mobile eye-tracking and motion-capture techniques yield rich, precisely quantifiable data that can inform our understanding of the relationship between visual and motor processes during task performance. However, these systems are rarely used in combination, in part because of the significant time and human resources required for post-processing and analysis. Recent advances in computer vision have opened the door for more efficient processing and analysis solutions. We developed a post-processing pipeline to integrate mobile eye-tracking and full-body motion-capture data. These systems were used simultaneously to measure visuomotor integration in an immersive virtual environment. Our approach enables calculation of a 3D gaze vector that can be mapped to the participant's body position and objects in the virtual environment using a uniform coordinate system. This approach is generalizable to other configurations, and enables more efficient analysis of eye, head, and body movements together during visuomotor tasks administered in controlled, repeatable environments.

Shared Features or Co-occurrence? Evaluating Symptoms of Developmental Coordination Disorder in Children and Adolescents with Autism Spectrum Disorder.

Motor differences are common in Autism Spectrum Disorder (ASD), but rarely evaluated against diagnostic criteria for Developmental Coordination Disorder (DCD). We aimed to determine whether motor problems in ASD represent the possible co-occurrence of DCD. We retrospectively reviewed standardized assessments and parent-reports to evaluate motor ability in 43 individuals with ASD against diagnostic criteria for DCD, and compared to 18 individuals with DCD. Over 97% of cases in the ASD group scored below the 16th percentile in motor ability, with most below the 5th percentile. Over 90% of cases in the ASD group met criteria for co-occurring DCD. Motor challenges are a clinically-significant problem in ASD; systematically assessing the prevalence of co-occurring ASD + DCD is necessary to optimize assessment and intervention.

An Eye-Tracking Method for Directly Assessing Children's Visual-Motor Integration.

BACKGROUND: Visual-motor integration is an integral component of many adaptive behaviors and has been linked to school readiness. In young school-age children, visual-motor integration is typically assessed with the Beery-Buktenica Developmental Test of Visual Motor Integration (Beery VMI), a standardized instrument that measures children's ability to copy 2-dimensional forms. The Beery VMI is scored according to children's final written product, but does not directly measure the process of visual-motor integration that underlies children's form copying. OBJECTIVE: We describe a new way of directly assessing visual-motor integration in real time. We demonstrate how head-mounted eye-tracking technology for young children can be used to describe the dynamics of visual-motor integration when children copy forms. DESIGN: This study used a cross-sectional design. METHODS: Typically developing kindergarten children (N = 20) were tested as they wore an eye-tracker while performing the Beery VMI. RESULTS: Participants' success (b = -0.66; SE = 0.08; Cohen f2 = 1.11) and their efficiency in visual (b = 0.29; SE = 0.02; Cohen f2 = 0.55) and motor (b = 0.12; SE = 0.01; Cohen f2 = 0.90) processes during form copying decreased as the stimulus complexity increased. LIMITATIONS: A small convenience sample was used to determine proof of concept. A larger, more representative sample is necessary to provide generalizable results. CONCLUSIONS: The new methods used here offer the possibility of more fine-grained assessments of eye-hand coordination in typically developing children and children with such clinical conditions as dysgraphia and developmental coordination disorder.

The Development of Object Fitting: The Dynamics of Spatial Coordination.

Fitting objects into apertures is an adaptive skill that is incorporated into the design of many tools. We match or align shapes with openings when we insert keys into locks, when we put lids atop containers, or when we align a screwdriver with the groove of a screw. Traditionally, the development of object fitting has focused on children's abilities to successfully complete shape sorter tasks (e.g., square peg through square hole). By measuring children's success in these tasks, investigators have determined that there is substantial development during the second year, but little research has addressed the processes children employ to solve object fitting challenges during this time period. Here, we provide a process based account of object fitting, which emphasizes how children coordinate information about spatial structure with action. We suggest that a process-based approach can illuminate the real-time dynamics of perceiving, acting, and thinking.

How beginning handwriting is influenced by letter knowledge: Visual-motor coordination during children's form copying.

Even with recent technological advances, handwriting remains the developmental foundation from which communication via written language unfolds. Despite the importance of handwriting to academic success, previous research with beginning school-age children has only indirectly measured the processes of handwriting using post hoc assessments of legibility and accuracy. We adapted new head-mounted eye-tracking methods to directly measure visual-motor coordination of preschool and early elementary school children (N = 40) as they copied familiar (English letters) and unfamiliar (Cyrillic symbols) letter-like forms in real time. Results indicated that younger children needed more time to visually process a letter or symbol and initiate a writing action compared with older children despite children of all ages writing letters in a similar amount of time. Analyses also revealed that children copied familiar English letters more efficiently than they copied unfamiliar Cyrillic symbols: They spent more time on and made more visual fixations to the Cyrillic symbols compared with the English letters during the copying task. Finally, children made more visual fixations to less frequently occurring English letters than to more frequently occurring ones. Results are considered in relation to how letter recognition influences the development of automaticity in early handwriting.