Locomotor Outcome Research Articles

Reading text messages at different stages of pedestrian circumvention affects strategies for collision avoidance in young and older adults

BackgroundReading text messages is associated with accidents while walking in community places. Research questionTo what extent does reading text messages at different stages of obstacle circumvention affect avoidance strategies while walking in young vs. older adults? MethodsSixteen healthy young and 14 older adults were assessed while walking and viewing a virtual environment (VE) simulating a subway station with three virtual pedestrians positioned 7.5 m away from the participant in the centre (0°), left and right (±40°). As participants advanced 0.5 m towards a target in the far space, a virtual pedestrian randomly approached them. Text messages were delivered at onset of pedestrian movement (0.5 m; early message) or during obstacle circumvention (2.5 m; late message). A Vicon motion capture system captured trajectory displacement while walking. ResultsIn both age groups, accuracy of message report (AMR) was reduced for early compared to late messages (p < 0.001), although older adults showed larger deterioration (p < 0.001) compared to younger participants. Locomotor outcomes (obstacle clearance, onset time of avoidance and walking speed) showed no differences between young and older participants (p > 0.05). Early messages led to slower walking speed (p < 0.001) and more frequent collisions compared to late messages and the no-message condition. Late messages yielded faster walking speed (p < 0.001) and onset time of avoidance (p < 0.02) compared to the other conditions. SignificanceResults indicate that the stage of an avoidance strategy at which text messages are received impacts on pedestrian circumvention, with early messages posing a greater challenge to collision avoidance. In older adults, the reduced AMR suggests larger dual-task interference and prioritization of the walking task. The lack of further walking speed reduction in older vs. young adults may put them at greater risk of collisions in crowded, unpredictable community environments.

Different functional bio-scaffolds share similar neurological mechanism to promote locomotor recovery of canines with complete spinal cord injury

Many studies have shown that rodents exhibit a certain degree of spontaneous motor function recovery even if they suffer from spinal cord complete transection injury. However, the characteristics of spontaneous locomotor recovery and its associated neurobiological mechanisms are unclear. In this study, we observed that spontaneous locomotor function recovery of hind limbs could also be detected in a canine thoracic (T8) spinal cord complete transection model. In addition, the spontaneous locomotor recovery of canines could be further promoted by chronic implantation of Taxol- or human bone marrow mesenchymal stem cell-modified bio-scaffolds. Moreover, functional bio-scaffolds implantation promoted locomotor outcome could be significantly weakened (drop to the spontaneous recovery level) but not totally abolished by resection in the lesion site. The neurological mechanism for functional bio-scaffolds improved locomotor outcome was primarily dependent on the formation of neuronal bridging but not the long-distance regeneration of descending motor axons throughout the lesion gap. Besides that, we found that spontaneously achieved locomotor recovery of hind limbs was unable to be weaken by repetitive resection of the lesion area, indicating the mechanism for spontaneous locomotor recovery was independent on functional neurological bridging throughout the lesion gap.

Diffusion Tensor Imaging: Tool for Tracking Injured Spinal Cord Fibres in Rat.

Spinal cord injury (SCI) is a severe disorder of the CNS leading to tissue damage and disability. Because it is critical to understand the pathological processes, it is important to find efficient ways to diagnose the severity of injured spinal cord tracts in situ from beginning up to a certain level of recovery following therapeutic interventions. In the current study, we set-up the criteria for diffusion tensor imaging (DTI) in order to capture changes of nerve fibre tracts in rat spinal cord compression injury. We tested four DTI parameters, such as fractional anisotropy, mean diffusivity, axial diffusivity and radial diffusivity at the lesion site, in time course of 7weeks. Afterwards, we compared DTI data with histological results and locomotor outcomes to examine their consistency and capability of reflecting the lesion development in time. Our data confirm that DTI is avaluable in vivo imaging tool capable to distinguish damaged white matter tracts after mild SCI in rat. Fractional anisotropy showed decreased values for injury site, while the mean diffusivity had higher values, with increased both axial and radial diffusivity in comparison to control subjects. Thus, the combination of DTI parameters can reflect the severity of lesion in time and may correlate with histological evaluation of spared tissue, but not with locomotor recovery following mild injury associated with spontaneous recovery.

