Development and Testing of the Spinal Cord Injury Bladder and Bowel Control Questionnaire (SCI-BBC-Q).

INTRODUCTION: Recovery of lower urinary tract (LUT) and lower gastrointestinal tract (LGIT) is a high priority for people with lived experience following spinal cord injury (SCI). A universally accepted validated patient-reported outcome (PRO) measure of the individual sensory and motor components of LGIT and LUT function, which allows tracking of recovery is lacking. To address this literature gap, the SCI Bladder and Bowel Control Questionnaire (SCI-BBC-Q) was developed. METHODS: The SCI-BBC-Q was developed as a direct assessment of the micturition and defecation experiences of an individual with SCI with possible neurogenic LUT and LGIT dysfunction. The SCI-BBC-Q development process consisted of two phases, measure development and evaluation. Measure development was guided by a conceptual framework, review of existing instruments and literature, and an iterative process of item incorporation, review, feedback, and consensus revision. Evaluation included cognitive interviewing, and assessments of feasibility, reliability, and content validity. RESULTS: The final 6-item SCI-BBC-Q is a PRO, which assesses motor and sensory function related to micturition and defecation, requiring ~5 min to complete. Assessments of clarity of the instrument components with regard to understanding of what is being asked in the questionnaire, feasibility of administration, reliability, internal consistency, and agreement with proxy measures have demonstrated that the SCI-BBC-Q provides consistent, stable, and reproducible data. Significant correlations were found between SCI-BBC-Q scores and the anorectal motor and sensory components of the International Standards for the Neurological Classification of SCI. CONCLUSION: The SCI-BBC-Q is a practical and reliable method for baseline and ongoing evaluation of patients with neurogenic LUT and LGIT dysfunction, especially in the acute and subacute period when function is changing due to neurological plasticity. It is also appropriate for use in monitoring response to treatments related to neurological recovery.

Non-invasive spinal cord electrical stimulation for arm and hand function in chronic tetraplegia: a safety and efficacy trial.

Cervical spinal cord injury (SCI) leads to permanent impairment of arm and hand functions. Here we conducted a prospective, single-arm, multicenter, open-label, non-significant risk trial that evaluated the safety and efficacy of ARCEX Therapy to improve arm and hand functions in people with chronic SCI. ARCEX Therapy involves the delivery of externally applied electrical stimulation over the cervical spinal cord during structured rehabilitation. The primary endpoints were safety and efficacy as measured by whether the majority of participants exhibited significant improvement in both strength and functional performance in response to ARCEX Therapy compared to the end of an equivalent period of rehabilitation alone. Sixty participants completed the protocol. No serious adverse events related to ARCEX Therapy were reported, and the primary effectiveness endpoint was met. Seventy-two percent of participants demonstrated improvements greater than the minimally important difference criteria for both strength and functional domains. Secondary endpoint analysis revealed significant improvements in fingertip pinch force, hand prehension and strength, upper extremity motor and sensory abilities and self-reported increases in quality of life. These results demonstrate the safety and efficacy of ARCEX Therapy to improve hand and arm functions in people living with cervical SCI. ClinicalTrials.gov identifier: NCT04697472 .

Treatment of Orthostatic Hypotension During Acute Inpatient Rehabilitation After Spinal Cord Injury: Usual Care vs. Anti-hypotensive Therapy.

BACKGROUND: To compare the pharmacological treatment of hypotension and orthostatic hypotension (OH) initiated based upon a blood pressure (BP) threshold, regardless of symptoms (TXT), to usual care pharmacological treatment of symptomatic hypotension (UC), during acute inpatient rehabilitation (AIR) following spinal cord injury (SCI). METHODS: Block randomization, based on the neurological level of injury as: cervical lesions (C1-C8); high thoracic lesions (T1-T5), and low thoracic lesions (T6-T12), was used to determine responses to the primary question "was the therapy session affected by low BP or concern for low BP development?" Study participants and therapists were unaware of the group assignment. RESULTS: A total of 66 participants enrolled; 25 (38%) in the TXT group, 29 (44%) in the UC group, and 12 (18%) withdrew. Responses to the primary question were recorded for 32 participants, 15 in the TXT, and 17 in the UC group. There was an average of 81 ±â€…51 therapy sessions/participant in the TXT and 60 ±â€…27 sessions/participant in the UC group. Of those therapy sessions, low BP or concerns for low BP affected an average of 9 ±â€…8 sessions/participant in the TXT group and 10 ±â€…12 sessions/participant in the UC group. Neither the total number of therapy sessions (P = 0.16) nor group assignment (P = 0.83) significantly predicted the number of sessions affected by low BP. CONCLUSIONS: These data are not conclusive but indicate that the treatment of asymptomatic hypotension and OH does not increase time spent in therapy compared to UC treatment of symptomatic hypotension and OH in newly injured patients with SCI. CLINICAL TRIALS REGISTRATION: #NCT02919917.

