Kate Wilmut | Oxford Brookes University (original) (raw)

Papers by Kate Wilmut

Research paper thumbnail of Modeling the Maturation of Grip Selection Planning and Action Representation: Insights from Typical and Atypical Motor Development

Frontiers in Psychology, 2016

We investigated the purported association between developmental changes in grip selection plannin... more We investigated the purported association between developmental changes in grip selection planning and improvements in an individual's capacity to represent action at an internal level [i.e., motor imagery (MI)]. Participants were groups of healthy children aged 6-7 years and 8-12 years respectively, while a group of adolescents (13-17 years) and adults (18-34 years) allowed for consideration of childhood development in the broader context of motor maturation. A group of children aged 8-12 years with probable DCD (pDCD) was included as a reference group for atypical motor development. Participants' proficiency to generate and/or engage internal action representations was inferred from performance on the hand rotation task, a well-validated measure of MI. A grip selection task designed to elicit the end-state comfort (ESC) effect provided a window into the integrity of grip selection planning. Consistent with earlier accounts, the efficiency of grip selection planning followed a non-linear developmental progression in neurotypical individuals. As expected, analysis confirmed that these developmental improvements were predicted by an increased capacity to generate and/or engage internal action representations. The profile of this association remained stable throughout the (typical) developmental spectrum. These findings are consistent with computational accounts of action planning that argue that internal action representations are associated with the expression and development of grip selection planning across typical development. However, no such association was found for our sample of children with pDCD, suggesting that individuals with atypical motor skill may adopt an alternative, sub-optimal strategy to plan their grip selection compared to their same-age control peers.

Research paper thumbnail of Tailoring reach-to-grasp to intended action: the role of motor practice

Experimental Brain Research

Motor learning results from repeated exposure to the same movement and allows a mover to increase... more Motor learning results from repeated exposure to the same movement and allows a mover to increase movement optimality. Typically, this has only been considered in single-step movements. In sequential movements, an initial reach movement is tailored to the demands of the onward movement. However, the exact role of motor practice in the tailoring to onward task demands is unknown. Eighteen adults performed blocks of 15 movements; each movement consisted of a reach phase and an onward phase (the object was placed in a tight-fitting hole, placed in a loose-fitting hole or thrown). Simple practice effects were seen; for the reach phase, the amount of time spent decelerating decreased over trials, and for the onward phase, the accuracy of the place/throw movements increased over trials. Furthermore, approximately 30 % of variance in the practice effect of the onward phase could be explained by the practice effect in the reach phase. Therefore, we suggest that the changes in the reach phas...

Research paper thumbnail of Influences of grasp selection in typically developing children

Acta psychologica

When reaching towards an object, adults favour grasps which, following the intended action, end i... more When reaching towards an object, adults favour grasps which, following the intended action, end in a comfortable position even when this requires them to start in an uncomfortable position (the end-state-comfort effect). However, this strategy is not consistently used by children who instead seem to favour a minimal pre-contact rotation of the hand, even when this results in an uncomfortable end position. In terms of multiple movements, the strategies used for grip selection are unclear; adults may still grasp for end-state-comfort given their propensity to plan to the end of a movement; however, children who are less able to concatenate movement may tend to start-state-comfort movements. The current study considered grip selection in children ranging from 4 to 12years and in a group of adults. Participants were asked to rotate a disc so that an arrow pointed towards a specific target(s), the number of sequences in a movement was increased from one to three. Planning for end-state-c...

Research paper thumbnail of Gait patterns in children with Developmental Coordination Disorder

Previous research has shown that adults with Developmental Coordination Disorder (DCD) show incre... more Previous research has shown that adults with Developmental Coordination Disorder (DCD) show increased variability of foot placement measures and movement of the centre of mass (CoM) while walking. The current study considered the gait patterns of young and older children with DCD. Fourteen young children with DCD (7-12 years), 15 older children with DCD (12-17 years) and 29 age and gender matched typically developing children took part. Children were asked to walk up and down a flat 10m long pathway for one minute while the movement of their feet and trunk was recorded using motion analysis. The gait pattern of children with DCD was characterised by wider steps, elevated variability in the time spent in double support and stride time and greater medio-lateral velocity and acceleration compared to their peers. An elevated variability in medio-lateral acceleration was also seen in the young but not the older children with DCD. In addition, the young children showed a greater variability in velocity and acceleration in all three directions compared to the older children. The data suggest that the high incidence of trips and falls seen in children with DCD may be due to differences in the control of the centre of mass.

