Visual Error Augmentation for Enhancing Motor Learning and Rehabilitative Relearning

We developed a real-time controller for a 2 degree-of-freedom robotic system using xPC Target. This system was used to investigate how different methods of performance error feedback can lead to faster and more complete motor learning in individuals asked to compensate for a novel visuo-motor transformation (a 30 degree rotation). Four groups of normal human subjects were asked to reach with their unseen arm to visual targets surrounding a central starting location. A cursor tracking hand motion was provided during each reach. For one group of subjects, deviations from the ideal compensatory hand movement (i.e. trajectory errors) were amplified with a gain of 2 whereas another group was provided visual feedback with a gain of 3.1. Yet another group was provided cursor feedback wherein the cursor was rotated by an additional (constant) offset angle. We compared the rates at which the hand paths converged to the steady-state trajectories. Our results demonstrate that error-augmentation can improve the rate and extent of motor learning of visuomotor rotations in healthy subjects. We also tested this method on straightening the movements of stroke subjects, and our early results suggest that error amplification can facilitate neurorehabilitation strategies in brain injuries such as stroke

Visuomotor Learning Enhanced by Augmenting Instantaneous Trajectory Error Feedback during Reaching

We studied reach adaptation to a 30u visuomotor rotation to determine whether augmented error feedback can promote faster and more complete motor learning. Four groups of healthy adults reached with their unseen arm to visual targets surrounding a central starting point. A manipulandum tracked hand motion and projected a cursor onto a display immediately above the horizontal plane of movement. For one group, deviations from the ideal movement were amplified with a gain of 2 whereas another group experienced a gain of 3.1. The third group experienced an offset equal to the average error seen in the initial perturbations, while a fourth group served as controls. Learning in the gain 2 and offset groups was nearly twice as fast as controls. Moreover, the offset group averaged more reduction in error. Such error augmentation techniques may be useful for training novel visuomotor transformations as required of robotic teleoperators or in movement rehabilitation of the neurologically impaired

Ytterbium-doped tantalum pentoxide waveguide lasers

We have demonstrated a Yb:Ta2O5 waveguide laser fabricated by RF magnetron sputtering on oxidised silicon. The waveguide laser was end-pumped with a laser diode at 977 nm and lasing was observed between 1015 and 1020 nm. The launched pump power threshold and slope efficiency were measured to be ~25 mW and 1.78 %, respectively

Reducible Correlations in Dicke States

We apply a simple observation to show that the generalized Dicke states can be determined from their reduced subsystems. In this framework, it is sufficient to calculate the expression for only the diagonal elements of the reudced density matrices in terms of the state coefficients. We prove that the correlation in generalized Dicke states $|GD_N^{(\ell)}>$ can be reduced to $2\ell$-partite level. Application to the Quantum Marginal Problem is also discussed.Comment: 12 pages, single column; accepted in J. Phys. A as FT

Case 2 : Saving the Rural Ontario Maternity Services – Can We Do It?

Inaya, manager of the ‘low-risk’ project at Provincial Council for Maternal and Child Health (PCMCH), had to come up with an integrative solution for the issues encompassing maternity care in Ontario. The low-risk project aims “to design and develop effective low risk maternal and newborn strategy for Ontario (2015-2018) to ensure that all women have an equitable choice of delivery options, and access to the right level of care at the right time, no matter where they live in the province”. In response to external and internal challenges facing Ontario’s hospitals, the province has seen the closure of rural maternity programs over the last few years. The women in communities that are unable to sustain local services must travel to access distant services, and depending on the distance to the nearest referral center, may be away from their homes and communities during the critical pregnancy period and child birth. The separation of pregnant women from their families and communities can cause negative outcomes. The health and economic impacts of the inability to access local maternal programs are well documented. Different stakeholders have indicated the importance of alternative, sustainable models of interprofessional collaboration of midwifery, primary and specialty care, and the efficient allocation of human health resources (PCMCH, 2015). To create the framework of the model, PCMCH formed a leadership team and expert panel consisting of different care providers. Inaya had to identify barriers and potential solutions by engaging different care providers and exploring the challenges from their perspectives. The findings would be used to work with relevant partners, such as associations of different health care professionals, to develop potential solutions for the Ministry. The goal of the case is to provide readers with the opportunity to apply the concept of collaboration and also explore the barriers to achieving inter-professional collaboration from the key stakeholders’ perspectives

