Journal of neurotrauma
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Significant cardiovascular and autonomic dysfunction occurs after spinal cord injury (SCI). It is now recognized that cardiovascular disease is a leading cause of morbidity and mortality in SCI. Patients with SCI may also suffer severe orthostatic hypotension and autonomic dysreflexia. ⋯ Although no studies have examined the sympathetic arm of the baroreflex in those with SCI, despite this being arguably more important to blood pressure regulation than the cardiovagal baroreflex, nine articles have examined sympathetic responses to orthostatic challenges; these findings are reviewed. Future studies are needed to describe whether dysfunctional baroreflex sensitivity after SCI is due to arterial stiffening or a neural component. Further, measurement of forearm vascular conductance and/or muscle sympathetic nerve activity is required to directly evaluate the sensitivity of the sympathetic arm of the baroreflex in those with SCI.
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Journal of neurotrauma · Oct 2012
Comparative StudyComparing the predictive value of multiple cognitive, affective, and motor tasks after rodent traumatic brain injury.
Controlled cortical impact injury (CCI) is a widely-used, clinically-relevant model of traumatic brain injury (TBI). Although functional outcomes have been used for years in this model, little work has been done to compare the predictive value of various cognitive and sensorimotor assessment tests, singly or in combination. Such information would be particularly useful for assessing mechanisms of injury or therapeutic interventions. ⋯ We also compared individual functional measures with histological outcomes such as lesion volume and neuronal cell loss across anatomical regions. In addition, we created a novel composite behavioral score index from individual complementary behavioral scores, and it provided superior discrimination across injury severities compared to individual tests. In summary, this study demonstrates the feasibility of using a larger number of complementary functional outcome behavioral tests than those traditionally employed to follow post-traumatic recovery after TBI, and suggests that the composite score may be a helpful tool for screening new neuroprotective agents or for addressing injury mechanisms.
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Journal of neurotrauma · Oct 2012
A discrimination task used as a novel method of testing decision-making behavior following traumatic brain injury.
Traumatic brain injury (TBI) results in a multitude of deficits following injury. Some of the most pervasive in humans are the changes that affect frontally-mediated cognitive functioning, such as decision making. The assessment of decision-making behavior in rodents has been extensively tested in the field of the experimental analysis of behavior. ⋯ Upon reaching criterion, a reversal discrimination was evaluated in which the reinforcer was placed in unscented sand. Finally, a novel scent discrimination (basil versus coffee with basil reinforced), and a reversal (coffee) were evaluated. The results indicated that the Dig task is a simple experimental preparation that can be used to assess deficits in decision-making behavior following TBI.
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Journal of neurotrauma · Oct 2012
Cerebrovascular responses to orthostatic stress after spinal cord injury.
Orthostatic hypotension (OH) is a debilitating condition affecting individuals with spinal cord injury (SCI) that may be associated with cerebral hypoperfusion. We studied orthostatic cerebral control in individuals with SCI with different levels and severities of injury to spinal cardiovascular autonomic pathways. We measured beat-to-beat cardiovascular and cerebrovascular responses to passive orthostatic stress in 16 controls and 26 subjects with chronic SCI. ⋯ Individuals with autonomically complete SCI reported increased severity of symptoms relative to controls (p<0.05). Symptom severity was correlated with the efficacy of dynamic autoregulation. During orthostatic stress, SCI individuals have impaired cerebrovascular control that is related to the level and severity of autonomic injury.