Madeleine Grealy

Improving cognitive function after brain injury: The use of exercise and virtual reality

OBJECTIVE To assess the impact of exercise and virtual reality (VR) on the cognitive rehabilitation of persons with traumatic brain injury (TBI). DESIGN Before-after trial assessed cognitive function after a 4-week intervention program. A random allocation crossover assessed changes in reaction and movement times after a single bout of VR exercise and a no-exercise control condition. SETTING Brain injury rehabilitation unit in Edinburgh, Scotland. PATIENTS (1) Four-week intervention: a consecutive sample of 13 suitable TBI adults were compared to control populations (n > 25) of previous TBI patients of similar age, severity, and time postinjury. (2) Single-bout intervention: a consecutive sample of 13 suitable adults with moderate TBI, 6.29 to 202.86 weeks postinjury. INTERVENTION Nonimmersive VR exercise. MAIN OUTCOME MEASURES (1) Tests of attention, information processing, learning, and memory. (2) Reaction and movement times. RESULTS After the 4-week intervention patients performed significantly better than controls on the digit symbol (p < .01). verbal (p < .01), and visual learning tasks (p < .05). Significant improvements in reaction times (p < .01) and movement times (p < .05) were gained following a single bout of VR exercise. CONCLUSION Exercising in a virtual environment offers the potential for significant gains in cognitive function.

A Taxometric Analysis of Type-D Personality

Objective: To test the dimensionality of Type-D personality, using taxometric procedures, to assess if Type-D personality is taxonic or dimensional. Type-D personality is treated as a categorical variable and caseness has been shown to be a risk factor for poor prognosis in coronary heart disease. However, at present, there is no direct evidence to support the assumption that Type D is categorical and able to differentiate true cases from noncases. Methods: In total, 1012 healthy young adults from across the United Kingdom and Ireland completed the DS14, the standard index of Type D, and scores were submitted to two taxometric procedures MAMBAC and MAXCOV. Results: Graphical representations (comparing actual with simulated data) and fit indices indicated that Type D is more accurately represented as a dimensional rather than categorical construct. Conclusion: Type D is better represented as a dimensional construct. Implications for theory development and clinical practice with respect to Type D are examined as well as the wider use of taxometrics within psychosomatic medicine (e.g., to investigate if there are medically unexplained syndrome taxons, such as a Gulf War Syndrome taxon). NA = negative affectivity; SI = social inhibition; MAMBAC = mean above minus below a cut; MAXCOV = maximum covariance; MAXEIG = maximum Eigenvalue; L-MODE = L-mode factor analysis; CCFI = curve comparison fit index.

Guiding the swing in golf putting

Actions that involve making contact with surfaces often demand perceptual regulation of the impact — for example, of feet with ground when walking or of bat with ball when hitting. Here we investigate how this control of impact is achieved in golf putting, where control of the clubhead motion at ball impact is paramount in ensuring that the ball will travel the required distance. Our results from ten professional golfers indicate that the clubhead motion is spatially scaled and perceptually regulated by coupling it onto an intrinsic guide generated in the nervous system.

SENSORY AND INTRINSIC COORDINATION OF MOVEMENT

A recently generalized theory of perceptual guidance (general τ theory) was used to analyse coordination in skilled movement. The theory posits that (i) guiding movement entails controlling closure of spatial and/or force gaps between effectors and goals, by sensing and regulating the τs of the gaps (the time–to–closure at current closure rate), (ii) a principal way of coordinating movements is keeping the τs of different gaps in constant ratio (known as τ–coupling), and (iii) intrinsically paced movements are guided and coordinated by τ–coupling onto a τ–guide, τg, generated in the nervous system and described by the equation τg = 0.5(t minus T2/t) where T is the duration of the body movement and t is the time from the start of the movement. Kinematic analysis of hand to mouth movements by human adults, with eyes open or closed, indicated that hand guidance was achieved by maintaining, during 80 to 85% of the movement, the τ–couplings τα–τr and τr–τg, where τr is τ of the hand–mouth gap, τα is τ of the angular gap to be closed by steering the hand and τg is an intrinsic τ–guide.

