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Sensorimotor difficulties are common in children with autism spectrum disorder, and it has been suggested that motor planning problems underlie their atypical movements. At early school-age, motor planning development typically involves changes in visuomotor integration, a function known to be affected in autism spectrum disorder. However, there is a lack of detailed characterization of typical motor planning development during this stage, and how motor planning develops in children with autism spectrum disorder is largely unknown. This longitudinal kinematic study examined goal-directed sequential manual movements in children with autism spectrum disorder and in typically developing children across ages 7, 8, and 9 years. We manipulated goal-difficulty and availability of initial visual information to investigate visuomotor integration and chaining of subparts during movement performance. The results revealed emerging group differences at older age, suggesting atypical motor planning development in children with autism spectrum disorder. Notably, unlike the typically developing group, availability of initial visual information did not facilitate motor planning for the autism spectrum disorder group. The results show that motor planning differences in autism spectrum disorder appear related to atypical visuomotor integration and global processing of sensorimotor information. The findings also emphasize the importance of considering developmental aspects in research and practice related to motor problems in children with autism spectrum disorder.

In our daily lives, we often engage in various manual activities with specific goals in mind. To adapt effectively to an ever-changing environment, it is important for us to anticipate future events while carrying out our actions. Motor planning plays a crucial role in most of our daily activities, underscoring the significance of comprehending its development and its connection to cognitive and perceptual development. In this endeavor, it is critical to also consider atypical development, including the role of motor planning in the prevalent motor problems experienced by children with autism. The primary goal of this thesis was to enhance our comprehension of motor planning development in early school-age children, including both those with typical development and those with autism. The main focus was to investigate the performance of sequential manual movements and detailed characteristics of motor planning from a developmental perspective. To achieve this goal, 3D motion capture technology was utilized. In Study I, variations in motor planning abilities among typically developing 6- and 10-year-old children were examined compared to adults. The findings demonstrated significant enhancements in movement organization between the ages of 6 and 10. However, it is important to note that, even at 10 years old, the children had not yet attained the same level of motor planning ability as adults. Additionally, at the age of 6, the children’s sequential movements were more exploratory and relied strongly on feedback processes. It was also evident that they encountered difficulties in making real-time adjustments. By the age of 10, the children demonstrated movement speed and smoothness similar to that of adults, but differences in motor planning outcomes still persisted when compared to adults. Study II investigated differences in motor planning and movement execution between 6-year-old children with autism and typically developing children. In addition, it explored the associations between movement parameters and cognitive functions within the group of children with autism. The findings indicated that, compared to typically developing children, children with autism displayed difficulties in planning sequential movements and exhibited decreased performance consistency. Difficulties in movement execution were further evident towards the end of the movement, which was probably related to suboptimal planning. Among the children with autism, movement time and smoothness were linked to working memory ability, while proactivity in object adjustment (a specific planning aspect of the study task) was associated with general cognitive functioning and non-verbal fluid abilities. Study III was a longitudinal study that examined the development of motor planning in children with autism in comparison to typically developing children during early school age (ages 7, 8, and 9 years). Findings revealed that the children with autism displayed atypical motor planning development in sequential movements. Specifically, increased reliance on initial visual information, particularly at the age of 9, facilitated motor planning improvements in the typically developing children but not the children with autism. These findings support that early school age seems to be an important period when the reorganization of sequential movements develops into more adult-like behavior. These improvements appear to be associated with an increased reliance on initial visual information and changes in visuomotor integration in typical development. However, the children with autism demonstrated less efficient motor planning and atypical motor planning development during this period. This is primarily attributed to their reliance on initial visual information, which supports the notion that difficulties in visuomotor integration have an impact on motor planning development in children with autism. Overall, these findings underscore the importance of considering developmental aspects in both research and practice related to motor problems in children with autism.

Introduction: Children with autism spectrum disorder (ASD) frequently display atypical motor functioning. This longitudinal study investigated atypical visuomotor integration in the development of action planning as one possible source.

Participants and Methods: Fourteen children with ASD and 17 typically developing (TD) controls participated three times over the ages 7 (T1) to 9 (T3) years. 3D kinematic registrations were made during performance of a manual sequential peg-rotation task with either visible or occluded goal-display condition before onset. Time, condition, and group differences were analyzed on onset-latency, part peak velocity in reach-to-grasp (PPV-RtG), remaining angle of peg-rotation at goal (p-RA), and fitting-duration.

Results: Time-point generated significant (p < 0.05) main effects for all variables. Stratifying by condition revealed shorter latency (both groups), higher PPV-RtG (visual-condition TD-group), lower p-RA (visual-condition TD-group; occluded-condition ASD-group), and shorter fitting-duration (visual-condition TD-group; occluded-condition both groups) with increasing age. Group generated significant main effects for fitting-duration. Stratifying by condition revealed longer fitting-durations (both conditions), and increased p-RA (occluded-condition at T1; visible-condition at T3) in the ASD-group. Condition generated significant main effects for all variables except fitting-duration. Stratifying by group revealed shorter latency (both groups), higher PPV-RtG (TD-group at T3), and reduced p-RA (TD-group at T3) in the visual-condition.

