Journal of neurotrauma
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Journal of neurotrauma · Mar 2018
Spinal Cord Injury Disrupts Resting-State Networks in the Human Brain.
Despite 253,000 spinal cord injury (SCI) patients in the United States, little is known about how SCI affects brain networks. Spinal MRI provides only structural information with no insight into functional connectivity. Resting-state functional MRI (RS-fMRI) quantifies network connectivity through the identification of resting-state networks (RSNs) and allows detection of functionally relevant changes during disease. ⋯ Finally, connectivity changed over time after SCI: the primary motor cortex decreased connectivity with the primary somatosensory cortex, the visual cortex decreased connectivity with the primary motor cortex, and the visual cortex decreased connectivity with the sensory parietal cortex. These unique findings demonstrate the functional network plasticity that occurs in the brain as a result of injury to the spinal cord. Connectivity changes after SCI may serve as biomarkers to predict functional recovery following an SCI and guide future therapy.
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Journal of neurotrauma · Mar 2018
Rapamycin Exacerbates Cardiovascular Dysfunction after Complete High-Thoracic Spinal Cord Injury.
Autonomic dysreflexia (AD) is a potentially life-threatening syndrome in individuals with spinal cord injury (SCI) above the T6 spinal level that is characterized by episodic hypertension in response to noxious stimuli below the lesion. Maladaptive intraspinal plasticity is thought to contribute to the temporal development of AD, and experimental approaches that reduce such plasticity mitigate the severity of AD. The mammalian target of rapamycin (mTOR) has gained interest as a mediator of plasticity, regeneration, and nociceptor hypersensitivity in the injured spinal cord. ⋯ Moreover, RAP significantly increased the frequency of daily spontaneous AD and increased the absolute blood pressure induced by CRD at three weeks post-injury. These dynamic cardiovascular effects were not, however, correlated with changes in the density of nociceptive c-fibers or c-Fos+ neurons throughout the spinal cord, indicating that intraspinal plasticity associated with AD was not altered by treatment. These findings caution against the use of RAP as a therapeutic intervention for SCI because it evokes toxic weight loss and exacerbates cardiovascular dysfunction perhaps mediated by increased peripheral nociceptor sensitivity and/or vascular resistance.
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Journal of neurotrauma · Mar 2018
The Graded and Redefined Assessment of Strength, Sensibility and Prehension (GRASSP) Version 2 provides interval measure properties.
The Graded and Redefined Assessment of Strength, Sensibility and Prehension (GRASSP) is a valid, reliable, and responsive outcome measure to evaluate upper limb function in individuals with tetraplegia. GRASSP generates ordinal total scores; therefore, applicability as an interval level measurement requires testing of its measurement properties. This study examined the metric characteristics with Rasch Analysis to derive interval level scales of the respective GRASSP subtests. ⋯ Redundancies among some measurement items allowed shortening of the subscales without reasonable loss of reliability. Absence of DIF for the examination stage supported robustness of the subscales over time. The modified GRASSP, now Version 2, subtest scores can be applied as interval level measurements, and the reduction of items within subscales allows for shorter assessment times in clinical studies without degrading metric properties.
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Journal of neurotrauma · Mar 2018
Protective Effects of Estradiol and Dihydrotestosterone Following Spinal Cord Injury.
Spinal cord injury (SCI) results in lesions that destroy tissue and disrupt spinal tracts, producing deficits in locomotor and autonomic function. We previously demonstrated that motoneurons and the muscles they innervate show pronounced atrophy after SCI, and these changes are prevented by treatment with testosterone. Here, we assessed whether the testosterone active metabolites estradiol and dihydrotestosterone have similar protective effects after SCI. ⋯ SCI-induced decreases in motoneuron dendritic length were attenuated by all hormone treatments. SCI-induced reductions in muscle fiber cross-sectional areas were prevented by treatment with either dihydrotestosterone or estradiol combined with dihydrotestosterone, but estradiol treatment was ineffective. These findings suggest that deficits in micturition and regressive changes in motoneuron and muscle morphology seen after SCI are ameliorated by treatment with estradiol or dihydrotestosterone, further supporting a role for steroid hormones as neurotherapeutic agents in the injured nervous system.