Differential Performance of SF-36 Items in Healthy Adults With and Without Functional Limitations

Horner-Johnson W, Krahn GL, Suzuki R, Peterson JJ, Roid G, Hall T, the RRTC Expert Panel on Health Measurement. Differential performance of SF-36 items in healthy adults with and without functional limitations.

Objective

To determine whether Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36) items show differential item functioning among healthy adults with various types of functional limitations as compared with a healthy sample with no identified limitations.

Design

Survey responses were analyzed by using partial correlations.

Setting

General community.

Participants

Participants (N=206) included (1) adults with spinal cord injury (SCI), (2) adults who were deaf or hard of hearing, (3) adults who were legally blind, (4) adults with psychiatric or emotional conditions, and (5) adults with no reported functional limitations. Participants were screened to ensure the absence of substantial health problems.

Interventions

Not applicable.

Main Outcome Measure

SF-36.

Results

Partial correlations showed a significant negative correlation, indicating differential item functioning (ie, apparent bias) for people with SCI on all 10 SF-36 Physical Functioning items. For people who were blind, 5 items showed a significant negative correlation. Two items had significant negative correlations for the deaf/hard-of-hearing group. One item showed significant negative performance for people with mental health conditions.

Conclusions

Our data indicated a possibility for measurement bias caused by the blending of health and function concepts in the SF-36.     

Impact of associated conditions resulting from spinal cord injury on health status and quality of life in people with traumatic central cord syndrome

Noonan VK, Kopec JA, Zhang H, Dvorak MF. Impact of associated conditions resulting from spinal cord injury on health status and quality of life in people with traumatic central cord syndrome.

Objective

To determine the effect of associated spinal cord injury (SCI) conditions on the health status and quality of life (QOL) in people with traumatic central cord syndrome.

Design

Cross-sectional design.

Setting

Community-based.

Participants

Subjects (N=70) with traumatic central cord syndrome who were a minimum of 2 years postinjury.

Interventions

Not applicable.

Main Outcome Measures

Presence of associated SCI conditions (neuropathic pain, spasticity, bowel, bladder, and/or sexual dysfunction, decreased motor function); health status (36-Item Short-Form Health Survey [SF-36], symptom satisfaction); and QOL.

Results

The SF-36 physical component score (PCS) was lower in subjects who reported problems with bowel, bladder, and/or sexual function (−6.9; 95% confidence interval [CI], −11.6 to −2.2). The PCS was decreased in subjects with a lower motor score and this relationship was negatively affected by spasticity and being less educated. The SF-36 mental component score was negatively affected by neuropathic pain and a lower motor score. Neuropathic pain and a lower motor score were both associated with subjects being dissatisfied with their symptoms. Subjects who had a higher motor score were more likely to have a higher QOL (odds ratio, 1.7; 95% CI, 1.1 to 2.7).

Conclusions

The associated SCI conditions bowel, bladder, and/or sexual dysfunction, neuropathic pain, decreased motor function, and spasticity negatively affect the health status of persons with traumatic central cord syndrome. Diminished motor recovery was the only associated SCI condition to impact QOL. By developing a conceptual model and adjusting for confounders, an estimate for each associated SCI condition's effect on patient outcomes was obtained. Our results indicate the importance of treating or ameliorating associated SCI conditions in order to maximize physical and mental functioning.     

Clinical correlates of elevated serum concentrations of cytokines and autoantibodies in patients with spinal cord injury

Davies AL, Hayes KC, Dekaban GA. Clinical correlates of elevated serum concentrations of cytokines and autoantibodies in patients with spinal cord injury.

Objective

To determine the serum cytokine profiles of patients with spinal cord injury (SCI) and varying clinical presentations relative to healthy, able-bodied, age-matched control subjects.

Design

Cross-sectional study.

Setting

Clinical research unit.

Participants

People with SCI (N=56) and different clinical presentations, and healthy, able-bodied, age-matched control subjects (N=35).

Interventions

Not applicable.

