Development of Motor Imagery in School-Aged Children with Autism Spectrum Disorder: A Longitudinal Study.

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.

Visual tracking at 4 months in preterm infants predicts 6.5-year cognition and attention.

BACKGROUND: Visual tracking of moving objects requires sustained attention and prediction of the object's trajectory. We tested the hypothesis that measures of eye-head tracking of moving objects are associated to long-term neurodevelopment in very preterm infants. METHODS: Visual tracking performance was assessed at 4 month's corrected age in 57 infants with gestational age <32 weeks. An object moved in front of the infant with sinusoidal or triangular (i.e. abrupt) turns of the direction. Gaze gain, smooth pursuit gain, and timing of gaze to object motion were analyzed. At 6.5 years the Wechsler Intelligence Scale for Children (WISC-IV), the Brown Attention Deficit Disorder (Brown ADD), and visual examination were performed. RESULTS: Gaze gain and smooth pursuit gain at 4 months were strongly related to all WISC-IV parameters at 6.5 years. Gaze gain for the triangular and sinusoidal motion patterns related similarly to the cognitive scores. For the sinusoidal motion pattern, timing related to most Brown ADD parameters. There were no statistically significant differences in associations dependent on motion pattern. Visual function did not influence the results. CONCLUSION: The ability to attend to and smoothly track a moving object in infancy is an early marker of cognition and attention at 6.5 years. IMPACT: Potential long-term implications of infant visual tracking of moving objects for school-age neurodevelopment has not been previously studied in very preterm infants. Early coordination of eye and head movements in gaze gain, smooth pursuit, and timing of gaze to object motion are closely associated with cognition and attention at 6.5 years. As related functions at 6.5 years include perceptual and verbal skills, working memory, processing speed and attention, predictive elements in gaze tracking of moving objects might be a suitable target for future intervention studies.

Motor planning and movement execution during goal-directed sequential manual movements in 6-year-old children with autism spectrum disorder: A kinematic analysis.

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.

Kinematic characteristics of second-order motor planning and performance in 6- and 10-year-old children and adults: Effects of age and task constraints.

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 (Mage  = 6.7 years) and one older (Mage  = 10.3 years), and one adult group (Mage  = 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.

Reaching skills of infants born very preterm predict neurodevelopment at 2.5 years.

The purpose was to investigate associations between quality of reaching for moving objects at 8 months corrected age and neurodevelopment at 2.5 years in children born very preterm (gestational age (GA), 24-31 weeks). Thirtysix infants were assessed while reaching for moving objects. The movements were recorded by a 3D motion capture system. Reaching parameters included aiming, relative length of the reach, number of movement units, proportion of bimanual coupled reaches and number of hits. Neurodevelopment was assessed at 2.5 years by the Bayley Scales of Infant Development III. There were strong associations between infant reaching kinematics and neurodevelopment of cognition and language but the patterns differed: in children born extremely preterm (GA < 28 weeks), planning and control of reaching was strongly related to outcome, while in children born very preterm (GA 28-31 weeks) number of hits and bimanual strategies were of greater relevance. In conclusion, for extremely preterm infants, basic problems on how motion information is incorporated with action planning prevail, while in very preterm infants the coordination of bimanual reaches is more at the focus. We conclude that the results reflect GA related differences in neural vulnerability and that early motor coordination deficits have a cascading effect on neurodevelopment.

Infants plan prehension while pivoting.

Skilled object retrieval requires coordination of the perceptual and motor systems. Coordination is especially challenging when body position is changing and visual search is required to locate the target. In three experiments, we used a "pivot paradigm" to induce changes in body position: Participants were passively pivoted 180° toward a target placed at varied locations to the left and right of the center of a reaching board. Experiment 1 showed that 6- to 15-month-old infants (n = 41) plan prehension so quickly that they retrieve targets mid-turn and scale their reaches to target location relative to turn direction. Experiment 2 characterized planning mid-turn reaching in 6- to 8-month-olds (n = 5) wearing a head-mounted eye tracker. Reach planning depended on when the target appeared in the field of view-not on target fixation. Experiment 3 used head-mounted eye tracking and motion tracking to assess perceptual-motor coordination in adults (n = 13). Adults displayed more mid-turn reaching than infants. But like infants, adults scaled reaching to target location relative to turn direction, and contact time depended on when the target came into view-not on target fixation. Findings show that fast, efficient perceptual-motor coordination supports flexibility in infant prehension, and constraints on coordination are similar across the lifespan.

