Robert Price

Selective dorsal rhizotomy: efficacy and safety in an investigator‐masked randomized clinical trial

The objective of this single‐center investigator‐masked randomized clinical trial was to investigate the efficacy and safety of selective dorsal rhizotomy (SDR) in children with spastic diplegia. Forty‐three children with spastic diplegia were randomly assigned on an intention‐to‐treat basis to receive SDR plus physical therapy (PT), or PT alone. Thirty‐eight children completed follow‐up through 24 months. Twenty‐one children received SDR (SDR+PT group) and 17 received PT (PT Only group). SDR was guided with electrophysiological monitoring and performed by one experienced neurosurgeon. All subjects received equivalent PT. Spasticity was quantified with an electromechanical torque measurement device (spasticity measurement system [SMS]). The Gross Motor Function Measure (GMFM) was used to document changes in functional mobility. Primary outcome measures were collected at baseline, 6, 12, and 24 months by evaluators masked to treatment.

Comprehensive analysis of dynamic elastic response feet: Seattle ankle/lite foot versus SACH foot

This study evaluated biomechanical and metabolic performance differences between two prosthetic foot designs in light of their mechanical properties. Ten unilateral below-knee amputee subjects, at least 1 year after amputation, capable of walking and running, were studied. Differences in heel and forefoot compliance explained differences in gait events and alignment. Increased efficiency of pushoff in the Seattle Ankle/Lite Foot exists as evidenced by the decrease loading on the opposite limb during double support and a less shortened step length on the sound side compared to the SACH foot. The natural frequency of oscillation for the prosthetic feet was determined to be too high to provide energy storage and release synchronized with kinematic requirements because neither metabolic cost savings nor differences in metabolic efficiency were found. Comfortable walking speed and the nadir of metabolic rate and efficiency are not different. Via accelerometer measurement, it was found that the more compliant and lossy SACH foot heel was less likely to transmit high frequency vibration.

Pushrim biomechanics and injury prevention in spinal cord injury: Recommendations based on CULP-SCI investigations

Over 50 percent of manual wheelchair users with spinal cord injury (SCI) are likely to develop upper-limb pain and injury. The majority of studies related to pain have implicated wheelchair propulsion as a cause. This paper draws from a large multisite trial and a long-standing research program to make specific recommendations related to wheelchair propulsion that may decrease the risk of upper-limb injury. The studies include over 60 subjects over 1 yr after a traumatic SCI below the second thoracic level. Specific aspects of the propulsive stroke that may relate to injury include cadence, magnitude of force, and the pattern of the hand during the nonpropulsive part of the stroke. Lower peak forces, slower cadence, and a circular propulsive stroke in which the hand falls below the pushrim during recovery may help prevent injury. In addition, wheelchair users should use the lightest weight adjustable wheelchair possible. Future work should include interventional trials and larger studies that allow for more complex statistical models that can further detail the relationship between wheelchair propulsion, user characteristics, and upper-limb injuries.

Effect of balance training on recovery of stability in children with cerebral palsy

This study examined the effect of massed practice in balance recovery of stability in six children (four males, two females; mean age 9 years 2 months, SD 2 years, range 7 years 5 months to 12 years 11 months) with cerebral palsy (CP). Four children were diagnosed with spastic diplegia (Gross Motor Function Classification System [GMFCS] level II) and two with spastic hemiplegia (GMFCS level I). A single-subject, multiple-baseline experimental design involving three pairs of children matched for diagnosis was used. A moveable forceplate system was used to test and train reactive balance control. Area per second (i.e. area covered by the center of pressure over a one second period) and time to stabilization from center of pressure measures were calculated following perturbations. The intervention phase consisted of massed practice on the moving platform (100 perturbations/day for 5 days). Analysis included hierarchical linear modeling and a repeated measures ANOVA. All children demonstrated a significant improvement in their ability to recover stability as demonstrated by reduced center of pressure area and time to stabilization following training. These improvements were still present 30 days following completion of training. Results suggest that postural control mechanisms in school-age children (7 to 13 years) with CP are modifiable.

