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Bone density and other possible predictors of fracture risk in children and adolescents with spastic quadriplegia.

date:
author: Henderson RC.
publication: Dev Med Child Neurol. 1997 Apr;39(4):224-7.
pubmed_ID: 9183259
:
Forty-three patients with spastic quadriplegia (mean age 7.9 years, range 3.3 to 17.2 years) underwent bone mineral density (BMD) measurement of the lumbar spine and were evaluated between 2.6 and 5.5 years (mean 3.8) later to determine whether this measurement had predicted risk of fracture over the subsequent period of observation. Other potential risk factors that were evaluated include body weight z score, serum vitamin D levels, previous fracture, and hip spica casting. The baseline measurements showed that BMD falls further below normal with increasing age and was more than one standard deviation below age-matched normal mean in 38 of the 43 patients. Fracture rate did not differ between those with low and those with very low spinal BMD. Similarly, serum vitamin D levels and body weight z scores were not predictive of fracture. However, fracture rate was over fourfold greater following spica casting and more than threefold greater following an initial fracture. Fracture rates in the study group were similar to those reported for age- and sex-matched normal children, though generally the location of the fractures and mechanisms of injury differed.

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Bisphosphonates to treat osteopenia in children with quadriplegic cerebral palsy: a randomized, placebo-controlled clinical trial.

date: 11/01/2002
author: Henderson RC, Lark RK, Kecskemethy HH, Miller F, Harcke HT, Bachrach SJ.
publication: J Pediatr. 2002 Nov;141(5):644-51.
pubmed_ID: 12410192

OBJECTIVE: To evaluate in a double-blind, placebo-controlled clinical trial the safety and efficacy of intravenous pamidronate to treat osteopenia in nonambulatory children with cerebral palsy. STUDY DESIGN: Six pairs of subjects generally matched within each pair for age, sex, and race completed the protocol. One member of each pair randomly received plain saline placebo, the other pamidronate. Drug/placebo was administered intravenously daily for 3 consecutive days, and this 3-day dosing session was repeated at 3-month intervals for one year. Evaluations were continued for 6 months after the year of treatment. Bone mineral density (BMD) was measured in the distal femur, a site specifically developed for use in this contracted population, and the lumbar spine. RESULTS: In the metaphyseal region of the distal femur, BMD increased 89% +/- 21% (mean +/- SEM) over the 18-month study period in the pamidronate group compared with 9% +/- 6% in the control group. Age-normalized z scores increased from -4.0 +/- 0.6 to -1.8 +/- 1.0 in the pamidronate group and did not significantly change in the control group (-4.2 +/- 0.3 to -4.0 +/- 0.3). The first dosing with pamidronate caused a transient drop in serum calcium that was asymptomatic and not treated. No other potentially adverse effects were noted. CONCLUSIONS: In this small controlled clinical trial, pamidronate was found to be a safe and very effective agent to increase BMD in nonambulatory children with cerebral palsy.

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Bone mineral density and fractures in boys with Duchenne muscular dystrophy.

date: 02/01/2000
author: Larson CM, Henderson RC.
publication: J Pediatr Orthop. 2000 Jan-Feb;20(1):71-4.
pubmed_ID: 10641693

The relationships between bone density, mobility, and fractures were assessed in 41 boys with Duchenne muscular dystrophy. Bone density in the lumbar spine was only slightly decreased while the boys were ambulatory (mean z-score, -0.8), but significantly decreased with loss of ambulation (mean z-score, -1.7). In contrast, bone density in the proximal femur was profoundly diminished even when gait was minimally affected (mean z-score, -1.6), and then progressively decreased to nearly 4 standard deviations below age-matched normals (mean z-score, -3.9). These are consistent with the findings that 18 (44%) of the boys sustained a fracture, 66% of these fractures involved the lower extremities, and there were no spinal compression fractures. Furthermore, four (44%) of nine boys who were walking with aids or support at the time of fracture never resumed walking after the fracture. Osteoporosis is most profound in the lower extremities of boys with Duchenne muscular dystrophy, and begins to develop early while still ambulating. Frequent fractures that may result in loss of ambulation are the clinical consequences.