The Development of Sensorimotor Intelligence in Infants.

Infancy is the most dynamic part of human development. During this period, all basic sensorimotor and cognitive abilities are established. In this chapter, we will trace some of the important achievements of this development with a focus on how infants achieve predictive control of actions, i.e., how they come to coordinate their behavior with the ongoing events in the world without lagging behind. With the maturation of the brain, new possibilities that have profound effects on cognition open up. Some of them are core abilities, i.e., they function at birth or very early in development. Important examples are the structured perception of objects and surfaces and the control of arm movements. Closely after birth, infants move their arms to the vicinity of objects in front of them demonstrating that they have some control of their arms and indicating that they perceive objects as such. Another example is the rapid onset of smooth-pursuit eye movements during the second month of life and the emerging ability to predict when and where an occluded moving object will reappear. At 4months of age, out of sight is no longer of mind. The child's sensorimotor system is especially designed to facilitate the extraction of knowledge about the world including other people. In addition, the infant is endowed with motives that ensure that the innate predispositions are transformed into a system of knowledge for guiding actions predictively. By perceiving and acting on the world, infants develop their cognition and through developmental studies; we can learn more about these processes.

Impaired cognitive ability at 2.5 years predicts later visual and ophthalmological problems in children born very preterm.

AIM: To identify possible predictive factors for visual problems at 6.5 years in children born very preterm. METHODS: During 2004-2007, all very preterm infants (gestational age [GA] <32 weeks) in Uppsala County, Sweden were screened for retinopathy of prematurity (ROP) neonatally; at four months, visual tracking was tested; at 2.5 years, visuospatial and cognitive tests were carried out. At 6.5 years, 84 preterm children and a reference group of 64 full-term children underwent ophthalmological testing. RESULTS: Mean visual acuity (VA) did not differ between the groups, but subnormal VA (≤0.8) was more common in the preterm group (31% vs 14%; p < 0.05). More often than full-term children, preterm children had impaired contrast sensitivity (<0.5) (36% vs 19%; p < 0.05) and strabismus (8% vs 0%; p < 0.05). Low GA, ROP, intraventricular haemorrhage 3-4/periventricular leukomalacia and cognitive disability at 2.5 years predicted ophthalmological and visual problems at 6.5 years. Visual tracking ability at four months was not predictive of ophthalmological outcome. CONCLUSION: Children born preterm had more ophthalmological problems at 6.5 years of age, including subtle dysfunctions. ROP, early brain injury and impaired cognitive function around 2.5 years predicted later ophthalmological dysfunctions.

Infants prospectively control reaching based on the difficulty of future actions: To what extent can infants' multiple-step actions be explained by Fitts' law?

Prospective motor control, a key element of action planning, is the ability to adjust one's actions with respect to task demands and action goals in an anticipatory manner. The current study investigates whether 14-month-olds can prospectively control their reaching actions based on the difficulty of the subsequent action. We used a reach-to-place task, with difficulty of the placing action varied by goal size and goal distance. To target prospective motor control, we determined the kinematics of the prior reaching movements using a motion-tracking system. Peak velocity of the first movement unit of the reach served as indicator for prospective motor control. Both difficulty aspects (goal size and goal distance) affected prior reaching, suggesting that both these aspects of the subsequent action have an impact on the prior action. The smaller the goal size and the longer the distance to the goal, the slower infants were in the beginning of their reach toward the object. Additionally, we modeled movement times of both reaching and placing actions using a formulation of Fitts' law (as in heading). The model was significant for placement and reaching movement times. These findings suggest that 14-month-olds can plan their future actions and prospectively control their related movements with respect to future task difficulties. (PsycINFO Database Record

Visual tracking in very preterm infants at 4 mo predicts neurodevelopment at 3 y of age.

