Cognitive performance in hypotensive persons with spinal cord injury

A Comprehensive Review of the Importance of the Main Comorbidities in Developing Cognitive Disorders in Patients With Spinal Cord Injuries

Spinal cord injuries (SCI) refer to lesions in the spinal cord due to direct trauma (traumatic SCI-TSCI), such as vehicle accidents, falls, and violent events, or other pathological conditions (non-traumatic SCI) such as metabolic disorders, inflammation, or degenerative disorders. Depending on the location of the injury, patients may experience movement and/or sense disabilities in their lower limbs, torso, or upper limbs. Even though poorly studied, it has been found that such patients have a higher risk of developing cognitive disorders, such as deficits in concentration, short and long memory, comprehension, and problem-solving, as well as mental deficits in the form of difficulty socializing and expressing emotions. The main contributing factor of cognitive impairment in patients with SCI has been identified as a traumatic brain injury (TBI), but other comorbidities play an important role. In spite of the correlation that has been found between certain comorbidities and cognitive impairment in patients with SCI, further investigation into the importance of these pathological states as well as future research into the approach of these patients is necessary.

Valsalva maneuver pressure recovery time is prolonged following spinal cord injury with correlations to autonomically-influenced secondary complications

PURPOSE

This work's purpose was to quantify rapid sympathetic activation in individuals with spinal cord injury (SCI), and to identify associated correlations with symptoms of orthostatic hypotension and common autonomically mediated secondary medical complications.

METHODS

This work was a cross-sectional study of individuals with SCI and uninjured individuals. Symptoms of orthostatic hypotension were recorded using the Composite Autonomic Symptom Score (COMPASS)-31 and Autonomic Dysfunction following SCI (ADFSCI) survey. Histories of secondary complications of SCI were gathered. Rapid sympathetic activation was assessed using pressure recovery time of Valsalva maneuver. Stepwise multiple linear regression models identified contributions to secondary medical complication burden.

RESULTS

In total, 48 individuals (24 with SCI, 24 uninjured) underwent testing, with symptoms of orthostatic hypotension higher in those with SCI (COMPASS-31, 3.3 versus 0.6, p < 0.01; ADFSCI, 21.2 versus. 3.2, p < 0.01). Pressure recovery time was prolonged after SCI (7.0 s versus. 1.7 s, p < 0.01), though poorly correlated with orthostatic symptom severity. Neurological level of injury after SCI influenced pressure recovery time, with higher injury levels associated with more prolonged time. Stepwise multiple linear regression models identified pressure recovery time as the primary explanation for variance in number of urinary tract infections (34%), histories of hospitalizations (12%), and cumulative secondary medical complication burden (24%). In all conditions except time for bowel program, pressure recovery time outperformed current clinical tools for assessing such risk.

CONCLUSIONS

SCI is associated with impaired rapid sympathetic activation, demonstrated here by prolonged pressure recovery time. Prolonged pressure recovery time after SCI predicts higher risk for autonomically mediated secondary complications, serving as a viable index for more "autonomically complete" injury.

Cognitive, behavioral and psychiatric symptoms in patients with spinal cord injury: a scoping review

Spinal Cord Injury (SCI) is a condition where the spinal cord is damaged and experiences partial or complete loss of motor and/or sensory function, which is typically less than normal. After SCI, patients may exhibit more severe psychiatric symptoms and experience cognitive impairments, including reduced speed and attention processing capacity, as well as difficulties with executive function and episodic memory retention. Among the behavioral and psychiatric symptoms, depression, anxiety, substance use disorder, and posttraumatic stress disorder are the most common. This review aims to investigate the cognitive, behavioral, or psychiatric symptoms of the patient with SCI and their influence on the rehabilitation process. Studies were identified from an online search of PubMed, Web of Science, Cochrane Library, and Embase databases. Studies published between 2013-2023 were selected. This review has been registered on OSF (n) 3KB2U. We have found that patients with SCI are at high risk of cognitive impairment and experience a wide range of difficulties, including tasks based on processing speed and executive function. This clinical population may experience adjustment disorders with depression and anxiety, as well as other psychiatric symptoms such as fatigue, stress, and suicidal ideation. This review has demonstrated that SCI patients may experience psychiatric symptoms and cognitive impairments that affect their functioning. At the same time, these patients may be more prone to various adjustment and mood disorders. Moreover, these two aspects may interact with each other, causing a range of symptoms, increasing the risk of hospitalization, and delaying the rehabilitation process.

Transcutaneous Spinal Cord Stimulation to Stabilize Seated Systolic Blood Pressure in Persons With Chronic Spinal Cord Injury: Protocol Development

Transcutaneous spinal cord stimulation (tSCS) is an emerging therapeutic strategy to target spinal autonomic circuitry to normalize and stabilize blood pressure (BP) in hypotensive persons living with chronic spinal cord injury (SCI). Our aim is to describe our current methodological approach to identify individual tSCS parameters that result in the maintenance of seated systolic blood pressure (SBP) within a pre-defined target range. The parent study is a prospective, randomized clinical trial in which eligible participants will undergo multiple mapping sessions to optimize tSCS parameter settings to promote stable SBP within a target range of 110-120 mm Hg for males and 100-120 mm Hg for females. Parameter mapping includes cathode electrode placement site (T7/8, T9/10, T11/12, and L1/2), stimulation frequency (30, 60 Hz), current amplitudes (0-120 mA), waveform (mono- and biphasic), pulse width (1000 μs), and use of carrier frequency (0, 10 kHz). Each participant will undergo up to 10 mapping sessions involving different electrode placement sites and parameter settings. BP will be continuously monitored throughout each mapping session. Stimulation amplitude (mA) will be increased at intervals of between 2 and 10 mA until one of the following occurs: 1) seated SBP reaches the target range; 2) tSCS intensity reaches 120 mA; or 3) the participant requests to stop. Secondary outcomes recorded include 1) symptoms related to autonomic dysreflexia and orthostatic hypotension, 2) Likert pain scale, and 3) skin appearance after removal of the tSCS electrode. Clinical Trials Registration: NCT05180227.

Autonomic Cardiovascular Control, Psychological Well-Being, and Cognitive Performance in People With Spinal Cord Injury

PURPOSE

To examine associations between parameters of psychological well-being, injury characteristics, cardiovascular autonomic nervous system (ANS) control, and cognitive performance in persons with spinal cord injury (SCI) compared with age-matched uninjured controls. This is an observational, cross-sectional study including a total of 94 participants (52 with SCI and 42 uninjured controls: UIC). Cardiovascular ANS responses were continuously monitored at rest and during administration of the Paced Auditory Serial Addition Test (PASAT). Self-report scores on the SCI-Quality of Life questionnaires are reported for depression, anxiety, fatigue, resilience, and positive affect. Participants with SCI performed significantly more poorly on the PASAT compared with the uninjured controls. Although not statistically significant, participants with SCI tended to report more psychological distress and less well-being than the uninjured controls. In addition, when compared with uninjured controls, the cardiovascular ANS responses to testing were significantly altered in participants with SCI; however, these responses to testing did not predict PASAT performance. Self-reported levels of anxiety were significantly related to PASAT score in the SCI group, but there was no significant relationship between PASAT and the other indices of SCI-Quality of Life. Future investigations should more closely examine the relationship among cardiovascular ANS impairments, psychological disorders, and cognitive dysfunction to better elucidate the underpinnings of these deficits and to guide interventions aimed at improving physiological, psychological, and cognitive health after SCI. Tetraplegia, paraplegia, blood pressure variability, cognitive, mood.

Item Banks for Measuring the Effect of Blood Pressure Dysregulation on Health-Related Quality of Life in Persons With Spinal Cord Injury

OBJECTIVE

To report on the development and calibration of the new Blood Pressure Dysregulation Measurement System (BPD-MS) item banks that assess the effect of BPD on health-related quality of life (HRQOL) and the daily activities of Veterans and non-Veterans with spinal cord injury (SCI).

DESIGN

Cross-sectional survey study.

SETTING

Two Veteran Affairs medical centers and a SCI model system site.

PARTICIPANTS

454 respondents with SCI (n=262 American Veterans and n=192 non-Veterans; N=454).

INTERVENTIONS

Not applicable MAIN OUTCOME MEASURES: The BPD-MS item banks.