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Soleus motor neuron excitability before and after standing.

date: 08/01/2004
author: Deshpande P, Shields RK.
publication: Electromyogr Clin Neurophysiol. 2004 Jul-Aug;44(5):259-64.
pubmed_ID: 15378863

H-reflexes have been used to assess the effect of various postures on the excitability of the soleus motor neuronal pool. The purpose of this study was to determine if the excitability of the motor neuron pool, measured via H-reflexes in a seated position, change after a standing protocol in able-bodied individuals. We hypothesized that the excitability of the motor neuronal pool is minimally affected by the standing protocol leading to a reproducible H-reflex. Ten healthy individuals (height = 69.05+/-2.27 inches, weight = 161.7+/-22.44 lbs, age = 27.7+/-7.0 years) participated in the study. Soleus H-reflex recruitment curves were established before and after a standing protocol in a seated position. The standing protocol involved 12 minutes of active upright standing interspersed with 10 minutes of relaxed passive standing in a standing frame, similar to a protocol currently used for spinal cord injured subjects. The maximum M-waves and H-reflex amplitudes were not systematically changed before and after standing. There was also a strong agreement between the H-reflexes and M-waves measured before and after standing (ICC = 0. 99 and .96, respectively). We conclude that the H-reflexes measured in this study were reproducible, indicating that standing had no long lasting effect on the motor neuronal pool excitability. The findings support that the method discussed in this report is appropriate to assess the effects of electrically induced standing on motor neuron pool excitability in individuals with spasticity from spinal cord injury.

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Quantifying weight-bearing by children with cerebral palsy while in passive standers.

date: 12/01/2007
author: Herman D, May R, Vogel L, Johnson J, Henderson RC.
publication: Pediatr Phys Ther. 2007 Winter;19(4):283-7.
pubmed_ID: 18004195

PURPOSE: Children who are nonambulatory are placed into standers with the goal of providing benefits from weight-bearing. The purpose of this study was to quantify weight-bearing loads by children with cerebral palsy while in standers. METHODS: Electronic load-measuring footplates were fabricated specifically for this study. Weight-bearing loads were continuously measured in 19 children who were nonambulatory during routine 30-minute standing sessions (3-6 sessions/child, total 110 sessions). RESULTS: Weight-bearing ranged widely (23%-102%) with a mean of 68% of body weight. There was some variation over the course of a session and between different sessions, but more variance was noted between subjects. CONCLUSIONS: Actual weight borne in a stander is quite variable, and in some instances only a fraction of actual body weight. Further studies are required to delineate relevant factors and identify ways to maximize weight-bearing loads while in a stander.

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Standing with the assistance of a tilt table improves minute ventilation in chronic critically ill patients.

date: 12/01/2004
author: Chang AT, Boots RJ, Hodges PW, Thomas PJ, Paratz JD.
publication: Arch Phys Med Rehabil. 2004 Dec;85(12):1972-6.
pubmed_ID: 15605335

OBJECTIVE: To investigate the effect of standing with assistance of the tilt table on ventilatory parameters and arterial blood gases in intensive care patients. DESIGN: Consecutive sample. SETTING: Tertiary referral hospital. PARTICIPANTS: Fifteen adult patients who had been intubated and mechanically ventilated for more than 5 days (3 subjects successfully weaned, 12 subjects being weaned). INTERVENTION: Passive tilting to 70 degrees from the horizontal for 5 minutes using a tilt table. MAIN OUTCOME MEASURES: Minute ventilation (VE), tidal volume (VT), respiratory rate, and arterial partial pressure of oxygen (PaO2) and carbon dioxide (PaCO2). RESULTS: Standing in the tilted position for 5 minutes produced significant increases in VE (P <.001) and produced both increases in respiratory rate (P <.001) and VT (P =.016) compared with baseline levels. These changes were maintained during the tilt intervention and immediately posttilt. Twenty minutes after the tilt, there were no significant changes in ventilatory measures of VE, VT, or arterial blood gases PaO2 and PaCO2 compared with initial values. CONCLUSIONS: Standing for 5 minutes with assistance of a tilt table significantly increased ventilation in critical care patients during and immediately after the intervention. There were no improvements in gas exchange posttilt. Using a tilt table provided an effective method to increase ventilation in the short term.