Main Outcome Measures

Serum levels of the proinflammatory cytokines interleukin (IL) 1β, IL-6, tumor necrosis factor alpha (TNF-α), the anti-inflammatory cytokines IL-4 and IL-10, the regulatory cytokine IL-2, the IL-1 receptor antagonist (IL-1RA), and autoantibodies against myelin-associated glycoprotein and GM₁ ganglioside (anti-GM₁) immunoglobulin (IgG and IgM), as determined by enzyme-linked immunosorbent assay. The relationship between elevated serum cytokine levels and clinical variables was also studied.

Results

SCI subjects exhibited serum concentrations of IL-6, TNF-α, IL-1RA, and anti-GM₁ (IgG) that were greater (P<.05) than control group values. Elevated cytokine concentrations were not associated with high white blood cell counts, level of injury, or American Spinal Injury Association classification; they were evident in SCI subjects who were asymptomatic for medical complications, but were further elevated in subjects with pain, urinary tract infection (UTI), and pressure ulcers.

Conclusions

Elevated levels of circulating proinflammatory cytokines and autoantibodies are present in the serum of SCI subjects without medical complications, and are further elevated in SCI subjects with neuropathic pain, UTI, or pressure ulcers, relative to healthy, able-bodied control subjects. These findings may be indicative of a protective autoimmunity, simply a consequence of occult or evident infection, or evidence of cytokine dysregulation that may contribute to an immune-mediated impairment of axonal conduction.     

Personal Bankruptcy After Traumatic Brain or Spinal Cord Injury: The Role of Medical Debt

Relyea-Chew A, Hollingworth W, Chan L, Comstock BA, Overstreet KA, Jarvik JG. Personal bankruptcy after traumatic brain or spinal cord injury: the role of medical debt.

Objective

To estimate the prevalence of medical debt among traumatic brain injury (TBI) and spinal cord injury (SCI) patients who discharged their debts through bankruptcy.

Design

A cross-sectional comparison of bankruptcy filings of injured versus randomly selected bankruptcy petitioners.

Setting

Patients hospitalized with SCI or TBI (1996-2002) and personal bankruptcy petitioners (2001-2004) in western Washington State.

Participants

Subjects (N=186) who filed for bankruptcy, comprised of 93 patients with previous SCI or TBI and 93 randomly selected bankruptcy petitioners.

Interventions

Not applicable.

Main Outcome Measures

Medical and nonmedical debt, assets, income, expenses, and employment recorded in the bankruptcy petition.

Results

Five percent of randomly selected petitioners and 26% of petitioners with TBI or SCI had substantial medical debt (debt that accounted for more than 20% of all unsecured debts). SCI and TBI petitioners had fewer assets and were more likely to be receiving government income assistance at the time of bankruptcy than controls. SCI and TBI patients with a higher blood alcohol content at injury were more likely to have substantial medical debts (odds ratio=2.70; 95% confidence interval, 1.04-7.00).

Conclusions

Medical debt plays an important role in some bankruptcies after TBI or SCI. We discuss policy options for reducing financial distress after serious injury.     

Changes and determinants of life satisfaction after spinal cord injury: a cohort study in the Netherlands

van Koppenhagen CF, Post MW, van der Woude LH, de Witte LP, van Asbeck FW, de Groot S, van den Heuvel W, Lindeman E. Changes and determinants of life satisfaction after spinal cord injury: a cohort study in The Netherlands.

Objective

To determine the impact of spinal cord injury (SCI) on life satisfaction of persons with SCI 1 year after discharge of inpatient rehabilitation.

Design

A cohort study. Life satisfaction before SCI was retrospectively measured at the start of active rehabilitation. One year after discharge from inpatient rehabilitation, current life satisfaction was measured.

Setting

Eight rehabilitation centers in The Netherlands.

Participants

Persons (N=147) aged 18 to 65 and wheelchair-dependent at least for long distances.

Interventions

Not applicable.

Main Outcome Measure

The Life Satisfaction Questionnaire.