Lower Limb Motion Estimation Using Ultrasound Imaging: A Framework for Assistive Device Control.

Powered assistive devices need improved control intuitiveness to enhance their clinical adoption. Therefore, the intent of individuals should be identified and the device movement should adhere to it. Skeletal muscles contract synergistically to produce defined lower limb movements, so unique contraction patterns in lower extremity musculature may provide a means of device joint control. Ultrasound (US) imaging enables direct measurement of the local deformation of muscle segments. Hence, the objective of this study was to assess the feasibility of using US to estimate human lower limb movements. A novel algorithm was developed to calculate US features of the rectus femoris muscle during a non-weight-bearing knee flexion/extension experiment by nine able-bodied subjects. Five US features of the skeletal muscle tissue were studied, namely thickness, angle between aponeuroses, pennation angle, fascicle length, and echogenicity. A multiscale ridge filter was utilized to extract the structures in the image and a random sample consensus (RANSAC) model was used to segment muscle aponeuroses and fascicles. A localization scheme further guided RANSAC to enable tracking in a US image sequence. Gaussian process regression models were trained using segmented features to estimate both knee joint angle and angular velocity. The proposed segmentation-estimation approach could estimate knee joint angle and angular velocity with an average root mean square error value of 7.45° and 0.262 rad/s, respectively. The average processing rate was 3-6 frames/s that is promising toward real-time implementation. Experimental results demonstrate the feasibility of using US to estimate human lower extremity motion. The ability of the algorithm to work in real time may enable the use of US as a neural interface for lower limb applications. Intuitive intent recognition of human lower extremity movements using wearable US imaging may enable volitional assistive device control and enhance locomotor outcomes for those with mobility impairments.

The Impact of Cognitive Dysfunction on Locomotor Rehabilitation Potential in Multiple Sclerosis.

Background:Cognitive dysfunction is a frequent manifestation of multiple sclerosis (MS) but its effect on locomotor rehabilitation is unknown.Objective:To study the impact of cognitive impairment on locomotor rehabilitation outcome in people with MS.Methods:We performed a retrospective analysis involving ambulatory patients with MS who were admitted for intensive, inpatient, multidisciplinary rehabilitation at the National Multiple Sclerosis Center of Melsbroek between the years 2012 and 2017. The Brief Repeatable Battery of Neuropsychological Tests (BRB-N) was used to determine the cognitive status of subjects as either impaired (COG–) or preserved (COG+). Locomotor outcome was compared between groups with the difference in 6-minute walk test (6MWT) measured at admission and discharge (Δ6MWT). In addition, individual test scores of the BRB-N for attention (Paced Auditory Serial Addition Test 2” and 3”), visuospatial learning/memory (7/24 Spatial Recall Test), verbal learning/memory (Selective Reminding Test) and verbal fluency (Controlled Oral Word Association Test) were correlated to the Δ6MWT.Results:A total of 318 complete and unique records were identified. Both groups showed a significant within-group Δ6MWT during hospitalization (COG+: 47.51 m; COG–: 40.97 m; P < .01). In contrast, Δ6MWT values were comparable between groups. The odds of achieving a minimal clinical important difference on the 6MWT did not differ significantly between both groups. Only attention/concentration was significantly correlated with Δ6MWT (r = 0.16, P = .013).Conclusion:Cognitive impairment based on BRB-N results appears not to impede locomotor rehabilitation in ambulatory patients with MS. Attentional deficits are correlated to the extent of locomotor rehabilitation, suggesting the presence of a subtle effect of cognition.