RESULTS

BPD item pools were developed and refined using literature reviews, qualitative data from focus groups, and cognitive debriefing of persons with SCI and professional caregivers. The item banks then underwent expert review, reading level assessment, and translatability review prior to field testing. The items pools consisted of 180 unique questions (items). Exploratory and confirmatory factor analyses, item response theory modeling, and differential item function investigations resulted in item banks that included a total of 150 items: 75 describing the effect of autonomic dysreflexia on HRQOL, 55 describing the effect of low blood pressure (LBP) on HRQOL, and 20 describing the effect of LBP on daily activities. In addition, 10-item short forms were constructed based on item response theory-derived item information values and the clinical relevance of item content.

CONCLUSIONS

The new BPD-MS item banks and corresponding 10-item short forms were developed using established rigorous measurement development standards, which represents the first BPD-specific patient-reported outcomes measurement system unique for use in the SCI population.

Massive body-brain disconnection consequent to spinal cord injuries drives profound changes in higher-order cognitive and emotional functions: A PRISMA scoping review

Spinal cord injury (SCI) leads to a massive disconnection between the brain and the body parts below the lesion level representing a unique opportunity to explore how the body influences a person's mental life. We performed a systematic scoping review of 59 studies on higher-order cognitive and emotional changes after SCI. The results suggest that fluid abilities (e.g. attention, executive functions) and emotional regulation (e.g. emotional reactivity and discrimination) are impaired in people with SCI, with progressive deterioration over time. Although not systematically explored, the factors that are directly (e.g. the severity and level of the lesion) and indirectly associated (e.g. blood pressure, sleeping disorders, medication) with the damage may play a role in these deficits. The inconsistency which was found in the results may derive from the various methods used and the heterogeneity of samples (i.e. the lesion completeness, the time interval since lesion onset). Future studies which are specifically controlled for methods, clinical and socio-cultural dimensions are needed to better understand the role of the body in cognition.

Clinical trial of home blood pressure monitoring following midodrine administration in hypotensive individuals with spinal cord injury

BACKGROUND

Individuals with spinal cord injury (SCI) above thoracic level-6 (T6) experience impaired descending cortical control of the autonomic nervous system which predisposes them to blood pressure (BP) instability, including includes hypotension, orthostatic hypotension (OH), and autonomic dysreflexia (AD). However, many individuals do not report symptoms of these BP disorders, and because there are few treatment options that have been proven safe and effective for use in the SCI population, most individuals remain untreated.

OBJECTIVE

The primary aim of this investigation was to determine the effects of midodrine (10 mg) prescribed TID or BID in the home environment, compared to placebo, on 30-day BP, study withdrawals, and symptom reporting associated with OH and AD in hypotensive individuals with SCI.

DESIGN/METHODS

Participants were randomly assigned to received midodrine/placebo or placebo/midodrine, with a 2-weeks washout period in between, and both the participants and investigators were blinded to randomization order. Study medication was taken 2 or 3 times/day, depending on their sleep/wake schedule, BP, and any related symptoms were recorded before and 1 h after each dosage and periodically throughout the day.

RESULTS

Nineteen individuals with SCI were recruited; however, 9 withdrew prior to completion of the full protocol. A total of 1892 BP recordings (75 ± 48 recordings/participant/30-day period) were collected in the 19 participants over the two 30-day monitoring periods. Average 30-day systolic BP was significantly increased with midodrine compared to placebo (114 ± 14 vs. 96 ± 11 mmHg, respectively; P = 0.004), and midodrine significantly reduced the number of hypotensive BP recordings compared to placebo (38.7 ± 41.9 vs. 73.3 ± 40.6, respectively; P = 0.01). However, compared to placebo, midodrine increased fluctuations in BP, did not improve symptoms of OH, but did significantly worsen the intensity of symptoms associated with AD (P = 0.03).

CONCLUSION

Midodrine (10 mg) administered in the home environment effectively increases BP and reduces the incidence of hypotension; however these beneficial effects come at the expense of worsened BP instability and AD symptom intensity.

Myokines may target accelerated cognitive aging in people with spinal cord injury: A systematic and topical review

Persons with spinal cord injury (SCI) can suffer accelerated cognitive aging, even when correcting for mood and concomitant traumatic brain injury. Studies in healthy older adults have shown that myokines (i.e. factors released from muscle tissue during exercise) may improve brain health and cognitive function. Myokines may target chronic neuroinflammation, which is considered part of the mechanism of cognitive decline both in healthy older adults and SCI. An empty systematic review, registered in PROSPERO (CRD42022335873), was conducted as proof of the lack of current research on this topic in people with SCI. Pubmed, Embase, Cochrane and Web of Science were searched, resulting in 387 articles. None were considered eligible for full text screening. Hence, the effect of myokines on cognitive function following SCI warrants further investigation. An in-depth narrative review on the mechanism of SCI-related cognitive aging and the myokine-cognition link was added to substantiate our hypothetical framework. Readers are fully updated on the potential role of exercise as a treatment strategy against cognitive aging in persons with SCI.

Cognitive Impairment in Individuals With Spinal Cord Injury: Findings of a Systematic Review With Robust Variance and Network Meta-analyses

BACKGROUND AND OBJECTIVES

Estimates of the prevalence (10%-60%) of cognitive impairment in individuals with spinal cord injury (SCI) are too broad, and which domains of cognition are most affected is unclear. We performed a meta-analysis to investigate impairments across domains of cognitive functioning to provide a nuanced picture of research conducted to date into cognitive impairment after SCI.

METHODS

Results of peer-reviewed studies published in English between 1980 and 2021 comparing ≥20 participants with SCI with able-bodied controls were synthesized using meta-analysis. The primary outcomes were neurocognitive test scores categorized into 5 cognitive domains as listed in the Diagnostic and Statistical Manual of Mental Disorders: Complex Attention, Executive Functioning, Learning and Memory, Language, and Perceptual Motor Function. Two researchers independently assessed and verified extracted data to comply with meta-analytic reporting guidelines. Robust variance estimation meta-analysis was conducted to determine an overall pooled effect size across all cognitive domains using data extracted from studies. Using network meta-analysis, we synthesized eligible studies and made comparisons with the 5 domains of cognitive functioning serving as the outcomes and SCI as the condition.

RESULTS

Of 4,783 potential studies, 13 met final inclusion criteria. Studies met 6 of 8 quality assessment criteria generally. Results suggested that adults with SCI experience reduced cognitive functioning (effect size: -0.84; 95% CI -1.24 to -0.44, p < 0.001) compared with able-bodied individuals, with deficits mostly in attention (g = -0.64; 95% CI -0.92 to -0.38) and executive functioning (g = -0.61, 95% CI -0.89 to -0.04). Publication bias and high heterogeneity (I2: 86%) qualify these findings and highlight the need to improve research methods in this area.

DISCUSSION

Adults with SCI seem more likely than adults who are able-bodied to display cognitive impairments mostly in areas of attention and executive functioning. Research practices must become consistent to reduce heterogeneity so that the validity and reliability of the results of future studies into cognitive impairment after SCI improves.

The role of arousal and motivation in emotional conflict resolution: Implications for spinal cord injury

Under many conditions, emotional information is processed with priority and it may lead to cognitive conflict when it competes with task-relevant information. Accordingly, being able to ignore emotional information relies on cognitive control. The present perspective offers an integrative account of the mechanism that may underlie emotional conflict resolution in tasks involving response activation. We point to the contribution of emotional arousal and primed approach or avoidance motivation in accounting for emotional conflict resolution. We discuss the role of arousal in individuals with impairments in visceral pathways to the brain due to spinal cord lesions, as it may offer important insights into the “typical” mechanisms of emotional conflict control. We argue that a better understanding of emotional conflict control could be critical for adaptive and flexible behavior and has potential implications for the selection of appropriate therapeutic interventions.

