John Standeven

Changes in Dynamic Trunk/Head Stability and Functional Reach After Hippotherapy

OBJECTIVES To determine if hippotherapy (therapy using a horse) improves head/trunk stability and upper extremity (UE) reaching/targeting in children with spastic diplegia cerebral palsy (SDCP). DESIGN Pre-postoperative follow-up with a 12-week intervention and 12-week washout period after intervention. SETTING A human performance laboratory with 6 camera video motion capture systems for testing. PARTICIPANTS Eleven children (age 5-13y, average 8y) with SDCP, 8 children (age 5-13y, average 8y) without disabilities. INTERVENTION Hippotherapy intervention performed at 3 therapeutic horseback riding centers. MAIN OUTCOME MEASURES Video motion capture using surface markers collecting data at 60 Hz, a mechanical barrel to challenge trunk and head stability, and functional reach/targeting test on static surface. RESULTS Significant changes with large effect sizes in head/trunk stability and reaching/targeting, elapsed time, and efficiency (reach/path ratio) after 12 weeks of hippotherapy intervention. Changes were retained after a 12-week washout period. CONCLUSIONS Hippotherapy improves trunk/head stability and UE reaching/targeting. These skills form the foundation for many functional tasks. Changes are maintained after the intervention ceases providing a skill foundation for functional tasks that may also enhance occupational performance and participation.

Effect of hippotherapy on motor control, adaptive behaviors, and participation in children with autism spectrum disorder: a pilot study.

OBJECTIVE The purpose of this investigation was to determine whether hippotherapy increased function and participation in children with autism spectrum disorder (ASD). We hypothesized improvements in motor control, which might increase adaptive behaviors and participation in daily activities. METHOD Six children with ASD ages 5-12 participated in 12 weekly 45-min hippotherapy sessions. Measures pre- and post-hippotherapy included the Vineland Adaptive Behavior Scales-II and the Child Activity Card Sort. Motor control was measured preintervention and postintervention using a video motion capture system and force plates. RESULTS Postural sway significantly decreased postintervention. Significant increases were observed in overall adaptive behaviors (receptive communication and coping) and in participation in self-care, low-demand leisure, and social interactions. CONCLUSION These results suggest that hippotherapy has a positive influence on children with ASD and can be a useful treatment tool for this population.

Stroke survivor gait adaptation and performance after training on a Powered Ankle Foot Orthosis

With over 600 thousand people each year surviving a stroke, it has become the leading cause of serious long-term disability in the United States [1], [2]. The adverse financial and social conditions attributed to stroke have prompted researchers and entrepreneurs to explore the viability of rehabilitation robots. The Powered Ankle Foot Orthosis (PAFO) utilizes robotic tendon technology and supports motion with a single degree of freedom, ankle rotation in the Sagittal plane. Motion capture data, robot sensor data, and functional 6 minute walk data were collected on three stroke subjects. All subjects had some positive changes in their key gait variables while using the PAFO. These changes were more dramatic while harnessed and using a treadmill as opposed to walking over ground. Robot sensor data showed significant improvements on key variables for the three subjects. Motion capture data showed improvements in knee range of motion for subject 1, and the 6 minute walk data showed an increase in distance walked for subjects 1 and 3. Comfort, stability, and robustness proved to be critical design parameters for developing a gait therapy robot capable of collecting repeatable data with low variability.

Cervical spine motion during extrication.

BACKGROUND It has been estimated that up to one-quarter of spinal cord injuries may be significantly worsened during extrication or early treatment after a motor vehicle accident. STUDY OBJECTIVES The purpose of this study was to analyze the planar motions of the head relative to the torso during extrication from an automobile in a laboratory setting. METHODS Video motion capture was used to quantify the range of motion of the head relative to the torso in 10 participants as they were extricated from a mock motor vehicle during four different extrication techniques: 1) Unassisted Unprotected, 2) Unassisted Protected with a cervical collar (CC), 3) Assisted and Protected with a CC, and 4) Assisted and Protected with a CC and Kendrick Extrication Device. RESULTS The results indicated a significant decrease in movement for all motions when the driver exited the vehicle unassisted with CC protection, compared to exiting unassisted and without protection. Decreases in movement were also observed for an event (i.e., Pivot in seat) during extrication with paramedic assistance and protection. However, no movement reduction was observed in another event (i.e., Recline on board) with both paramedic assistance and protection. CONCLUSION In this study, no decrease in neck movement occurred for certain extrication events that included protection and assistance by the paramedics. Future work should further investigate this finding.