Research paper thumbnail of How Do I Fit through That Gap? Navigation through Apertures in Adults with and without Developmental Coordination Disorder

During everyday life we move around busy environments and encounter a range of obstacles, such as... more During everyday life we move around busy environments and encounter a range of obstacles, such as a narrow aperture forcing us to rotate our shoulders in order to pass through. In typically developing individuals the decision to rotate the shoulders is body scaled and this movement adaptation is temporally and spatially tailored to the size of the aperture. This is done effortlessly although it actually involves many complex skills. For individuals with Developmental Coordination Disorder (DCD) moving in a busy environment and negotiating obstacles presents a real challenge which can negatively impact on safety and participation in motor activities in everyday life. However, we have a limited understanding of the nature of the difficulties encountered. Therefore, this current study considered how adults with DCD make action judgements and movement adaptations while navigating apertures. Fifteen adults with DCD and 15 typically developing (TD) controls passed through a series of aperture sizes which were scaled to body size (0.9-2.1 times shoulder width). Spatial and temporal characteristics of movement were collected over the approach phase and while crossing the aperture. The decision to rotate the shoulders was not scaled in the same way for the two groups, with the adults with DCD showing a greater propensity to turn for larger apertures compared to the TD adults when body size alone was accounted for. However, when accounting for degree of lateral trunk movement and variability on the approach, we no longer saw differences between the two groups. In terms of the movement adaptations, the adults with DCD approached an aperture differently when a shoulder rotation was required and then adapted their movement sooner compared to their typical peers. These results point towards an adaptive strategy in adults with DCD which allows them to account for their movement difficulties and avoid collision.

Research paper thumbnail of Does implicit motor imagery ability predict reaching correction efficiency? A test of recent models of human motor control

Journal of motor behavior

Neurocomputational models of reaching indicate that efficient purposive correction of movement mi... more Neurocomputational models of reaching indicate that efficient purposive correction of movement midflight (e.g., online control) depends on one's ability to generate and monitor an accurate internal (neural) movement representation. In the first study to test this empirically, the authors investigated the relationship between healthy young adults' implicit motor imagery performance and their capacity to correct their reaching trajectory. As expected, after controlling for general reaching speed, hierarchical regression demonstrated that imagery ability was a significant predictor of hand correction speed; that is, faster and more accurate imagery performance associated with faster corrections to reaching following target displacement at movement onset. They argue that these findings provide preliminary support for the view that a link exists between an individual's ability to represent movement mentally and correct movement online efficiently.

Research paper thumbnail of Handwriting speed in children with Developmental Coordination Disorder: are they really slower

Research in developmental disabilities, 2013

Handwriting difficulties are often included in descriptions of Developmental Coordination Disorde... more Handwriting difficulties are often included in descriptions of Developmental Coordination Disorder (DCD). They are cited as the most common reason for referral to health professionals following parent and teacher concerns about slow and untidy writing. The aim of this study was to compare handwriting performance in English children with and without DCD across a range of writing tasks, to gain a better understanding of the nature of 'slowness' so commonly reported. Twenty-eight 8-14 year-old children with a diagnosis of DCD participated in the study, with 28 typically developing age and gender matched controls. Participants completed the four handwriting tasks from the Detailed Assessment of Speed of Handwriting (DASH) and wrote their own name; all on a digitizing writing tablet. The number of words written, speed of pen movements and the time spent pausing during the tasks were calculated. The findings confirmed what many professionals report, that children with DCD produce less text than their peers. However, this was not due to slow movement execution, but rather a higher percentage of time spent pausing. Discussion centres on the understanding of the pausing phenomenon in children with DCD and areas for further research.

Research paper thumbnail of Reduced looming sensitivity in primary school children with Developmental Co-ordination Disorder

Developmental science, 2012

Almost all locomotor animals are sensitive to optical expansion (visual looming) and for most ani... more Almost all locomotor animals are sensitive to optical expansion (visual looming) and for most animals this sensitivity is evident very early in their development. In humans there is evidence that responses to looming stimuli begin in the first 6 weeks of life, but here we demonstrate that as children become independent their perceptual acuity needs to be 50 to 100 times better than has been demonstrated in infants in order to be skilful at collision avoidance at a roadside. We have recently established that sensitivity to the detection of visual looming in 6- to 11-year-old children is significantly below that of adults (Wann, Poulter & Purcell, 2011). Here, using comparable methods, we explore looming detection sensitivity in children with Developmental Co-ordination Disorder (DCD), who show broad patterns of impairment in visuo-motor control. We presented visual simulations of approaching vehicles, scaled to represent different approach rates, to children with DCD aged between 6 and 11 years (n = 11) and typically developing age and gender matched controls (n = 11). Looming detection thresholds were measured under foveal and perifoveal viewing conditions, for isotropic expansion and isotropic expansion with simulated viewpoint motion. Our results show that there are situations in which children with DCD may fail to detect vehicles approaching at speeds in excess of 22 km/h, suggesting a developmental immaturity in looming sensitivity. This provides one of the first clear demonstrations of low-level motion processing deficits in children with DCD. The decrement observed may give rise to potential errors in the road crossing behaviour of these children, whereby approaching vehicles could be perceived as stationary. These findings further contribute towards understanding the adverse statistic that children under 9 years of age are four times more likely than adults to be involved in a road accident as a pedestrian.