The effects of age on medio-lateral stability during normal and narrow base walking

We examined age-related differences in frontal plane stability during performance of narrow base (NB) walking relative to usual gait. A cross-sectional analysis of participants from the Baltimore Longitudinal Study of Aging (BLSA) was performed on data from the BLSA Motion Analysis Laboratory. Participants were 34 adults aged 54-92 without history of falls. We measured step error rates during NB gait and spatial-temporal parameters, frontal plane stability, and gait variability during usual and NB gait. There was a non-significant age-associated linear increase in step error rate (P=0.12) during NB gait. With increasing age, step width increased (P=0.002) and step length and stride velocity decreased (P<0.001), especially during NB gait. Age-associated increases in medio-lateral (M-L) center of mass (COM) peak velocity (P<0.001) and displacement (P=0.005) were also greater during NB compared to usual gait. With increasing age there was greater variability in stride velocity (P=0.001) and step length (P<0.001) under both conditions. Age-associated differences related to M-L COM stability suggest that the quantification of COM control during NB gait may improve identification of older persons at increased falls risk.

The Seattle FICSIT/MoveIt study: the effect of exercise on gait and balance in older adults.

While exercise is generally recommended for older adults, the specific role of exercise in preventing falls and frail health is unclear. The Seattle FICSIT/Movelt study is a population‐based, randomized, controlled trial comparing the effects of three 6‐month exercise interventions (endurance training, strength training, or combined endurance and strength training), and three 3‐month endurance training interventions (stationary cycle, walking, or aerobic movement). Primary study outcomes are aerobic capacity, strength, gait, balance, and physical functional status. The study enrolls adults age 68–85 who have leg weakness and impaired gait. It differs from most previous community‐based exercise studies in several respects: recruitment of subjects from a defined population; eligibility criteria based upon physiologic and functional status deficits; random assignment to exercise groups; assessment of both physiologic and functional status outcomes; follow‐up beyond the completion of supervised exercise; and a large sample size (Total N = 180).

Botulinum Toxin for Spasticity in Children With Cerebral Palsy: A Comprehensive Evaluation

BACKGROUND. Spasticity is a prevalent disabling clinical symptom for children with cerebral palsy. Treatment of spasticity with botulinum toxin in children with cerebral palsy was first reported in 1993. Botulinum toxin provides a focal, controlled muscle weakness with reduction in spasticity. Interpretation of the literature is difficult because of the paucity of reliable measures of spasticity and challenges with measuring meaningful functional changes in children with disabilities. OBJECTIVE. This study documents the effects of botulinum toxin A injections into the gastrocnemius muscles in children with spastic diplegia. Outcomes are evaluated across all 5 domains of the National Centers for Medical and Rehabilitation Research domains of medical rehabilitation. METHODS. A randomized, double-masked, placebo-controlled design was applied to 33 children with spastic diplegia with a mean age of 5.5 and Gross Motor Function Classification System Levels of I through III. Participants received either 12 U/kg botulinum toxin A or placebo saline injections to bilateral gastrocnemius muscles. Outcomes were measured at baseline and 3, 8, 12, and 24 weeks after injection. RESULTS. Significant decreases in the electromyographic representation of spasticity were documented 3 weeks after botulinum toxin A treatment. A significant decrease in viscoelastic aspects of spasticity was present at 8 weeks, and subsequent increases in dorsiflexion range were documented at 12 weeks for the botulinum toxin A group. Improvement was found in performance goals at 12 weeks and in maximum voluntary torque and gross motor function at 24 weeks for the botulinum toxin A. There were no significant differences between groups in satisfaction with performance goals, energy expenditure, Ashworth scores, or frequency of adverse effects. CONCLUSIONS. The safety profile of 12 U/kg of botulinum toxin A is excellent. Although physiologic and mechanical effects of treatment with botulinum toxin A were documented with functional improvement at 6 months, family satisfaction with outcomes were no different. Communication is needed to ensure realistic expectations of treatment.

