Children in wheelchairs.

Three hundred and seventy-five families replied to a questionnaire about the use of their disabled children''s wheelchairs. Many problems were found, such as difficulty in folding the chair and placing it in the car boot and difficulty in using pulbic transport. These families need adequate guidance to anticipate and deal with the problems. Provision of a wheelchair does not solve the mobility problems. The parents are faced with the task of transporting both the disabled child and the wheelchair whenever they want to use their own car or public transport. Ease of folding and lightness are important criteria for wheelchairs carried by cars. Parents need careful guidance about selecting suitable cars and also need to be shown how to lift the chairs without endangering their backs. Such advice should be provided by every wheelchair clinic and assessment and rehabilitation certre.     

Spinal cord stimulation as a tool for physiological research

The use of spinal cord stimulation for alleviation of disabilities due to motor neuron lesions has provided the opportunity to explore a new approach to measurement of spinal cord physiology. Externalized leads of epidural electrodes provide the possibility of recording evoked spinal cord activity, while both externalized or implanted leads can be used to study cortical evoked responses and twitches induced by spinal cord stimulation. The use of such electrophysiological techniques can be expected to expand greatly the applicability of the technique for alleviating motor disabilities, through a better definition of the degree, nature and extent of the lesion.     

A Functionally Relevant Tool for the Body following Spinal Cord Injury

A tool such as a prosthetic device that extends or restores movement may become part of the identity of the person to whom it belongs. For example, some individuals with spinal cord injury (SCI) adapt their body and action representation to incorporate their wheelchairs. However, it remains unclear whether the bodily assimilation of a relevant external tool develops as a consequence of altered sensory and motor inputs from the body or of prolonged confinement sitting or lying in the wheelchair. To explore such relationships, we used a principal component analysis (PCA) on collected structured reports detailing introspective experiences of wheelchair use in 55 wheelchair-bound individuals with SCI. Among all patients, the regular use of a wheelchair induced the perception that the body’s edges are not fixed, but are instead plastic and flexible to include the wheelchair. The PCA revealed the presence of three major components. In particular, the functional aspect of the sense of embodiment concerning the wheelchair appeared to be modulated by disconnected body segments. Neither an effect of time since injury nor an effect of exposure to/experience of was detected. Patients with lesions in the lower spinal cord and with loss of movement and sensation in the legs but who retained upper body movement showed a higher degree of functional embodiment than those with lesions in the upper spinal cord and impairment in the entire body. In essence, the tool did not become an extension of the immobile limbs; rather, it became an actual tangible substitution of the functionality of the affected body part. These findings suggest that the brain can incorporate relevant artificial tools into the body schema via the natural process of continuously updating bodily signals. The ability to embody new essential objects extends the potentiality of physically impaired persons and can be used for their rehabilitation.     

Field testing: assessment of physical fitness of disabled adults

The objectives of this investigation were (i) to develop simple field-test procedures for examining the cardio-respiratory and muscular strength fitness of lower-limb disabled individuals and (ii) to compare fitness levels across disabilities and physical activity levels. Forty-nine disabled adults (42 males and 7 females) were classified according to (i) functional and/or muscular deficit and, (ii) level of habitual physical activity. A forearm ergometer test was used to determine peak oxygen intake (VO2 peak). Sex-specific regression equations developed from the direct test were used in conjunction with a modified Astrand-Ryhming equation to predict VO2 peak from sub-maximal test results. Likewise, an equation was developed to predict isokinetic upper body strength (UBS) from cable tensiometry and hand grip force. The predictive power of the sub-maximal ergometer test was fair (r = 0.67), while the isometric strength measurements were relatively effective in predicting isokinetic total UBS (r = 0.82). Class 1 differed significantly from all other classes with respect to VO2 peak and UBS. The more active individuals also achieved significantly higher scores (p less than 0.05) for both variables. This study shows that an estimate of peak oxygen intake and UBS can be obtained from simple field tests and that active disabled individuals are more fit than their inactive counterparts.     