BACKGROUND: Typically developing infants track moving objects with eye and head movements in a smooth and predictive way at 4 mo of age, but this ability is delayed in very preterm infants. We hypothesized that visual tracking ability in very preterm infants predicts later neurodevelopment. METHOD: In 67 very preterm infants (gestational age<32 wk), eye and head movements were assessed at 4 mo corrected age while the infant tracked a moving object. Gaze gain, smooth pursuit, head movements, and timing of gaze relative the object were analyzed off line. Results of the five subscales included in the Bayley Scales of Infant Development (BSID-III) at 3 y of age were evaluated in relation to the visual tracking data and to perinatal risk factors. RESULTS: Significant correlations were obtained between gaze gain and cognition, receptive and expressive language, and fine motor function, respectively, also after controlling for gestational age, severe brain damage, retinopathy of prematurity, and bronchopulmonary dysplasia. CONCLUSION: This is the first study demonstrating that the basic ability to visually track a moving object at 4 mo robustly predicts neurodevelopment at 3 y of age in children born very preterm.

Maturational and situational determinants of reaching at its onset.

At 3 months of age, reaching behavior was measured in a group of 10 girls and 10 boys born at term. The assessments were carried out on the average 2 days after reaching onset. Reaching kinematics was measured in both supine and reclined positions. Girls reached more than boys, had straighter reaching trajectories and movements of shorter durations as well as fewer movement units. The reclined position gave rise to straighter trajectories in both girls and boys. Several anthropometric parameters were measured. Girls had less length and volume of the forearm than boys but similar upper arm volumes. There was a weak relation between kinematic and anthropometric variables.

Improved Visual Perception in Very Low Birth Weight Infants on Enhanced Nutrient Supply.

BACKGROUND: Optimal nutrient supply to very low birth weight (VLBW: BW <1,500 g) infants is important for growth and neurodevelopment. Growth restriction is common among these infants and may be associated with neurocognitive impairments. OBJECTIVES: To compare an enhanced nutrient supply to a routine supply given to VLBW infants and to evaluate the effects on visual perception of global form and motion measured by visual event-related potentials (VERP). METHODS: A total of 50 VLBW infants were randomized to an intervention group that received an increased supply of energy, protein, fat, essential fatty acids, and vitamin A or a control group that received standard nutritional care. At 5 months' corrected age the infants were examined using VERP to investigate the responses to global form and motion. VERP were analysed at the first (f1) and third (f3) harmonics of the stimulus frequency. RESULTS: Data from 31 subjects were eligible for analysis. The motion VERP responses for the f1 and f3 components were stronger in the area near the posterior midline region in the intervention group compared to the controls in the group analyses (p = 0.02 and p = 0.001, respectively). CONCLUSION: The results showed a more consistent response to global motion among infants receiving enhanced nutrition. The intervention may have improved visual perception of global motion.

Simulating newborn face perception.

A frequently asked question concerns what a newborn infant can actually see. The contrast sensitivity function of newborn infants is well known, but its implications for the ability of newborns to perceive faces of adults remain unclear. We filtered gray scale animations of facial expressions in terms of both spatial frequency and contrast to correspond to the properties of newborn infants' acuity and showed them to adult participants. We reasoned that if adults were unable to identify the depicted facial expressions, then it would also seem unlikely that newborn infants could identify the same expressions. We found that for the simulated acuity the different expressions could be rather well identified at a distance of 30 cm, but when the distance was increased to 120 cm their discriminability was much degraded. This shows that although the perception of faces and facial expressions can function at the low visual resolution of the newborn infant, it is insufficient for distinguishing faces and facial expressions at moderate distances.

Eighteen-month-olds' ability to make gaze predictions following distraction or a long delay.