Research paper thumbnail of Reaching to throw compared to reaching to place: a comparison across individuals with and without Developmental Coordination Disorder

Research in developmental disabilities, 2013

This study was funded by an ESRC grant awarded to Kate Wilmut (RES-061-25-0472). We would like to... more This study was funded by an ESRC grant awarded to Kate Wilmut (RES-061-25-0472). We would like to thank all of the participants who took part in this study, Ian Wilmut who made the equipment and Prof. John Wann who kindly lent the VICON system. Onward intentions for reaching in DCD 2

Research paper thumbnail of To throw or to place: does onward intention affect how a child reaches for an object

Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale, 2013

Picking up an object is a seemingly simple and isolated task; however, research has demonstrated ... more Picking up an object is a seemingly simple and isolated task; however, research has demonstrated that adults plan a reach-to-grasp movement on the basis of forthcoming actions. For example a greater deceleration period is seen in an initial reach movement which precedes a place movement compared to a throw movement. This task-specific or second-order motor planning is also seen in infants and toddlers; however, the developmental progression is unclear. Reach-to-grasp movements of 48 children, split into four age groups (4–5, 6–7, 8–9 and 10–11 years) were recorded. These movements preceded a tight place, a loose place or a throw action. All the children showed some degree of tailoring kinematics to the onward action. In the 4–5 year-old group, this was demonstrated by a longer movement duration in the place actions compared to the throw action. In the older children the proportion of time spent decelerating increased as the precision requirements of the task increased. These results demonstrate that all children are able to use second-order planning to integrate onward task demands into their movements. The capacity for this increases with age but is not fully mature at 11 years. These developmental effects may be explained by the relative weighting of costs involved in tailoring a reach action compared to the benefits of producing a more efficient onward action.

Research paper thumbnail of Grip selection for sequential movements in children and adults with and without Developmental Coordination Disorder

Human movement science, 2013

When generating a movement adults favour grasps which start the body in an uncomfortable position... more When generating a movement adults favour grasps which start the body in an uncomfortable position if they end in a comfortable position (the end-state-comfort effects). In contrast, children with Developmental Coordination Disorder (DCD) select grasps which require little initial hand rotation even though they result in an uncomfortable end position. The current study considered grip selection of individuals with DCD when asked to make simple one step movements and when making more complex multi-staged movements. Adults with DCD (N=17, mean age 24:09, SD age=52 months) and children with DCD (N=20, mean age 9:00, SD age=20 months) and age and gender matched controls rotated a disc so an arrow pointed toward a specific target(s). Task complexity was increased by increasing the number of targets from 1 to 3. Planning for end-state-comfort was seen in all groups albeit to a lesser extent in children versus adults. The children with DCD showed fewer grips for end-state-comfort compared to their peers and this was explained by a propensity to select minimal initial rotation grasps. This result was mirrored in adults with DCD but only for the longest movement sequence. These results suggest some changes in ability from childhood to adulthood in individuals with DCD.

Research paper thumbnail of Constraints and facilitators to participation in physical activity in teenagers with Developmental Co-ordination Disorder: an exploratory interview study

Child: care, health and development, 2013

Background Despite their movement difficulties, youngsters with Developmental Co-ordination Diso... more Background Despite their movement difficulties, youngsters with Developmental Co-ordination Disorder (DCD) generally have sufficient capability for physical activity. However, they tend to be less physically active and less physically fit than their well co-ordinated age peers. The aim of this study was to use qualitative research methods to understand which factors constrain and facilitate participation in physical activity in teenagers with DCD, in order to help inform future health promotion programmes.Method Semi-structured interviews were conducted with eight teenagers with DCD (aged 13–15) and their parents. The interviews focused on how much physical activity was typically undertaken by the child and the perceived constraints and facilitators to being physically active. Interviews were transcribed and subjected to categorical-content analysis.Results Half of the children and all but one of the parents reported that the children did little physical activity. Although most children disliked competitive team games, they reported many physical activities that they did enjoy and they reported wanting to be more physically active. Perceived internal constraints to participation included poor motor skill, lack of motivation and reports of fatiguing easily. Perceived external constraints included difficulty travelling to activities, negative comments from peers and teachers' lack of understanding of DCD.Conclusions Reports of low levels of physical activity support previous literature and are a cause for concern for this group. The teenagers expressed the desire to be more active, yet the interviews revealed both personal and environmental constraints to engagement in physical activity. It is clear that these factors interact in a dynamic way and that teachers, schools and communities play an important role in creating a motivational environment for youngsters with DCD to engage in physical activity and learn to maintain an active lifestyle as they move into adulthood.