Progesterone effects on oligodendrocyte differentiation in injured spinal cord

Spinal cord lesions result in chronic demyelination as a consequence of secondary injury. Although oligodendrocyte precursor cells proliferate the differentiation program fails. Successful differentiation implies progressive decrease of transcriptional inhibitors followed by upregulation of activators. Progesterone emerges as an anti-inflammatory and pro-myelinating agent which improves locomotor outcome after spinal cord injury.In this study, we have demonstrated that spinal cord injury enhanced oligodendrocyte precursor cell number and decreased mRNA expression of transcriptional inhibitors (Id2, Id4, hes5). However, mRNA expression of transcriptional activators (Olig2, Nkx2.2, Sox10 and Mash1) was down-regulated 3 days post injury. Interestingly, a differentiation factor such as progesterone increased transcriptional activator mRNA levels and the density of Olig2- expressing oligodendrocyte precursor cells. The differentiation program is regulated by extracellular signals which modify transcriptional factors and epigenetic players. As TGFβ1 is a known oligodendrocyte differentiation factor which is regulated by progesterone in reproductive tissues, we assessed whether TGFβ1 could mediate progesterone remyelinating actions after the lesion.Notwithstanding that astrocyte, oligodendrocyte precursor and microglial cell density increased after spinal cord injury, the number of these cells which expressed TGFβ1 remained unchanged regarding sham operated rats. However, progesterone treatment increased TGFβ1 mRNA expression and the number of astrocytes and microglial TGFβ1 expressing cells which would indirectly enhance oligodendrocyte differentiation. Therefore, TGFβ1 arises as a potential mediator of progesterone differentiating effects on oligodendrocyte linage.

Dichotomous Locomotor Recoveries Are Predicted by Acute Changes in Segmental Blood Flow after Thoracic Spinal Contusion Injuries in Pigs

Neuroimaging facilitates the translation of animal pre-clinical research to human application. The large porcine spinal cord is useful for testing invasive interventions. Ideally, the safety and efficacy of a delayed intervention is tested in pigs that have recovered sufficiently after spinal cord injury (SCI) to allow either deterioration or improvement of function to be detected. We set out to create moderate severity T9 injuries in Yucatan minipigs by conducting a bridging study adapting methods previously developed in infant piglets. The injury severity was varied according to two pneumatic impactor parameters: the piston compression depth into tissue or the velocity. To stratify locomotor recovery, a 10-point scale used in prior piglet studies was redefined through longitudinal observations of spontaneous recovery. Using hindlimb body weight support to discriminate injury severity, we found that end-point recovery was strongly bimodal to either non-weight-bearing plegia with reciprocating leg movements (<5/10) or recovery of weight bearing that improved toward a ceiling effect (≥ 8/10). No intermediate recovery animals were observed at 2 months post-injury. The ability of intra-operative ultrasound and acute magnetic resonance imaging (MRI) to provide immediate predictive feedback regarding tissue and vascular changes following SCI was assessed. There was an inverse association between locomotor outcome and early gray matter hemorrhage on MRI and ultrasound. Epicenter blood flow following contusion predicted recovery or non-recovery of weight-bearing. The depth of the dorsal cerebrospinal fluid space, which varied between animals, influenced injury severity and confounded the results in this fixed-stroke paradigm.

Early movement restriction leads to maladaptive plasticity in the sensorimotor cortex and to movement disorders