Cardiovascular and cerebrovascular responses to urodynamics testing after spinal cord injury: The influence of autonomic injury

Autonomic dysfunction is a prominent concern following spinal cord injury (SCI). In particular, autonomic dysreflexia (AD; paroxysmal hypertension and concurrent bradycardia in response to sensory stimuli below the level of injury) is common in autonomically-complete injuries at or above T6. AD is currently defined as a >20 mmHg increase in systolic arterial pressure (SAP) from baseline, without heart rate (HR) criteria. Urodynamics testing (UDS) is performed routinely after SCI to monitor urological sequelae, often provoking AD. We, therefore, aimed to assess the cardiovascular and cerebrovascular responses to UDS and their association with autonomic injury in individuals with chronic (>1 year) SCI. Following blood draw (plasma norepinephrine [NE]), continuous SAP, HR, and middle cerebral artery blood flow velocity (MCAv) were recorded at baseline (10-minute supine), during standard clinical UDS, and recovery (10-minute supine) (n = 22, age 41.1 ± 2 years, 15 male). Low frequency variability in systolic arterial pressure (LF SAP; a marker of sympathetic modulation of blood pressure) and cerebral resistance were determined. High-level injury (≥T6) with blunted/absent LF SAP (<1.0 mmHg²) and/or low plasma NE (<0.56 nmol•L⁻¹) indicated autonomically-complete injury. Known electrocardiographic markers of atrial (p-wave duration variability) and ventricular arrhythmia (T-peak–T-end variability) were evaluated at baseline and during UDS. Nine participants were determined as autonomically-complete, yet 20 participants had increased SAP >20 mmHg during UDS. Qualitative autonomic assessment did not discriminate autonomic injury. Maximum SAP was higher in autonomically-complete injuries (207.1 ± 2.3 mmHg) than autonomically-incomplete injuries (165.9 ± 5.3 mmHg) during UDS (p < 0.001). HR during UDS was reduced compared to baseline (p = 0.056) and recovery (p = 0.048) only in autonomically-complete lesions. MCAv was not different between groups or phases (all p > 0.05). Cerebrovascular resistance index was increased during UDS in autonomically-complete injuries compared to baseline (p < 0.001) and recovery (p < 0.001) reflecting intact cerebral autoregulation. Risk for both atrial and ventricular arrhythmia increased during UDS compared to baseline (p < 0.05), particularly in autonomically-complete injuries (p < 0.05). UDS is recommended yearly in chronic SCI but is associated with profound AD and an increased risk of arrhythmia, highlighting the need for continued monitoring during UDS. Our data also highlight the need for HR criteria in the definition of AD and the need for quantitative consideration of autonomic function after SCI.

The Relationship between Cognitive Performance and Quality of Life in Elite Athletes after Spinal Cord Injury

BACKGROUND

The present investigation was designed to determine cognitive performance and quality of life (QoL) in a group of elite athletes who sustained spinal cord injury (SCI).

METHODS

nine participants suffering a SCI participated in the study. Different cognitive functions were evaluated through the following tests: COWAT, Digit Span, Stroop color-word and QoL through the WHOQoL-BREF scale.

RESULTS

Generally, participants positively assessed their overall quality of life and health status. Although the tests conducted indicate reduced cognitive function among the athletes, it did not affect the reduction in QoL. Single correlations between the results of cognitive tests and QoL could be treated as coincidental.

CONCLUSIONS

Despite the observed decline in selected cognitive functions, the participants positively assessed their quality of life and physical health.Reduced cognitive functioning could be influenced by the impact of sleep-disordered breathing, pain, depressive disorders and medication. This indicates the need for an individualized approach to define the patient's deficits, needs and best care. Further studies with a larger group of participants are needed.

Management of blood pressure disorders in individuals with spinal cord injury

Blood pressure regulation is impacted by a spinal cord injury (SCI) due to impaired descending sympathetic vascular control. Common blood pressure problems in the SCI population include persistently low blood pressure with bouts of orthostatic hypotension and autonomic dysreflexia, which are more prevalent in individuals with lesions above the sixth thoracic vertebral level; however, they may occur regardless of the neurological level of injury. Although blood pressure disorders adversely impact daily function and quality of life, most individuals with SCI do not acknowledge this association. Few pharmacological options have been rigorously tested for safety and efficacy to manage blood pressure disorders in the SCI population. Furthermore, clinical management of any one blood pressure disorder may adversely impact others, as such treatment is complicated and not often prioritized.

Autonomic cardiovascular dysfunction during simple arithmetic test in a patient with cervical spinal cord injury-a case report

INTRODUCTION

Spinal cord injury (SCI) disrupts autonomic control of the cardiovascular system, which may lead to autonomic dysfunction. Growing amounts of evidence support the possibility that systemic and cerebral hemodynamic dysfunctions may contribute to cognitive deficits in patients with SCI.

CASE PRESENTATION

We present a case of autonomic cardiovascular dysfunction in a 55-year old female patient following non-traumatic cervical SCI. This case illustrates how a simple arithmetic test may elicit fluctuations in blood pressure causing cognitive disturbances.

DISCUSSION

Clinical awareness of autonomic dysfunction and cognitive deficits is relevant in neurorehabilitation of patients with SCI. Assessment of autonomic function should be evaluated according to recommendation from International Standards to document remaining Autonomic Function after Spinal Cord Injury (ISAFSCI) [1].

High-intensity, whole-body exercise improves blood pressure control in individuals with spinal cord injury: A prospective randomized controlled trial

Blood pressure regulation following spinal cord injury (SCI) is often compromised due to impaired vascular sympathetic control, leading to increased reliance on cardiovagal baroreflex sensitivity to maintain pressure. Whole-body exercise improves cardiovagal baroreflex sensitivity in uninjured individuals, though has not been explored in those with SCI. Our objective was to determine changes in cardiovagal baroreflex sensitivity following 6 months of high-intensity, whole-body exercise in individuals with SCI compared to lower-intensity, arms only exercise, or waitlist. This randomized controlled trial recruited individuals with SCI aged 18-40 years old. Sixty-one individuals were randomized, with 38 completing at least one cardiovagal baroreflex sensitivity assessment. Whole-body exercise was performed with hybrid functional electrical stimulation rowing prescribed as two to three times per week, for 30-60 minutes with a target heart rate of >75% of maximum. The arms only exercise group performed upper body rowing exercise with the same prescription as whole-body exercise. Waitlist controls were not enrolled in any explicit training regimen. After 6 months, those in arms only exercise or waitlist crossed over to whole-body exercise. Cardiovagal baroreflex sensitivity was assessed via the neck suction technique at baseline and at three-month intervals thereafter. Intention to treat analysis with a structured equation model demonstrated no significant effect of waitlist control or arms only exercise on cardiovagal baroreflex sensitivity. Whole-body exercise significantly improved cardiovagal baroreflex sensitivity at 6 months for those initially randomized (p = 0.03), as well as those who crossed over from arms only exercise or waitlist control (p = 0.03 for each). However, amount of exercise performed and aerobic gains (VO2max) each poorly correlated with increases in cardiovagal baroreflex sensitivity (R2<0.15). In post-hoc analyses, individuals with paraplegia made significantly greater gains in baroreflex sensitivity compared to those with tetraplegia (p = 0.02), though gains within this group were again poorly correlated to gains in aerobic capacity. Clinicaltrials.gov number NCT02139436.

Motor demands of cognitive testing may artificially reduce executive function scores in individuals with spinal cord injury

Objective: To determine whether the motor demands of cognitive tests contribute to differences in cognitive function scores in participants with and without spinal cord injury (SCI).Design: Cohort study.Setting: Rehabilitation research laboratory.Participants: 68 individuals without SCI ("NON") and 22 individuals with motor complete SCI ("SCI").Interventions: None.Outcome Measures: NIH Toolbox cognitive assessments, including two with motor demands and reaction-time based scoring (Dimensional Change Card Sort (DCCS), Flanker Inhibitory Control and Attention (Flanker) and two without timed scoring (List Sorting Working Memory (List Sorting), Picture Sequence Memory Test (Picture Sequence). Tests were administered with and without the assistance of a proctor on two randomly-determined days (>24 hr interval). For DCCS and Flanker, the motor-task score offset was estimated as the difference between the proctored and non-proctored scores.Results: For demographically-corrected data, proctoring reduced DCCS and Flanker scores (P < 0.001) but mitigated apparent differences between SCI and NON (all P > 0.403). SCI and NON did not differ for List Sorting (P > 0.072) but did differ significantly for Picture Sequence (P < 0.001). Significant practice effects existed for memory-based tests (List Sorting and Picture Sequence); all P < 0.015, effect size>0.645.Conclusions: DCCS and Flanker scores for individuals with SCI may be artificially reduced consequent to secondary motor demands of the tests. Proctoring and computation of a motor-response score offset enables comparisons to be made between individuals with SCI and a Non-SCI control cohort; however, further work is needed to determine whether offset-adjusted scores can be compared to standardized normative values.

