Methodological issues in measures of imitative reaction times

Ideomotor (IM) theory suggests that observing someone else perform an action activates an internal motor representation of that behaviour within the observer. Evidence supporting the case for an ideomotor theory of imitation has come from studies that show imitative responses to be faster than the same behavioural measures performed in response to spatial cues. In an attempt to replicate these findings, we manipulated the salience of the visual cue and found that we could reverse the advantage of the imitative cue over the spatial cue. We suggest that participants utilised a simple visuomotor mechanism to perform all aspects of this task, with performance being driven by the relative visual salience of the stimuli. Imitation is a more complex motor skill that would constitute an inefficient strategy for rapid performance

Constrained action selection in children with developmental coordination disorder

The effect of advance (‘precue’) information on short aiming movements was explored in adults, high school children, and primary school children with and without developmental coordination disorder (n = 10, 14, 16, 10, respectively). Reaction times in the DCD group were longer than in the other groups and were more influenced by the extent to which the precue constrained the possible action space. In contrast, reaction time did not alter as a function of precue condition in adults. Children with DCD showed greater inaccuracy of response (despite the increased RT). We suggest that the different precue effects reflect differences in the relative benefits of priming an action prior to definitive information about the movement goal. The benefits are an interacting function of the task and the skill level of the individual. Our experiment shows that children with DCD gain a benefit from advance preparation in simple aiming movements, highlighting their low skill levels. This result suggests that goal-directed RTs may have diagnostic potential within the clinic

Manual control age and sex differences in 4 to 11 year old children

To what degree does being male or female influence the development of manual skills in pre-pubescent children? This question is important because of the emphasis placed on developing important new manual skills during this period of a child's education (e.g. writing, drawing, using computers). We investigated age and sex-differences in the ability of 422 children to control a handheld stylus. A task battery deployed using tablet PC technology presented interactive visual targets on a computer screen whilst simultaneously recording participant's objective kinematic responses, via their interactions with the on-screen stimuli using the handheld stylus. The battery required children use the stylus to: (i) make a series of aiming movements, (ii) trace a series of abstract shapes and (iii) track a moving object. The tasks were not familiar to the children, allowing measurement of a general ability that might be meaningfully labelled 'manual control', whilst minimising culturally determined differences in experience (as much as possible). A reliable interaction between sex and age was found on the aiming task, with girls' movement times being faster than boys in younger age groups (e.g. 4-5 years) but with this pattern reversing in older children (10-11 years). The improved performance in older boys on the aiming task is consistent with prior evidence of a male advantage for gross-motor aiming tasks, which begins to emerge during adolescence. A small but reliable sex difference was found in tracing skill, with girls showing a slightly higher level of performance than boys irrespective of age. There were no reliable sex differences between boys and girls on the tracking task. Overall, the findings suggest that prepubescent girls are more likely to have superior manual control abilities for performing novel tasks. However, these small population differences do not suggest that the sexes require different educational support whilst developing their manual skills

Kinematic Measures of Imitation Fidelity in Primary School Children

We sought to develop a method for measuring imitation accuracy objectively in primary school children. Children imitated a model drawing shapes on the same computer-tablet interface they saw used in video clips, allowing kinematics of model and observers' actions to be directly compared. Imitation accuracy was reported as a correlation reflecting the statistical dependency between values of the model's and participant's sets of actions, or as a mean absolute difference between them. Children showed consistent improvement in imitation accuracy across middle childhood. They appeared to rationalize the demands of the task by remembering duration and size of action, which enabled them to reenact speed through motor-planning mechanisms. Kinematic measures may provide a window into the cognitive mechanisms involved in imitation

The 'Goldilocks Zone': getting the measure of manual asymmetries

Some studies have shown that manual asymmetries decrease in older age. These results have often been explained with reference to models of reduced hemispheric specialisation. An alternative explanation, however, is that hand differences are subtle, and capturing them requires tasks that yield optimal performance with both hands. Whereas the hemispheric specialisation account implies that reduced manual asymmetries should be reliably observed in older adults, the ‘measurement difficulty’ account suggests that manual asymmetries will be hard to detect unless a task has just the right level of difficulty – i.e. within the ‘Goldilocks Zone’, where it is not too easy or too hard, but just right. Experiment One tested this hypothesis and found that manual asymmetries were only detected when participants performed in this zone; specifically, performance on a tracing task was only superior in the preferred hand when task constraints were high (i.e. fast speed tracing). Experiment Two used three different tasks to examine age differences in manual asymmetries; one task produced no asymmetries, whilst two tasks revealed asymmetries in both younger and older groups (with poorer overall performance in the old group across all tasks). Experiment Three revealed task-dependent asymmetries in both age groups, but highlighted further detection difficulties linked with the metric of performance and compensatory strategies used by participants. Results are discussed with reference to structural learning theory, whereby we suggest that the processes of inter-manual transfer lead to relatively small performance differences between the hands (despite a strong phenomenological sense of performance disparities)