The Clinical Relevance of Autonomic Dysfunction, Cerebral Hemodynamics, and Sleep Interactions in Individuals Living With SCI.

A myriad of physiological impairments is seen in individuals after a spinal cord injury (SCI). These include altered autonomic function, cerebral hemodynamics, and sleep. These physiological systems are interconnected and likely insidiously interact leading to secondary complications. These impairments negatively influence quality of life. A comprehensive review of these systems, and their interplay, may improve clinical treatment and the rehabilitation plan of individuals living with SCI. Thus, these physiological measures should receive more clinical consideration. This special communication introduces the under investigated autonomic dysfunction, cerebral hemodynamics, and sleep disorders in people with SCI to stakeholders involved in SCI rehabilitation. We also discuss the linkage between autonomic dysfunction, cerebral hemodynamics, and sleep disorders and some secondary outcomes are discussed. Recent evidence is synthesized to make clinical recommendations on the assessment and potential management of important autonomic, cerebral hemodynamics, and sleep-related dysfunction in people with SCI. Finally, a few recommendations for clinicians and researchers are provided.

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.

Remote Ischemic conditioning as an emerging tool to improve corticospinal transmission in individuals with chronic spinal cord injury.

PURPOSE OF REVIEW: Remote ischemic conditioning (RIC) involves transient blood flow restriction to one limb leading to systemic tissue-protective effects. RIC shares some potential underlying mechanisms with intermittent hypoxia (IH), in which brief bouts of systemic hypoxia trigger increases in growth factor expression and neural plasticity. RIC has shown promise in acute myocardial infarction and stroke but may be applicable toward chronic neuropathology as well. Consequently, this review discusses similarities and differences between RIC and IH and presents preliminary and ongoing research findings regarding RIC. RECENT FINDINGS: Several publications demonstrated that combining RIC with motor training may enhance motor learning in adults with intact nervous systems, though the precise mechanisms were unclear. Our own preliminary data has found that RIC, in conjunction with task specific exercise, can increase corticospinal excitability in a subset of people without neurological injury and in those with chronic cervical spinal cord injury or amyotrophic lateral sclerosis. SUMMARY: RIC is a low-cost intervention easy to deliver in a clinical or home setting. Its potential application to facilitate neural plasticity and motor learning during rehabilitation training for individuals with chronic neurological disorders is a novel concept requiring further investigation to characterize mechanisms, safety, and efficacy.

Elucidating mechanisms of attenuated skin vasodilation during passive heat stress in persons with spinal cord injury.

OBJECTIVE: Persons with spinal cord injury (SCI) are unable to efficiently dissipate heat via thermoregulatory vasodilation as efficiently as able-bodied persons during whole body passive heat stress (PHS). Skin blood flow (SkBF) is controlled by dual sympathetic vasomotor systems: noradrenergic vasoconstrictor (VC) nerves and cholinergic vasodilator (VD) nerves. Thus, impaired vasodilation could result from inappropriate increases in noradrenergic VC tone that compete with cholinergic vasodilation or diminished cholinergic tone. To address this issue, we used bretylium (BR) which selectively blocks neural release of norepinephrine, thereby reducing noradrenergic VC tone. If impaired vasodilation during PHS is due to inappropriate increase in VC tone, BR treatment will improve SkBF responses during PHS. DESIGN: Prospective interventional trial. SETTING: laboratory. PARTICIPANTS: 22 veterans with SCI. INTERVENTIONS: Skin surface areas with previously defined intact vs. impaired thermoregulatory vasodilation were treated with BR iontophoresis with a nearby untreated site serving as control/CON. Participants underwent PHS until core temperature rose 1°C. OUTCOME MEASURES: Laser doppler flowmeters measured SkBF over BR and CON sites in areas with impaired and intact thermoregulatory vasodilation. Cutaneous vascular conductance (CVC) was calculated for all sites. Peak-PHS CVC was normalized to baseline (BL): (CVC peak-PHS/CVC BL) to quantify SkBF change. RESULTS: CVC rise in BR sites was significantly less than CON sites in areas with intact (P = 0.03) and impaired (P = 0.04) thermoregulatory vasodilation. CONCLUSION: Cutaneous blockade of neural release of noradrenergic neurotransmitters affecting vasoconstriction did not enhance thermoregulatory vasodilation during PHS in persons with SCI; rather BR attenuated the response. Cutaneous blockade of neural release of noradrenergic neurotransmitters affecting vasoconstriction did not restore cutaneous active vasodilation during PHS in persons with SCI.

