Development of prospective control of catching moving objects in preterm at-risk infants

Quantifying interaction with robotic toys in pre-term and full-term infants

Infants born pre-term are at an increased risk for developmental, behavioral, and motor delay and subsequent disability. When these problems are detected early, clinical intervention can be effective at improving functional outcomes. Current methods of early clinical assessment are resource intensive, require extensive training, and do not always capture infants' behavior in natural play environments. We developed the Play and Neuro Development Assessment (PANDA) Gym, an affordable, mechatronic, sensor-based play environment that can be used outside clinical settings to capture infant visual and motor behavior. Using a set of classification codes developed from the literature, we analyzed videos from 24 pre-term and full-term infants as they played with each of three robotic toys designed to elicit different types of interactions-a lion, an orangutan, and an elephant. We manually coded for frequency and duration of toy interactions such as kicking, grasping, touching, and gazing. Pre-term infants gazed at the toys with similar frequency as full-term infants, but infants born full-term physically engaged more frequently and for longer durations with the robotic toys than infants born pre-term. While we showed we could detect differences between full-term and pre-term infants, further work is needed to determine whether differences seen were primarily due to age, developmental delays, or a combination.

Harnessing cognitive strategy use for functional problems and proposed underlying mechanisms in childhood-onset dystonia

BACKGROUND

There is a significant gap in knowledge about rehabilitation techniques and strategies that can help children and young people with hyperkinetic movement disorders (HMD) including dystonia to successfully perform daily activities and improve overall participation. A promising approach to support skill acquisition is the Cognitive Orientation to daily Occupational Performance (CO-OP) intervention. CO-OP uses cognitive strategies to help patients generate their own solutions to overcome self-identified problems encountered in everyday living.

PURPOSE

1. To identify and categorize strategies used by children with HMD to support skill acquisition during CO-OP; 2. To review the possible underlying mechanisms that might contribute to the cognitive strategies, in order to facilitate further studies for developing focused rehabilitation approaches.

METHODS

A secondary analysis was performed on video-recorded data from a previous study exploring the efficacy of CO-OP for childhood onset HMD, in which CO-OP therapy sessions were delivered by a single occupational therapist. For the purpose of this study, we reviewed a total of 40 randomly selected hours of video footage of CO-OP sessions delivered to six participants (age 6-19 years) over ten intervention sessions. An observational recording sheet was applied to identify systematically the participants' or therapist's verbalizations of cognitive strategies during the therapy. The strategies were classified into six categories in line with published literature.

RESULTS

Strategies used by HMD participants included distraction, externally focussed attention, internally focussed attention, emotion self-regulation, motor imagery and mental self-guidance. We postulate different underlying working mechanisms for these strategies, which have implications for the therapeutic management of children and young people with HMD including dystonia.

CONCLUSIONS

Cognitive strategy training can fundamentally change and improve motor performance. On-going work will address both the underlying neural mechanisms of therapeutic change and the mediators and moderators that influence how change unfolds.

Effects of auditovisual feedback on eye-hand coordination in children with cerebral palsy

BACKGROUND

Children with spastic hemiplegic cerebral palsy have deficits in eye-hand coordination. This limits manual actions performed with the affected hand, especially fine motor skills such as grasping and manipulation. Visual-motor integration, grasping skills, and visual perception are collectively involved in eye-hand coordination.

AIMS

We investigated the effects of augmented biofeedback training on eye-hand coordination in children with spastic hemiplegic cerebral palsy.

METHODS AND PROCEDURES

Forty-five spastic hemiplegic cerebral palsy children (5-8 years old) were included. Children were assigned randomly into three equal groups. One group received traditional physical therapy to facilitate visual-motor integration and grasping skills for 3 months. The second group received augmented biofeedback training. The third group received a combination of augmented biofeedback training and traditional physical therapy. Children were evaluated with the Peabody Developmental Motor Scale (2nd edition) (PDMS-2). Treatment sessions were conducted for 60 min, three times a week, for 3 consecutive months.

OUTCOMES AND RESULTS

Children that received augmented biofeedback training alongside traditional physical therapy had significantly improved scores in the Visual-Motor Integration and grasping subtests compared to children that received only one intervention.

CONCLUSIONS AND IMPLICATIONS

Augmented biofeedback training alongside physical therapy improved eye-hand coordination in children with spastic hemiplegic cerebral palsy.