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Randomised trial of the effects of four weeks of daily stretch on extensibility of hamstring muscles in people with spinal cord injuries.

date: 01/01/2003
author: Harvey LA, Byak AJ, Ostrovskaya M, Glinsky J, Katte L, Herbert RD.
publication: Aust J Physiother. 2003;49(3):176-81.
pubmed_ID: 12952517

The aim of this assessor-blind randomised controlled trial was to determine the effect of four weeks of 30 minute stretches each weekday on extensibility of the hamstring muscles in people with recent spinal cord injuries. A consecutive sample of 16 spinal cord-injured patients with no or minimal voluntary motor power in the lower limbs and insufficient hamstring muscle extensibility to enable optimal long sitting were recruited. Subjects’ legs were randomly allocated to experimental and control conditions. The hamstring muscles of the experimental leg of each subject were stretched with a 30 Nm torque at the hip for 30 minutes each weekday for four weeks. The hamstring muscles of the contralateral leg were not stretched during this period. Extensibility of the hamstring muscles (hip flexion range of motion with knee extended, measured with a 48 Nm torque at the hip) of both legs was measured by a blinded assessor at the commencement of the study and one day after the completion of the four-week stretch period. Changes in hamstring muscle extensibility from initial to final measurements were calculated. The effect of stretching was expressed as the mean difference in these changes between stretched and non-stretched legs. The mean effect of stretching was 1 degree (95% CI -2 to 5 degrees). Four weeks of 30 minute stretches each weekday does not affect the extensibility of the hamstring muscle in people with spinal cord injuries.

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Effect of dynamic weight bearing on neuromuscular activation after spinal cord injury.

date: 06/01/2007
author: Edwards LC, Layne CS.
publication: Am J Phys Med Rehabil. 2007 Jun;86(6):499-506.
pubmed_ID: 17515690

OBJECTIVE: To determine whether individuals who have a spinal cord injury have neuromuscular and physiologic responses to a personalized exercise program during dynamic weight bearing (DWB). DESIGN: Four subjects with spinal cord injuries (T6, T5-6, C2-5, and C5) completed a 12-wk exercise program that included DWB. Surface electromyography (EMG) was recorded from the right gastrocnemius, biceps femoris, rectus femoris, rectus abdominus, and external oblique. Heart rate (HR) and blood pressure (BP) were recorded throughout training. Descriptive statistics were used to analyze the data. RESULTS: The results of this study indicate that the subjects actively responded to exercise during DWB, as measured by EMG, HR, and BP. CONCLUSIONS: The results suggest that exercise during DWB can induce physiologic and neuromuscular responses in individuals who have a spinal cord injury, and that exercise during DWB may serve as a preparatory program for more advanced rehabilitation.

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New assistive technology for passive standing.

date: 03/01/1999
author: Gear AJ, Suber F, Neal JG, Nguyen WD, Edlich RF.
publication: J Burn Care Rehabil. 1999 Mar-Apr;20(2):164-9.
pubmed_ID: 10188115

The anesthetic skin of patients with spinal cord injuries makes these patients a high-risk population for burn injuries. Innovations in rehabilitation engineering can now provide the disabled with mechanical devices that allow for passive standing. Passive standing has been shown to counteract many of the effects of chronic immobilization and spinal cord injury, including bone demineralization, urinary calculi, cardiovascular instability, and reduced joint range of motion and muscular tone. This article will describe several unique assistive devices that allow for passive standing and an improvement in daily living for people with disabilities.

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Orthostasis and transcapillary fluid shifts.

date: 01/01/1995
author: Hinghofer-Szalkay HG.
publication: J Gravit Physiol. 1995;2(1):P131-3.
pubmed_ID: 11538896

Postural blood volume changes aggravate the regulation of arterial blood pressure and perfusion vis-a-vis the hydrostatic effects of orthostasis, ie, blood pooling below the hydrostatic indifferent points and reduced cardiac preload. Corresponding problems surface with extended passive standing, particularly in highly trained, dehydrated, or otherwise compromised subjects, or after long-lasting immobilization, as with space flight.