Neuropsychological Study in Patients with Spinal Cord Injuries

The present investigation was designed to determinate the nature, pattern, and extent of cognitive deficits in a group of participants with subacute and chronic spinal cord injury (SCI). Methods: A cross-sectional study was conducted in both patients with subacute and chronic SCI. Different cognitive functions were evaluated through a neuropsychological protocol designed for this purpose, taking into account the patient’s emotional state. Results: A total of 100 patients suffering a spinal cord injury were evaluated. There were no differences between the two groups when age, sex, level of education, and region of origin were studied. The chronic injured patients obtained lower scores in the neuropsychological evaluation protocol respective to the subacute injured patients. Conclusions: Subjects with chronic spinal cord injury presented a cognitive profile that differed greatly in the number of altered cognitive functions as well as in their magnitude from the subacute spinal cord injured patient profile. Moreover, cognitive dysfunction may be important beyond the end of the first stage of rehabilitation as it can affect an individual’s quality of life and possible integration in society.

Multidimensional review of cognitive impairment after spinal cord injury

Cognitive impairment is highly prevalent in the population with spinal cord injury (SCI) and exerts a significant impact on functional independence and quality of life in this population. A number of neuroscientists have conducted preliminary investigations of cognitive deficits after SCI, but achieved marginally contradictory results due to some limitations such as the heterogeneity in the sample population, sample size, types of tests utilized, study design, and time since SCI. Therefore, this review mainly focuses on the characteristics, assessments, potential causality and treatment of cognitive impairment for better understanding such deficits in the SCI population.

Effect of 6-Month Exercise Training on Neurovascular Function in Spinal Cord Injury

INTRODUCTION

Although previous data show exacerbated incidence of cognitive impairment after spinal cord injury (SCI), the physiology that underlies this postinjury cognitive decline is unknown. One potential culprit is impairment in the ability of cerebral vasculature to alter regional flow to sustain neural metabolism (i.e., "neurovascular coupling"). We hypothesized that cerebrovascular responses to a working memory task are impaired in individuals with SCI and can be improved by aerobic exercise training.

METHODS

We assessed the effect of injury and 6-month full-body aerobic exercise training on the cerebral blood flow response to cognitive demand (i.e., neurovascular coupling) in 24 individuals with SCI and 16 controls. Cognitive demand was introduced in a graded fashion using a working memory task.

RESULTS

Reaction time tended to be higher in individuals with SCI, especially those with high-level (≥T4) injuries, possibly due to upper motor impairments. Neurovascular coupling was graded across task difficulty (P < 0.01) and followed cognitive demand, and injury itself did not have a significant effect (group effect P = 0.99, interaction P = 0.70). Individuals with low-level injuries (

CONCLUSION

Previously reported cognitive impairment after SCI may reflect a decline in neurovascular coupling primarily due to physical deconditioning rather than injury itself. The latter can be mitigated by aerobic exercise training.

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Key Words Collapse

MESH Headings

• Adult
• Cardiorespiratory Fitness
• Cognitive Dysfunction/etiology
• Cognitive Dysfunction/physiopathology
• Cognitive Dysfunction/therapy
• Exercise Therapy
• Female
• Humans
• Male
• Neurovascular Coupling
• Spinal Cord Injuries/physiopathology
• Spinal Cord Injuries/rehabilitation
• Young Adult

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Grants

• 15SDG23290000 American Heart Association-American Stroke Association

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Affiliation(s) Collapse

Duration and magnitude of bidirectional fluctuation in blood pressure: the link between cerebrovascular dysfunction and cognitive impairment following spinal cord injury

Individuals with spinal cord injury (SCI) have a significantly increased risk for cognitive impairment that is associated with cerebrovascular remodeling and endothelial dysfunction. The sub-acute stage following high thoracic SCI is characterized by increased fibrosis and stiffness of cerebral arteries. However, a more prolonged duration after SCI exacerbates cerebrovascular injury by damaging endothelium. Endothelial dysfunction is associated with reduced expression of transient receptor potential cation channel 4 that mediates the production of nitric oxide and epoxyeicosatrienoic acids following shear stress and the response to carbachol and other endothelium-dependent vasodilators. Reduced expression of CD31 in cerebral arteries also suggests the loss of endothelial cell integrity following chronic SCI. Repetitively transient hypertension and intermittent hypotension contribute to cerebrovascular endothelial dysfunction in the animals with a sub-acute stage of high thoracic SCI. The increase in vascular remodeling and endothelial dysfunction ultimately reduce cerebral blood flow, which promotes cerebral hypoperfusion and cognitive dysfunction in the chronic phase of SCI. In conclusion, the duration and magnitude of fluctuations in blood pressure after SCI play a vital role in the onset and progress of cerebrovascular dysfunction, which promotes the development of cognitive impairment.

Increased pulse wave velocity in persons with spinal cord injury: the effect of the renin-angiotensin-aldosterone system

Increased pulse wave velocity (PWV), a marker of cardiovascular disease (CVD), has been reported in otherwise healthy individuals with spinal cord injury (SCI) compared with age-matched uninjured controls. Due to decentralized descending sympathetic vascular control, individuals with injuries above T6 are prone to orthostatic hypotension and, as a result, depend on the renin-angiotensin-aldosterone system (RAAS) to maintain orthostatic blood pressure (BP). The purpose of this study was to determine resting PWV, a noninvasive surrogate of central arterial stiffness, in individuals with cervical (C4-T1; n = 11) and thoracic (T6-T12; n = 11) SCI, compared with age-matched controls (controls; n = 11). Next, our aim was to describe group differences in BP, plasma norepinephrine (NE), and renin response to head-up tilt (HUT). Finally, we sought to determine the relationship between PWV and the orthostatic change in BP, NE, and the plasma renin during HUT among the groups. PWV was significantly increased in both cervical (8.81 ± 1.91 m/s) and thoracic (7.36 ± 1.58 m/s) SCI compared with the controls (5.53 ± 0.95 m/s; P < 0.05). The change from supine to 60° HUT in BP and NE was significantly reduced and change in plasma renin was significantly increased in the cervical group compared with the thoracic and control groups. Group affiliation and change in plasma renin were significant predictors of PWV (R² = 0.63, P = 0.001). These data suggest that dependency on the RAAS for orthostatic BP maintenance may be associated with increased PWV and risk of CVD in the SCI population.NEW & NOTEWORTHY Our novel findings suggest that increased arterial stiffness in individuals with SCI may be due to greater dependency on the RAAS to maintain hemodynamic stability during an orthostatic challenge. Asymptomatic orthostatic hypotension can occur in persons with SCI during transition from the supine to the seated position and during other upright activities of daily living; however, it is seldom addressed by clinicians.

Beneficial Cardiac Structural and Functional Adaptations After Lumbosacral Spinal Cord Epidural Stimulation and Task-Specific Interventions: A Pilot Study

Cardiac myocyte atrophy and the resulting decreases to the left ventricular mass and dimensions are well documented in spinal cord injury. Therapeutic interventions that increase preload can increase the chamber size and improve the diastolic filling ratios; however, there are no data describing cardiac adaptation to chronic afterload increases. Research from our center has demonstrated that spinal cord epidural stimulation (scES) can normalize arterial blood pressure, so we decided to investigate the effects of scES on cardiac function using echocardiography. Four individuals with chronic, motor-complete cervical spinal cord injury were implanted with a stimulator over the lumbosacral enlargement. We assessed the cardiac structure and function at the following time points: (a) prior to implantation; (b) after scES targeted to increase systolic blood pressure; (c) after the addition of scES targeted to facilitate voluntary (i.e., with intent) movement of the trunk and lower extremities; and (d) after the addition of scES targeted to facilitate independent, overground standing. We found significant improvements to the cardiac structure (left ventricular mass = 10 ± 2 g, p < 0.001; internal dimension during diastole = 0.1 ± 0.04 cm, p < 0.05; internal dimension during systole = 0.06 ± 0.03 cm, p < 0.05; interventricular septum dimension = 0.04 ± 0.02 cm, p < 0.05), systolic function (ejection fraction = 1 ± 0.4%, p < 0.05; velocity time integral = 2 ± 0.4 cm, p < 0.001; stroke volume = 4.4 ± 1.5 ml, p < 0.01), and diastolic function (mitral valve deceleration time = -32 ± 11 ms, p < 0.05; mitral valve deceleration slope = 50 ± 25 cm s-1, p < 0.05; isovolumic relaxation time = -6 ± 1.9 ms, p < 0.05) with each subsequent scES intervention. Despite the pilot nature of this study, statistically significant improvements to the cardiac structure, systolic function, and diastolic function demonstrate that scES combined with task-specific interventions led to beneficial cardiac remodeling, which can reverse atrophic changes that result from spinal cord injury. Long-term improvements to cardiac function have implications for increased quality of life and improved cardiovascular health in individuals with spinal cord injury, decreasing the risk of cardiovascular morbidity and mortality.