A comparative evaluation of dexmedetomidine and fentanyl with ropivacaine (0.75%) for epidural anesthesia in lower limb orthopedic surgery

Background: The aim of the study was to compare sensory and motor block characteristics, sedation score, post-operative analgesia and hemodynamic changes following epidural ropivacaine 15 ml (0.75%) supplemented with either dexmedetomidine (1 µg/kg) or fentanyl (1 µg/kg) in lower limb orthopedic surgery.Methods: The study was conducted in 60 patients of either sex belonging to ASA status I , II or III, aged 20 to 60 years undergoing lower limb orthopedic surgeries. In this prospective, randomized controlled study patients were divided into two different groups. Group RD receiving dexmedetomidine 1 mcg/kg+15 ml ropivacaine (0.75%) and group RF receiving fentanyl 1 mcg/kg+15 ml ropivacaine (0.75%). Each group included 30 patients.Results: The onset of sensory analgesia at shin of tibia was significantly early with dexmedetomidine (251.7±131.9 secs) as compared to fentanyl (503±63 secs) and similarly the onset of motor block was significantly early in group RD (533±239.6 secs) as compared to group RF (712.66±90.25 secs). Time for complete motor blockade was also significantly faster with group RD (57.1±5.1 mins) as compared to (61.5±3.2 mins) in group RF. The mean time for two segment regression was 274.3±43.6 mins in group RD, while 243.2±19.2 mins in group RF which was statistically significant (p<0.05). The decrease in heart rate, systolic, diastolic blood pressure and mean arterial blood pressure was significantly more in group RD as compared to RF.Conclusions: Addition of dexmedetomidine to epidural ropivacaine produces rapid onset of sensory and motor blockade, prolonged duration of analgesia, with better hemodynamic stability as compared to fentanyl, hence being a useful alternative adjuvant

Comparison between isobaric levobupivacaine 0.5% and hyperbaric bupivacaine 0.5% in spinal anesthesia in lower limb surgeries and lower abdominal surgeries in adult patients

 Background: The aim of our study was to compare sensory and motor block characteristics and hemodynamic changes following intrathecal hyperbaric bupivacaine (0.5%) and isobaric levobupivacaine (0.5%) in elective lower limb and lower abdominal surgeries.Methods: 60 patients of either sex, aged 18-60 years, ASA grade I or II scheduled for elective lower abdominal and lower limb surgeries were randomized into two groups, group B (n=30) and group L (n=30) and received either 3 ml of intrathecal hyperbaric bupivacaine or isobaric levobupivacaine intrathecally.Results: The mean time of onset of sensory block at shin of tibia in both the groups was comparable i.e. levobupivacaine (1.19±0.2 minutes) and bupivacaine (1.1+0.2 minutes). The mean time for total duration of sensory block was 211.1±8.2 minutes in group L, while 193.13±13.7 minutes in group B. Time for total duration of motor block in group L was 198.76±8.428 minutes and in group B was 182.6±13.989 minutes. Statistically significant difference was observed in total duration of sensory and motor block in both levobupivaciane and bupivacaine group (p<0.0001). Patients in group L were hemodynamically more stable with significantly less decrease in pulse rate, systolic blood pressure and diastolic blood pressure as compared to group B.Conclusions: We observed that 0.5% isobaric levobupivacaine provided better hemodynamic stability, longer duration of sensory and motor block as compared to bupivacaine.