The abilities to flexibly allocate attention, select between conflicting stimuli, and make anticipatory gaze movements are important for young children's exploration and learning about their environment. These abilities constitute voluntary control of attention and show marked improvements in the second year of a child's life. Here we investigate the effects of visual distraction and delay on 18-month-olds' ability to predict the location of an occluded target in an experiment that requires switching of attention, and compare their performance to that of adults. Our results demonstrate that by 18 months of age children can readily overcome a previously learned response, even under a condition that involves visual distraction, but have difficulties with correctly updating their prediction when presented with a longer time delay. Further, the experiment shows that, overall, the 18-month-olds' allocation of visual attention is similar to that of adults, the primary difference being that adults demonstrate a superior ability to maintain attention on task and update their predictions over a longer time period.

Perception of conversations: the importance of semantics and intonation in children's development.

In conversations, adults readily detect and anticipate the end of a speaker's turn. However, little is known about the development of this ability. We addressed two important aspects involved in the perception of conversational turn taking: semantic content and intonational form. The influence of semantics was investigated by testing prelinguistic and linguistic children. The influence of intonation was tested by presenting participants with videos of two dyadic conversations: one with normal intonation and one with flattened (removed) intonation. Children of four different age groups--two prelinguistic groups (6- and 12-month-olds) and two linguistic groups (24- and 36-month-olds)--and an adult group participated. Their eye movements were recorded, and the frequency of anticipated turns was analyzed. Our results show that (a) the anticipation of turns was reliable only in 3-year-olds and adults, with younger children shifting their gaze between speakers regardless of the turn taking, and (b) only 3-year-olds anticipated turns better if intonation was normal. These results indicate that children anticipate turns in conversations in a manner comparable (but not identical) to adults only after they have developed a sophisticated understanding of language. In contrast to adults, 3-year-olds rely more strongly on prosodic information during the perception of conversational turn taking.

Dynamic reaching in infants during binocular and monocular viewing.

This study examined reaching in 6-, 8-, and 10-month-olds during binocular and monocular viewing in a dynamic reaching situation. Infants were rotated toward a flat vertical board and reached for objects at one of seven positions along a horizontal line at shoulder height. Hand selection, time to contact the object, and reaching accuracy were examined in both viewing conditions. Hand selection was strongly dependent on object location, not on infants' age or whether one eye was covered. Monocular viewing and age did, however, affect time to object contact and contact errors: Infants showed longer contact times when one eye was covered, and 6-month-olds made more contact errors in the monocular condition. For right-hand selection, contact times were longer when the covered right eye was leading during the chair rotation. For left-hand selection, there were no differences in contact time due to whether the covered eye was leading during rotation.

Visualization and analysis of eye movement data from children with typical and atypical development.

Looking at other children's interactions provides rich learning opportunities for a small child. How children with autism look at other children is largely unknown. Using eye tracking, we studied gaze performance in children with autism and neurotypical comparison children while they were watching videos of semi-naturalistic social interactions between young children. Using a novel, bottom-up approach we identified event-related measures that distinguished between groups with high accuracy. The observed effects remained in a subset of the total sample matched on IQ, and were replicated across several different stimuli. The described method facilitates the detection of meaningful patterns in complex eye tracking data. Also, the approach significantly improves visualization, which will help investigators understand, illustrate, and generate new hypotheses.

Getting the closer object? An information-based dissociation between vision for perception and vision for movement in early infancy.

In human adults two functionally and neuro-anatomically separate systems exist for the use of visual information in perception and the use of visual information to control movements (Milner & Goodale, 1995, 2008). We investigated whether this separation is already functioning in the early stages of the development of reaching. To this end, 6- and 7-month-old infants were presented with two identical objects at identical distances in front of an illusory Ponzo-like background that made them appear to be located at different distances. In two further conditions without the illusory background, the two objects were presented at physically different distances. Preferential reaching outcomes indicated that the allocentric distance information contained in the illusory background affected the perception of object distance. Yet, infants' reaching kinematics were only affected by the objects' physical distance and not by the perceptual distance manipulation. These findings were taken as evidence for the two-visual systems, as proposed by Milner and Goodale (2008), being functional in early infancy. We discuss the wider implications of this early dissociation.