Varying physiological response to arm-crank exercise in specific spinal injuries

The purpose of this arm-crank ergometry (ACE) study was to provide a greater understanding of the influence to which specific cervical and thoracic spinal cord injuries contribute to reduction in optimal cardio-respiratory and metabolic function. Twenty five male volunteers aged 20 to 47 years participated. Twenty disabled wheelchair-confined spinal cord injured (SCI) subjects were equally divided into four 'site-specific' groups based on the lesion being within either high- or low- cervical or thoracic anatomical regions. Five physically non-disabled controls (As) were included. Measured variables tended to decrease progressively from As to high-level quadriplegics. Analysis revealed a high variance in maximum cardio-respiratory performance levels between groups (P < 0.001). These findings confirm that limitation to upper body physical capabilities in the SCI during high-intensity ACE is dependent on specific lesion site. Considerable variability in performance levels were measured in those suffering lesions within closely approximating anatomical regions. Results also suggest a greater importance in the location of cervical rather than thoracic injuries in contributing towards higher relative losses in maximal cardio-respiratory and metabolic potential. Alterations in body composition and varying severity of muscle paralysis likely also play a contributing role in reducing optimal metabolic function in SCI individuals. The importance for stringent classification techniques of spinal cord lesion site in predicting upper body physical exercise potential in the SCI has therefore been highlighted in this study.     

Feeding Consequences of Hand and Foot Disability in Wild Adult Chimpanzees (<Emphasis Type="Italic">Pan troglodytes schweinfurthii</Emphasis>)

Many wild primates experience long-term limb disability, and their ability to cope with disability has implications for survival and fitness. We quantified the arboreal feeding and postural behaviors of adult chimpanzees to study the consequences of physical limb disabilities. We collected behavioral data for a total of 8 mo on chimpanzees at Sebitoli, Kibale National Park, Uganda, focusing on the time spent feeding, common feeding tree species, body postures, and substrate use. Of the 51 chimpanzees we observed, 16 (31%) exhibited limb anomalies, which varied in form and severity. Disabled chimpanzees climbed as high as chimpanzees without disabilities and did not differ from nondisabled chimpanzees in the amount they used feeding tree species. Adult chimpanzees with severe hand disability spent significantly more time feeding than nondisabled individuals. In addition, manually disabled adults did not suspend themselves from branches during feeding as frequently as nondisabled adults and used larger substrates for gripping and sitting than nondisabled adults. These results indicate that disabled individuals compensate to carry out feeding activities in trees.     

Expression of nerve growth factor receptor mRNA is developmentally regulated and increased after axotomy in rat spinal cord motoneurons

In situ hybridization histochemistry and RNA blot analysis were used to study expression of nerve growth factor receptor (NGF-R) mRNA in rat spinal cord motoneurons. The results show that NGF-R mRNA is expressed at high levels in rat spinal cord motoneurons at the time of naturally occurring cell death. This expression is sustained, but reduced, during synapse formation and is subsequently greatly reduced in the adult spinal cord. A unilateral crush lesion of the sciatic nerve resulted in an 8-fold increase in NGF-R mRNA in adult rat spinal cord motoneurons 3 days after lesion, compared with the nonlesioned side. NGF-R mRNA induction was even more pronounced 7 and 14 days after lesion, reaching levels 12 times higher than those on the nonlesioned side. However, 6 weeks after lesion, when the motor function of the leg was largely restored, NGF-R expression had decreased to levels similar to those on the contralateral side. We therefore suggest that NGF-R mediates a trophic or axonal guidance function for developing and regenerating spinal cord motoneurons.     

Children's Wheelchair Clinic

During the first year of a children''s monthly wheelchair clinic 29 out of 34 chairs supplied in the past were found to be unsatisfactory. The advantages of a central clinic for a region where clinicians and technical officers can meet are emphasized, as is also the need for wider dispersal of knowledge about wheelchairs for disabled children.     