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.

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.

Increased Prevalence of Blood Pressure Instability Over Twenty-Four Hours in Chronic Spinal Cord Injury.

Spinal cord injury (SCI) leads to cardiovascular dysregulation, including persistent low blood pressure (BP), orthostatic hypotension, and autonomic dysreflexia, leading to daily BP instability that may not be adequately recognized. We compared mean systolic BP, diastolic BP, and heart rate from awake and asleep measurements over a 24-h period among persons with chronic SCI (n = 33; 30 cervical injuries and three upper thoracic injuries), ambulatory/non-injured (Ambulatory-NI; n = 13), and non-injured (NI) in a wheelchair (n = 9). Stability of awake BP was evaluated by deviation of systolic BP from 115 mmHg and percent of systolic BP measurement within and outside of 90-140 mmHg. Variability over 24 h was compared using coefficient of variation and average real variability. Awake hyper- and hypotensive events (change in systolic BP ±20 mmHg from the median) were compared to symptoms reported by the participants corresponding to BP events. Participants with SCI had a lower percentage of awake systolic BP measurements within 90-140 mmHg than Ambulatory-NI and a greater deviation below 115 mmHg. Coefficient of variation and successive differences of awake systolic and diastolic BP were greater in SCI than Ambulatory-NI. Finally, all SCI participants had hyper- and/or hypotensive events and 88% experienced the BP events asymptomatically. In conclusion, participants with SCI had significantly greater BP instability compared with NI, with many hyper- and hypotensive events occurring without symptoms. Clinical management of BP instability, regardless of symptoms, should be a priority after SCI to reduce the risk of cardiovascular disease and improve quality of life.

Are Thermoregulatory Sweating and Active Vasodilation in Skin Controlled by Separate Nerves During Passive Heat Stress in Persons With Spinal Cord Injury?

Background: Sudomotor responses (SR) and active vasodilation (AVD) are the primary means of heat dissipation during passive heat stress (PHS). It is unknown if they are controlled by a single or separate set of nerves. Older qualitative studies suggest that persons with spinal cord injury (SCI) have discordant areas of sweating and vasodilation. Objectives: To test the hypothesis that neural control of SR and AVD is through separate nerves by measuring SR and vasodilation in persons with SCI to determine if these areas are concordant or discordant. Methods: Nine persons with tetraplegia, 13 with paraplegia, and nine able-bodied controls underwent PHS (core temperature rise 1°C) twice. Initially, the starch iodine test measured SR post-PHS in skin surface areas surrounding the level of injury. Subsequently, laser Doppler imagery scans measured vasodilation pre- and post-PHS in areas with and without SR. Percent change in red blood cell (RBC) flux was compared in areas with and without SR. Results: Persons with tetraplegia were anhidrotic on all areas; however, the same areas demonstrated minimal RBC flux change significantly less than equivalent able-bodied skin surface areas. In persons with paraplegia, areas of intact SR correlated with areas of RBC flux change quantitatively comparable to able-bodied persons. In anhidrotic areas, RBC flux change was significantly less than areas with SR and likely resulted from non-AVD mechanisms. Conclusion: In persons with SCI under PHS, areas with intact SR and AVD are concordant, suggesting these two aspects of thermoregulation are controlled by a single set of nerves.

Evaluation of Cardiovascular Autonomic Function during Inpatient Rehabilitation following Traumatic Spinal Cord Injury.

Assessment of the degree of impaired autonomic nervous system (ANS) function is not part of routine clinical practice during inpatient rehabilitation following traumatic spinal cord injury (SCI). The goal of this investigation was to determine the utility of the International Standards for Neurologic Classification of SCI (ISNCSCI) and the recently revised International Standards to document remaining Autonomic Function after SCI (ISAFSCI) in documenting cardiovascular ANS impairment during inpatient rehabilitation following traumatic SCI. Beat-to-beat recording of supine heart rate (HR) and blood pressure (BP) were collected at the bedside for estimation of total cardiovascular ISAFSCI score, cardio-vagal modulation (i.e., high frequency HR variability [HFHRV]) and sympathetic vasomotor regulation (i.e., Mayer wave component of systolic BP [SBPmayer]). A total of 41 participants completed baseline testing, which was conducted 11 ± 5 days from the admission ISNCSCI examination. There were no differences in supine HR or BP based on the ISNCSCI or ISAFSCI assessments. The HFHRV was generally lower with more distal lesions (r2 = 0.15; p = 0.01), and SBPmayer was significantly lower in those with American Spinal Injury Association Impairment Scale (AIS) A compared with AIS B, C, D (Cohen's d = -1.4; p < 0.001). There were no significant differences in HFHRV or SBPmayer in patients with or without ISAFSCI evidence of cardiovascular ANS impairment. These preliminary data suggest that neither the ISNCSCI nor the ISAFSCI are sensitive to changes in ANS cardiovascular function following traumatic SCI. Bedside assessment of HR and BP variabilities may provide insight, but are not readily available in the clinical setting. Further research is required to evaluate methods that accurately assess the degree of ANS impairment following traumatic SCI.

