Abstract: Arm motion in healthy humans is characterized by smooth and relatively short paths. The current study focused on 3D reaching in stroke patients. Sixteen right-hemiparetic stroke patients and 8 healthy adults performed 42 reaching movements towards 3 visual targets located at an extended arm distance. Performance was assessed in terms of spatial and temporal features of the movement; i.e., hand path, arm posture and smoothness. Differences between groups and within subjects were hypothesized for spatial and temporal aspects of reaching under the assumption that both are independent. As expected, upper limb motion of patients was characterized by longer and jerkier hand paths and slower speeds. Assessment of the number of sub-movements within each movement did not clearly discriminate between groups. Principal component analyses revealed specific clusters of either spatial or temporal measures, which accounted for a large proportion of the variance in patients but not in healthy controls. These findings support the notion of a separation between spatial and temporal features of movement. Stroke patients may fail to integrate the two aspects when executing reaching movements towards visual targets.

Abstract: Purpose: Motor recovery of the upper limb (UL) is related to exercise intensity, defined as movement repetitions divided by minutes in active therapy, and task difficulty. However, the degree to which UL training in virtual reality (VR) applications deliver intense and challenging exercise and whether these factors are considered in different centres for people with different sensorimotor impairment levels is not evidenced. We determined if (1) a VR programme can deliver high UL exercise intensity in people with sub-acute stroke across different environments and (2) exercise intensity and difficulty differed among patients with different levels of UL sensorimotor impairment.Methods: Participants with sub-acute stroke (<6 months) with Fugl-Meyer scores ranging from 14 to 57, completed 10 approximately 50-min UL training sessions using three unilateral and one bilateral VR activity over 2 weeks in centres located in three countries. Training time, number of movement repetitions, and success rates were extracted from game activity logs. Exercise intensity was calculated for each participant, related to UL impairment, and compared between centres.Results: Exercise intensity was high and was progressed similarly in all centres. Participants had most difficulty with bilateral and lateral reaching activities. Exercise intensity was not, while success rate of only one unilateral activity was related to UL severity.Conclusion: The level of intensity attained with this VR exercise programme was higher than that reported in current stroke therapy practice. Although progression through different activity levels was similar between centres, clearer guidelines for exercise progression should be provided by the VR application.Implications for rehabilitationVR rehabilitation systems can be used to deliver intensive exercise programmes.VR rehabilitation systems need to be designed with measurable progressions through difficulty levels.

Abstract: The present experiment was carried out to explore the response of driving subjects to emergency braking. The field trial consisted of driving behind a leading vehicle while the following drivers' responses were recorded by telemetry. A group of 51 individuals performed a series of trials at two driving speeds (60 and 80km/h), two following distances (6 and 12 m), and two braking conditions (real and dummy braking). Not all of these subjects completed all conditions or the minimum number of trials. The dependent variables were the total braking time (TBT) and its subcomponents: braking reaction time (BRT), and accelerator-to-brake movement time (MT). These data were analysed in three separate three-way ANOVAs with repeated measures on all factors. The results showed that when subjects were not aware of the forthcoming braking, the distance and braking conditions had major effects on all dependent variables. At the shorter following distance drivers reacted and moved faster. Similarly, when the brakes were real compared with dummy (i.e. brake lights only) drivers reacted faster. In addition, drivers reacted to onset of brake lights in 83% of the cases when dummy braking was applied, compared with 97% when real brakes were applied. Speed of driving did not show any significant effects and did not appear to influence the cognitive or attentional set to anticipate an emergency manoeuvre. These findings suggest that changes in angular velocity during optic expansion of the leading vehicle may be used as a cue to modulate braking movement, while onset of brake lights alone may be enough to trigger a ‘ballistic’ preventive response.