Inspiratory Muscle Performance Is Related to Seated Balance Function in People With Spinal Cord Injury: An Observational Study.

OBJECTIVE: To examine the relationship between inspiratory muscle performance (IMP) and functional sitting balance (FSB) in persons with chronic spinal cord injury (SCI). We hypothesized that a moderate correlation would be found between IMP and FSB and that individuals with better balance would have better IMP. DESIGN: The SCI-specific modification of the Function in Sitting Test (FIST-SCI) measured FSB. The IMP measures included (1) maximal inspiratory pressure (MIP), (2) sustained MIP (SMIP), and (3) inspiratory duration. Upper extremity motor score (UEMS) and level of injury (LOI) were taken from International Standards for Neurological Classification of Spinal Cord Injury examinations. Spearman correlational analyses assessed relationships among these factors in the sample (N=37). Mann-Whitney U tests explored differences between 2 comparison group pairs (tetraplegia group [TG] vs paraplegia group [PG]; independent transfer group [ITG] vs assisted transfer group [ATG]). Regression analysis examined variables predictive of FSB in the TG. SETTING: Research facility. PARTICIPANTS: Volunteers with tetraplegia (n=21, American Spinal Injury Association Impairment Scale (AIS) A=8, B=7, C=6) and paraplegia (n=16, AIS A=9, B=4, C=3) (N=37). INTERVENTION: Not applicable. MAIN OUTCOME MEASURES: IMP, LOI, UEMS, FIST-SCI. RESULTS: UEMS, MIP, SMIP, and LOI had moderate to high correlations with FIST-SCI scores (ρ=0.720 (P<.001), 0.480 (P=.003), 0.467 (P=.004), 0.527 (P=.001), respectively). UEMS, MIP, and FIST-SCI scores were higher in the PG and ITG than the TG and ATG, respectively (PG vs. TG P values=<.001, .008, .002, respectively, and ITG vs. ATG P values=<.001, .032, <.001, respectively). Further, SMIP and UEMS predicted FIST-SCI balance scores in the TG, accounting for 55% of total variance (P<.001) (FIST-SCI=11.88+0.03 [SMIP]+0.425 [UEMS]). CONCLUSIONS: The relationship between IMP and balance appears preserved after SCI. FSB was predicted, in part, via UEMS and SMIP in the TG. Future research should focus on the effect of SCI-based breathing interventions on FSB.

Inspiratory Muscle Performance and Anthropometric Measures-Novel Assessments Related to Pulmonary Function in People with Spinal Cord Injury: A Pilot Study.

OBJECTIVE: To investigate the feasibility and validity of using the novel axillary:umbilical (A:U) ratio and sustained maximal inspiratory pressure (SMIP) as supplementary measures in the assessment of respiratory function in people with spinal cord injury. DESIGN: Pilot study with a single day of data collection. All measurements were taken with participants in their personal wheelchairs to best represent normal functioning and positioning for each individual. SETTING: Research institution. PARTICIPANTS: A convenience sample of 30 community dwelling volunteers with chronic spinal cord injury (C2-T12, American Spinal Injury Association Impairment Scale A-D) participated. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Participants underwent anthropometric measurements (trunk height, abdominal circumference, axillary circumference) and assessment of inspiratory muscle performance, incluidng maximal inspiratory pressure, SMIP, and inspiratory duration, as well as standard pulmonary function tests. RESULTS: The A:U ratio and SMIP were recorded for all participants. The SMIP was significantly related to more respiratory performance measures than the maximal inspiratory pressure (P<.05) and the A:U ratio was significantly related to more respiratory performance measures than any other anthropometric measure (P<.05). Additionally, an A:U ratio cutoff point detected individuals with a peak expiratory flow ≥ 80% of their predicted value with a sensitivity and specificity of 85.7% and 91.3%, respectively (area under the curve: 0.92). CONCLUSIONS: It is feasible to capture the A:U Ratio and SMIP in individuals with spinal cord injury. Further, the strong significant relationships of SMIP and the A:U ratio to respiratory performance measures suggests their clinical importance in the pulmonary assessment and risk stratification of people with chronic spinal cord injury.