Research paper thumbnail of Locomotor behaviour of children while navigating through apertures

Experimental Brain Research, 2011

During everyday locomotion, we encounter a range of obstacles requiring specific motor responses;... more During everyday locomotion, we encounter a range of obstacles requiring specific motor responses; a narrow aperture which forces us to rotate our shoulders in order to pass through is one example. In adults, the decision to rotate their shoulders is body scaled (Warren and Whang in J Exp Psychol Hum Percept Perform 13:371–383, 1987), and the movement through is temporally and spatially tailored to the aperture size (Higuchi et al. in Exp Brain Res 175:50–59, 2006; Wilmut and Barnett in Hum Mov Sci 29:289–298, 2010). The aim of the current study was to determine how 8-to 10-year-old children make action judgements and movement adaptations while passing through a series of five aperture sizes which were scaled to body size (0.9, 1.1, 1.3, 1.5 and 1.7 times shoulder width). Spatial and temporal characteristics of movement speed and shoulder rotation were collected over the initial approach phase and while crossing the doorway threshold. In terms of making action judgements, results suggest that the decision to rotate the shoulders is not scaled in the same way as adults, with children showing a critical ratio of 1.61. Shoulder angle at the door could be predicted, for larger aperture ratios, by both shoulder angle variability and lateral trunk variability. This finding supports the dynamical scaling model (Snapp-Childs and Bingham in Exp Brain Res 198:527–533, 2009). In terms of movement adaptations, we have shown that children, like adults, spatially and temporally tailor their movements to aperture size.

Research paper thumbnail of Locomotor adjustments when navigating through apertures

Human Movement Science, 2010

We would like to thank Roy Barnett for constructing the partitions, Fleur Corbett for data collec... more We would like to thank Roy Barnett for constructing the partitions, Fleur Corbett for data collection, the Movement Science Group at Oxford Brookes University for providing the motion capture system and the School of Social Sciences and Law at Oxford Brookes University for funding this project. Navigation through apertures 2

Research paper thumbnail of Speech and oro-motor function in children with Developmental Coordination Disorder: A pilot study

Human Movement Science, 2010

Acknowledgements: We acknowledge C Selami for help liasing with families, K Greaves-Ramal for hel... more Acknowledgements: We acknowledge C Selami for help liasing with families, K Greaves-Ramal for help with data processing, Prof. J Wann for the use of the equipment, and all of the children and families who took part in this study.

Research paper thumbnail of Looming detection within natural scenes and potential errors in roadside judgments

Research paper thumbnail of Roadside judgments in children with Developmental Coordination Disorder

Research in Developmental Disabilities, 2011

Project rationale • Participant profile • Methodology • Two experiments 1. Which vehicle is trave... more Project rationale • Participant profile • Methodology • Two experiments 1. Which vehicle is travelling faster? 2. Would you have time to cross the road? Project Rationale • Road traffic accidents are the third leading cause of death for children 5-9 years • Evidence of deficits in detecting visual motion in 'clumsy' children • Deficits in perceptual acuity could have serious implications at the roadside!

Research paper thumbnail of Selection and assessment of children with Developmental Coordination Disorder

Developmental Medicine and Child Neurology, 2010

Research paper thumbnail of The Use of Prescanning in the Parameterization of Sequential Pointing and Reaching Movements

Journal of Motor Behavior, 2008

The accuracy of reaching movements is improved when active gaze can be used to fixate on targets.... more The accuracy of reaching movements is improved when active gaze can be used to fixate on targets. The advantage of free gaze has been attributed to the use of ocular proprioception or efference signals for on-line control. The time course of this process, however, is not established, and it is unclear how far in advance gaze can move and still be used to parameterize subsequent movements. In this experiment, we considered the advantage of prescanning targets for both pointing and reaching movements. The authors manipulated the visual information and examined the extent to which prescanning of targets could compensate for a reduction in on-line visual feedback.

Research paper thumbnail of Texture segmentation in Williams syndrome

Neuropsychologia, 2007

Williams syndrome (WS) is a developmental disorder in which visuo-spatial cognition is poor relat... more Williams syndrome (WS) is a developmental disorder in which visuo-spatial cognition is poor relative to verbal ability. At the level of visuo-spatial perception, individuals with WS can perceive both the local and global aspects of an image. However, the manner in which local elements are integrated into a global whole is atypical, with relative strengths in integration by luminance, closure, and alignment compared to shape, orientation and proximity. The present study investigated the manner in which global images are segmented into local parts. Segmentation by seven gestalt principles was investigated: proximity, shape, luminance, orientation, closure, size (and alignment: Experiment 1 only).