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.

Ready, Set, Go! Low Anticipatory Response during a Dyadic Task in Infants at High Familial Risk for Autism

Children with autism spectrum disorder (ASD) demonstrate a host of motor impairments that may share a common developmental basis with ASD core symptoms. School-age children with ASD exhibit particular difficulty with hand-eye coordination and appear to be less sensitive to visual feedback during motor learning. Sensorimotor deficits are observable as early as 6 months of age in children who later develop ASD; yet the interplay of early motor, visual and social skill development in ASD is not well understood. Integration of visual input with motor output is vital for the formation of internal models of action. Such integration is necessary not only to master a wide range of motor skills, but also to imitate and interpret the actions of others. Thus, closer examination of the early development of visual-motor deficits is of critical importance to ASD. In the present study of infants at high risk (HR) and low risk (LR) for ASD, we examined visual-motor coupling, or action anticipation, during a dynamic, interactive ball-rolling activity. We hypothesized that, compared to LR infants, HR infants would display decreased anticipatory response (perception-guided predictive action) to the approaching ball. We also examined visual attention before and during ball rolling to determine whether attention engagement contributed to differences in anticipation. Results showed that LR and HR infants demonstrated context appropriate looking behavior, both before and during the ball's trajectory toward them. However, HR infants were less likely to exhibit context appropriate anticipatory motor response to the approaching ball (moving their arm/hand to intercept the ball) than LR infants. This finding did not appear to be driven by differences in motor skill between risk groups at 6 months of age and was extended to show an atypical predictive relationship between anticipatory behavior at 6 months and preference for looking at faces compared to objects at age 14 months in the HR group.

Development of Visual Motion Perception for Prospective Control: Brain and Behavioral Studies in Infants

During infancy, smart perceptual mechanisms develop allowing infants to judge time-space motion dynamics more efficiently with age and locomotor experience. This emerging capacity may be vital to enable preparedness for upcoming events and to be able to navigate in a changing environment. Little is known about brain changes that support the development of prospective control and about processes, such as preterm birth, that may compromise it. As a function of perception of visual motion, this paper will describe behavioral and brain studies with young infants investigating the development of visual perception for prospective control. By means of the three visual motion paradigms of occlusion, looming, and optic flow, our research shows the importance of including behavioral data when studying the neural correlates of prospective control.

Mapping the feel of the arm with the sight of the object: on the embodied origins of infant reaching

For decades, the emergence and progression of infant reaching was assumed to be largely under the control of vision. More recently, however, the guiding role of vision in the emergence of reaching has been downplayed. Studies found that young infants can reach in the dark without seeing their hand and that corrections in infants' initial hand trajectories are not the result of visual guidance of the hand, but rather the product of poor movement speed calibration to the goal. As a result, it has been proposed that learning to reach is an embodied process requiring infants to explore proprioceptively different movement solutions, before they can accurately map their actions onto the intended goal. Such an account, however, could still assume a preponderant (or prospective) role of vision, where the movement is being monitored with the scope of approximating a future goal-location defined visually. At reach onset, it is unknown if infants map their action onto their vision, vision onto their action, or both. To examine how infants learn to map the feel of their hand with the sight of the object, we tracked the object-directed looking behavior (via eye-tracking) of three infants followed weekly over an 11-week period throughout the transition to reaching. We also examined where they contacted the object. We find that with some objects, infants do not learn to align their reach to where they look, but rather learn to align their look to where they reach. We propose that the emergence of reaching is the product of a deeply embodied process, in which infants first learn how to direct their movement in space using proprioceptive and haptic feedback from self-produced movement contingencies with the environment. As they do so, they learn to map visual attention onto these bodily centered experiences, not the reverse. We suggest that this early visuo-motor mapping is critical for the formation of visually-elicited, prospective movement control.