Prolonged Targeted Cardiovascular Epidural Stimulation Improves Immunological Molecular Profile: A Case Report in Chronic Severe Spinal Cord Injury

In individuals with severe spinal cord injury (SCI), the autonomic nervous system (ANS) is affected leading to cardiovascular deficits, which include significant blood pressure instability, with the prevalence of systemic hypotension and orthostatic intolerance resulting in an increased risk of stroke. Additionally, persons with SCI rostral to thoracic vertebral level 5 (T5), where sympathetic nervous system fibers exit the spinal cord and innervate the immune system, have clinically significant systemic inflammation and increased infection risk. Our recent studies show that lumbosacral spinal cord epidural stimulation (scES), applied at the lumbosacral level using targeted configurations that promote cardiovascular stability (CV-scES), can safely and effectively normalize blood pressure in persons with chronic SCI. Herein we present a case report in a female (age 27 years) with chronic clinically motor complete cervical SCI demonstrating that 97-sessions of CV-scES, which increased systemic blood pressure, improved orthostatic tolerance in association with increased cerebral blood flow velocity in the middle cerebral artery, also promoted positive immunological changes in whole-blood gene expression. Specifically, there was evidence of the down-regulation of inflammatory pathways and the up-regulation of adaptative immune pathways. The findings of this case report suggest that the autonomic effects of epidural stimulation, targeted to promote cardiovascular homeostasis, also improves immune system function, which has a significant benefit to long-term cardiovascular and immunologic health in individuals with long-standing SCI.

Clinical Trial Registration:www.ClinicalTrials.gov, identifier NCT02307565.

Quality of Life after Spinal Cord Injury: A Multiple Case Study Examination of Elite Athletes

A three-times World Champion in BMX (an acronym for Bicycle Motocross) dirt jumps, a Junior World Champion in ski jumping, and a European karate Champion sustained spinal cord injuries at the cervical and thoracic level. Such a severe trauma is tantamount to the end of a professional sporting career. In such a situation, the athlete’s life significantly changes in every aspect of it: health, professional, and social. The greatest sports champions have not yet been portrayed in the context of a strategy they used to deal with an abrupt end of a professional career due to severe injury. A semi-structured interview was conducted with study participants who additionally filled out the WHO Quality of Life Scale. This multiple case series presents the quality of life in elite athletes as well as the social activities they have undertaken regardless of the tragic accident. The results of the research indicate that these people are characterized rather by a positive sense of quality in life, and the way they function in a difficult situation is an inspiration to others.

Lower-Limb Sensorimotor Deprivation-Related Brain Activation in Patients With Chronic Complete Spinal Cord Injury

This study aims to investigate functional brain reorganization brought about by the loss of physical movement and sensory feedback in lower limbs in chronic spinal cord injury (SCI). Eleven paraplegia patients with SCI and 13 healthy controls (HCs) were recruited. The experimental task used was a visuomotor imagery task requiring subjects to engage in visualization of repetitive tapping movements of the upper or lower limbs. Blood oxygen level-dependent (BOLD) responses were captured during the experimental task, along with the accuracy rate and the response time. The SCI patients performed worse in the Rey Auditory Verbal Learning Test (RAVLT) and the Trail Making Test. SCI patients had a larger BOLD signal in the left lingual gyrus and right external globus pallidus (GPe) when imagining lower-limb movements. For the upper-limb task, SCI patients showed stronger BOLD responses than the HCs in extensive areas over the brain, including the bilateral precentral gyrus (preCG), bilateral inferior parietal gyrus, right GPe, right thalamus, left postcentral gyrus, and right superior temporal gyrus. In contrast, the HCs displayed stronger BOLD responses in the medial frontal gyrus and anterior cingulate gyrus for both upper- and lower-limb tasks than the SCI patients. In the SCI group, for the upper-limb condition, the amplitudes of BOLD responses in the left preCG were negatively correlated with the time since injury (r = -0.72, p = 0.012). For the lower-limb condition, the amplitudes of BOLD responses in the left lingual gyrus were negatively correlated with the scores on the Short Delay task of the RAVLT (r = -0.73, p = 0.011). Our study provided imaging evidence for abnormal changes in brain function and worsened cognitive test performance in SCI patients. These findings suggested possible compensatory strategies adopted by the SCI patients for the loss of sensorimotor function from the lower limbs when performing a limb imagery task.

Heart rate and blood pressure response improve the prediction of orthostatic cardiovascular dysregulation in persons with chronic spinal cord injury

Unstable blood pressure after spinal cord injury (SCI) is not routinely examined but rather predicted by level and completeness of injury (i.e., American Spinal Injury Association Impairment Scale AIS classification). Our aim was to investigate hemodynamic response to a sit-up test in a large cohort of individuals with chronic SCI to better understand cardiovascular function in this population. Continuous blood pressure and ECG were recorded from individuals with SCI (n = 159) and non-injured individuals (n = 48). We found orthostatic hypotension occurred within each level and AIS classification (n = 36). Moreover, 45 individuals with chronic SCI experienced a drop in blood pressure that did not meet the criteria for orthostatic hypotension, but was accompanied by dramatic increases in heart rate, reflecting orthostatic intolerance. A cluster analysis of hemodynamic response to a seated position identified eight distinct patterns of interaction between blood pressure and heart rate during orthostatic stress indicating varied autonomic responses. Algorithmic cluster analysis of heart rate and blood pressure is more sensitive to diagnosing orthostatic cardiovascular dysregulation. This indicates blood pressure instability cannot be predicted by level and completeness of SCI, and the consensus statement definition of orthostatic hypotension is insufficient to characterize the variability of blood pressure and heart rate responses during orthostatic stress. Both blood pressure and heart rate responses are needed to characterize autonomic function after SCI.

The Neural Mechanisms Underlying Processing Speed Deficits in Individuals Who Have Sustained a Spinal Cord Injury: A Pilot Study

Our objective was to determine differences in brain activation during a processing-speed task in individuals with SCI compared to a group of age-matched healthy controls and to a group of older healthy controls. Ten individuals with cervical SCI (C3-C5), 10 age-matched healthy controls and 10 older healthy controls participated in a cross-sectional study in which performance on neuropsychological tests of processing speed and brain activation were the main outcome measures. The brain areas used by the individuals with SCI during the processing-speed task differed significantly from the age-matched healthy controls, but were similar to the older control cohort, and included activation in frontal, parietal and hippocampal areas. This suggests that individuals with SCI may compensate for processing-speed deficits by relying on brain regions that classically support control cognitive processes such as executive control and memory.

Cardiovascular Autonomic Dysfunction in Spinal Cord Injury: Epidemiology, Diagnosis, and Management

Spinal cord injury (SCI) disrupts autonomic circuits and impairs synchronistic functioning of the autonomic nervous system, leading to inadequate cardiovascular regulation. Individuals with SCI, particularly at or above the sixth thoracic vertebral level (T6), often have impaired regulation of sympathetic vasoconstriction of the peripheral vasculature and the splanchnic circulation, and diminished control of heart rate and cardiac output. In addition, impaired descending sympathetic control results in changes in circulating levels of plasma catecholamines, which can have a profound effect on cardiovascular function. Although individuals with lesions below T6 often have normal resting blood pressures, there is evidence of increases in resting heart rate and inadequate cardiovascular response to autonomic provocations such as the head-up tilt and cold face tests. This manuscript reviews the prevalence of cardiovascular disorders given the level, duration and severity of SCI, the clinical presentation, diagnostic workup, short- and long-term consequences, and empirical evidence supporting management strategies to treat cardiovascular dysfunction following a SCI.