Motor control and body representations in the central nervous system are built, i.e., patterned, during development by sensorimotor experience and somatosensory feedback/reafference. Yet, early emergence of locomotor disorders remains a matter of debate, especially in the absence of brain damage. For instance, children with developmental coordination disorders (DCD) display deficits in planning, executing and controlling movements, concomitant with deficits in executive functions. Thus, are early sensorimotor atypicalities at the origin of long-lasting abnormal development of brain anatomy and functions? We hypothesize that degraded locomotor outcomes in adulthood originate as a consequence of early atypical sensorimotor experiences that induce developmental disorganization of sensorimotor circuitry. We showed recently that postnatal sensorimotor restriction (SMR), through hind limb immobilization from birth to one month, led to enduring digitigrade locomotion with ankle-knee overextension, degraded musculoskeletal tissues (e.g., gastrocnemius atrophy), and clear signs of spinal hyperreflexia in adult rats, suggestive of spasticity; each individual disorder likely interplaying in self-perpetuating cycles. In the present study, we investigated the impact of postnatal SMR on the anatomical and functional organization of hind limb representations in the sensorimotor cortex and processes representative of maladaptive neuroplasticity. We found that 28 days of daily SMR degraded the topographical organization of somatosensory hind limb maps, reduced both somatosensory and motor map areas devoted to the hind limb representation and altered neuronal response properties in the sensorimotor cortex several weeks after the cessation of SMR. We found no neuroanatomical histopathology in hind limb sensorimotor cortex, yet increased glutamatergic neurotransmission that matched clear signs of spasticity and hyperexcitability in the adult lumbar spinal network. Thus, even in the absence of a brain insult, movement disorders and brain dysfunction can emerge as a consequence of reduced and atypical patterns of motor outputs and somatosensory feedback that induce maladaptive neuroplasticity. Our results may contribute to understanding the inception and mechanisms underlying neurodevelopmental disorders, such as DCD.

Using zebrafish larval models to study brain injury, locomotor and neuroinflammatory outcomes following intracerebral haemorrhage

Intracerebral haemorrhage (ICH) is a devastating condition with limited treatment options, and current understanding of pathophysiology is incomplete.Spontaneous cerebral bleeding is a characteristic of the human condition that has proven difficult to recapitulate in existing pre-clinical rodent models. Zebrafish larvae are frequently used as vertebrate disease models and are associated with several advantages, including high fecundity, optical translucency and non-protected status prior to 5 days post-fertilisation. Furthermore, other groups have shown that zebrafish larvae can exhibit spontaneous ICH. The aim of this study was to investigate whether such models can be utilised to study the pathological consequences of bleeding in the brain, in the context of pre-clinical ICH research. Here, we compared existing genetic (bubblehead) and chemically inducible (atorvastatin) zebrafish larval models of spontaneous ICH and studied the subsequent disease processes. Through live, non-invasive imaging of transgenic fluorescent reporter lines and behavioural assessment we quantified brain injury, locomotor function and neuroinflammation following ICH. We show that ICH in both zebrafish larval models is comparable in timing, frequency and location. ICH results in increased brain cell death and a persistent locomotor deficit. Additionally, in haemorrhaged larvae we observed a significant increase in macrophage recruitment to the site of injury. Live in vivo imaging allowed us to track active macrophage-based phagocytosis of dying brain cells 24 hours after haemorrhage. Morphological analyses and quantification indicated that an increase in overall macrophage activation occurs in the haemorrhaged brain. Our study shows that in zebrafish larvae, bleeding in the brain induces quantifiable phenotypic outcomes that mimic key features of human ICH. We hope that this methodology will enable the pre-clinical ICH community to adopt the zebrafish larval model as an alternative to rodents, supporting future high throughput drug screening and as a complementary approach to elucidating crucial mechanisms associated with ICH pathophysiology.

Internal decompression of the acutely contused spinal cord: Differential effects of irrigation only versus biodegradable scaffold implantation