Volitional control of anticipatory ocular smooth pursuit after viewing, but not pursuing, a moving target: evidence for a re-afferent velocity store

Abstract Although human subjects cannot normally initiate smooth eye movements in the absence of a moving target, previous experiments have established that such movements can be evoked if the subject is required to pursue a regularly repeated, transient target motion stimulus. We sought to determine whether active pursuit was necessary to evoke such an anticipatory response or whether it could be induced after merely viewing the target motion. Subjects were presented with a succession of ramp target motion stimuli of identical velocity and alternating direction in the horizontal axis. In initial experiments, the target was exposed for only 120 ms as it passed through centre, with a constant interval between presentations. Ramp velocity was varied from ±9 to 45°/s in one set of trials; the interval between ramp presentations was varied from 640 to 1920 ms in another. Subjects were instructed either to pursue the moving target from the first presentation or to hold fixation on another, stationary target during the first one, two or three presentations of the moving display. Without fixation, the first smooth movement was initiated with a mean latency of 95 ms after target onset, but with repeated presentations anticipatory smooth movements started to build up before target onset. In contrast, when the subjects fixated the stationary target for three presentations of the moving target, the first movement they made was already anticipatory and had a peak velocity that was significantly greater than that of the first response without prior fixation. The conditions of experiment 1 were repeated in experiment 3 with a longer duration of target exposure (480 ms), to allow higher eye velocities to build up. Again, after three prior fixations, the anticipatory velocity measured at 100 ms after target onset (when visual feedback would be expected to start) was not significantly different to that evoked after the subjects had made three active pursuit responses to the same target motion, reaching a mean of 20°/s for a 50°/s target movement. In a further experiment, we determined whether subjects could use stored information from prior active pursuit to generate anticipatory pursuit in darkness if there was a high expectancy that the target would reappear with identical velocity. Subjects made one predictive response immediately after target disappearance, but very little response thereafter until the time at which they expected the target to reappear, when they were again able to re-vitalise the anticipatory response before target appearance. The findings of these experiments provide evidence that information related to target velocity can be stored and used to generate future anticipatory responses even in the absence of eye movement. This suggests that information for storage is probably derived from a common pre-motor drive signal that is inhibited during fixation, rather than an efference copy of eye movement itself. Furthermore, a high level of expectancy of target appearance can facilitate the release of this stored information in darkness.

Increasing older adults’ walking through primary care: results of a pilot randomized controlled trial

Background. Physical activity can positively influence health for older adults. Primary care is a good setting for physical activity promotion. Objective. To assess the feasibility of a pedometer-based walking programme in combination with physical activity consultations. Methods. Design: Two-arm (intervention/control) 12-week randomized controlled trial with a 12-week follow-up for the intervention group. Setting: One general practice in Glasgow, UK. Participants: Participants were aged ≥65 years. The intervention group received two 30-minute physical activity consultations from a trained practice nurse, a pedometer and a walking programme. The control group continued as normal for 12 weeks and then received the intervention. Both groups were followed up at 12 and 24 weeks. Outcome measures: Step counts were measured by sealed pedometers and an activPALTM monitor. Psychosocial variables were assessed and focus groups conducted. Results. The response rate was 66% (187/284), and 90% of those randomized (37/41) completed the study. Qualitative data suggested that the pedometer and nurse were helpful to the intervention. Step counts (activPAL) showed a significant increase from baseline to week 12 for the intervention group, while the control group showed no change. Between weeks 12 and 24, step counts were maintained in the intervention group, and increased for the control group after receiving the intervention. The intervention was associated with improved quality of life and reduced sedentary time. Conclusions. It is feasible to recruit and retain older adults from primary care and help them increase walking. A larger trial is necessary to confirm findings and consider cost-effectiveness.