Conclusions: The results show different sensory-motor integration in the children with ASD, characterized by not benefitting from pre-existing visual information in action planning in accordance with their TD peers, particularly evident at 9 years. Our findings, based on longitudinal data, support suggestions that visuomotor integration underpinning action planning may operate differently in ASD.

Introduction: Motor planning deviances may negatively affect interpersonal motor interactions in ASD, although detailed studies are sparse. This study examined motor planning kinematics in an interpersonal and non-interpersonal context in 9-year-old children with ASD and neurotypical peers.

Patients and methods: Twelve children with ASD and 17 controls performed two different sequential manual tasks (preferred hand): grasping and placing a peg on a wooden disc (non-interpersonal) or in the hand of an examiner (interpersonal). Three-dimensional kinematic recordings of arm/hand movements were performed. Group and task differences were explored for total movement duration (MD), and for peak velocity (PV) and placement of peak velocity (PPV) during reach-to-grasp and transport-to-place movements, respectively.

Results: Task differences were found in terms of longer MD and higher transport-to-place-PV in the disc- compared to hand-task. An interaction effect was evident for reach-to-grasp-PPV, where the control-group, but not ASD, had earlier reach-to-grasp-PPV and longer relative deceleration in the hand-task compared to the disc-task.

Conclusion: Results show that the interpersonal context influenced initial reach-to-grasp motor planning in the control-group, but not the ASD-group. Later in the sequential movement (transport-to-place), the interpersonal context seemed to influence motor planning independent of group. Taken together, this indicates support towards a more careful peg-placing in the interpersonal hand-task in the control-group but much less clearly so in the ASD-group.

Relevance for users and families: Atypical motor planning may influence motor interaction with peers. Investigations of motor planning and movement organization in ASD could thus inform interventions also targeting interpersonal exchange.

Autism spectrum disorder (ASD) is a diagnosis based on social communication deficits and prevalence of repetitive stereotyped behaviors, but sensorimotor disturbances are commonly exhibited. This longitudinal study aimed at exploring the development of the ability to form mental motor representations (motor imagery; MI) in 14 children with ASD and 17 typically developing (TD) children at 7, 8 and 9 years of age. MI was investigated using a hand laterality paradigm from which response times (RT) and error rates were extracted and compared with performance on a visually based mental rotation task (VI). A criterion task was used to ensure that the children could perform the task. The results showed wide performance variability in the ASD group with more failures than TD in the MI criterion task, especially at 7 years. For all age levels and both the MI and VI tasks, the error rates were significantly higher and RTs longer for the ASD group compared with TD. Signs of MI strategies were however noted in the ASD group as biomechanically constrained orientations had longer RTs than less constrained orientations, a RT pattern that differed from the VI task. The presence of MI in the ASD group was most evident at 9 years, but the error rates remained high at all ages, both in the MI and VI task. In comparison, the TD group showed stable MI strategies at all ages. These findings indicate that MI ability is delayed and/or impaired in children with ASD which may be related to difficulties performing required mental rotations.

Introduction: Difficulties with action planning and visuomotor integration may contribute to atypical motorfunctioning in children with autism spectrum disorder (ASD), although detailed studies of sensorimotorintegration in action planning are sparse. This ongoing study investigates visuomotor integration in actionplanning in 7-year-old children with and without ASD.

Patients and methods: A sub-sample of 6 children with ASD and 6 typically developing (TD) controls wereincluded. Recordings of gaze synchronized with 3D kinematic registration were made during performance of amanual sequential peg rotation task with variations in goal insertion complexity. Group differences and relations between movement duration and number of gaze shifts over the sequential movement phases(latency, reach-to-grasp, grasp, and transport-to-fit) were explored.

Results: No significant group differences were found for either movement duration or number of gaze shifts.When controlling for the between-participants variance, total number of gaze shifts and number of gaze shiftsin reach-to-grasp were related to movement duration in the initial phases of the movement in the TD-group but not in the ASD-group.

Conclusion: The results indicate that, whilst performance measures were similar between groups, the overallpattern of visuomotor integration was related to feed-forward movement processes in the sequentialmovement in the TD-group but not in the ASD-group. This finding adds support to previous suggestions thatvisuomotor integration underpinning action planning may operate differently in ASD. Synchronizedexamination of gaze and detailed movement registration appears as a promising methodology for detailed investigation of visuomotor integration in action planning.