Severe spinal cord injury leads to hemorrhage, edema and elevated tissue pressures that propagate ischemia. Liquefactive necrosis of damaged tissue eventually results in chronic cavities due to a wound healing process lacking adhesive contractile cells. Biomaterials can potently influence wound healing responses. Internal decompression (ID) refers to pial opening, allowing spontaneous extrusion and irrigation of fluid necrotic debris relieving pressure and resulting in a space for biomaterial scaffold insertion. After thoracic contusions, rats were randomized to: contusion only, contusion + ID and contusion + ID + PLGA-PLL scaffold implantation, to test for neuroprotection and endogenous repair over 3 months. ID alone reduced inflammatory activity, cavity volume, and increased tissue sparing. Scaffold biodegradation produced delayed ingrowth of inflammatory and other cells resulting in endogenously derived laminin-rich tissue, marked reduction in cavitation and presence of tissue remodeling macrophages. Extensive recruitment of Schwann cells into adjacent spared white matter occurred, greatest in scaffold-implanted animals. Despite tissue preservation with myelin repair, no groups differed significantly in open field locomotion. However, across all rats, spared epicenter tissue and locomotor outcomes were correlated. Scaffold-implanted animals showed no obvious toxicity. To study the clinical feasibility, timing and indications for scaffold implantation, Göttingen minipigs underwent ID and were implanted with scaffolds 4, 6, and 24 h after T10 contusion. High intra-spinal tissue pressures fell to pre-injury levels after ID and scaffold implantation. Extrusion of necrotic debris left sufficient space for a sized scaffold. These results provided the preclinical rationale for a current clinical study of biomaterial scaffold implantation into the human injured spinal cord.

Methylprednisolone treatment enhances early recovery following surgical decompression for degenerative cervical myelopathy without compromise to the systemic immune system

BackgroundDegenerative cervical myelopathy (DCM) is caused by degenerative or congenital changes to the discs and soft tissues of the cervical spine, which leads to chronic compression of the spinal cord. The current treatment for moderate to severe DCM consists of surgical decompression, which, while effective in most cases, can result in neuroinflammation and spinal cord reperfusion injury, leading to perioperative neurological complications and suboptimal neurological recovery. The primary objective of this study was to assess, in a translationally relevant animal model of DCM, the efficacy of perioperative methylprednisolone (MP) in enhancing neurological recovery and to evaluate its effect on the inflammatory response following decompression.MethodsDCM was induced in C57BL/6 mice. Briefly, an aromatic polyether material was implanted underneath the C5-C6 laminae to cause progressive compression of the cervical spinal cord due to focal ossification. Decompressive surgery was undertaken at 12 weeks post initial biomaterial implantation. Animals received one dose of MP (30 mg/kg) or vehicle 30 min before decompression and at 2 weeks after decompression. Acute analysis of secreted cytokines and spinal cord microvasculature was complemented with immunohistochemistry for glial and neuronal cell markers. Locomotor outcomes were measured using the CatWalk system. The composition of circulating white blood cells was analyzed by flow cytometry.ResultsA single dose of MP before decompression significantly sped locomotor recovery (*p < 0.05) and reduced the incidence of perioperative motor complications, without affecting the composition of circulating white blood cells. Histological assessment of the spinal cord showed significant neuronal preservation and a modest reduction in parenchymal inflammation.ConclusionsOur data suggest that MP reduces perioperative neurological complications following decompressive surgery for DCM by protecting neurons from inflammation, without compromising the composition of circulating immune cells. We propose that MP, which is commonly used for neurological disorders including spinal cord injury, be considered as a perioperative adjunct to decompressive surgery to attenuate neurological complications.

Relieving compression against injured spinal cord via non-suturing muscle layer in rat

Background: The sustained compression to the spinal cord caused by muscle scars after surgery in Spinal Cord Injury (SCI) models makes it difficult to evaluate the effectiveness of therapeutic regimens. The present study aims to evaluate potential strategies to reduce such compression. Materials and Methods: Rat SCI models were used and divided into two groups: one with muscle layer sutured after surgery and the other not sutured. The time point of muscle scar formation was determined by hematoxylin and eosin stain. Magnetic Resonance Image (MRI) was performed after the determined time point to observe the severity of compression of muscle scar against the injured spinal cord in both groups. The Basso, Beattie, and Bresnahan score (BBB score) was used to evaluate the locomotor outcomes. Results: The scar formed in the third week after the muscle was dissected. MRI in the fourth week after surgery indicated that the rats with muscle layer sutured experienced more severe compression against the spinal cord than those not sutured. The concave caused by muscle scars in the injured spinal cord tissue of the muscle layer sutured rats was more obvious than that in non-sutured ones. There were no statistically significant differences in the BBB score between the two groups (p>0.05). Conclusion: The compression to the injured spinal cord caused by muscle scars after surgical procedures could be relieved if the muscle layer is not sutured, and this non-suturing management may makes it easy to evaluate the effectiveness of therapeutic regimens in rat SCI models.