Effect of Size and Frame of Visual Field on the Accuracy of an Aiming Movement

The aim of this study was to analyse the effects of manipulating the size and contour of the visual field on the accuracy of an aiming task. Subjects were required to perform pointing movements without seeing their moving hand. The target was displayed in either a wide structured visual field (control condition), a narrow visual field with orthogonal frame, or a narrow visual field with circular frame. The visual information surrounding the target was always provided prior to movement onset, but during the execution of the movement on only half of the trials. Overall, the results showed that undershooting was a common performance characteristic in all of the conditions. In comparison to the control performance, an increase of the degree of undershoot was found when the target was displayed inside a narrower visual field. An additional radial error was found when the contour of the visual scene was circular, but only when the visual context was available during the movement. The same pattern of results was observed for variable error. However, angular errors were not found to vary over the different conditions. Overall, the findings suggested that the visual context contributed to the assessment of the target locations, and the subsequent motor programming. Furthermore, visual information aided the on-line control of the unseen hand, but the extent of this was dependent on the size and shape of the frame denoting the visual scene. Finally, in the absence of any unexpected perturbation, the en-route amendment of the arm trajectory, based on visual information processing, seemed to be more related to distance than azimuth control.

Transforming from cocoon to butterfly: the potential role of the body in the process of posttraumatic growth

The diagnosis of cancer has the potential to elicit positive change (posttraumatic growth [PTG]) through the experience of trauma and adversity. However, psychology and clinical practices and most recently positive psychology have been criticized for their indifference toward the influence of the body on positive psychological functioning. The aim of this study was to broaden the understanding of PTG, including its process and outcomes, using interpretive phenomenological analysis. Ten female breast cancer survivors, from an already existing study, participated in an individual, open-ended interview. These were transcribed verbatim and analyzed for themes that reflected the women’s experience of growing from adversity. The role of the body was found to be a vital component to the process and outcomes of PTG and was deconstructed into three smaller themes: fear of new body, negative effects of chemotherapy on the body (fatigue, loss of desire), and reconnection with body (cocoon to butterfly, listening to body, body as a barometer/monitoring). In addition, the analysis revealed how these 10 women perceived the body as an integral component to their self-identity and how this affected their achievement of PTG. Future research should begin to acknowledge and conduct further study into the neglected role of the body as a contributor or determinant of the PTG process.

Detecting motor abnormalities in preterm infants.

Abstract. As a consequence of the fragility of various neural structures, preterm infants born at a low gestation and/or birthweight are at an increased risk of developing motor abnormalities. The lack of a reliable means of assessing motor integrity prevents early therapeutic intervention. In this paper, we propose a new method of assessing neonatal motor performance, namely the recording and subsequent analysis of intraoral sucking pressures generated when feeding nutritively. By measuring the infants control of sucking in terms of a new development of tau theory, normal patterns of intraoral motor control were established for term infants. Using this same measure, the present study revealed irregularities in sucking control of preterm infants. When these findings were compared to a physiotherapists assessment six months later, the preterm infants who sucked irregularly were found to be delayed in their motor development. Perhaps a goal-directed behaviour such as sucking control that can be measured objectively at a very young age, could be included as part of the neurological assessment of the preterm infant. More accurate classification of a preterm infants movement abnormalities would allow for early therapeutic interventions to be realised when the infant is still acquiring the most basic of motor functions.

Towards a design tool for visualizing the functional demand placed on older adults by everyday living tasks

This paper discusses the development of a design tool using data calculated from the biomechanical functional demand on joints in older adults during activities of daily living, portrayed using a visual ‘traffic-light’ system. Whole body movements of 84 older adults were analysed using a 3D motion capture system and reaction forces were measured by force platforms, and translated into a 3D software model. Although originally intended as a tool for designers, the early evaluation of this method of visualizing the data suggests that it may be of value across those involved in the professional care of older adults.