Psychometric Testing and Clinical Utility of a Modified Version of the Function in Sitting Test for Individuals With Chronic Spinal Cord Injury.

OBJECTIVES: Seated balance (SB) is substantially compromised and greatly impacts the function of individuals living with a spinal cord injury (SCI). A clinically applicable criterion standard measure for SB does not exist for this population. Initial validation and reliability analysis of the Function in Sitting Test (FIST) in SCI has been published, but the authors of this study report that modifications to the tool may be necessary. This study aimed to explore the psychometrics and clinical utility of a modified version of the FIST to better measure SCI-specific functional tasks in sitting. DESIGN: The FIST was modified (FIST-SCI) by an expert panel and used by 2 graders to evaluate the SB of individuals with chronic SCI (cSCI) on 2 separate days. The Motor Assessment Scale item 3 (MAS-SCI) was included as a comparison measure. SETTING: Research facility. PARTICIPANTS: Individuals with cSCI longer than 1 year (N=38) participated in the study. Injury levels of individuals participating in this study spanned C1 to T10 (American Spinal Injury Association Impairment Scale A, 17 subjects; B, 12 subjects; and C, 9 subjects). Thirteen individuals required assistance to transfer. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Validity, reliability, internal consistency, sensitivity, specificity, and responsiveness. RESULTS: Validity testing found a moderate relationship between the MAS-SCI and the FIST-SCI (ρ, .522; P<.05). FIST-SCI scores distinguished individuals requiring assistance to transfer from those who were independent (t=4.51; P<.05). Inter- and intra-rater reliability were excellent (intraclass correlation coefficient (2,k)=.985 and .983, respectively) and internal consistency was excellent (α=.94). A FIST-SCI cutoff score of 45 or greater was 92% sensitive and specific in characterizing transfer ability. Standard error of the measure (1.3) and minimal detectable change (3.5) were similar to previous work. CONCLUSIONS: Initial validity of the FIST-SCI is reported, but further assessment is required. Reliability is excellent in the cSCI population. FIST-SCI scores provide clinical insight into the seated functional ability of individuals with cSCI.

Differences in Acute Metabolic Responses to Bionic and Nonbionic Ambulation in Spinal Cord Injured Humans and Controls.

OBJECTIVES: To (1) compare energy expenditure during seated rest, standing, and prolonged bionic ambulation or bipedal ambulation in participants with spinal cord injury (SCI) and noninjured controls, respectively, and (2) test effects on postbionic ambulation glycemia in SCI. DESIGN: Two independent group comparison of SCI and controls. SETTING: Academic Medical Center. PARTICIPANTS: Ten participants with chronic SCI (C7-T1, American Spinal Injury Association Impairment Scale A-C) and 10 controls (N=20). INTERVENTIONS: A commercial bionic exoskeleton. MAIN OUTCOME MEASURES: Absolute and relative (to peak) oxygen consumption, perceived exertion, carbohydrate/fat oxidation, energy expenditure, and postbionic ambulation plasma glucose/insulin. RESULTS: Average work intensity accompanying 45 minutes of outdoor bionic ambulation was <40% peak oxygen consumption, with negligible drift after reaching steady state. Rating of perceived exertion (RPE) did not differ between groups and reflected low exertion. Absolute energy costs for bionic ambulation and nonbionic ambulation were not different between groups despite a 565% higher ambulation velocity in controls and 3.3× higher kilocalorie per meter in SCI. Fuel partitioning was similar between groups and the same within groups for carbohydrate and fat oxidation. Nonsignificant (9%) lowering of the area under a glucose tolerance curve following bionic ambulation required 20% less insulin than at rest. CONCLUSION: Work intensity during prolonged bionic ambulation for this bionic exoskeleton is below a threshold for cardiorespiratory conditioning but above seated rest and passive standing. Bionic ambulation metabolism is consistent with low RPE and unchanged fuel partitioning from seated rest. Bionic ambulation did not promote beneficial effects on glycemia in well-conditioned, euglycemic participants. These findings may differ in less fit individuals with SCI or those with impaired glucose tolerance. Observed trends favoring this benefit suggest they are worthy of testing.

A Secondary Analysis of Short- and Long-Term Variability of Inspiratory Muscle Performance in People Living With SCI.