The impact of level of injury on patterns of cognitive dysfunction in individuals with spinal cord injury

Context: While it is well recognized that physical and physiological changes are more prominent in individuals with higher neurologic levels of spinal cord injury (SCI), the impact of level of lesion on cognition is less clear. Design: Cross-sectional, 3-group. Setting: Non-profit rehabilitation research foundation. Participants: 59 individuals with SCI (30 with tetraplegia, 29 with paraplegia) and 30 age-matched healthy controls (HC). Interventions: None. Outcome Measures: Neuropsychological tests in the domains of attention, working memory, processing speed, executive control, and learning and memory. Results: Results indicated significantly lower test performance in individuals with paraplegia on new learning and memory testing compared to HC. In contrast, compared to HC the group with tetraplegia, showed a significantly impaired performance on a processing speed task, and both the tetraplegia and the paraplegia groups were similarly impaired on a verbal fluency measure. SCI groups did not differ on any cognitive measure. Conclusion: Individuals with SCI may display different patterns of cognitive performance based on their level of injury.

Cognitive Profiles Among Individuals With Spinal Cord Injuries: Predictors and Relations With Psychological Well-being

OBJECTIVES

To examine predictors of profiles of cognitive functioning among individuals receiving acute inpatient spinal cord injury (SCI) rehabilitation, as well as associations between their cognitive functioning and psychological well-being (life satisfaction and depression) 6 months after the baseline assessment.

DESIGN

Prospective observational study design, with 2 assessments approximately 6 months apart.

SETTING

A rehabilitation unit at a level 1 trauma hospital during acute SCI hospitalization and outpatient setting after discharge.

PARTICIPANTS

Individuals (N=89) with SCI.

INTERVENTION

None.

MAIN OUTCOME MEASURES

Cognitive functioning (assessed by the Repeatable Battery for the Assessment of Neuropsychological Status), life satisfaction (measured by the Life Satisfaction Index A), and depressive symptoms (measured by the Patient Health Questionnaire-9).

RESULTS

Latent profile analysis identified 3 classes of individuals with similar patterns of cognitive functioning: class1 (average levels of cognitive performance across all assessed domains; n=48), class 2 (average cognitive performance, except in recall and memory; n=23), and class 3 (low cognitive functioning across multiple domains of cognition; n=18). Fewer years of education, history of smoking, history of substance use other than alcohol, and greater postconcussion symptoms were associated with higher odds of classification in class 3 (P<.05). Six months post baseline, individuals in class 3 reported significantly lower levels of life satisfaction than individuals in class 1 (χ²(1)=5.86; P=.045) and marginally higher depressive symptoms than individuals in class 2 (χ²(1)=5.48; P=.057)_. CONCLUSIONS: The impact of impaired cognition during acute rehabilitation may persist after discharge and influence the psychological well-being of individuals with SCI. Identifying individuals with cognitive dysfunction and attending to modifiable risk factors and may help ameliorate maladjustment after SCI.

Cognitive Dysfunction in Persons with Chronic Spinal Cord Injuries

Cognitive dysfunction (CD) is pervasive in individuals who have chronic spinal cord injuries (SCI). Although classically associated with concomitant traumatic brain injuries, many other causes have been proposed, including premorbid neuropsychological conditions, mood disorders, substance abuse, polypharmacy, chronic pain and fatigue, sleep apnea, autonomic dysregulation, post-intensive care unit syndrome, cortical reorganizations, and neuroinflammation. The consequences of CD are likely widespread, affecting rehabilitation and function. CD in those with SCI should be recognized, and potentially treated, in order to provide the best patient care.

Vascular-Cognitive Impairment following High-Thoracic Spinal Cord Injury Is Associated with Structural and Functional Maladaptations in Cerebrovasculature

Individuals living with chronic spinal cord injury (SCI) often exhibit impairments in cognitive function, which impede their rehabilitation and transition into the community. Although a number of clinical studies have demonstrated the impact of impaired cardiovascular control on cognitive impairment, the mechanistic understanding of this deleterious relationship is still lacking. The present study investigates whether chronic disruption of cardiovascular control following experimental SCI results in cerebrovascular decline and vascular cognitive impairment. Fourteen weeks following a high thoracic SCI (at the third thoracic segment), rats were subjected to a battery of in vivo and in vitro physiological assessments, cognitive-behavioral tests, and immunohistochemical approaches to investigate changes in cerebrovascular structure and function in the middle cerebral artery (MCA). We show that in the MCA of rats with SCI, there is a 55% (SCI vs. control: 13.4 ± 1.9% vs. 29.63 ± 2.8%, respectively) reduction in the maximal vasodilator response to carbachol, which is associated with reduced expression of endothelial marker cluster of differentiation 31 (CD31) and transient receptor potential cation channel 4 (TRPV 4) channels. Compared with controls, MCAs in rats with SCI were found to have 50% (SCI vs. control: 1.5 ± 0.2 vs. 1 ± 0.1 a.u., respectively) more collagen 1 in the media of vascular wall and 37% (SCI vs. control: 30.5 ± 2.9% vs. 42.0 ± 4.0%, respectively) less distensibility at physiological intraluminal pressure. Further, the cerebral blood flow (CBF) in the hippocampus was reduced by 32% in the SCI group (SCI vs. control: 44.3 ± 4.5 mL/100 g/min vs. 65.0 ± 7.2 mL/100 g/min, respectively) in association with impairment of short-term memory based on a novel object recognition test. There were no changes in the sympathetic innervation of the vasculature and passive structure in the SCI group. Chronic experimental SCI is associated with structural alterations and endothelial dysfunction in cerebral arteries that likely contribute to significantly reduced CBF and vascular cognitive impairment.

Double-blinded, placebo-controlled crossover trial to determine the effects of midodrine on blood pressure during cognitive testing in persons with SCI

Study Design:

Clinical trial.

Objectives:

Individuals with spinal cord injury (SCI) above T6 experience impaired descending cortical control of the autonomic nervous system which predisposes them to hypotension. However, treatment of hypotension is uncommon in the SCI population because there are few safe and effective pharmacological options available. The primary aim of this investigation was to test the efficacy of a single dose of midodrine (10 mg), compared to placebo, to increase and normalize systolic blood pressure (SBP) between 110–120 mmHg during cognitive testing in hypotensive individuals with SCI. Secondary aims were to determine the effects of midodrine on cerebral blood flow velocity (CBFv) and global cognitive function.

Setting:

United States clinical research laboratory.

Methods:

Forty-one healthy hypotensive individuals with chronic (≥ 1-year post-injury) SCI participated in this 2-day study.

Seated SBP, CBFv, cognitive performance were monitored before and after administration of identical encapsulated tablets, containing either midodrine or placebo.

Results:

Compared to placebo, midodrine increased SBP (4±13 vs. 18±24 mmHg, respectively; p<0.05); however, responses varied widely with midodrine (−15.7 to +68.6 mmHg). Further, the proportion of SBP recordings within the normotensive range did not improve during cognitive testing with midodrine compared to placebo. Although higher SBP was associated with higher CBFv (p=0.02), global cognitive function was not improved with midodrine.

Conclusions:

The findings indicate that midodrine increases SBP and may be beneficial in some hypotensive patients with SCI; however, large heterogeneity of responses to midodrine suggest careful monitoring of patients following administration.

Diverse cognitive impairment after spinal cord injury is associated with orthostatic hypotension symptom burden

This study: 1) compared cognitive functioning between individuals with chronic (>1 year) spinal cord injury (SCI) and non-injured controls and, 2) assessed associations between symptoms of autonomic dysreflexia and orthostatic hypotension with cognitive functioning in SCI participants with a history of unstable blood pressure (BP). Thirty-two individuals with SCI (C4-L2, American Spinal Injury Association Impairment Scale A-D) and thirty age, sex-matched non-injured controls participated in this study. Participants completed a motor-free neuropsychological test battery assessing 1) memory, 2) attention/concentration/psychomotor speed and, 3) executive function. Nineteen participants with SCI who had injuries ≥T6 and a history of unstable BP also completed the Autonomic Dysfunction Following Spinal Cord Injury (ADFSCI) questionnaire. Cognitive function was significantly lower in people with SCI across measures of memory and executive function compared to non-injured controls. Significant, moderate-to-large associations were observed between cumulative (frequency x severity) orthostatic hypotension and total BP instability symptoms scores, with measures of attention/concentration/psychomotor speed and executive function. These data demonstrate a 10 - 65% reduced performance across specific realms of cognitive functioning in individuals with SCI relative to non-injured controls. Furthermore, cumulative subjective scores for symptoms of unstable BP were associated with diverse cognitive deficits. These findings, in individuals without co-occurring traumatic brain injury, imply cardiovascular dysregulation plays a role in cognitive deficits observed in this population.