Diffusion tensor imaging of spinal cord parenchyma lesion in rat with chronic spinal cord injury

PurposeAdequate evaluation of spinal cord parenchyma and accurate identification of injury range are considered two premises for the research and treatment of chronic spinal cord injury (SCI). Diffusion tensor imaging (DTI) provides information about water diffusion in spinal cord, and thus makes it possible to realize these premises. MethodIn this study, we conducted magnetic resonance imaging (MRI) for Wistar rats 84days after spinal cord contusion. DTI metrics including fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD) from different positions of the injured cord were collected, analyzed, and compared with the histological results and locomotor outcomes. Moreover, we performed fiber tractography, and examined the difference in cavity percentage obtained respectively via conventional MRI, DTI and histology. ResultsResults showed that the chronic SCI rats had the largest changes of all DTI metrics at the epicenter; the farther away from the epicenter, the smaller the variation. FA, AD and RD were all influenced by SCI in a greater space range than MD. The good consistency of FA values and histological results in specific regions evidenced FA's capability of reflecting Wallerian degeneration after SCI. DTI metrics at the epicenter in ventral funiculus also showed a close correlation with the BBB scores. Additionally, supported by the histological results, DTI enables a more accurate measurement of cavity percentage compared to the conventional MRI. ConclusionDTI parameters might comprehensively reflect the post-SCI pathological status of spinal cord parenchyma at the epicenter and distal parts during the chronic stage, while showing good consistency with locomotor performance. DTI combined with tractography could intuitively display the distribution of spared fibers after SCI and accurately provide information such as cavity area. This may shed light on the research and treatment of chronic SCI.

Effects of Training Intensity on Locomotor Performance in Individuals With Chronic Spinal Cord Injury: A Randomized Crossover Study

Background. Many physical interventions can improve locomotor function in individuals with motor incomplete spinal cord injury (iSCI), although the training parameters that maximize recovery are not clear. Previous studies in individuals with other neurologic injuries suggest the intensity of locomotor training (LT) may positively influence walking outcomes. However, the effects of intensity during training of individuals with iSCI have not been tested. Objective. The purpose of this pilot, blinded-assessor randomized trial was to evaluate the effects of LT intensity on walking outcomes in individuals with iSCI. Methods. Using a crossover design, ambulatory participants with iSCI >1 year duration performed either high- or low-intensity LT for ≤20 sessions over 4 to 6 weeks. Four weeks following completion, the training interventions were alternated. Targeted intensities focused on achieving specific ranges of heart rate (HR) or ratings of perceived exertion (RPE), with intensity manipulated by increasing speeds or applying loads. Results. Significantly greater increases in peak treadmill speeds (0.18 vs 0.02 m/s) and secondary measures of metabolic function and overground speed were observed following high- versus low-intensity training, with no effects of intervention order. Moderate to high correlations were observed between differences in walking speed or distances and differences in HRs or RPEs during high- versus low-intensity training. Conclusion. This pilot study provides the first evidence that the intensity of stepping practice may be an important determinant of LT outcomes in individuals with iSCI. Whether such training is feasible in larger patient populations and contributes to improved locomotor outcomes deserves further consideration.