Introduction: Motor anomalies are frequent in autism spectrum disorder (ASD). Effective and efficient motor acts rely on the formation of motor plans that serve as predictive models or blue-prints of upcoming actions. We studied movement initiation latencies (MILs) and movement durations in a peg-rotation (PR) task and response times (RT) in a motor imagery (MI) task in children with ASD.

Patients and Methods: Thirteen 7–8 year-old children with ASD (4 girls) and 17 typically developing (TD) children (9 girls) participated. MILs and PR task duration, extracted from 3D kinematic recordings, and RTs on a MI task (hand laterality judgement task) was compared between children with ASD and TD. The PR-task varied in constraints and the possibility to pre-plan actions was experimentally controlled.

Results: Nine of the ASD children passed the MI task showing biomechanical constraints effect but the error rate was however higher than in TD. The MILs on the PR-task were shorter when pre-planning was possible, indicating a time cost for movement planning. This cost was highest for the children who failed the MI task, specifically for the PR-task with the highest constraint where task durations also were the highest. Overall, TD children had shorter PR-task durations than ASD.

Conclusion: MI ability was highly varied for the ASD children. Interestingly, the children with ASD failing the MI task showed the greatest increase in MILs in relation to task difficulty indicative of pre-planning. They also had increased task durations, specifically for the most difficult condition, suggestive of poorer on-line control.

Background: Atypical motor functioning is prevalent in children with autism spectrum disorder (ASD). Knowledge of the underlying kinematic properties of these problems is sparse.

Aims: To investigate characteristics of manual motor planning and performance difficulties/diversity in children with ASD by detailed kinematic measurements. Further, associations between movement parameters and cognitive functions were explored.

Methods and procedures: Six-year-old children with ASD (N = 12) and typically developing (TD) peers (N = 12) performed a sequential manual task comprising grasping and fitting a semi-circular peg into a goal-slot. The goal-slot orientation was manipulated to impose different motor planning constraints. Movements were recorded by an optoelectronic system.

Outcomes and results: The ASD-group displayed less efficient motor planning than the TD-group, evident in the reach-to-grasp and transport kinematics and less proactive adjustments of the peg to the goal-slot orientations. The intra-individual variation of movement kinematics was higher in the ASD-group compared to the TD-group. Further, in the ASD-group, movement performance associated negatively with cognitive functions.

Conclusions and implications: Planning and execution of sequential manual movements proved challenging for children with ASD, likely contributing to problems in everyday actions. Detailed kinematic investigations contribute to the generation of specific knowledge about the nature of atypical motor performance/diversity in ASD. This is of potential clinical relevance.

This study explored age‐related differences in motor planning as expressed in arm‐hand kinematics during a sequential peg moving task with varying demands on goal insertion complexity (second‐order planning). The peg was a vertical cylinder with either a circular or semicircular base. The task was to transport the peg between two positions and rotate it various amounts horizontally before fitting into its final position. The amount of rotation required was either 0°, 90°, 180°, or −90°. The reaching for the peg, the displacement of it, and the way the rotation was accomplished was analyzed. Assessments of end state comfort, goal interpretation errors, and type of grip used were also included. Participants were two groups of typically developing children, one younger (M_age = 6.7 years) and one older (M_age = 10.3 years), and one adult group (M_age = 34.9 years). The children, particularly 6‐year‐olds, displayed less efficient prehensile movement organization than adults. Related to less efficient motor planning, 6‐year‐olds, mainly, had shorter reach‐to‐grasp onset latencies, higher velocities, and shorter time to peak velocities, and longer grasp durations than adults. Importantly, the adults rotated the peg during transport. In contrast, the children made corrective rotations after the hand had arrived at the goal.

Introduction: Knowledge about motor imagery (MI) ability in autism spectrum disorder (ASD) is limited and inconclusive in young children with ASD. The aim of the current study was to investigate MI ability in 7-year-old children with ASD.

Patients and methods: Thirteen children with ASD and 13 typically developing (TD) children performed a computerized hand laterality judgement task (HLJ) and a non-corporeal visual imagery (VI) control task. All participants passing a criterion test performed the tasks with images at 4 different rotational increments to vary the MI biomechanical demands (HLJ task) or VI angle rotational demands (VI task). Response times (RT) and accuracy were extracted.

Results: Four children with ASD did not pass the HLJ criterion test and one failed the VI criterion test. The ASD-group had evidently more incorrect responses than TD on both tasks. Analyses of RT showed a biomechanical effect in the MI task and an angle increment effect in the VI task in both groups. Children with ASD had longer RT than TD children on VI but not MI tasks. 

Conclusion: Findings suggest that both the ASD and control children used MI to solve the HLJ task. However, failures to pass the HLJ criterion test and the increased error rate in the ASD group indicate that MI ability is weaker in young children with autism than TD controls. Notably, a large individual variability in employment of MI within the ASD group was found, ranging from functional, fractional but existing, to absent MI ability.