A Contusive Model of Unilateral Cervical Spinal Cord Injury Using the Infinite Horizon Impactor

While the majority of human spinal cord injuries occur in the cervical spinal cord, the vast majority of laboratory research employs animal models of spinal cord injury (SCI) in which the thoracic spinal cord is injured. Additionally, because most human cord injuries occur as the result of blunt, non-penetrating trauma (e.g. motor vehicle accident, sporting injury) where the spinal cord is violently struck by displaced bone or soft tissues, the majority of SCI researchers are of the opinion that the most clinically relevant injury models are those in which the spinal cord is rapidly contused.¹ Therefore, an important step in the preclinical evaluation of novel treatments on their way to human translation is an assessment of their efficacy in a model of contusion SCI within the cervical spinal cord. Here, we describe the technical aspects and resultant anatomical and behavioral outcomes of an unilateral contusive model of cervical SCI that employs the Infinite Horizon spinal cord injury impactor.Sprague Dawley rats underwent a left-sided unilateral laminectomy at C5. To optimize the reproducibility of the biomechanical, functional, and histological outcomes of the injury model, we contused the spinal cords using an impact force of 150 kdyn, an impact trajectory of 22.5° (animals rotated at 22.5°), and an impact location off of midline of 1.4 mm. Functional recovery was assessed using the cylinder rearing test, horizontal ladder test, grooming test and modified Montoya''s staircase test for up to 6 weeks, after which the spinal cords were evaluated histologically for white and grey matter sparing.The injury model presented here imparts consistent and reproducible biomechanical forces to the spinal cord, an important feature of any experimental SCI model. This results in discrete histological damage to the lateral half of the spinal cord which is largely contained to the ipsilateral side of injury. The injury is well tolerated by the animals, but does result in functional deficits of the forelimb that are significant and sustained in the weeks following injury. The cervical unilateral injury model presented here may be a resource to researchers who wish to evaluate potentially promising therapies prior to human translation.     

Phospholipids of normal and experimentally injured spinal cord of the miniature pig

Experimental spinal cord trauma was produced in 3-month-old SS-1 minature pigs by dropping a 25 g weight from a height of 20 cm upon the exposed spinal cord. The histological lesion consisted of edema and hemorrhage. Phospholipid concentration and composition, cholesterol concentration and phospholipid fatty acid composition were determined in whole spinal cord 3 hours after injury, and in spinal cord myelin 5 hours after injury. Three hours after injury phospholipid and cholesterol concentration were decreased by about 14% in the whole spinal cord. Trauma had no effect on the phospholipid composition of whole spinal cord and myelin. Fatty acid composition of myelin also did not change after injury, and changed very slightly in the whole spinal cord. It is concluded that edema following spinal cord trauma is much more extensive than previously assumed. Furthermore, peroxidation of membrane lipid fatty acids does not appear to be a significant factor in spinal cord pathology 3 hours after injury.     

Growth of axons through a lesion in the intact CNS of fetal rat maintained in long-term culture.

The ability of neurons in the central nervous system (CNS) to grow through a lesion and restore conduction has been analysed in developing spinal cord in vitro. The preparation consists of the entire CNS of embryonic rat, isolated and maintained in culture. Conduction of electrical activity and normal morphological appearance (light microscopical and electron microscopical) were maintained in the spinal cord of such preparations for up to 7 d in culture. A complete transverse crush of the spinal cord abolished all conduction for 2 d. After 3-5 d, clear recovery had occurred: electrical conduction across the crush was comparable with that in uninjured preparations. Furthermore, the spinal cord had largely regained its gross normal appearance at the crush site. Axons stained in vivo by carbocyanine dyes had, by 5 d, grown in profusion through the lesion and several millimetres beyond it. These experiments, like those made in neonatal opossum (Treherne et al. 1992) demonstrate that central neurons of immature mammals, unlike those in adults, can respond to injury by rapid and extensive outgrowth of nerve fibres in the absence of peripheral nerve bridges or antibodies that neutralize inhibitory factors. However, unlike the opossum, in which outgrowth occurred at 24 degrees C, although there was prolonged survival of rat spinal cords at this temperature, outgrowth of axons across the lesion required a temperature of 29 degrees C. With rapid and reliable regeneration in vitro it becomes practicable to assay the effects of molecules that promote or inhibit restoration of functional connections.     