Variability and misclassification of worker estimated hand force

Ergonomic studies often use worker estimated hand force reproduced on a dynamometer to quantify force exposures but this method has not been well-studied in real work settings. This study evaluated the validity of worker estimates of hand force in a field study and determined the misclassification of worker estimated hand force exposures compared to directly measured forces. Eight experienced sheet metal assemblers completed ¼-inch diameter fastener installations using 6 different pneumatic tools. Grip forces were recorded by a pressure mat and were compared to worker estimated forces demonstrated on a dynamometer. Directly measured and worker estimated readings showed moderate correlations (0.53-0.67) for four installation tools and fair to moderate for two tools. The coefficient for variation of force estimates was 65% within repeated subject trials and 78% between averaged subject trials but 69% between subject trials during actual tool installations. Misclassification of worker estimated exposures varied by two cut-points: 29% using 4.0 kg and 49% using 6.0 kg. The force match procedure may provide adequate differentiation of high and low exposures in some settings, but is likely to result in substantial misclassification in other settings.

Using Free Internet Videogames in Upper Extremity Motor Training for Children with Cerebral Palsy

Movement therapy is one type of upper extremity intervention for children with cerebral palsy (CP) to improve function. It requires high-intensity, repetitive and task-specific training. Tedium and lack of motivation are substantial barriers to completing the training. An approach to overcome these barriers is to couple the movement therapy with videogames. This investigation: (1) tested the feasibility of delivering a free Internet videogame upper extremity motor intervention to four children with CP (aged 8–17 years) with mild to moderate limitations to upper limb function; and (2) determined the level of intrinsic motivation during the intervention. The intervention used free Internet videogames in conjunction with the Microsoft Kinect motion sensor and the Flexible Action and Articulated Skeleton Toolkit software (FAAST) software. Results indicated that the intervention could be successfully delivered in the laboratory and the home, and pre- and post- impairment, function and performance assessments were possible. Results also indicated a high level of motivation among the participants. It was concluded that the use of inexpensive hardware and software in conjunction with free Internet videogames has the potential to be very motivating in helping to improve the upper extremity abilities of children with CP. Future work should include results from additional participants and from a control group in a randomized controlled trial to establish efficacy.

Spinal cord and brain injury protection: testing concept for a protective device

Study design:Test development for a device that could prevent both brain and spinal cord injuries during motorcycling and horseback riding.Objective:The objective of this study was to develop a method and test a concept device that could protect against both spinal cord (SCI) and brain injuries (BI).Setting:St Louis, Missouri, USA.Methods:A Hybrid III dummy (that is, head, neck and torso) was used as a pendulum bob during three test conditions: (1) no protection, (2) standard motorcycle helmet and (3) SCI and BI test structure (SCIBITS). Triaxial accelerometers, a C1 force transducer and a video system were used to collect data as the dummy axially impacted a rigid barrier at speeds ranging from 10 to 605 cm s−1. SCIBITS consisted of a fused fiberglass thoracic jacket/head shield unit. Separation between the dummy head and the head shield permitted freedom of head movement within safe limits as impact forces to the head shield were transferred from the head and neck to the upper thorax. The BI threshold was 200–300 g, and the SCI threshold was 3010 N.Results:The SCIBITS protected against spinal cord injury, whereas the motorcycle helmet did not. The helmet protected against BI and the SCIBITS provided partial protection.Conclusions:The experiments describe the efficacy of an impact testing system utilizing an instrumented dummy suspended as a pendulum bob. The equipment will facilitate the design and construction of a functional device for protection against both SCI and BI in relation to both motorcycling and horseback riding.

Trunk and neck kinematics during overground manual wheelchair propulsion in persons with tetraplegia.