Sleep Complaints and Sleep Quality in Spinal Cord Injury: A Web-Based Survey

STUDY OBJECTIVES

The purpose of this study was to determine sleep quality and presence of sleep disorders in participants with spinal cord injury (SCI).

METHODS

A web-based survey, available online from February 2011 to July 2013, using validated sleep questionnaires, advertised via the internet and locally through SCI consumer organizations in the United States, Australia, New Zealand, and Canada, was designed to evaluate sleep in adults with self-reported SCI. Demographic characteristics and medical history were obtained from participant self-report.

RESULTS

In our study population, 70% of the 304 participants were male with a mean age of 45 ± 13 years. The mean duration of injury was 16 ± 12 years. Cervical injuries were reported by 49% and thoracic injuries noted in 40% of participants. Increased sleep apnea risk was noted in 31% of participants, with 66% reporting snoring. Insomnia symptoms were reported by 54% of the respondents. Almost 40% of participants ranked their sleep quality as "fairly bad" to "very bad" in the previous month, 29% reported "often" or "almost always" waking up because of pain, and 22% had difficulty falling asleep because of leg cramps. In the past year, 27% of the respondents reported daily uncomfortable leg sensations and 28% found these leg symptoms to be "moderately to extremely distressing."

CONCLUSIONS

This study increases the awareness that insomnia, sleep apnea, and poor sleep quality are common in individuals with chronic SCI; often coexisting. There is a need for increased screening for sleep problems by healthcare providers taking care of individuals living with SCI.

Relationships between orthostatic hypotension, frailty, falling and mortality in elderly care home residents

BACKGROUND

Orthostatic hypotension (OH; profound falls in blood pressure when upright) is a common deficit that increases in incidence with age, and may be associated with falling risk. Deficit accumulation results in frailty, regarded as enhanced vulnerability to adverse outcomes. We aimed to evaluate the relationships between OH, frailty, falling and mortality in elderly care home residents.

METHODS

From the Minimum Data Set (MDS) document, a frailty index (FI-MDS) was generated from a list of 58 deficits, ranging from 0 (no deficits) to 1.0 (58 deficits). OH was evaluated from beat-to-beat blood pressure and heart rate (finger plethysmography) collected during a 15-min supine-seated orthostatic stress test. Retrospective and prospective falling rates (falls/year) were extracted from facility falls incident reports. All-cause 3-year mortality was determined. Data are reported as mean ± standard error.

RESULTS

Data were obtained from 116 older adults (aged 84.2 ± 0.9 years; 44% males) living in two long term care facilities. The mean FI-MDS was 0.36 ± 0.01; FI-MDS was correlated with age (r = 0.277; p = 0.003). Those who were frail (FI ≥ 0.27) had larger Initial (- 17.8 ± 4.2 vs - 6.1 ± 3.3 mmHg, p = 0.03) and Consensus (- 22.7 ± 4.3 vs - 11.5 ± 3.3 mmHg, p = 0.04) orthostatic reductions in systolic arterial pressure. Frail individuals had higher prospective and retrospective falling rates and higher 3-year mortality. Receiver operating characteristic curves evaluated the ability of FI-MDS alone to predict prospective falls (sensitivity 72%, specificity 36%), Consensus OH (sensitivity 68%, specificity 60%) and 3-year mortality (sensitivity 77%, specificity 49%). Kaplan Meier survival analyses showed significantly higher 3-year mortality in those who were frail compared to the non-frail (p = 0.005).

CONCLUSIONS

Frailty can be captured using a frailty index based on MDS data in elderly individuals living in long term care, and is related to susceptibility to orthostatic hypotension, falling risk and 3-year mortality. Use of the MDS to generate a frailty index may represent a simple and convenient risk assessment tool for older adults living in long term care. Older adults who are both frail and have impaired orthostatic blood pressure control have a particularly high risk of falling and should receive tailored management to mitigate this risk.

Patterns of cognitive deficits in persons with spinal cord injury as compared with both age-matched and older individuals without spinal cord injury

Context/Objective: Cognitive deficits can impact as many as 60% of individuals with spinal cord injury (SCI). In an effort to identify the nature of cognitive deficits in SCI, we examined neuropsychological test performance in individuals with SCI, age matched healthy controls and older healthy controls.Design: Participants completed a motor-free neuropsychological test battery assessing attention, working memory, information processing speed, new learning /memory and executive control.Setting: Outpatient rehabilitation research facility.Participants: Participants included 60 individuals with chronic spinal cord injury [SCI; 32 with paraplegia (T2-T12) and 28 with tetraplegia (C3-T1)], 30 age-matched healthy controls (AMHC; 30-40 years old) and 20 older healthy controls (OHC; 50-60 years old).Outcome Measures: Wechsler Intelligence Scale - 3^rd edition (WAIS-III) Digit Span and Letter-Number Sequencing; Symbol Digit Modalities Test (SDMT) - oral version; California Verbal Learning Test-II; Paced Auditory Serial Addition Test (PASAT); Wechsler Abbreviated Scale of Intelligence (WASI); Delis-Kaplan Executive Function System; Verbal Fluency subtest.Results: Significant differences were noted between the SCI and AMHC groups on measures of information processing speed, new learning and memory, and verbal fluency. No significant differences were noted between the groups on tests of attention or working memory.Conclusion: The current study documented differences in specific realms of cognitive functioning between a chronic SCI sample and AMHC. Implications for cognitive rehabilitation and overall quality of life are discussed. Additional research is needed utilizing a more comprehensive battery of motor-free neuropsychological tests that avoid the confound of upper limb motor limitations on cognitive performance.

Cognitive function after spinal cord injury: A systematic review

OBJECTIVE

To systematically examine the incidence of cognitive impairment in individuals with spinal cord injury (SCI), as well as identify potential contributing and confounding factors.

METHODS

Studies quantitatively reporting cognitive ability after spinal cord injury were searched electronically via Medline, CINAHL, Embase, and PsycINFO. Manual screening for references within articles was also performed. A total of 2,481 studies were screened and a total of 70 were included in this review, 21 reporting cognitive function after SCI compared to an able-bodied control group and 49 with no able-bodied controls. Studies were analyzed for the incidence of impairment and the interactions with concomitant traumatic brain injury, psychological or somatic complaints, decentralized cardiovascular control, sleep apnea, neurologic level of injury, and age.

RESULTS

There is a high volume of evidence reporting substantial cognitive impairment in individuals with SCI. Potential co-contributors include concomitant brain injury, psychological or somatic comorbidities, decentralized cardiovascular control, and sleep apnea. Cognitive functioning was negatively correlated with age. No clear agreement was found for the incidence of cognitive impairment or its association with level of injury.

CONCLUSION

Current evidence suggests that individuals with SCI should be examined and addressed for cognitive impairment. Future studies aimed at identifying potential secondary causative factors should employ stringent controls for co-occurring brain trauma since it appears to be a major contributor and confounder to impaired cognition.

A Community Perspective on Bowel Management and Quality of Life after Spinal Cord Injury: The Influence of Autonomic Dysreflexia

Autonomic dysfunction is common in individuals with spinal cord injury (SCI) and leads to numerous abnormalities, including profound cardiovascular and bowel dysfunction. In those with high-level lesions, bowel management is a common trigger for autonomic dysreflexia (AD; hypertension provoked by sensory stimuli below the injury level). Improving bowel care is integral for enhancing quality of life (QoL). We aimed to describe the relationships between bowel care, AD, and QoL in individuals with SCI. We performed an online community survey of individuals with SCI. Those with injury at or above T7 were considered at risk for AD. Responses were received from 287 individuals with SCI (injury levels C1-sacral and average duration of injury 17.1 ± 12.9 [standard deviation] years). Survey completion rate was 73% (n = 210). Bowel management was a problem for 78%: it interfered with personal relationships (60%) and prevented staying (62%) and working (41%) away from home. The normal bowel care duration was >60 min in 24% and most used digital rectal stimulation (59%); 33% reported bowel incontinence at least monthly. Of those at risk for AD (n = 163), 74% had AD symptoms during bowel care; 32% described palpitations. AD interfered with activities of daily living in 51%. Longer durations of bowel care (p < 0.001) and more severe AD (p = 0.04) were associated with lower QoL. Bowel management is a key concern for individuals with SCI and is commonly associated with symptoms of AD. Further studies should explore ways to manage bowel dysfunction, increase self-efficacy, and ameliorate the impact of AD to improve QoL.