Objectives: To explore the expected variability in repeated short-term (ST) and long-term (LT) inspiratory muscle performance (IMP) in individuals with chronic spinal cord injury (SCI). Methods: Maximal inspiratory pressure (MIP), sustained MIP (SMIP), and inspiratory duration (ID) were collected from 22 individuals with chronic SCI (C1-T9, American Spinal Injury Association Impairment Scale [AIS] A-C) over 18 months. ST data were collected four times within 2 weeks (n = 19). LT data were collected at two time points at least 7 months apart (n = 20). Results: SMIP was the most reliable IMP assessment with an intraclass correlation coefficient (ICC) of 0.959, followed by MIP (ICC 0.874) and ID (ICC 0.689). The ID was the only ST measure to have a significant difference [MIP: F(3, 54) = 2.5, p = .07; SMIP: F(3, 54) = 1.3, p = .29; ID: F(1.4, 25.6) = 4.8, p = .03]. Post hoc analysis showed the mean day 1 ST ID measure was significantly different from both days 3 and 4. The percent change of ID from day 3 to day 6 was 11.6%. No LT measures differed significantly [mean change (SD) [95% CI] for MIP: 5.2 cm H2O (18.8) [-3.6, 13.9], p = .235; SMIP: 60.9 pressure time unit (166.1) [-16.9, 138.6], p = .118; ID: 0.1 s (2.5) [-1.1, 1.3], p = .855]. Conclusion: These data provide a foundation for understanding normal variance in ST and LT IMP in the SCI population. Change in MIP function outside 10% is likely a true and meaningful change and may help clinicians recognize individuals with SCI at risk for respiratory compromise. Future studies should explore changes in MIP and SMIP that are associated with meaningful functional changes.

Comparison of two inspiratory muscle training protocols in people with spinal cord injury: a secondary analysis.

STUDY DESIGN/SETTING: Secondary analysis. OBJECTIVES: To compare the change in maximal inspiratory pressure (PImax) over the first 4 weeks of two different inspiratory muscle training (IMT) protocols and explore if either method is more effective for people with spinal cord injury. METHODS: Data originated from two published studies. Participants completed flow-resistive IMT (F-IMT) at 80% daily PImax, 7 days/week (supervised weekly), or threshold IMT (T-IMT) at 30-80% weekly PImax, twice-daily, 5 days/week (supervised every session). Seven participants from each trial were matched by training adherence, level of spinal cord injury, impairment grade (A-C), and height. Differences between F-IMT and T-IMT groups in training intensity, breaths taken, inspiratory work, and the change in the PImax from baseline at the end of week four were analysed. RESULTS: Over 4 weeks, there was no difference in the change in PImax between groups (Absolute change in PImax (cmH2O): p = 0.456, Percent change in PImax relative to baseline: p = 0.128). F-IMT participants trained at a higher intensity (median: 77 vs 22 cmH2O, p = 0.001 and 80% baseline vs 61% baseline, p = 0.038) but took fewer breaths (840 vs 1404 breaths, p = 0.017) than T-IMT participants. Inspiratory work was similar between groups (64,789 vs 65,910 (% PImax × number of breaths), p = 0.535). CONCLUSIONS: Our findings support both methods of IMT as the change in PImax and inspiratory work were similar between groups. However, daily high-intensity F-IMT with intermittent supervision, required fewer breaths and less participant and therapist time. Future studies should examine optimal dosage and supervision required to achieve increased PImax.

Comparison of Patients Discharged to Skilled Nursing and Inpatient Rehabilitation Facilities After Hospitalization for COVID-19: A Retrospective Study.