Research paper thumbnail of Modeling the Maturation of Grip Selection Planning and Action Representation: Insights from Typical and Atypical Motor Development

Frontiers in Psychology, 2016

We investigated the purported association between developmental changes in grip selection plannin... more We investigated the purported association between developmental changes in grip selection planning and improvements in an individual's capacity to represent action at an internal level [i.e., motor imagery (MI)]. Participants were groups of healthy children aged 6-7 years and 8-12 years respectively, while a group of adolescents (13-17 years) and adults (18-34 years) allowed for consideration of childhood development in the broader context of motor maturation. A group of children aged 8-12 years with probable DCD (pDCD) was included as a reference group for atypical motor development. Participants' proficiency to generate and/or engage internal action representations was inferred from performance on the hand rotation task, a well-validated measure of MI. A grip selection task designed to elicit the end-state comfort (ESC) effect provided a window into the integrity of grip selection planning. Consistent with earlier accounts, the efficiency of grip selection planning followed a non-linear developmental progression in neurotypical individuals. As expected, analysis confirmed that these developmental improvements were predicted by an increased capacity to generate and/or engage internal action representations. The profile of this association remained stable throughout the (typical) developmental spectrum. These findings are consistent with computational accounts of action planning that argue that internal action representations are associated with the expression and development of grip selection planning across typical development. However, no such association was found for our sample of children with pDCD, suggesting that individuals with atypical motor skill may adopt an alternative, sub-optimal strategy to plan their grip selection compared to their same-age control peers.

Research paper thumbnail of Tailoring reach-to-grasp to intended action: the role of motor practice

Experimental Brain Research

Motor learning results from repeated exposure to the same movement and allows a mover to increase... more Motor learning results from repeated exposure to the same movement and allows a mover to increase movement optimality. Typically, this has only been considered in single-step movements. In sequential movements, an initial reach movement is tailored to the demands of the onward movement. However, the exact role of motor practice in the tailoring to onward task demands is unknown. Eighteen adults performed blocks of 15 movements; each movement consisted of a reach phase and an onward phase (the object was placed in a tight-fitting hole, placed in a loose-fitting hole or thrown). Simple practice effects were seen; for the reach phase, the amount of time spent decelerating decreased over trials, and for the onward phase, the accuracy of the place/throw movements increased over trials. Furthermore, approximately 30 % of variance in the practice effect of the onward phase could be explained by the practice effect in the reach phase. Therefore, we suggest that the changes in the reach phas...

Research paper thumbnail of Influences of grasp selection in typically developing children

Acta psychologica

When reaching towards an object, adults favour grasps which, following the intended action, end i... more When reaching towards an object, adults favour grasps which, following the intended action, end in a comfortable position even when this requires them to start in an uncomfortable position (the end-state-comfort effect). However, this strategy is not consistently used by children who instead seem to favour a minimal pre-contact rotation of the hand, even when this results in an uncomfortable end position. In terms of multiple movements, the strategies used for grip selection are unclear; adults may still grasp for end-state-comfort given their propensity to plan to the end of a movement; however, children who are less able to concatenate movement may tend to start-state-comfort movements. The current study considered grip selection in children ranging from 4 to 12years and in a group of adults. Participants were asked to rotate a disc so that an arrow pointed towards a specific target(s), the number of sequences in a movement was increased from one to three. Planning for end-state-c...

Research paper thumbnail of Gait patterns in children with Developmental Coordination Disorder

Previous research has shown that adults with Developmental Coordination Disorder (DCD) show incre... more Previous research has shown that adults with Developmental Coordination Disorder (DCD) show increased variability of foot placement measures and movement of the centre of mass (CoM) while walking. The current study considered the gait patterns of young and older children with DCD. Fourteen young children with DCD (7-12 years), 15 older children with DCD (12-17 years) and 29 age and gender matched typically developing children took part. Children were asked to walk up and down a flat 10m long pathway for one minute while the movement of their feet and trunk was recorded using motion analysis. The gait pattern of children with DCD was characterised by wider steps, elevated variability in the time spent in double support and stride time and greater medio-lateral velocity and acceleration compared to their peers. An elevated variability in medio-lateral acceleration was also seen in the young but not the older children with DCD. In addition, the young children showed a greater variability in velocity and acceleration in all three directions compared to the older children. The data suggest that the high incidence of trips and falls seen in children with DCD may be due to differences in the control of the centre of mass.