Use of ambulatory blood pressure monitoring in adolescents with SCI: a case series

Introduction

Due the impact of maturation on cardiovascular hemodynamics the degree of cardiovascular dysfunction, attributable to spinal cord injury (SCI), in the pediatric and adolescent population remains unclear. While few studies have begun to assess this, there is still a void in the literature regarding the prevalence of cardiovascular dysfunction and how best to identify and treat it in this population.

Case presentation

The purpose of this case series is to present the cardiovascular profile of three adolescent patients with chronic SCI, ages 14-16, following 2 or 3 days of 24-h Ambulatory Blood Pressure Monitoring (ABPM).

Discussion

We found that there are variations across the different cases in most cardiovascular hemodynamic categories and a clarification of the International Standards to document remaining Autonomic Function after Spinal Cord Injury (ISAFSCI) may be needed to accurately identify the remaining autonomic cardiovascular function in the adolescent SCI population.

Alterations in autonomic cerebrovascular control after spinal cord injury

Among chronic cardiovascular and metabolic sequelae of spinal cord injury (SCI) is an up-to four-fold increase in the risk of ischemic and hemorrhagic stroke, suggesting that individuals with SCI cannot maintain stable cerebral perfusion. In able-bodied individuals, the cerebral vasculature is able to regulate cerebral perfusion in response to swings in arterial pressure (cerebral autoregulation), blood gases (cerebral vasoreactivity), and neural metabolic demand (neurovascular coupling). This ability depends, at least partly, on intact autonomic function, but high thoracic and cervical spinal cord injuries result in disruption of sympathetic and parasympathetic cerebrovascular control. In addition, alterations in autonomic and/or vascular function secondary to paralysis and physical inactivity can impact cerebrovascular function independent of the disruption of autonomic control due to injury. Thus, it is conceivable that SCI results in cerebrovascular dysfunction that may underlie an elevated risk of stroke in this population, and that rehabilitation strategies targeting this dysfunction may alleviate the long-term risk of adverse cerebrovascular events. However, despite this potential direct link between SCI and the risk of stroke, studies exploring this relationship are surprisingly scarce, and the few available studies provide equivocal results. The focus of this review is to provide an integrated overview of the available data on alterations in cerebral vascular function after SCI in humans, and to provide suggestions for future research.

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

BACKGROUND

Due to interruption of cardiovascular autonomic control unstable blood pressure (BP) is common in individuals with spinal cord injury (SCI) above the sixth thoracic vertebral level. The impact of unstable BP on cerebral blood flow (CBF) is not well appreciated, but symptoms associated with altered cerebral perfusion are reported, which can negatively impact daily life activities.

METHODS

We measured seated BP and CBF in participants with SCI and able-bodied (AB) controls on three laboratory visits to determine the inter-day reliability (intraclass correlation coefficient: ICC). BP was assessed at the finger using photoplethysmography and at the brachial artery with manual sphygmomanometry. CBF velocities (CBFv) were assessed at the middle cerebral artery using transcranial Doppler (TCD) ultrasound.

RESULTS

Data were collected in 15 participants with chronic SCI (C3-T4) and 10 AB controls, the groups did not differ for age, height, weight or BMI; however, brachial BP (P < 0.001), finger BP (P < 0.01) and CBFv (P < 0.05) were significantly lower in the SCI group compared to the controls. The inter-day ICC for brachial BP ranged from 0.51 to 0.79, whereas the ICC for finger BP was not as high (0.17 to 0.47). The inter-day ICC for CBFv ranged from 0.45 to 0.96, indicating fair to substantial reliability.

CONCLUSIONS

These data indicate good inter-day reliability of brachial BP and TCD recording of CBFv; however, the assessment of finger BP appears to be somewhat less reliable. In addition, these data confirm reduced resting CBFv in association with hypotension in individuals with SCI compared to matched controls with low BP.

Reproductive Health of Men with Spinal Cord Injury

Most men with spinal cord injury (SCI) are infertile due to a combination of erectile dysfunction, ejaculatory dysfunction, and abnormal semen quality. This article addresses issues that should be considered when managing the reproductive health of men with SCI. The authors present recommendations based on their decades of experience in managing the reproductive health of more than 1,000 men with SCI. Men with SCI face obstacles when pursuing sexual activity and/or biologic fatherhood. Hypogonadism and premature symptoms of aging may interfere with sexual function. Erectile dysfunction is prevalent in the SCI population, and treatments for erectile dysfunction in the general population are also effective in the SCI population. Most men with SCI cannot ejaculate with sexual intercourse. The procedures of penile vibratory stimulation (PVS) and/or electroejaculation (EEJ) are effective in obtaining an ejaculate from 97% of men with SCI. The ejaculate often contains sufficient total motile sperm to consider the assisted conception procedures of intrauterine insemination or even intravaginal insemination at home. If PVS and/or EEJ fail, sperm may be retrieved surgically from the testis or epididymis. Surgical sperm retrieval typically yields enough motile sperm only for in vitro fertilization with intracytoplasmic sperm injection. The majority of new cases of SCI occur in young men at the peak of their reproductive health. With proper medical management, these men can expect to experience active sexual lives and biologic fatherhood, if these are their goals. Numerous tools are available to physicians for helping these patients reach their goals.

Effects of midodrine and L-NAME on systemic and cerebral hemodynamics during cognitive activation in spinal cord injury and intact controls

We previously showed that increases in mean arterial pressure (MAP) following administration of midodrine hydrochloride (MH) and nitro‐L‐arginine methyl ester (L‐NAME) resulted in increased mean cerebral blood flow velocity (MFV) during head‐up tilt in hypotensive individuals with spinal cord injury (SCI) and question if this same association was evident during cognitive activation. Herein, we report MAP and MFV during two serial subtraction tasks (SSt) given before (predrug) and after (postdrug) administration of MH; (10 mg), L‐NAME (1 mg/kg) or no drug (ND) in 15 subjects with SCI compared to nine able‐bodied (AB) controls. Three‐way factorial analysis of variance (ANOVA) models were used to determine significant main and interaction effects for group (SCI, AB), visit (MH, L‐NAME, ND), and time (predrug, postdrug) for MAP and MFV during the two SSt. The three‐way interaction was significant for MAP (F = 4.262; P = 0.020); both MH (30 ± 26 mmHg; P < 0.05) and L‐NAME (27 ± 22 mmHg; P < 0.01) significantly increased MAP in the SCI group, but not in the AB group. There was a significant visit by time interaction for MFV suggesting an increase from predrug to postdrug following L‐NAME (6 ± 8 cm/sec; P < 0.05) and MH (4 ± 7 cm/sec; P < 0.05), regardless of study group, with little change following ND (3 ± 3 cm/sec). The relationship between change in MAP and MFV was significant in the SCI group following administration of MH (r² = 0.38; P < 0.05) and L‐NAME (r² = 0.32; P < 0.05). These antihypotensive agents, at the doses tested, raised MAP, which was associated with an increase MFV during cognitive activation in hypotensive subjects with SCI.

Specific Deficit in Implicit Motor Sequence Learning following Spinal Cord Injury

Background

Physical and psychosocial rehabilitation following spinal cord injury (SCI) leans heavily on learning and practicing new skills. However, despite research relating motor sequence learning to spinal cord activity and clinical observations of impeded skill-learning after SCI, implicit procedural learning following spinal cord damage has not been examined.

Objective

To test the hypothesis that spinal cord injury (SCI) in the absence of concomitant brain injury is associated with a specific implicit motor sequence learning deficit that cannot be explained by depression or impairments in other cognitive measures.

Methods

Ten participants with SCI in T1-T11, unharmed upper limb motor and sensory functioning, and no concomitant brain injury were compared to ten matched control participants on measures derived from the serial reaction time (SRT) task, which was used to assess implicit motor sequence learning. Explicit generation of the SRT sequence, depression, and additional measures of learning, memory, and intelligence were included to explore the source and specificity of potential learning deficits.

Results

There was no between-group difference in baseline reaction time, indicating that potential differences between the learning curves of the two groups could not be attributed to an overall reduction in response speed in the SCI group. Unlike controls, the SCI group showed no decline in reaction time over the first six blocks of the SRT task and no advantage for the initially presented sequence over the novel interference sequence. Meanwhile, no group differences were found in explicit learning, depression, or any additional cognitive measures.

Conclusions

The dissociation between impaired implicit learning and intact declarative memory represents novel empirical evidence of a specific implicit procedural learning deficit following SCI, with broad implications for rehabilitation and adjustment.