OBJECTIVE: The aim of the study is to identify differences in demographics, severity of disease, and rates of hospital readmission among adults discharged to skilled nursing facilities and inpatient rehabilitation facilities after hospitalization for coronavirus 2019. DESIGN: This is a retrospective cohort study of adults hospitalized with coronavirus 2019 infection at academic medical centers participating in the Vizient Clinical Data Base between April 1, 2020, and June 30, 2021, who were discharged to skilled nursing facilities or inpatient rehabilitation facilities ( N = 39,882). Data from the Clinical Data Base are used with permission of Vizient, Inc. All rights reserved. RESULTS: Among adults hospitalized with coronavirus 2019 infection, those discharged to skilled nursing facilities were 1.4 times more likely to require hospital readmission than those discharged to inpatient rehabilitation facilities. They were, on average, older (73 vs. 61 yrs, P < 0.001) and had shorter hospital lengths of stay (15 vs. 26 days, P < 0.0001) than the patients discharged to inpatient rehabilitation facilities. Persons discharged to inpatient rehabilitation facilities were more likely to have received intensive care and mechanical ventilation while hospitalized ( P < 0.001). CONCLUSIONS: Individuals discharged to inpatient rehabilitation facilities after hospitalization for coronavirus 2019 differ from those discharged to skilled nursing facilities on a number of key variables, including age, hospital length of stay, having received intensive care, and odds of hospital readmission.

Adherence to and impact of home-based high-intensity IMT in people with spinal cord injury: a pilot study.

STUDY DESIGN: The pilot study was completed in 5 phases (Control and 4 phases of IMT) incorporating assessments at Baseline 1 (BL1), BL2, Follow-up 1 (F1), F2, F3, and F4. OBJECTIVE: To assess the adherence and impact of a daily high-intensity (80% of max) inspiratory muscle training (IMT) home program with once weekly supervision for people with spinal cord injury (SCI). SETTING: Assessments: research institution or zoom. IMT: participant's home. METHODS: Participants completed daily IMT in IMT Phase 1 and 2, once weekly in IMT Phase 3, self-selected frequency in IMT Phase 4. All phases had one weekly supervised session except IMT Phase 4. Primary outcomes included adherence and a difficulty score [DS (0- not difficult to 10- the most difficult)]. Secondary outcomes included respiratory function and seated balance. RESULTS: Data from 10 people with chronic SCI (>1 year) (Cervical level of injury: 6, AIS: A-B, injury duration: 10.9 years 95% CI [3.9, 18.1]) were used in the analysis. Participants completed 69% of their training days in IMT Phase 1 and 65% overall reporting an average DS of 7.4 ± 1.4. Only one participant completed training during IMT Phase 4. One participant's training load was reduced due to suspected overtraining. Maximal inspiratory pressure (MIP), sustained MIP (SMIP), and total power (TP), improved significantly (p < 0.05) from BL2 to F1. CONCLUSION: Our data suggest that people with SCI can perform high-intensity IMT at home to improve inspiratory performance. It is strongly recommended that participants be intermittently monitored for adherence and safety. CLINICALTRIALS: gov Registration number: NCT04210063.

Effectiveness of Abdominal Functional Electrical Stimulation for Improving Bowel Function in People With a Spinal Cord Injury: A Study Protocol for a Double-Blinded Randomized Placebo-Controlled Clinical Trial.

Background: People with a spinal cord injury (SCI) have a high rate of bowel-related morbidity, even compared with people with other neurological disorders. These complications lower quality of life and place a financial burden on the health system. A noninvasive intervention that improves the bowel function of people with an SCI should reduce morbidity, improve quality of life, and lead to cost savings for health care providers. Objectives: To investigate the effectiveness of noninvasive abdominal functional electrical stimulation (FES) for improving bowel function in people with a chronic SCI. Methods: A prospective, double-blinded, 1:1 randomized, placebo-controlled intervention trial will be conducted with 80 adults with chronic SCI (>12 months since injury) above T8 single neurological level. The intervention will be a 45-minute abdominal FES (or placebo) session, 3 days per week, for 6 weeks. Main Study Parameters/Endpoints: Primary endpoint is whole gut transit time before and after 6 weeks of abdominal FES. Secondary endpoints measured before and after 6 weeks of abdominal FES are (1) colonic transit time; (2) quality of life (EQ-5D-5L); (3) participant-reported bowel function (International SCI Bowel Function Basic Data Set Questionnaire and visual analogue scale); (4) respiratory function (forced vital capacity, forced expiratory volume in 1 second, peak expiratory flow, maximal inspiratory pressure, and maximal expiratory pressure); (5) bladder symptoms (Neurogenic Bladder Symptom Score); (6) daily bowel management diary; and (7) unplanned hospital visits. Conclusion: Safety data will be collected, and a cost utility analysis using quality of life scores will be performed. Trial registration: Australian New Zealand Clinical Trials Registry (ANZCTR): ACTRN12621000386831.

