Active robotic training improves locomotor function in a stroke survivor

Abstract Background Clinical outcomes after robotic training are often not superior to conventional therapy. One key factor responsible for this is the use of control strategies that provide substantial guidance. This strategy not only leads to a reduction in volitional physical effort, but also interferes with motor relearning. Methods We tested the feasibility of a novel training approach (active robotic training) using a powered gait orthosis (Lokomat) in mitigating post-stroke gait impairments of a 52-year-old male stroke survivor. This gait training paradigm combined patient-cooperative robot-aided walking with a target-tracking task. The training lasted for 4-weeks (12 visits, 3 × per week). The subject’s neuromotor performance and recovery were evaluated using biomechanical, neuromuscular and clinical measures recorded at various time-points (pre-training, post-training, and 6-weeks after training). Results Active robotic training resulted in considerable increase in target-tracking accuracy and reduction in the kinematic variability of ankle trajectory during robot-aided treadmill walking. These improvements also transferred to overground walking as characterized by larger propulsive forces and more symmetric ground reaction forces (GRFs). Training also resulted in improvements in muscle coordination, which resembled patterns observed in healthy controls. These changes were accompanied by a reduction in motor cortical excitability (MCE) of the vastus medialis, medial hamstrings, and gluteus medius muscles during treadmill walking. Importantly, active robotic training resulted in substantial improvements in several standard clinical and functional parameters. These improvements persisted during the follow-up evaluation at 6 weeks. Conclusions The results indicate that active robotic training appears to be a promising way of facilitating gait and physical function in moderately impaired stroke survivors.http://deepblue.lib.umich.edu/bitstream/2027.42/112853/1/12984_2011_Article_375.pd

Bimanual Movement Characteristics and Real-World Performance Following Hand-Arm Bimanual Intensive Therapy in Children with Unilateral Cerebral Palsy

The purpose of this study was to quantify characteristics of bimanual movement intensity during 30 h of hand-arm bimanual intensive therapy (HABIT) and bimanual performance (activities and participation) in real-world settings using accelerometers in children with unilateral cerebral palsy (UCP). Twenty-five children with UCP participated in a 30 h HABIT program. Data were collected from bilateral wrist-worn accelerometers during 30 h of HABIT to quantify the movement intensity and three days pre- and post-HABIT to assess real-world performance gains. Movement intensity and performance gains were measured using six standard accelerometer-derived variables. Bimanual capacity (body function and activities) was assessed using standardized hand function tests. We found that accelerometer variables increased significantly during HABIT, indicating increased bimanual symmetry and intensity. Post-HABIT, children demonstrated significant improvements in all accelerometer metrics, reflecting real-world performance gains. Children also achieved significant and clinically relevant changes in hand capacity following HABIT. Therefore, our findings suggest that accelerometers can objectively quantify bimanual movement intensity during HABIT. Moreover, HABIT enhances hand function as well as activities and participation in real-world situations in children with UCP

Virtual Reality Assessment of Arm Choice Under Cognitive Load

This repository contains data and analysis scripts associated with Potts, Williamson, Jacob, Kantak, and Buxbaum (Under Review) https://osf.io/preprints/psyarxiv/fp4dq

Reaching the cognitive-motor interface: Cognitive load diminishes arm choice efficiency and motor performance in neurotypicals and individuals with stroke

Daily life requires use of the arms for a variety of tasks under competing cognitive demands, such as reaching for objects in a visually-cluttered kitchen cabinet while holding a conversation. Prior studies have suggested that such demands may impact motor performance, including selection of the most efficient arm to use to reach to a target in a given location. The research conducted here expands upon prior studies by 1) examining the role of cognitive load in arm choice efficiency using a novel virtual reality paradigm designed to mimic the demands of real-life visual search, object selection, and reaching to targets, and 2) examining the impact of such demands on motor performance in individuals with stroke. To manipulate cognitive demand, we varied the semantic similarity of objects in the reaching space and the presence or absence of a secondary task. We hypothesized that cognitive load would modulate efficiency of arm choice and performance in both neurotypicals and individuals with stroke. The results showed reduced efficiency of arm choice for the stroke and neurotypical control groups under increased demand. Under cognitive load, participants with stroke also showed slower reach initiation, slower movements, increased reach curvature, and increased performance differences between the paretic and non-paretic arms. These data indicate that cognitive factors influence arm choice efficiency in naturalistic reaching tasks in neurotypical individuals, and both arm choice efficiency and motor performance in stroke. Efficiency and performance decrements under cognitive load may in turn influence reduced use of the paretic arm during daily activities

Bimanual Movement Characteristics and Real-World Performance Following Hand–Arm Bimanual Intensive Therapy in Children with Unilateral Cerebral Palsy