Abstract Purpose: To test the hypothesis that movement of the head and trunk increases as a consequence of speed during manual wheelchair propulsion over the ground in individuals with tetraplegia. Methods: Seven adult participants with tetraplegia who used manual wheelchairs (5 men and 2 women, aged 33.0 ± 10.2) were selected for the study. Participants propelled over the ground at three different speeds while video motion capture methods collected kinematic data. Variables investigated were forward flexion, lateral flexion and axial rotation for both the head and trunk. Repeated measures ANOVA were used to determine effects of speed on head and trunk movements. Results: Both neck and trunk forward flexion significantly increased as a result of speed (p = 0.034, p = 0.031), with a large effect size (r = 0.6, r = 0.6) between slow and fast speeds. Lateral flexion and axial rotation were minimal for the neck and trunk and did not significantly increase with speed. Conclusions: Results suggest that manual wheelchair users with tetraplegia compensate for trunk muscle weakness by flexing the upper trunk and neck forward during manual wheelchair propulsion and that these movements increase with speed. Further studies should examine if these movements relate to overuse injuries and interventions that focus on improving manual wheelchair biomechanics of individuals with tetraplegia. Implications for Rehabilitation Individuals who use manual wheelchairs utilize their upper extremities almost exclusively for both everyday mobility and participation in daily life activities which can often lead to overuse injuries and pain. Despite having a lack of trunk muscle innervation, manual wheelchair users with tetraplegia are able to compensate for this weakness by using the upper trunk and neck. The way in which force is translated from the trunk through the upper extremities to the pushrim may impact propulsion biomechanics, and ultimately the extent in which upper extremity pain and injury develops. A better understanding of how individuals with trunk impairments propel a manual wheelchair will help clinicians determine optimal wheelchair positioning and training during rehabilitation for individuals with tetraplegia. Clinicians can determine ways in which they can support manual wheelchair users to allow for most efficient biomechanics.

Evaluation of anti-vibration interventions for the hand during sheet metal assembly work

OBJECTIVE Occupational use of vibrating hand tools contributes to the development of upper extremity disorders. While several types of vibration damping materials are commercially available, reductions in vibration exposure are usually tested in the laboratory rather than in actual work environments. This study evaluated reductions in hand vibration with different vibration damping interventions under actual work conditions. METHODS Three experienced sheet metal assemblers at a manufacturing facility installed sheet metal fasteners with a pneumatic tool using no vibration damping (bare hand) and each of six anti-vibration interventions (five different gloves and a viscoelastic tool wrap). Vibration was measured with tri-axial accelerometers on the tool and the back of the hand. RESULTS Unweighted mean vibration measured at the hand showed reduced vibration (p<0.001) for all six interventions (range = 3.07-5.56 m/s(2)) compared to the bare hand condition (12.91 m/s(2)). CONCLUSIONS All of the interventions were effective at reducing vibration at the hand during testing under usual work conditions. Field testing beyond laboratory-based testing accounts for the influences of worker, tools, and materials on vibration transmission to the body from specific work operations.

Reliability and validity of the Microsoft Kinect for assessment of manual wheelchair propulsion

Concurrent validity and test-retest reliability of the Microsoft Kinect in quantification of manual wheelchair propulsion were examined. Data were collected from five manual wheelchair users on a roller system. Three Kinect sensors were used to assess test-retest reliability with a still pose. Three systems were used to assess concurrent validity of the Kinect to measure propulsion kinematics (joint angles, push loop characteristics): Kinect, Motion Analysis, and Dartfish ProSuite (Dartfish joint angles were limited to shoulder and elbow flexion). Intraclass correlation coefficients revealed good reliability (0.87-0.99) between five of the six joint angles (neck flexion, shoulder flexion, shoulder abduction, elbow flexion, wrist flexion). ICCs suggested good concurrent validity for elbow flexion between the Kinect and Dartfish and between the Kinect and Motion Analysis. Good concurrent validity was revealed for maximum height, hand-axle relationship, and maximum area (0.92-0.95) between the Kinect and Dartfish and maximum height and hand-axle relationship (0.89-0.96) between the Kinect and Motion Analysis. Analysis of variance revealed significant differences (p < 0.05) in maximum length between Dartfish (mean 58.76 cm) and the Kinect (40.16 cm). Results pose promising research and clinical implications for propulsion assessment and overuse injury prevention with the application of current findings to future technology.