Pharmacological inhibition of spinal cord injury-stimulated ribosomal biogenesis does not affect locomotor outcome

After unresolved endoplasmic reticulum stress, recovery of protein synthesis including increased expression of ribosomal components and translation factors may induce cell death. Using a mouse model of moderate contusive spinal cord injury (SCI) at the T9 level, upregulation of ribosomal biogenesis was observed in the injury epicenter at 24h after trauma. Such upregulation coincided with endoplasmic reticulum stress response as previously reported in this model. It was also accompanied by changes in expression of many other genes associated with translational regulation. Systemic treatment with a pharmacological inhibitor of RNA-Polymerase-1, BMH-21 reduced rRNA transcription in the spinal cord. Moreover, in the injury epicenter, treatment with BMH-21 increased expression of oligodendrocyte-specific transcripts including Mbp and Cldn11 at 3days post injury. Although such findings may suggest at least transient reduction of oligodendrocyte death, locomotor outcome was mostly unaffected except slightly accelerated recovery of hindlimb function at week 2 post-injury. Therefore, at least in mice, RNA-Polymerase-1 does not appear to be a robust target for therapies to protect spinal cord tissue after contusion. However, these findings raise an interesting possibility that altered rate of ribosomal biogenesis contributes to the apparent translational reprogramming after contusive SCI. Such a reprogramming could be a major regulator of SCI-induced gene expression.

Performance and environmental factors related to the main locomotor outcome in persons with an unilateral transtibial amputation equipped with energy storage and return feet

Objective. To assess performance and environmental factors in persons with an Unilateral TransTibial amputation (UTTA) equipped with an Energy Storage And Return (ESAR) foot. Method . Prosthetic Profile of the Amputees (PPA) questionnaire was sent to 295 adults with an UTTA. Results . Seventy-eight questionnaires met all criteria. The main locomotor outcome, was optimal in 51% of cases. The performance that best predicted the optimal main locomotor outcome was the ability to walk alone outside in inclement weather (OR [95%CI] = 36 [9.65–136.16]). The most predictive environmental factor was the acceptance of the amputation by the family and friends (OR [95%CI] = 6 [1.17–30.72]). Conclusions . A marked proportion of persons with UTTA showed a suboptimal walking performance at least 6 months after the attribution of an ESAR foot.

Performance and environmental factors related to the main locomotor outcome in persons with an unilateral transtibial amputation equipped with energy storage and return feet

Objectif. &#201;valuer les facteurs performance et environnement chez les Personnes atteintes d&#8217;une Amputation Transtibial Unilat&#233;rale (PATU) &#233;quip&#233;es d&#8217;un Pied proth&#233;tique &#224; Stockage/Restitution d&#8217;&#201;nergie (PSRE). M&#233;thode. Le questionnaire Profil Proth&#233;tique de l&#8217;Amput&#233; (PPA) a &#233;t&#233; envoy&#233; &#224; 295 personnes avec un PSRE. R&#233;sultats. Soixante-seize questionnaires r&#233;pondaient &#224; tous les crit&#232;res. Le niveau optimal de locomotion a &#233;t&#233; observ&#233; dans 51 % des cas. Les items des facteurs performance et environnement qui pr&#233;disaient le mieux le niveau optimal de locomotion &#233;taient respectivement la &#171; capacit&#233; de marcher seul dehors dans les intemp&#233;ries &#187; (OR [95 %CI] = 36 [9,65&#8211;136,16]) et &#171; l&#8217;acceptation de l&#8217;amputation par la famille et les amis &#187; (OR [95 %CI] = 6 [1,17&#8211;30,72]). Conclusion. Une proportion consid&#233;rable de PATU montre une performance sous optimale de marche, 6mois apr&#232;s l&#8217;attribution d&#8217;un PSRE.

Experimental Traumatic Brain Injury Induces Bone Loss in Rats.