Spinal cord injury-related bone impairment and fractures: an update on epidemiology and physiopathological mechanisms

A sudden loss of motor function in segments of the spinal cord results in immobilisation and is complicated by bone loss and fractures in areas below the level of injury. Despite the acceptance of osteoporosis and fractures as two major public health problems, in people with spinal cord injuries, the mechanisms are not adequately investigated. Multiple risk factors for bone loss and fractures are present in this disabled population. This review is an update on the epidemiology and physiopathological mechanisms in spinal cord injury-related bone impairment and fractures.     

Differences in performance between trained and untrained subjects during a 30-s sprint test in a wheelchair ergometer

To compare physiological responses and propulsion technique of able bodied subjects with no prior experience of wheelchairs (AB) and wheelchair dependent subjects (WD), ten AB and nine WD performed a 30-s sprint test in a wheelchair ergometer. The WD had spinal cord injuries with a lesion at T8 or lower. The WD and AB did not show significantly different physiological responses. The power values averaged for the right wheel over the 30 s of the test were 50.2 (SD 14.7) W and 48.0 (SD 4.4) W for WD and AB, respectively. No significant differences in torque application could be discerned, although WD subjects seemed to have a more flattened torque curve with a smaller negative deflection at the beginning of the push. The WD applied a significantly higher horizontal propulsive force to the handrims but did not apply force more effectively. The percentages of effective force to total propulsive force were 61 (SD 16)% for WD and 57 (SD 4)% for AB. With regard to the kinematic parameters, AB followed the handrims significantly longer than WD (end angle AB 65°, WD 44°), started the push phase with their arms more in retroflexion and flexed their trunks further forward. The AB did however show a movement pattern comparable to that of wheelchair athletes measured in a comparable experiment. It could not be decided conclusively that inexperience in wheelchair propulsion led to a less effective propulsion technique. Despite the selection of WD with respect to lesion level, interindividual differences in terms of level of training may have been responsible for the absence of significant results.     

Mechanisms of blood pressure and heart rate variability: an insight from low-level paraplegia

It is still unclear whether the low-frequency oscillation in heart rate is generated by an endogenous neural oscillator or by a baroreflex resonance. Our aim was to investigate this issue by analyzing blood pressure and heart rate variability and the baroreflex function in paraplegic subjects with spinal cord injury below the fourth thoracic vertebra. These subjects were selected because they represent a model of intact central neural drive to the heart, with a partially impaired autonomic control of the vessels. In our study, arterial blood pressure and ECG were recorded in 33 able-bodied controls and in 33 subjects with spinal cord lesions between the fifth thoracic and the fourth lumbar vertebra 1) during supine rest (lowest sympathetic activation), 2) sitting on a wheelchair (light sympathetic activation), and 3) during exercise (moderate sympathetic activation). Blood pressure and heart rate spectra, coherence, and baroreflex function (sequence technique) were estimated in each condition. Compared with controls, paraplegic subjects showed a reduction of the low-frequency power of blood pressure and heart rate, and, unlike controls, a 0.1-Hz peak did not appear in their spectra. Sympathetic activation increased the 0.1-Hz peak of blood pressure and heart rate and the coherence at 0.1 Hz in controls only. Paraplegic subjects also had significantly lower baroreflex effectiveness and greater blood pressure variability. In conclusion, the disappearance of the 10-s oscillation of heart rate and blood pressure in subjects with spinal cord lesion supports the hypothesis of the baroreflex nature of this phenomenon.     