Results

Mean satisfaction with life ± SD as a whole was 5.3±0 before SCI and 4.3±1.3 one year after inpatient rehabilitation. Sexual life, self-care, and vocational situation showed the largest impact of SCI (P<.05), whereas the social relationships domains appeared to be the least affected. Decrease of life satisfaction after SCI was larger when using the retrospective ratings than when using general population scores. Significant determinants of life satisfaction after SCI were high lesion level (β=.31, P<.05), pain (β=.19, P<.05), and secondary impairments (β=.22, P<.05).

Conclusions

Life satisfaction decreased in persons with SCI. Level of lesion and suffering secondary impairments or pain were associated with low life satisfaction 1 year after discharge from inpatient rehabilitation.     

Community Reintegration in Rehabilitated South Indian Persons With Spinal Cord Injury

Samuelkamaleshkumar S, Radhika S, Cherian B, Elango A, Winrose W, Suhany BT, Prakash MH. Community reintegration in rehabilitated South Indian persons with spinal cord injury.

Objectives

To explore community reintegration in rehabilitated South Indian persons with spinal cord injury (SCI) and to compare the level of community reintegration based on demographic variables.

Design

Survey.

Setting

Rehabilitation center of a tertiary care university teaching hospital.

Participants

Community-dwelling persons with SCI (N=104).

Interventions

Not applicable.

Main Outcome Measures

Craig Handicap Assessment and Reporting Technique (CHART).

Results

The mean scores for each CHART domain were physical independence 98±5, social Integration 96±11, cognitive independence 92±17, occupation 70±34, mobility 65±18, and economic self sufficiency 53±40. Demographic variables showed no statistically significant difference with any of the CHART domains except for age and mobility, level of education, and social integration.

Conclusions

Persons with SCI in rural South India who have completed comprehensive, mostly self-financed, rehabilitation with an emphasis on achieving functional ambulation, family support, and self-employment and who attend a regular annual follow-up show a high level of community reintegration in physical independence, social integration, and cognitive independence. CHART scores in the domains of occupation, mobility, and economic self-sufficiency showed lower levels of community reintegration.     

Longitudinal Changes in Physical Capacity Over 20 Years in Athletes With Spinal Cord Injury

Shiba S, Okawa H, Uenishi H, Koike Y, Yamauchi K, Asayama K, Nakamura T, Tajima F. Longitudinal changes in physical capacity over 20 years in athletes with spinal cord injury.

Objective

To investigate the longitudinal changes in physical capacity over 20 years in athletes with spinal cord injury (SCI).

Design

Longitudinal study (20-y follow-up).

Setting

Laboratory setting.

Participants

Persons with SCI (N=7).

Interventions

Not applicable.

Main Outcome Measures

Maximum oxygen consumption V?o₂max) measured in 1986-1988 and in 2006.

Results

Subjects with SCI maintained stable V?o₂max in 2006. Six of the 7 continued various wheelchair sports activities, while 1 person quit sports activities 1 year after the baseline study. The latter person showed reduced V?o₂max by 53%, while 2 persons who continued strenuous wheelchair sports activities showed increased V?o₂max by 43% and 45% after 20 years.

Conclusion

The results indicated that physical capacity reflected the level of sports activity in subjects with SCI who maintained sports activities.     

Association between mobility mode and C-reactive protein levels in men with chronic spinal cord injury

Morse LR, Stolzmann K, Nguyen HP, Jain NB, Zayac C, Gagnon D, Tun CG, Garshick E. Association between mobility mode and C-reactive protein levels in men with chronic spinal cord injury.

Objective

To assess clinical determinants of systemic inflammation in persons with chronic spinal cord injury (SCI).

Design

Cross-sectional survey.

Setting

Veterans Affairs medical center.

Participants

As part of an epidemiologic study assessing SCI-related health conditions, 63 men with chronic SCI provided a blood sample and information regarding locomotive mode and personal habits.

Interventions

Not applicable.

Main Outcome Measure

Plasma high-sensitivity C-reactive protein (CRP).