Sensory-motor problems in Autism

Despite being largely characterized as a social and cognitive disorder, strong evidence indicates the presence of significant sensory-motor problems in Autism Spectrum Disorder (ASD). This paper outlines our progression from initial, broad assessment using the Movement Assessment Battery for Children (M-ABC2) to subsequent targeted kinematic assessment. In particular, pronounced ASD impairment seen in the broad categories of manual dexterity and ball skills was found to be routed in specific difficulties on isolated tasks, which were translated into focused experimental assessment. Kinematic results from both subsequent studies highlight impaired use of perception-action coupling to guide, adapt and tailor movement to task demands, resulting in inflexible and rigid motor profiles. In particular difficulties with the use of temporal adaption are shown, with "hyperdexterity" witnessed in ballistic movement profiles, often at the cost of spatial accuracy and task performance. By linearly progressing from the use of a standardized assessment tool to targeted kinematic assessment, clear and defined links are drawn between measureable difficulties and underlying sensory-motor assessment. Results are specifically viewed in-light of perception-action coupling and its role in early infant development suggesting that rather than being "secondary" level impairment, sensory-motor problems may be fundamental in the progression of ASD. This logical and systematic process thus allows a further understanding into the potential root of observable motor problems in ASD; a vital step if underlying motor problems are to be considered a fundamental aspect of autism and allow a route of non-invasive preliminary diagnosis.

Reaching and grasping movements in infants at risk: a review

Although the influence of intrinsic and extrinsic factors on the development of reaching and grasping skills in typical infants has been extensively described in the literature, the effect of such factors on at-risk infants is still poorly understood. Therefore, the aims of the present study were to analyze the scientific publications, from 1980 to 2008, about factors influencing reaching and grasping movements in infants at risk and to describe methodological procedures used in the studies under review. A bibliographical review on empirical studies indexed on Medline, Lilacs and Science Direct data bases was done, using as keywords the terms: "reaching movements", "grasping", "catching", "prehension", "infants", "children", "risk", "deficit", "impairment" and "delay". 127 articles were identified, and 11 were selected. The following risk conditions were assessed in the papers: prematurity, cerebral palsy, Down syndrome, intrauterine cocaine exposure and agenesis of corpus callosum. Methodological issues as well as the intrinsic and extrinsic factors manipulated in the experiments are discussed in the light of changes in theoretical approach to motor behavior.

Preterm infants' timing strategies to optical collisions

BACKGROUND

A virtual object approaching on a collision course will elicit defensive blinking in infants. Previous research has shown that when precisely timing their blinks, full-term infants shift from using a strategy based on visual angle/angular velocity to a strategy based on time between 22 and 30 weeks of age.

AIM

To investigate which timing strategy preterm infants use to determine when to make the defensive blink.

METHODS

Eight preterm infants were tested at 26 weeks, corrected for prematurity. For three of these infants, longitudinal data at 22, 26, and 30 weeks were available. The virtual object approached the infants with different constant velocities and constant accelerations.

RESULTS

At 26 weeks, three infants blinked when the virtual object's visual angle reached a threshold value causing them to have problems with fast, accelerating approaches. Four infants blinked when the virtual object was a certain time away, allowing them to blink in time on all approach conditions. One infant stood out because he relied on a timing strategy based on angular velocity on all three test sessions, causing him to blink late on a large number of trials even at 30 weeks.

CONCLUSION

As good timing is essential for successful interaction with the environment, the inability to switch from a timing strategy that is prone to errors to a strategy that enables successful defensive blinking reflects lack of flexibility to adjust appropriately to local circumstances. This might be an early indication of perceptuo-motor problems that warrants further investigation.

Differentiating prospective control information for catching in at-risk and control adolescents

This paper investigated the use of prospective control in catching and how the results can be used as a sensitive tool to detect diffuse signs of brain dysfunction. A detailed analysis of 286 catching movements of eight adolescents (two males, six females [four very-low-birth weight {VLBW}, one small for gestational age {SGA}, and three appropriate for gestational age]; mean age 14 y 5 mo [SD 6 mo]; range 14-15 y) was performed blind for this purpose. The moving target approached the participants from the side at three different, non-constant accelerations. The results showed that three adolescents used less advanced timing strategies that involved the lower-order variables of distance or velocity to govern movement initiation of at least one of their hands. Two of these were preterm VLBW and one was term SGA. The remaining adolescents, on the other hand, all relied on the higher-order variable of time-to-contact to initiate their hand movements, and were, therefore, considered low-risk. These results were compared with the cerebral magnetic resonance imaging results of the adolescents. The findings show that timing strategy pinpoints successfully those adolescents at risk of neurological problems. It was, therefore, concluded that the skill of using prospective information for catching can be used as a tool to detect diffuse signs of motor dysfunction, which are not readily detected by standard behavioural tests alone.