Phase 1 Safety Trial of Autologous Human Schwann Cell Transplantation in Chronic Spinal Cord Injury.

A phase 1 open-label, non-randomized clinical trial was conducted to determine feasibility and safety of autologous human Schwann cell (ahSC) transplantation accompanied by rehabilitation in participants with chronic spinal cord injury (SCI). Magnetic resonance imaging (MRI) was used to screen eligible participants to estimate an individualized volume of cell suspension to be implanted. The trial incorporated standardized multi-modal rehabilitation before and after cell delivery. Participants underwent sural nerve harvest, and ahSCs were isolated and propagated in culture. The dose of culture-expanded ahSCs injected into the chronic spinal cord lesion of each individual followed a cavity-filling volume approach. Primary outcome measures for safety and trend-toward efficacy were assessed. Two participants with American Spinal Injury Association Impairment Scale (AIS) A and two participants with incomplete chronic SCI (AIS B, C) were each enrolled in cervical and thoracic SCI cohorts (n = 8 total). All participants completed the study per protocol, and no serious adverse events related to sural nerve harvest or ahSC transplantation were reported. Urinary tract infections and skin abrasions were the most common adverse events reported. One participant experienced a 4-point improvement in motor function, a 6-point improvement in sensory function, and a 1-level improvement in neurological level of injury. Follow-up MRI in the cervical (6 months) and thoracic (24 months) cohorts revealed a reduction in cyst volume after transplantation with reduced effect over time. This phase 1 trial demonstrated the feasibility and safety of ahSC transplantation combined with a multi-modal rehabilitation protocol for participants with chronic SCI.

A case for inspiratory muscle training in SCI: potential role as a preventative tool in infectious respiratory diseases like COVID-19.

INTRODUCTION: Respiratory complications (RC) are a leading cause of death after spinal cord injury (SCI) due to compromised immune function and respiratory muscle weakness. Thus, individuals with SCI are at high risk of developing COVID-19 related RC. Results of a SCI clinical trial showed a supervised respiratory muscle training (RMT) program decreased risk of developing RC. The feasibility of conducting unsupervised RMT is not well documented. Four publications (n = 117) were identified in which unsupervised RMT was performed. Significant improvements in respiratory outcomes were reported in two studies: Maximal Inspiratory and Expiratory Pressure (MIP40% and MEP25%, respectively), Peak Expiratory Flow (PEF9%), seated and supine Forced Vital Capacity (FVC23% and 26%, respectively), and Peak Cough Flow (28%). This review and case report will attempt to show that an inspiratory muscle training (IMT) home exercise program (HEP) is feasible and may prepare the respiratory system for RC associated with COVID-19 in patients with SCI. CASE PRESENTATION: A 23-year-old with tetraplegia (P1), history of mechanical ventilation, and hospitalization for RC, completed 27 IMT HEP sessions in one month. MIP and sustained MIP (SMIP) increased from baseline by 28% and 26.5%, respectively. Expiratory volumes and rates also improved (FVC, FEV1, and PEF: 11.7%, 8.3%, and 14.2%, respectively). DISCUSSION: The effects of COVID-19 on patients with SCI remains inconclusive, but recent literature and the results of this case suggest that unsupervised IMT is feasible and may limit the severity of RC in patients with SCI who contract COVID-19.

Clinician-Focused Overview of Bionic Exoskeleton Use After Spinal Cord Injury.

Spinal cord injury (SCI) resulting in paralysis of lower limbs and trunk restricts daily upright activity, work capacity, and ambulation ability, putting persons with an injury at greater risk of developing a myriad of secondary medical issues. Time spent in the upright posture has been shown to decrease the risk of these complications in SCI. Unfortunately, the majority of ambulation assistive technologies are limited by inefficiencies such as high energy demand, lengthy donning and doffing time, and poor gait pattern precluding widespread use. These limitations spurred the development of bionic exoskeletons. These devices are currently being used in rehabilitation settings for gait retraining, and some have been approved for home use. This overview will address the current state of available devices and their utility.