Shoulder Biomechanics During the Push Phase of Wheelchair Propulsion: A Multisite Study of Persons With Paraplegia

OBJECTIVES To present a descriptive analysis and comparison of shoulder kinetics and kinematics during wheelchair propulsion at multiple speeds (self-selected and steady-state target speeds) for a large group of manual wheelchair users with paraplegia while also investigating the effect of pain and subject demographics on propulsion. DESIGN Case series. SETTING Three biomechanics laboratories at research institutions. PARTICIPANTS Volunteer sample of 61 persons with paraplegia who use a manual wheelchair for mobility. INTERVENTION Subjects propelled their own wheelchairs on a dynamometer at 3 speeds (self-selected, 0.9m/s, 1.8m/s) while kinetic and kinematic data were recorded. MAIN OUTCOME MEASURES Differences in demographics between sites, correlations between subject characteristics, comparison of demographics and biomechanics between persons with and without pain, linear regression using subject characteristics to predict shoulder biomechanics, comparison of biomechanics between speed conditions. RESULTS Significant increases in shoulder joint loading with increased propulsion velocity were observed. Resultant force increased from 54.4+/-13.5N during the 0.9m/s trial to 75.7+/-20.7N at 1.8m/s (P<.001). Body weight was the primary demographic variable that affected shoulder forces, whereas pain did not affect biomechanics. Peak shoulder joint loading occurs when the arm is extended and internally rotated, which may leave the shoulder at risk for injury. CONCLUSIONS Body-weight maintenance, as well as other interventions designed to reduce the force required to propel a wheelchair, should be implemented to reduce the prevalence of shoulder pain and injury among manual wheelchair users.

A comparison of the effects of three types of endurance training on balance and other fall risk factors in older adults

We hypothesized that short-term endurance training improves balance in older adults, if training involves movements that “stress” balance. We tested the hypothesis by looking for a dose-response relationship between movement during exercise and balance improvement. The study was a single-blinded, randomized controlled trial. Subjects were sedentary adults (N=106) aged 68–85 with at least mild deficits in balance. Exercise groups were: stationary cycle (low movement), walking (medium movement), and aerobic movement (high movement). Subjects attended supervised exercise classes three times a week for three months, followed by self-directed exercise of any type for three months. The primary test of the hypothesis compared changes in balance after three months of supervised exercise. One balance measure (distance walked on a six-meter narrow balance beam) improved in the hypothesized dose-response manner (cycle, 3% improvement; walking, 7% improvement; aerobic movement, 18% improvement: p<0.02, test of trend). Other balance measures did not improve with exercise. Only walking exercise improved gait speed (by 5%, p<0.02) and SF-36 role-physical score (by 24%, p<0.05). VO2max improved with walking (18%, p<0.004) and aerobic movement (10%, p<0.01), but improved less with cycling (8%, p>0.1). Leg strength improved significantly in all exercise groups. The study hypothesis was supported only for one balance measure. Only walking improved at least one measure of all major outcomes (endurance, strength, gait, balance, health status), suggesting that walking is most useful for fall prevention. Cycle exercise appeared least useful.

Effect of balance training on muscle activity used in recovery of stability in children with cerebral palsy: a pilot study

This study explored possible neural mechanisms that contribute to improvements in balance control produced by reactive balance training in children with cerebral palsy (CP). Six children with CP (four males, two females; mean age 9y 4mo), two with spastic hemiplegia (Gross Motor Function Classification System [GMFCS] level I) and four with spastic diplegia (GMFCS level II,) were given 5 days of intensive training in reactive balance control (100 perturbations per day on a moveable force platform). Surface electromyography was used to characterize changes in neuromuscular responses pretraining, immediately posttraining, and 1 month posttraining. Training in reactive balance control resulted in improvements in directional specificity of responses (a basic level of response organization) and other spatial/temporal characteristics including: (1) faster activation of muscle contraction after training, allowing children to recover stability faster; (2) emergence of a distal-proximal muscle sequence; and (3) improved ability to modulate the amplitude of muscle activity (increased amplitude of agonist and decreased amplitude of antagonist, reducing coactivation). Each child with spastic hemiplegia or diplegia showed a different combination of factors that contributed to improved performance; the level of change in neural factors depended on the severity of involvement of the child: hemiplegia vs diplegia, and level of involvement within each diagnostic category.