Research paper thumbnail of How Do I Fit through That Gap? Navigation through Apertures in Adults with and without Developmental Coordination Disorder

During everyday life we move around busy environments and encounter a range of obstacles, such as... more During everyday life we move around busy environments and encounter a range of obstacles, such as a narrow aperture forcing us to rotate our shoulders in order to pass through. In typically developing individuals the decision to rotate the shoulders is body scaled and this movement adaptation is temporally and spatially tailored to the size of the aperture. This is done effortlessly although it actually involves many complex skills. For individuals with Developmental Coordination Disorder (DCD) moving in a busy environment and negotiating obstacles presents a real challenge which can negatively impact on safety and participation in motor activities in everyday life. However, we have a limited understanding of the nature of the difficulties encountered. Therefore, this current study considered how adults with DCD make action judgements and movement adaptations while navigating apertures. Fifteen adults with DCD and 15 typically developing (TD) controls passed through a series of aperture sizes which were scaled to body size (0.9-2.1 times shoulder width). Spatial and temporal characteristics of movement were collected over the approach phase and while crossing the aperture. The decision to rotate the shoulders was not scaled in the same way for the two groups, with the adults with DCD showing a greater propensity to turn for larger apertures compared to the TD adults when body size alone was accounted for. However, when accounting for degree of lateral trunk movement and variability on the approach, we no longer saw differences between the two groups. In terms of the movement adaptations, the adults with DCD approached an aperture differently when a shoulder rotation was required and then adapted their movement sooner compared to their typical peers. These results point towards an adaptive strategy in adults with DCD which allows them to account for their movement difficulties and avoid collision.

Research paper thumbnail of Does implicit motor imagery ability predict reaching correction efficiency? A test of recent models of human motor control

Journal of motor behavior

Neurocomputational models of reaching indicate that efficient purposive correction of movement mi... more Neurocomputational models of reaching indicate that efficient purposive correction of movement midflight (e.g., online control) depends on one's ability to generate and monitor an accurate internal (neural) movement representation. In the first study to test this empirically, the authors investigated the relationship between healthy young adults' implicit motor imagery performance and their capacity to correct their reaching trajectory. As expected, after controlling for general reaching speed, hierarchical regression demonstrated that imagery ability was a significant predictor of hand correction speed; that is, faster and more accurate imagery performance associated with faster corrections to reaching following target displacement at movement onset. They argue that these findings provide preliminary support for the view that a link exists between an individual's ability to represent movement mentally and correct movement online efficiently.

Research paper thumbnail of Handwriting speed in children with Developmental Coordination Disorder: are they really slower

Research in developmental disabilities, 2013

Handwriting difficulties are often included in descriptions of Developmental Coordination Disorde... more Handwriting difficulties are often included in descriptions of Developmental Coordination Disorder (DCD). They are cited as the most common reason for referral to health professionals following parent and teacher concerns about slow and untidy writing. The aim of this study was to compare handwriting performance in English children with and without DCD across a range of writing tasks, to gain a better understanding of the nature of 'slowness' so commonly reported. Twenty-eight 8-14 year-old children with a diagnosis of DCD participated in the study, with 28 typically developing age and gender matched controls. Participants completed the four handwriting tasks from the Detailed Assessment of Speed of Handwriting (DASH) and wrote their own name; all on a digitizing writing tablet. The number of words written, speed of pen movements and the time spent pausing during the tasks were calculated. The findings confirmed what many professionals report, that children with DCD produce less text than their peers. However, this was not due to slow movement execution, but rather a higher percentage of time spent pausing. Discussion centres on the understanding of the pausing phenomenon in children with DCD and areas for further research.

Research paper thumbnail of Reduced looming sensitivity in primary school children with Developmental Co-ordination Disorder

Developmental science, 2012

Almost all locomotor animals are sensitive to optical expansion (visual looming) and for most ani... more Almost all locomotor animals are sensitive to optical expansion (visual looming) and for most animals this sensitivity is evident very early in their development. In humans there is evidence that responses to looming stimuli begin in the first 6 weeks of life, but here we demonstrate that as children become independent their perceptual acuity needs to be 50 to 100 times better than has been demonstrated in infants in order to be skilful at collision avoidance at a roadside. We have recently established that sensitivity to the detection of visual looming in 6- to 11-year-old children is significantly below that of adults (Wann, Poulter & Purcell, 2011). Here, using comparable methods, we explore looming detection sensitivity in children with Developmental Co-ordination Disorder (DCD), who show broad patterns of impairment in visuo-motor control. We presented visual simulations of approaching vehicles, scaled to represent different approach rates, to children with DCD aged between 6 and 11 years (n = 11) and typically developing age and gender matched controls (n = 11). Looming detection thresholds were measured under foveal and perifoveal viewing conditions, for isotropic expansion and isotropic expansion with simulated viewpoint motion. Our results show that there are situations in which children with DCD may fail to detect vehicles approaching at speeds in excess of 22 km/h, suggesting a developmental immaturity in looming sensitivity. This provides one of the first clear demonstrations of low-level motion processing deficits in children with DCD. The decrement observed may give rise to potential errors in the road crossing behaviour of these children, whereby approaching vehicles could be perceived as stationary. These findings further contribute towards understanding the adverse statistic that children under 9 years of age are four times more likely than adults to be involved in a road accident as a pedestrian.