Evaluating the impact of trigeminal neuralgia

Patients with idiopathic trigeminal neuralgia (TN) were categorised into 3 subtypes (n 5 225). Group 1 (n 5 155, 68.9%) had TN without concomitant pain, group 2 (n532, 14.2%) had TN with intermittent concomitant pain, and group 3 (n539, 16.9%) had TN with autonomic symptoms. We tested 2 hypotheses: (1) that different pain profiles would be associated with the different groups; (2) that the severe pain associated with TN would impact negatively on activities of daily living and thereby result in disability as defined by the World Health Organisation. A different pain profile was found across the groups. We obtained unequivocal evidence that TN causes disability with up to 45% of patients being absent from usual daily activities 15 days or more in the past 6 months. On the Hospital Anxiety and Depression Scale, 35.7% patients had mild-to-severe depression and over 50% were anxious. The Pain Catastrophizing Scale showed that 78% of patients had considerable negative thoughts with scores.20 and a mean score of 36.4. Prior to referral, only 54% had been prescribed carbamazepine while opioids had been prescribed in 14.6% of the patients. Prior to referral, over 80% had already been to 1 specialist centre which had not provided appropriate management. Patients with TN report varied characteristics but all result in some degree of psychosocial disability especially before adequate therapy is attained

Can Virtual Reality Trainers Improve the Compliance Discrimination Abilities of Trainee Surgeons?

The assessment of tissue compliance using a handheld tool is an important skill in medical areas such as laparoscopic and dental surgery. The increasing prevalence of virtual reality devices raises the question of whether we can exploit these systems to accelerate the training of compliance discrimination in trainee surgeons. We used a haptic feedback device and stylus to assess the abilities of naïve participants to detect compliance differences with and without knowledge of results (KR) (groups 1 and 2), as well as the abilities of participants who had undergone repetitive training over several days (group 3). Kinematic analyses were carried out to objectively measure the probing action. Untrained participants had poor detection thresholds (mean just noticeable difference, JND = 33%), and we found no effect of KR (provided after each trial) on performance (mean JND = 35%). Intensive training dramatically improved group performance (mean JND = 12%). Probing action (in particular, slower movement execution) was associated with better detection thresholds, but training did not lead to systematic changes in probing behaviour. These findings set a benchmark for training systems that act to increase perceptual sensitivity and guide the learner toward optimal movement strategies to improve discrimination

A System in the Wild: Deploying a Two Player Arm Rehabilitation System for Children With Cerebral Palsy in a School Environment

This paper outlines a system for arm rehabilitation for children with upper-limb hemiplegia resulting from cerebral palsy. Our research team designed a two-player, interactive (competitive or collaborative) computer play therapy system that provided powered assistance to children while they played specially designed games that promoted arm exercises. We designed the system for a school environment. To assess the feasibility of deploying the system in a school environment, the research team enlisted the help of teachers and staff in nine schools. Once the system was set up, it was used to deliver therapy without supervision from the research team. Ultimately, the system was found to be suitable for use in schools. However, the overriding need for schools to focus on academic activities meant that children could not use the system enough to achieve the amount of use desired for therapeutic benefit. In this paper, we identify the key challenges encountered during this study. For example, there was a marked reluctance to report system issues (which could have been fixed) that prevented children from using the system. We also discuss future implications of deploying similar studies with this type of system

A systematic examination of preoperative surgery warm-up routines

Recent evidence indicates that a preoperative warm-up is a potentially useful tool in facilitating performance. But what factors drive such improvements and how should a warm-up be implemented?In order to address these issues, we adopted a two-pronged approach: (1) we conducted a systematic review of the literature to identify existing studies utilising preoperative simulation techniques; (2) we performed task analysis to identify the constituent parts of effective warm-ups. We identified five randomised control trials, four randomised cross-over trials and four case series. The majority of these studies reviewed surgical performance following preoperative simulation relative to performance without simulation.Four studies reported outcome measures in real patients and the remainder reported simulated outcome measures. All but one of the studies found that preoperative simulation improves operative outcomes-but this improvement was not found across all measured parameters. While the reviewed studies had a number of methodological issues, the global data indicate that preoperative simulation has substantial potential to improve surgical performance. Analysis of the task characteristics of successful interventions indicated that the majority of these studies employed warm-ups that focused on the visual motor elements of surgery. However, there was no theoretical or empirical basis to inform the design of the intervention in any of these studies.There is an urgent need for a more rigorous approach to the development of "warm-up" routines if the potential value of preoperative simulation is to be understood and realised. We propose that such interventions need to be grounded in theory and empirical evidence on human motor performance