Regeneration of sensory axons within the injured spinal cord induced by intraganglionic cAMP elevation

The peripheral branch of primary sensory neurons regenerates after injury, but there is no regeneration when their central branch is severed by spinal cord injury. Here we show that microinjection of a membrane-permeable analog of cAMP in lumbar dorsal root ganglia markedly increases the regeneration of injured central sensory branches. The injured axons regrow into the spinal cord lesion, often traversing the injury site. This result mimics the effect of a conditioning peripheral nerve lesion. We also demonstrate that sensory neurons exposed to cAMP in vivo, when subsequently cultured in vitro, show enhanced growth of neurites and an ability to overcome inhibition by CNS myelin. Thus, stimulating cAMP signaling increases the intrinsic growth capacity of injured sensory axons. This approach may be useful in promoting regeneration after spinal cord injury.     

The Effects of Permanent Injury on the Behavior and Diet of Commensal Chacma Baboons (Papio ursinus) in the Cape Peninsula,South Africa

Primates may suffer injury from both natural (fights with conspecifics, predators) and human-induced (snares, power-lines and guns) causes. Though behavioral flexibility may allow primates to compensate for injuries, permanent disabilities, such as the loss of a limb, may adversely affect both foraging and locomotory efficiency and ultimately the survival and fitness of individuals. In the Cape Peninsula, South Africa, members of the chacma baboon population (Papio ursinus) experience chronic levels of conflict with humans that manifests in high levels (15%) of disabled baboons in groups that overlap with residential areas. In this study we investigate the potential impact of such disabilities by comparing the behavior and diet of disabled baboons with uninjured baboons matched closely for age, sex, and social status from groups of a similar size and composition for 8 mo, from May to December 2005. Disabled baboons spent more time resting and traveling and less time feeding than uninjured baboons. Disabled and uninjured baboons had similar diets but the former consumed fewer food items with high handling costs and fed more on high return foods than the latter. There was no difference in the frequency of grooming or social vigilance behaviors, as might be expected if disability had compromised either competitive ability or predation risk. Further, there was no difference in the survival of disabled or uninjured individuals in each group. Together these results suggest that while permanent injury may affect the behavior and diet of Peninsula baboons, that these constraints may be offset by access to anthropogenic food sources and the lack of natural predators. Disability in baboons may lead to obligate raiding of high-return anthropogenic foods, which is an important challenge for the ongoing management of this population.     

Amyloidosis in paraplegia correlation with decubitus ulcers

Six patients died with amyloidosis and four patients are living with amyloidosis out of 1,000 with spinal cord injuries who were studied.No correlation was found between Congo red retention and the length of time since injury or the site of the spinal cord lesion. However, it is felt that the longer decubitus ulcer persists, the greater is the probability of amyloidosis. It is believed that decubitus ulcers with secondary osteomyelitis are of primary importance as etiologic factors in amyloidosis associated with spinal cord injuries, and that pyelonephritis plays a very minor secondary role.     

Decreased cutaneous sensory axon-reflex vasodilatation below the lesion in patients with complete spinal cord injury

The histamine-induced skin flare response has been considered of practical value in determining the level of a spinal cord lesion, but clinical observations have varied widely with regard to the nature and degree of change below the lesion. We have quantified cutaneous sensory axon-reflex vasodilatation in patients with complete spinal cord injury (SCI) above and below the lesion, and compared the findings with normal subjects. Axon-reflex vasodilatation was induced by intradermal histamine injection, and measured by (a) laser Doppler fluxmetry and (b) tracing the surface area of the flare. Axon-reflex vasodilatation was present in all SCI patients above and below the lesion, but was significantly diminished below the lesion by both measures (pflux rise = 0.0008; pflare = 0.023), and in comparison with controls (by 39%). The flux increase was significantly correlated with the area of flare (r = 0.82; p = 0.02). Axon-reflex vasodilatation and visual analogue scale (VAS) pain scores on histamine injection were not significantly different above the lesion in SCI patients from controls. Baseline laser Doppler flux was not different at any test site in SCI and normal subjects. The cutaneous sensory axon-reflex is thus significantly diminished in SCI patients below the level of the lesion, but the underlying mechanism is unclear. A possible explanation under investigation is that increased basal or reflex sympathetic vasoconstriction mediated via the isolated spinal cord may counteract the vasodilatation produced by the cutaneous sensory terminals.