Orthostatic systemic and cerebral hemodynamics in newly injured patients with spinal cord injury.

BACKGROUND: Low blood pressure (BP) may lead to reduced cerebral blood flow velocity (CBFv) during an orthostatic challenge in newly injured patients with traumatic spinal cord injury (SCI), which, may relate to the neurological level of injury (NLI) as documented on the International Standards for the Neurologic Classification of SCI (ISNCSCI), or to evidence of cardiovascular autonomic impairment as determined by the International Standards to document remaining Autonomic Function after SCI (ISAFSCI). OBJECTIVE: To examine the influence of patient demographics, ISNCSCI and ISAFSCI scores on hemodynamic responses to a bedside sit-up test in newly injured patients with SCI. DESIGN: Cross-sectional, prospective analysis. METHODS: A modified sit-up test was conducted at the bedside with the hips at an angle between 45° and 90° and the legs horizontal, level with the hips. Heart rate, BP, and CBFv were recorded for 10 min in the supine and seated positions. RESULTS: Fifty-three newly injured patients (median 39.5 days post-injury) with traumatic SCI were enrolled. Overall, 28 (53%) patients met ISAFSCI criteria, and the number of criteria met (total score) was significantly related to orthostatic changes in CBFv. Change in SBP and change in CBFv were not significantly related, but NLI and total sensory score from the ISNCSCI were significant predictors of the change in CBFv. CONCLUSIONS: Total ISAFSCI score, NLI and sensory scores were positively associated with orthostatic changes in CBFv. Long term follow-up should be considered to determine the consequences of diminished CBFv on cognitive function and quality of life following SCI.

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.

Posteroanterior Cervical Transcutaneous Spinal Cord Stimulation: Interactions with Cortical and Peripheral Nerve Stimulation.

Transcutaneous spinal cord stimulation (TSCS) has demonstrated potential to beneficially modulate spinal cord motor and autonomic circuitry. We are interested in pairing cervical TSCS with other forms of nervous system stimulation to enhance synaptic plasticity in circuits serving hand function. We use a novel configuration for cervical TSCS in which the anode is placed anteriorly over ~C4-C5 and the cathode posteriorly over ~T2-T4. We measured the effects of single pulses of TSCS paired with single pulses of motor cortex or median nerve stimulation timed to arrive at the cervical spinal cord at varying intervals. In 13 participants with and 15 participants without chronic cervical spinal cord injury, we observed that subthreshold TSCS facilitates hand muscle responses to motor cortex stimulation, with a tendency toward greater facilitation when TSCS is timed to arrive at cervical synapses simultaneously or up to 10 milliseconds after cortical stimulus arrival. Single pulses of subthreshold TSCS had no effect on the amplitudes of median H-reflex responses or F-wave responses. These findings support a model in which TSCS paired with appropriately timed cortical stimulation has the potential to facilitate convergent transmission between descending motor circuits, segmental afferents, and spinal motor neurons serving the hand. Studies with larger numbers of participants and repetitively paired cortical and spinal stimulation are needed.

The preliminary effects of moderate aerobic training on cognitive function in people with TBI and significant memory impairment: a proof-of-concept randomized controlled trial.

This single-blinded RCT investigated cognitive effects of aerobic exercise in persons with TBI-related memory impairment. Five participants . were randomly assigned to 12-weeks of either supervised moderate intensity aerobic cycling or an active control. Outcome measures included neuropsychological assessments and structural neuroimaging (MRI,). The exercise group demonstrated greater improvements on auditory verbal learning (RAVLT; d=1.54) and processing speed (SDMT; d=1.58). The exercise group showed larger increases in volume of the left hippocampus (d=1.49) and right thalamus (d=1.44). These pilot data suggest that 12-weeks of moderate intensity aerobic cycling may improve memory and processing speed in those with TBI-related memory impairments.