Results

The mean ± standard deviation age was 56±14y, and participants were assessed 21±13y after injury. Adjusting for heart disease, hypertension, and body mass index (BMI), the mean CRP in 12 motorized wheelchair users (5.11mg/L) was not significantly greater than 23 participants who used a manual wheelchair (2.19mg/L) (P=.085) but was significantly greater than the 17 who walked with an assistive device (1.41mg/L) (P=.005) and the 12 who walked independently (1.63mg/L) (P=.027). CRP was significantly greater in participants with obesity but was not related to age, smoking, or SCI level and severity. CRP was elevated in participants reporting a urinary tract infection (UTI) or pressure ulcer within a year, but adjustment for this did not account for the elevated CRP in motorized wheelchair users.

Conclusions

These results suggest that CRP in chronic SCI is independently related to locomotive mode, BMI, and a history of pressure ulcers and UTI. It is suggested that future studies in SCI investigate whether modifying these factors influence systemic inflammation and cardiovascular health.     

Psychologic Factors and Risk of Mortality After Spinal Cord Injury

Krause JS, Carter R, Zhai Y, Reed K. Psychologic factors and risk of mortality after spinal cord injury.

Objective

To identify the association of 2 distinct psychologic constructs, personality and purpose in life (PIL), with risk of early mortality among persons with spinal cord injury (SCI).

Design

Prospective cohort study with health data collected in late 1997 and early 1998 and mortality status ascertained in December 2005.

Setting

A large rehabilitation hospital in the southeastern United States.

Participants

Adults (N=1386) with traumatic SCI, at least 1 year postinjury.

Interventions

Not applicable.

Main Outcome Measures

We first evaluated the significance of a single psychologic predictor (a total of 6 scales) while controlling for biographic and injury predictors using Cox proportional hazards modeling and subsequently built a comprehensive model based on an optimal group of psychologic variables.

Results

There were a total of 224 (16.2%) observed deaths in the full sample. The total number of deaths was reduced to 164 in the final statistical model (of 1128 participants) because of missing data. All 6 psychologic factors were statistically significant in the model that was adjusted for biographic and injury factors, whereas only 3 psychologic factors were retained in the final comprehensive model, including 2 personality scales (Impulsive Sensation Seeking, Neuroticism-Anxiety) and the PIL scale. The final comprehensive model only modestly improved the overall prediction of survival compared with the model with only biographic and injury variables, because the pseudo-R² increased from 0.121 to 0.129, and the concordance increased from 0.730 to 0.747.

Conclusions

The results affirm the importance of psychologic factors in relation to survival after SCI.     

Updating the Minimal Important Difference for Six-Minute Walk Distance in Patients With Chronic Obstructive Pulmonary Disease

Holland AE, Hill CJ, Rasekaba T, Lee A, Naughton MT, McDonald CF. Updating the minimal important difference for six-minute walk distance in patients with chronic obstructive pulmonary disease.

Objective

To establish the minimal important difference (MID) for the six-minute walk distance (6MWD) in persons with chronic obstructive pulmonary disease (COPD).

Design

Analysis of data from an observational study using distribution- and anchor-based methods to determine the MID in 6MWD.

Setting

Outpatient pulmonary rehabilitation program at 2 teaching hospitals.

Participants

Seventy-five patients with COPD (44 men) in a stable clinical state with mean age 70 years (SD 9y), forced expiratory volume in one second 52% (SD 21%) predicted and baseline walking distance 359 meters (SD 104m).

Interventions

Not applicable.

Main Outcome Measures

Participants completed the six-minute walk test before and after a 7-week pulmonary rehabilitation program. Participants and clinicians completed a global rating of change score while blinded to the change in 6MWD.

Results

The mean change in 6MWD in participants who reported themselves to be unchanged was 17.7 meters, compared with 60.2 meters in those who reported small change and 78.4 meters in those who reported substantial change (P=.004). Anchor-based methods identified an MID of 25 meters (95% confidence interval 20-61m). There was excellent agreement with distribution-based methods (25.5-26.5m, κ=.95). A change in 6MWD of 14% compared with baseline also represented a clinically important effect; this threshold was less sensitive than for absolute change (sensitivity .70 vs .85).

