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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.

Introduction: Improvements in obstetric/neonatal care have increased the survival rates of extremely-preterm-born (EP), though followed by an increased number, and degrees, of white matter injury (WMI), and long-lasting neurodevelopmental impairments. Study aim: to investigate consequences of EP birth on the evolving white matter microstructure and myelination; and its causative role on acquired IQ and sensory-motor functions.

Participants and methods: Two MRI methods (3T; DTI and SyMRI) used to calculate white matter properties and associations with IQ and sensory-motor functions in children born FT and EP at 12-y. In total N = 57 children; 32 FT (GA 38-42), and 25 EP (GA 22- <27) successfully performed MRI and administered WISC-V and Beery visual-motor integration (VMI) test. DTI used for analyzing fractional anisotropy (FA), mean diffusivity (MD), axial- (AD) and radial diffusivity (RD). SyMRI (T1-T2-R1-R2 and PD) for analyzing myelin segmentation, white-matter (WM), gray-matter (GM), cerebrospinal fluid (CSF), and brain parenchyma volume (BPV).

Results: Children born EP had significant smaller total brain (BPV), less GM, WM and more CSF/ICV compared to FT born. GA correlated positively with brain volumes, myelin, and with IQ and Beery-WMI. For EPs myelin correlated positively with GA, WISC-V and Beery-VMI. EPs had significant higher RD and AD compared to FT, no significant FA difference found. Within EP-group, myelin content correlated positively with FA and negatively with RD and AD.

Conclusion: These findings suggest that EP births is associated with high-risk for long-lasting, globally compromised white matter myelination and microstructural organization which causes adverse cognitive and sensory-motor functions.

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.

Introduction: Knowledge is lacking concerning long-term influences of preterm birth on action-cognition integrations related to corpus callosum (CC) maturation/myelination. Here, we investigate long-term-effects of preterm-birth on CC microstructures/organization in relation to cognition and functional-laterality.

Patients and methods: The sample included 82 children, 41 term-born (M-age=8.1y), and 41 preterm-born (M-age=8.2y); subdivided into V-PT, (GA=25–32w, N=23), and M-PT, (GA=33–35w, N=18), without major brain-deficits. DTI performed in 3T-MRI-scanners, generated maps of CC Genu, Truncus, Splenium (FA, MD, AD, RD-values). Results from WISC-IV (verbal-comprehension-VCI, perceptual-reasoning-PRI, working-memory-WM, processing-speed-PS, FSIQ), and Laterality-index (hand-, foot-, eye-preference) were analyzed related to DTI-outcomes.

Results: Significant group difference found regarding CC-FA-values (F(2,79)=5,3527, p=.006), post-hoc-test showed that VPT differed from term (p=.015) and MPT-born (p=.016), by lower FA-Genu, Truncus, Splenium. This pattern also found for MD, RD, and AD-values. Positive-correlations (p<.01) found between GA and all CC-FA-values, and negatively for all MD, RD and AD-Splenium. VPT-born showed lower (p=.005) FSIQ (M=93) than term (M=103). Correlations (p<.05) found between WM and CC-FA-values in Genu for VPT-born, and between CC-FA-values in Genu, Truncus and PRI-index (p<.01) for term-born. VPT-born showed lower Hand- and overall-laterality-index than term and MPT, and no significant correlations between laterality-index and CC-values. Term and MPT-children showed positive correlations (p<.01) between decreasing overall-laterality-index and FA-values, and negative for MD-Splenum, RD-Splenium and RD-Truncus. 

Conclusion: DTI revealed evidence for long-term impact of very-premature birth on CC related to atypical hemispheric maturation and behavioral integrations compared to term-born controls. The findings highlight importance of including functional-laterality to models investigating brain white-matter-microstructures.

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.

The ability to perform individual finger movements, highly important in daily activities, involves visual monitoring and proprioception. We investigated the influence of vision on the spatial and temporal control of independent finger movements, for the dominant and non-dominant hand and in relation to sex. Twenty-six healthy middle-aged to old adults (M age = 61 years; range 46–79 years; females n = 13) participated. Participants performed cyclic flexion–extension movements at the metacarpophalangeal joint of one finger at a time while keeping the other fingers as still as possible. Movements were recorded using 3D optoelectronic motion technique (120 Hz). The movement trajectory distance; speed peaks (movement smoothness); Individuation Index (II; the degree a finger can move in isolation from the other fingers) and Stationarity Index (SI; how still a finger remains while the other fingers move) were extracted. The main findings were: (1) vision only improved the II and SI marginally; (2) longer trajectories were evident in the no-vision condition for the fingers of the dominant hand in the female group; (3) longer trajectories were specifically evident for the middle and ring fingers within the female group; (4) females had marginally higher II and SI compared with males; and (5) females had fewer speed peaks than males, particularly for the ring finger. Our results suggest that visual monitoring of finger movements marginally improves performance of our non-manipulative finger movement task. A consistent finding was that females showed greater independent finger control compared with males.