The purpose of this study was to quantify characteristics of bimanual movement intensity during 30 h of hand–arm bimanual intensive therapy (HABIT) and bimanual performance (activities and participation) in real-world settings using accelerometers in children with unilateral cerebral palsy (UCP). Twenty-five children with UCP participated in a 30 h HABIT program. Data were collected from bilateral wrist-worn accelerometers during 30 h of HABIT to quantify the movement intensity and three days pre- and post-HABIT to assess real-world performance gains. Movement intensity and performance gains were measured using six standard accelerometer-derived variables. Bimanual capacity (body function and activities) was assessed using standardized hand function tests. We found that accelerometer variables increased significantly during HABIT, indicating increased bimanual symmetry and intensity. Post-HABIT, children demonstrated significant improvements in all accelerometer metrics, reflecting real-world performance gains. Children also achieved significant and clinically relevant changes in hand capacity following HABIT. Therefore, our findings suggest that accelerometers can objectively quantify bimanual movement intensity during HABIT. Moreover, HABIT enhances hand function as well as activities and participation in real-world situations in children with UCP

Active robotic training improves locomotor function in a stroke survivor

Abstract Background Clinical outcomes after robotic training are often not superior to conventional therapy. One key factor responsible for this is the use of control strategies that provide substantial guidance. This strategy not only leads to a reduction in volitional physical effort, but also interferes with motor relearning. Methods We tested the feasibility of a novel training approach (active robotic training) using a powered gait orthosis (Lokomat) in mitigating post-stroke gait impairments of a 52-year-old male stroke survivor. This gait training paradigm combined patient-cooperative robot-aided walking with a target-tracking task. The training lasted for 4-weeks (12 visits, 3 × per week). The subject’s neuromotor performance and recovery were evaluated using biomechanical, neuromuscular and clinical measures recorded at various time-points (pre-training, post-training, and 6-weeks after training). Results Active robotic training resulted in considerable increase in target-tracking accuracy and reduction in the kinematic variability of ankle trajectory during robot-aided treadmill walking. These improvements also transferred to overground walking as characterized by larger propulsive forces and more symmetric ground reaction forces (GRFs). Training also resulted in improvements in muscle coordination, which resembled patterns observed in healthy controls. These changes were accompanied by a reduction in motor cortical excitability (MCE) of the vastus medialis, medial hamstrings, and gluteus medius muscles during treadmill walking. Importantly, active robotic training resulted in substantial improvements in several standard clinical and functional parameters. These improvements persisted during the follow-up evaluation at 6 weeks. Conclusions The results indicate that active robotic training appears to be a promising way of facilitating gait and physical function in moderately impaired stroke survivors.</p

Effects of Motor Cortical Stimulation during Planar Reaching Movement

Background: The purpose was to examine the effects of single pulse transcranial magnetic stimulation (TMS) over primary motor cortex delivered at different times during a center-out reaching task in a robot reaching environment. Methods: Eleven right-handed subjects participated. Movement hotspots and thresholds were determined for each subject, and the stimulation intensity was set at 120% of the movement threshold. TMS was delivered at rest and when subjects performed a series of reaching tasks. The 5 different conditions were: no stimulation, sham stimulation, and stimulation at 150, 500, or 1000 ms post go cue. Outcome measures included TMS-evoked movement during rest and in the 150ms condition, trajectory deviations (no stimulation, sham, and 150ms conditions), and peak velocity (PV), path length, reaction time, acceleration time, and deceleration time for all conditions. Results: When TMS was applied at 150 ms, the evoked path lengths were significantly shorter than at rest and had less deviation than the no-stimulation condition (p &lt; 0.05). Peak velocities were lowest during the no-stimulation condition and highest during the 500ms condition (p &lt; 0.05). Path lengths were significantly shorter during the no-stimulation, sham, and 150ms condition compared to the 500ms and 1000ms conditions. Conclusions: TMS applied during the reaction time phase suppressed movements evoked by TMS, decreased trajectory deviations, and shortened path length, while TMS delivered after movement onset increased PV and path length. TMS stimulation may be delivered to enhance movement parameters and potentially facilitate reach training in the robotic rehabilitation environment

Posture-related Modulations in Motor Cortical Excitability of the Proximal and Distal Arm Muscles

[[abstract]]The effect of postural orientation on the motor corticospinal excitability (MCE) of proximal and distal upper extremity (UE) muscles was investigated. In a crossover design, recruitment curves (RCs), short interval cortical inhibition (SICI) and intracortical facilitation (ICF) of resting anterior deltoid (AD) and first dorsal interosseus (FDI) was assessed in two postures: sitting and standing. Six healthy adults without contraindications to transcranial magnetic stimulation (TMS) participated in the study. TMS was applied over the motor cortical representation of FDI and AD at intensities ranging from 90% to 200% of resting motor threshold (RMT) in increments of 10%. SICI and ICF were assessed for each muscle using a conditioning stimulus (80% RMT) preceding a test stimulus (120% RMT) with an interstimulus interval of 2 ms and 15 ms, respectively. For AD, but not FDI, there was a significant and consistent increase in RC slope during standing compared to sitting. For FDI, there was no difference in ICF and SICI between sitting and standing. However, for AD, while there was no difference in ICF between the two postures, there was a clear trend for SICI to decrease (p=0.06) in standing compared to sitting. These results indicate that postural change from sitting to standing, affects the MCE of proximal but not distal muscles. While this indicates the role of proximal UE muscles in postural control, it also implies that rehabilitation protocols for enhancing proximal arm motor function may be advantaged if administered in a standing posture