Category: Research and Articles

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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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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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Cerebrovascular and cardiovascular responses to graded tilt in patients with autonomic failure.

date: 09/28/1997
author: Bondar RL, Dunphy PT, Moradshahi P, Kassam MS, Blaber AP, Stein F, Freeman R.
publication: Stroke. 1997 Sep;28(9):1677-85.
pubmed_ID: 9303009
BACKGROUND AND PURPOSE: Patients with autonomic nervous system failure often experience symptoms of orthostatic intolerance while standing. It is not known whether these episodes are caused primarily by a reduced ability to regulate arterial blood pressure or whether changes in cerebral autoregulation may also be implicated. METHODS: Eleven patients and eight healthy age- and sex-matched control subjects were studied during a graded-tilt protocol. Changes in their steady state middle cerebral artery mean flow velocities (MFV), measured by transcranial Doppler, brain-level mean arterial blood pressures (MABPbrain), and the relationship between the two were assessed. RESULTS: Significant differences between patients and control subjects (P < .05) were found in both their MFV and MABPbrain responses to tilt. Patients’ MFV dropped from 60 +/- 10.2 cm/s in the supine position to 44 +/- 14.0 cm/s at 60 degrees head-up tilt, whereas MABPbrain fell from 109 +/- 11.7 to 42 +/- 16.9 mm Hg. By comparison, controls’ MFV dropped from 54 +/- 7.8 cm/s supine to 51 +/- 8.8 cm/s at 60 degrees, whereas MABPbrain went from 90 +/- 11.2 to 67 +/- 8.2 mm Hg. Linear regression showed no significant difference in the MFV-MABPbrain relationship between patients and control subjects, with slopes of 0.228 +/- 0.09 cm.s-1.mm Hg-1 for patients and 0.136 +/- 0.16 cm.s-1.mm Hg-1 for control subjects. CONCLUSIONS: The present study found significant differences between patients and control subjects in their MFV and MABPbrain responses to tilt but no difference in the autoregulatory MFV-MABPbrain relationship. These results suggest that patients’ decreased orthostatic tolerance may primarily be the result of impaired blood pressure regulation rather than a deficiency in cerebral autoregulation.

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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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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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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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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.

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Passive ankle dorsiflexion increases in patients after a regimen of tilt table-wedge board standing. A clinical report.

date: 11/01/1985
author: Bohannon RW, Larkin PA.
publication: Phys Ther. 1985 Nov;65(11):1676-8.
pubmed_ID: 4059330

We monitored the result of a tilt table-wedge board routine on the passive ankle dorsiflexion of 20 patients consecutively to determine the effectiveness of the treatment. The calculated frequency of the treatment, which was applied for 30 minutes on each of 5 to 22 treatment days, ranged from 2.3 to 6.4 treatments a week. All patients demonstrated increased passive ankle dorsiflexion. The increases ranged from 3 to 17 degrees and occurred at a calculated rate of 0.11 to 1.0 degrees a day. We believe the treatment is an effective clinical method for increasing passive ankle dorsiflexion in neurologically involved patients.

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Long-term followup of renal function after spinal cord injury.

date: 09/01/1985
author: Kuhlemeier KV, Lloyd LK, Stover SL.
publication: J Urol. 1985 Sep;134(3):510-3.
pubmed_ID: 4032551

Effective renal plasma flow was measured in acute spinal cord injury patients for up to 10 years after injury to determine the extent of renal deterioration in these patients and to identify the factors associated with a loss of renal function. The over-all mean decrease in effective renal plasma flow for all patients as a whole was 4.5 ml. per year. Factors associated with a statistically significant reduction in effective renal plasma flow included age, gender, renal calculi, quadriplegia, and a history of chills and fever. Other factors examined but not found to be statistically significant included years since injury, presence of severe decubiti, bladder calculi, bacteriuria and extent of injury. This study suggests that renal function usually can be preserved in spinal cord injury patients if the treatable risk factors are managed properly.

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Lower extremity functional neuromuscular stimulation in cases of spinal cord injury.

date: 07/15/1984
author: Cybulski GR, Penn RD, Jaeger RJ.
publication: Neurosurgery. 1984 Jul;15(1):132-46.
pubmed_ID: 6382044
Outside_URL: http://www.ncbi.nlm.nih.gov/pubmed/6382044
Functional neuromuscular stimulation (FNS) provides a mechanism for the activation of muscles paralyzed by injury to the spinal cord. Although this technique was first used to treat patients with spinal cord injury over 20 years ago, only recent advances in electronics and biomechanics have made it a promising aid for the rehabilitation of these patients. Thus far, restoration of palmar prehension and lateral prehension in quadriplegics and of standing and biped gait in paraplegics has been achieved under carefully controlled laboratory conditions. This article reviews the current status of FNS and its potential as a practical tool to aid spinal cord-injured patients. Neurosurgeons who care for these patients might be expected to be involved in the future use of FNS if implantable systems are developed and tested.