Journal of neurotrauma
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Journal of neurotrauma · Feb 2013
Dynamic motor compensations with permanent, focal loss of forelimb force after cervical spinal cord injury.
Incomplete cervical lesion is the most common type of human spinal cord injury (SCI) and causes permanent paresis of arm muscles, a phenomenon still incompletely understood in physiopathological and neuroanatomical terms. We performed spinal cord hemisection in adult rats at the caudal part of the segment C6, just rostral to the bulk of triceps brachii motoneurons, and analyzed the forces and kinematics of locomotion up to 4 months postlesion to determine the nature of motor function loss and recovery. A dramatic (50%), immediate and permanent loss of extensor force occurred in the forelimb but not in the hind limb of the injured side, accompanied by elbow and wrist kinematic impairments and early adaptations of whole-body movements that initially compensated the balance but changed continuously over the follow-up period to allow effective locomotion. ⋯ Ipsilateral foreleg deficits resulted mainly from interruption of axons that innervate the spinal cord segments caudal to the lesion, because chronic loss (about 35%) of synapses was detected at C7 while only 14% of triceps braquii motoneurons died, as assessed by synaptophysin immunohistochemistry and retrograde neural tracing, respectively. We also found a large pool of propriospinal neurons projecting from C2-C5 to C7 in normal rats, with topographical features similar to the propriospinal premotoneuronal system of cats and primates. Thus, concurrent axotomy at C6 of brain descending axons and cervical propriospinal axons likely hampered spontaneous recovery of the focal neurological impairments.
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Journal of neurotrauma · Feb 2013
Sialidase, chondroitinase ABC, and combination therapy after spinal cord contusion injury.
Axon regeneration in the central nervous system is severely hampered, limiting functional recovery. This is in part because of endogenous axon regeneration inhibitors that accumulate at the injury site. Therapeutic targeting of these inhibitors and their receptors may facilitate axon outgrowth and enhance recovery. ⋯ Sialidase-treated rats also had increased serotonergic axons caudal to the injury. ChABC treatment, in contrast, did not enhance functional recovery or alter axon numbers after moderate spinal cord contusion injury, and dampened the response of sialidase in the dual enzyme treatment group. We conclude that sialidase infusion enhanced recovery from spinal cord contusion injury, and that combining sialidase with ChABC failed to improve outcomes.
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Journal of neurotrauma · Jan 2013
A multiscale computational approach to estimating axonal damage under inertial loading of the head.
A computational modeling framework is developed to estimate the location and degree of diffuse axonal injury (DAI) under inertial loading of the head. DAI is one of the most common pathological features of traumatic brain injury and is characterized by damage to the neural axons in the white matter regions of the brain. We incorporate the microstructure of the white matter (i.e., the fiber orientations and fiber dispersion) through the use of diffusion tensor imaging (DTI), and model the white matter with an anisotropic, hyper-viscoelastic constitutive model. ⋯ Acceleration loading curves from accident reconstruction data were then applied to the FE models. The rotational (rather than translational) accelerations were shown to dominate the injury response, which is consistent with previous studies. Through this accident reconstruction, we demonstrate a conceptual framework to estimate the degree of axonal injury in the fiber tracts of the human brain, enabling the future development of relationships between computational simulation and neurocognitive impairment.
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Journal of neurotrauma · Jan 2013
Cognitive recovery and development after traumatic brain injury in childhood: a person-oriented, longitudinal study.
Influence of childhood traumatic brain injury (TBI) on cognitive recovery and subsequent development is poorly understood. In this longitudinal study we used cluster analysis to explore acute stage individual profiles of injury age and cognition in 118 children with traumatic brain injury. Repeated measures of cognitive function were conducted at 30 months, indicating recovery, and 10 years post-injury, indicating development. ⋯ This suggests that developmental change after TBI in childhood takes place on a continuum, with both chance of long-term catching up, and risk of poor development. An acute profile of higher FFD and lower PS seemed to reflect injury consequences and were followed by developmental gains. These results challenge previous findings, and warrant further investigation.
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Journal of neurotrauma · Jan 2013
Remote epidural hemorrhage after unilateral decompressive hemicraniectomy in brain-injured patients.
Epidural hemorrhage (EDH) that develops remote from the decompressed hemisphere can be associated with devastating morbidity after hemicraniectomy for traumatic brain injury (TBI). In this study, we investigated the incidence, risk factors, and outcome influence of post-craniectomy remote EDH. For this retrospective study, we enrolled 139 patients undergoing unilateral hemicraniectomy for TBI. ⋯ In conclusion, remote EDH in patients undergoing unilateral decompressive hemicraniectomy for TBI is not uncommon. The absence of contusional hemorrhage and presence of remote skull fracture are independent risk factors. Although postcraniectomy remote EDH is devastating, timely computed tomography scanning and immediate hematoma evacuation are efficient and crucial for patient outcomes.