Research paper thumbnail of Reaching to throw compared to reaching to place: a comparison across individuals with and without Developmental Coordination Disorder

Research in developmental disabilities, 2013

This study was funded by an ESRC grant awarded to Kate Wilmut (RES-061-25-0472). We would like to... more This study was funded by an ESRC grant awarded to Kate Wilmut (RES-061-25-0472). We would like to thank all of the participants who took part in this study, Ian Wilmut who made the equipment and Prof. John Wann who kindly lent the VICON system. Onward intentions for reaching in DCD 2

Research paper thumbnail of To throw or to place: does onward intention affect how a child reaches for an object

Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale, 2013

Picking up an object is a seemingly simple and isolated task; however, research has demonstrated ... more Picking up an object is a seemingly simple and isolated task; however, research has demonstrated that adults plan a reach-to-grasp movement on the basis of forthcoming actions. For example a greater deceleration period is seen in an initial reach movement which precedes a place movement compared to a throw movement. This task-specific or second-order motor planning is also seen in infants and toddlers; however, the developmental progression is unclear. Reach-to-grasp movements of 48 children, split into four age groups (4–5, 6–7, 8–9 and 10–11 years) were recorded. These movements preceded a tight place, a loose place or a throw action. All the children showed some degree of tailoring kinematics to the onward action. In the 4–5 year-old group, this was demonstrated by a longer movement duration in the place actions compared to the throw action. In the older children the proportion of time spent decelerating increased as the precision requirements of the task increased. These results demonstrate that all children are able to use second-order planning to integrate onward task demands into their movements. The capacity for this increases with age but is not fully mature at 11 years. These developmental effects may be explained by the relative weighting of costs involved in tailoring a reach action compared to the benefits of producing a more efficient onward action.

Research paper thumbnail of Grip selection for sequential movements in children and adults with and without Developmental Coordination Disorder

Human movement science, 2013

When generating a movement adults favour grasps which start the body in an uncomfortable position... more When generating a movement adults favour grasps which start the body in an uncomfortable position if they end in a comfortable position (the end-state-comfort effects). In contrast, children with Developmental Coordination Disorder (DCD) select grasps which require little initial hand rotation even though they result in an uncomfortable end position. The current study considered grip selection of individuals with DCD when asked to make simple one step movements and when making more complex multi-staged movements. Adults with DCD (N=17, mean age 24:09, SD age=52 months) and children with DCD (N=20, mean age 9:00, SD age=20 months) and age and gender matched controls rotated a disc so an arrow pointed toward a specific target(s). Task complexity was increased by increasing the number of targets from 1 to 3. Planning for end-state-comfort was seen in all groups albeit to a lesser extent in children versus adults. The children with DCD showed fewer grips for end-state-comfort compared to their peers and this was explained by a propensity to select minimal initial rotation grasps. This result was mirrored in adults with DCD but only for the longest movement sequence. These results suggest some changes in ability from childhood to adulthood in individuals with DCD.

Research paper thumbnail of Constraints and facilitators to participation in physical activity in teenagers with Developmental Co-ordination Disorder: an exploratory interview study

Child: care, health and development, 2013

Background Despite their movement difficulties, youngsters with Developmental Co-ordination Diso... more Background Despite their movement difficulties, youngsters with Developmental Co-ordination Disorder (DCD) generally have sufficient capability for physical activity. However, they tend to be less physically active and less physically fit than their well co-ordinated age peers. The aim of this study was to use qualitative research methods to understand which factors constrain and facilitate participation in physical activity in teenagers with DCD, in order to help inform future health promotion programmes.Method Semi-structured interviews were conducted with eight teenagers with DCD (aged 13–15) and their parents. The interviews focused on how much physical activity was typically undertaken by the child and the perceived constraints and facilitators to being physically active. Interviews were transcribed and subjected to categorical-content analysis.Results Half of the children and all but one of the parents reported that the children did little physical activity. Although most children disliked competitive team games, they reported many physical activities that they did enjoy and they reported wanting to be more physically active. Perceived internal constraints to participation included poor motor skill, lack of motivation and reports of fatiguing easily. Perceived external constraints included difficulty travelling to activities, negative comments from peers and teachers' lack of understanding of DCD.Conclusions Reports of low levels of physical activity support previous literature and are a cause for concern for this group. The teenagers expressed the desire to be more active, yet the interviews revealed both personal and environmental constraints to engagement in physical activity. It is clear that these factors interact in a dynamic way and that teachers, schools and communities play an important role in creating a motivational environment for youngsters with DCD to engage in physical activity and learn to maintain an active lifestyle as they move into adulthood.