Infants’ timing strategies to optical collisions: A longitudinal study

Blinking is a good indication of awareness to optical collisions in early infancy. In the current longitudinal study, infants were presented with the image of a looming virtual object approaching on a collision course under different constant velocities and constant accelerations. The aim was to investigate which timing strategies the infants used to determine when to make the defensive blink. Blinking when the virtual object reaches a threshold visual angle (angle-strategy) or angular velocity would result in difficulties with accelerating approaches, while blinking when the object is a certain time away (time-strategy) would enable successful responses to all approaches. Eleven infants were tested longitudinally at 22, 26, and 30 weeks. Five infants switched from an angle- to a time-strategy, while one infant switched from using angular velocity to a time-strategy. Five infants used a time-strategy already at 22 weeks. These findings show that with age there is an attunement in the perceptual systems of infants which makes them switch to better specifying variables, enabling them to successfully time their defensive blinking to impending optical collisions.

Developmental lesions of visual cortex influence control of reaching

We examined visually guided reaching movements in a young adult (EW) who had extensive bilateral lesions in the visual cortex since birth. EW lacked a right occipital lobe and ventral portions of the left and had poor visual acuity (3/400), yet could point to visual targets as quickly as 9 controls with visual cortex lesions acquired in adulthood and 4 adults without neurological disease. However, EW's endpoint variability and hand movement path curvature were much greater, especially for left hand movements, in concert with large sensorimotor transformation errors. Experimental reduction of acuity (to 3/240 or worse) in the normal controls produced symmetric increases in endpoint variability but did not change hand path curvature, indicating that EW's impaired movements were not due to poor vision alone. Results suggest that visual cortex in early life supports the development of lifelong neural mechanisms for the planning and control of reaching movements.

Development of perception in action in healthy and at-risk children

Devising effective assessment techniques and therapy for movement disorders in young children requires in-depth measures of the child's perceptuo-motor functioning. It is argued that the field of movement disorders can benefit from an ecological approach to perception and action, where perception subserves action and action influences perception. Three notions central to the ecological approach are described and illustrated with our recent research on infant and child perceptual and motor behaviour.

Cerebral lateralisation and rate of maturation

Multifactorial inheritance applied to brain development implies a large continuum of normal variation with deviation from the norm at the extremes of maturational rate. The greater population of neurons, greater arborization of neural networks and excessive synaptic density in early maturation imply that adaptability (plasticity) is a main advantage, as opposed to a deficit in adaptability associated with the reduced number of neurons, reduced connectivity and reduced synaptic density in late slow maturation. It is hypothesised that Planum Temporale (PT) asymmetry and hand-preference predict the rate of CNS maturation as does the cognitive profile on the Wechsler Adult Intelligence Scale (WAIS): PT leftward asymmetry, right-handedness and a left-hemisphere cognitive advantage signifies early fast maturation: PT rightward asymmetry, left-handedness and a right-hemisphere cognitive advantage signify late maturation, while PT symmetry and ambilaterality represent rates of maturation in between. The slower development of males implies a male predominance in disorders affecting late maturers: Developmental Dyslexia (DD) with a predominance of rightward PT asymmetry/symmetry, left-handedness and multiple functional deficits, as well as excessive regressive events confirmed on PT/MRI. Schizophrenia, hypothesised to be a disorder in late maturers, is distinguished by rightward asymmetry/symmetry. Left-handedness and DD are common as is prior delayed development supporting excessive regressive events as do the findings on PT/MRI. To reduce the risk of DD and schizophrenia requires a reduction in late maturation through the enhancement of maturational rate by optimal nutrition before and during pregnancy and later.

Keeping the arm in the limelight: advanced visual control of arm movements in neonates

To test whether newborn babies have voluntary control over their limbs, spontaneous arm-waving movements were measured in the dark while the baby lay supine with its head turned to one side. A narrow beam of light was shone over the baby's nose or chest in such a way that the arm the baby was facing was only visible when the hand encountered the, otherwise, invisible beam of light. The results showed the babies were capable of precisely controlling the position, velocity, and deceleration of their arms so as to keep the hand visible in the light. The findings indicate that newborns can purposely control their arm movements to meet external demands and that the development of visual control of arm movement is underway soon after birth.