Decentralized cardiovascular autonomic control and cognitive deficits in persons with spinal cord injury

Abstract

Summary: Spinal cord injury (SCI) results in motor and sensory impairments that can be identified with the American Spinal Injury Association (ASIA) Impairment Scale (AIS). Although, SCI may disrupt autonomic neural transmission, less is understood regarding the clinical impact of decentralized autonomic control. Cardiovascular regulation may be altered following SCI and the degree of impairment may or may not relate to the level of AIS injury classification. In general, persons with lesions above T1 present with bradycardia, hypotension, and orthostatic hypotension; functional changes which may interfere with rehabilitation efforts. Although many individuals with SCI above T1 remain overtly asymptomatic to hypotension, we have documented deficits in memory and attention processing speed in hypotensive individuals with SCI compared to a normotensive SCI cohort. Reduced resting cerebral blood flow (CBF) and diminished CBF responses to cognitive testing relate to test performance in hypotensive non-SCI, and preliminary evidence suggests a similar association in individuals with SCI. Persons with paraplegia below T7 generally present with a normal cardiovascular profile; however, our group and others have documented persistently elevated heart rate and increased arterial stiffness. In the non-SCI literature there is evidence supporting a link between increased arterial stiffness and cognitive deficits. Preliminary evidence suggests increased incidence of cognitive impairment in individuals with paraplegia, which we believe may relate to adverse cardiovascular changes. This report reviews relevant literature and discusses findings related to the possible association between decentralized cardiovascular autonomic control and cognitive dysfunction in persons with SCI.

Endoplasmic Reticulum Stress and Disrupted Neurogenesis in the Brain Are Associated with Cognitive Impairment and Depressive-Like Behavior after Spinal Cord Injury

“…[1][2][3][4][5][6][7][8][9] The cause of the cognitive deficits in these patients is controversial because of potentially confounding factors, such as concurrent traumatic brain injury (TBI). However, cognitive changes after SCI in patients have been reported without a history or signs of TBI.…”

Isolated spinal cord contusion in rats induces chronic brain neuroinflammation, neurodegeneration, and cognitive impairment

“…It has also been documented that chronic hypotension in persons with SCI is associated with deficits in memory and possibly attention and processing speed. 9,10 However, this issue has not been addressed experimentally with regard to mechanism. Only one prior experimental study has suggested cognitive decline after SCI-a projectile injury in pigs wearing body armor.…”

Inter-day reliability of blood pressure and cerebral blood flow velocities in persons with spinal cord injury and intact controls

“…22,49 Our data support the notion that not only is MFV reduced in persons with SCI compared to AB controls, but SFV and DFV are also significantly lower. These findings indicate persistent cerebral hypoperfusion throughout the entire cardiac cycle in hypotensive individuals with chronic SCI, which may contribute to the increased incidence of cerebrovascular disease 50 and ischemic stroke, 18 as well as cognitive deficits, 23,51,52 and impairment in health related QOL. 10 …”