Research paper thumbnail of Locomotor behaviour of children while navigating through apertures

Experimental Brain Research, 2011

During everyday locomotion, we encounter a range of obstacles requiring specific motor responses;... more During everyday locomotion, we encounter a range of obstacles requiring specific motor responses; a narrow aperture which forces us to rotate our shoulders in order to pass through is one example. In adults, the decision to rotate their shoulders is body scaled (Warren and Whang in J Exp Psychol Hum Percept Perform 13:371–383, 1987), and the movement through is temporally and spatially tailored to the aperture size (Higuchi et al. in Exp Brain Res 175:50–59, 2006; Wilmut and Barnett in Hum Mov Sci 29:289–298, 2010). The aim of the current study was to determine how 8-to 10-year-old children make action judgements and movement adaptations while passing through a series of five aperture sizes which were scaled to body size (0.9, 1.1, 1.3, 1.5 and 1.7 times shoulder width). Spatial and temporal characteristics of movement speed and shoulder rotation were collected over the initial approach phase and while crossing the doorway threshold. In terms of making action judgements, results suggest that the decision to rotate the shoulders is not scaled in the same way as adults, with children showing a critical ratio of 1.61. Shoulder angle at the door could be predicted, for larger aperture ratios, by both shoulder angle variability and lateral trunk variability. This finding supports the dynamical scaling model (Snapp-Childs and Bingham in Exp Brain Res 198:527–533, 2009). In terms of movement adaptations, we have shown that children, like adults, spatially and temporally tailor their movements to aperture size.

Research paper thumbnail of Locomotor adjustments when navigating through apertures

Human Movement Science, 2010

We would like to thank Roy Barnett for constructing the partitions, Fleur Corbett for data collec... more We would like to thank Roy Barnett for constructing the partitions, Fleur Corbett for data collection, the Movement Science Group at Oxford Brookes University for providing the motion capture system and the School of Social Sciences and Law at Oxford Brookes University for funding this project. Navigation through apertures 2

Research paper thumbnail of Speech and oro-motor function in children with Developmental Coordination Disorder: A pilot study

Human Movement Science, 2010

Acknowledgements: We acknowledge C Selami for help liasing with families, K Greaves-Ramal for hel... more Acknowledgements: We acknowledge C Selami for help liasing with families, K Greaves-Ramal for help with data processing, Prof. J Wann for the use of the equipment, and all of the children and families who took part in this study.

Research paper thumbnail of Looming detection within natural scenes and potential errors in roadside judgments

Research paper thumbnail of Roadside judgments in children with Developmental Coordination Disorder

Research in Developmental Disabilities, 2011

Project rationale • Participant profile • Methodology • Two experiments 1. Which vehicle is trave... more Project rationale • Participant profile • Methodology • Two experiments 1. Which vehicle is travelling faster? 2. Would you have time to cross the road? Project Rationale • Road traffic accidents are the third leading cause of death for children 5-9 years • Evidence of deficits in detecting visual motion in 'clumsy' children • Deficits in perceptual acuity could have serious implications at the roadside!

Research paper thumbnail of Selection and assessment of children with Developmental Coordination Disorder

Developmental Medicine and Child Neurology, 2010

Research paper thumbnail of The Use of Prescanning in the Parameterization of Sequential Pointing and Reaching Movements

Journal of Motor Behavior, 2008

The accuracy of reaching movements is improved when active gaze can be used to fixate on targets.... more The accuracy of reaching movements is improved when active gaze can be used to fixate on targets. The advantage of free gaze has been attributed to the use of ocular proprioception or efference signals for on-line control. The time course of this process, however, is not established, and it is unclear how far in advance gaze can move and still be used to parameterize subsequent movements. In this experiment, we considered the advantage of prescanning targets for both pointing and reaching movements. The authors manipulated the visual information and examined the extent to which prescanning of targets could compensate for a reduction in on-line visual feedback.

Research paper thumbnail of Texture segmentation in Williams syndrome

Neuropsychologia, 2007

Williams syndrome (WS) is a developmental disorder in which visuo-spatial cognition is poor relat... more Williams syndrome (WS) is a developmental disorder in which visuo-spatial cognition is poor relative to verbal ability. At the level of visuo-spatial perception, individuals with WS can perceive both the local and global aspects of an image. However, the manner in which local elements are integrated into a global whole is atypical, with relative strengths in integration by luminance, closure, and alignment compared to shape, orientation and proximity. The present study investigated the manner in which global images are segmented into local parts. Segmentation by seven gestalt principles was investigated: proximity, shape, luminance, orientation, closure, size (and alignment: Experiment 1 only).