Few studies have investigated the influence of traumatic brain injury (TBI) on bone homeostasis; however, pathophysiological mechanisms involved in TBI have potential to be detrimental to bone. The current study assessed the effect of experimental TBI in rats on the quantity and quality of two different weight-bearing bones, the femur and humerus. Rats were randomly assigned into either sham or lateral fluid percussion injury (FPI) groups. Open-field testing to assess locomotion was conducted at 1, 4, and 12 weeks post-injury, with the rats killed at 1 and 12 weeks post-injury. Bones were analyzed using peripheral quantitative computed tomography (pQCT), histomorphometric analysis, and three-point bending. pQCT analysis revealed that at 1 and 12 weeks post-injury, the distal metaphyseal region of femora from FPI rats had reduced cortical content (10% decrease at 1 week, 8% decrease at 12 weeks; p < 0.01) and cortical thickness (10% decrease at 1 week, 11% decrease at 12 weeks p < 0.001). There was also a 23% reduction in trabecular bone volume ratio at 1 week post-injury and a 27% reduction at 12 weeks post-injury in FPI rats compared to sham (p < 0.001). There were no differences in bone quantity and mechanical properties of the femoral midshaft between sham and TBI animals. There were no differences in locomotor outcomes, which suggested that post-TBI changes in bone were not attributed to immobility. Taken together, these findings indicate that this rat model of TBI was detrimental to bone and suggests a link between TBI and altered bone remodeling.

Aescin reduces oxidative stress and provides neuroprotection in experimental traumatic spinal cord injury

Aescin has many physiological functions that are highly relevant to spinal cord injury (SCI), including anti-inflammation, anti-oxidation, anti-oedema, and enhancing vascular tone. The present study investigated the putative therapeutic value of aescin in SCI, with a focus on its neuroprotective, anti-inflammatory, and anti-oxidative properties. Sodium aescinate (1.0mg/kg body weight) or equivalent volume of saline was administered 30min after injury by intravenous injection, with an additional dose daily for seven consecutive days after moderate SCI in rats. After contusion injury of the 8th thoracic (T8) spinal cord, aescin-treated rats developed less severe hind limb weakness than saline controls, as assayed by the Basso-Beattie-Bresnahan scale, the beam walking test, and a footprint analysis. The improved locomotor outcomes in aescin-treated rats corresponded to markedly decreased immune response, oxidative stress, neuronal loss, axon demyelination, spinal cord swelling, and cell apoptosis, measured around T8 after impact. Our data suggest aescin treatment as a novel, early, neuroprotective approach in SCI. Given the known safety of aescin in clinical applications, the results of this study suggest that it is a good candidate for SCI treatment in humans.

Intraspinal transplantation of subventricular zone-derived neural progenitor cells improves phrenic motor output after high cervical spinal cord injury

Following spinal cord injury (SCI), intraspinal transplantation of neural progenitor cells (NPCs) harvested from the forebrain sub-ventricular zone (SVZ) can improve locomotor outcomes. Cervical SCI often results in respiratory-related impairments, and here we used an established model cervical SCI (C2 hemisection, C2Hx) to confirm the feasibility of mid-cervical transplantation of SVZ-derived NPCs and the hypothesis that that this procedure would improve spontaneous respiratory motor recovery. NPCs were isolated from the SVZ of enhanced green fluorescent protein (GFP) expressing neonatal rats, and then intraspinally delivered immediately caudal to an acute C2Hx lesion in adult non-GFP rats. Whole body plethysmography conducted at 4 and 8wks post-transplant demonstrated increased inspiratory tidal volume in SVZ vs. sham transplants during hypoxic (P=0.003) or hypercapnic respiratory challenge (P=0.019). Phrenic nerve output was assessed at 8wks post-transplant; burst amplitude recorded ipsilateral to C2Hx was greater in SVZ vs. sham rats across a wide range of conditions (e.g., quiet breathing through maximal chemoreceptor stimulation; P<0.001). Stereological analyses at 8wks post–injury indicated survival of ~50% of transplanted NPCs with ~90% of cells distributed in ipsilateral white matter at or near the injection site. Peak inspiratory phrenic bursting after NPC transplant was positively correlated with the total number of surviving cells (P<0.001). Immunohistochemistry confirmed an astrocytic phenotype in a subset of the transplanted cells with no evidence for neuronal differentiation. We conclude that intraspinal transplantation of SVZ-derived NPCs can improve respiratory recovery following high cervical SCI.