Conclusions

The MID for 6MWD in COPD is 25 meters. Absolute change in 6MWD is a more sensitive indicator than percentage change from baseline. These data support the use of 6MWD as a patient-important outcome in research and clinical practice.     

Shoulder ultrasound abnormalities, physical examination findings, and pain in manual wheelchair users with spinal cord injury

Brose SW, Boninger ML, Fullerton B, McCann T, Collinger JL, Impink BG, Dyson-Hudson TA. Shoulder ultrasound abnormalities, physical examination findings, and pain in manual wheelchair users with spinal cord injury.

Objectives

To investigate the presence of ultrasound (US) abnormalities in manual wheelchair users with spinal cord injury (SCI) using a quantitative Ultrasound Shoulder Pathology Rating Scale (USPRS). To investigate physical examination (PE) findings using a quantitative Physical Examination of the Shoulder Scale (PESS), and to obtain data about pain and other subject characteristics such as age, years with SCI, and weight.

Design

Case series.

Setting

National Veterans' Wheelchair Games 2005 and 2006.

Participants

Volunteer sample of manual wheelchair users with SCI participating in the National Veterans' Wheelchair Games.

Interventions

Not applicable.

Main Outcome Measures

Presence of relationships between US findings, PE findings, pain, and subject characteristics.

Results

The USPRS correlated with age, duration of SCI, and weight (all P<.01), and showed a positive trend with the total Wheelchair User's Shoulder Pain Index (WUSPI) score (r=.258, P=.073). Several US findings related to presence of PE findings for specific structures. The PESS score correlated with the WUSPI (r=.679, P<.001) and duration of SCI (P<.05). The presence of untreated shoulder pain that curtailed activity was noted in 24.5% of subjects, and this was related to increased WUSPI scores (P=.002).

Conclusions

PE and US abnormalities are common in manual wheelchair users with SCI. The USPRS and PESS demonstrated evidence for external validity and hold promise as research tools. Untreated shoulder pain is common in manual wheelchair users with SCI, and further investigation of this pain is indicated.     

Posttraumatic Stress Disorder and Spinal Cord Injury

Krause JS, Saunders LL, Newman S. Posttraumatic stress disorder and spinal cord injury.

Objectives

To identify the prevalence of posttraumatic stress disorder (PTSD) after spinal cord injury (SCI) in a sample averaging over 2 decades postinjury at assessment. Related objectives are to confirm the factor structure, compare subscales with those reported in a nonclinical sample, and identify the relationship of PTSD with depression.

Design

Survey.

Setting

A medical university in the Southeastern United States.

Participants

Participants were initially identified through specialty hospitals in the Midwest and Southeastern United States. A cohort of adults (N=927) with traumatic SCI of at least 1 year duration at enrollment in 2002 to 2003 and a minimum of 7 years at the time of assessment completed the study materials.

Interventions

Not applicable.

Main Outcomes Measures

PTSD was measured by the Purdue Posttraumatic Stress Disorder Scale-Revised, and depression was measured by the Patient Health Questionnaire 9-item.

Results

PTSD was reported by less than 10% of the participants. Item endorsement decreased as a function of years postinjury, primarily because of low rates of endorsement among those 21 or more years postinjury. Confirmatory factor analysis did not result in an acceptable fit for subscales, item sets, or factors previously reported in the literature. Participants scored higher than a nonclinical sample (reported in the literature) on the arousal and avoidance subscales but lower on the re-experiencing subscale. Item endorsements were lower for the first set of items that relate directly to the SCI itself, with the highest item endorsement for “have difficulty remembering important aspects of event.” PTSD rarely occurred in the absence of a depressive disorder.

Conclusions

PTSD does not appear to be highly prevalent in long-term SCI survivors, and endorsement of items related to re-experiencing and even recalling the injury are rare. Because SCI often is accompanied by mild traumatic brain injury, difficulty recalling the event may have an organic rather than psychologic component.     

Provider Perspectives on Soldiers With New Spinal Cord Injuries Returning From Iraq and Afghanistan

Weaver FM, Burns SP, Evans CT, Rapacki LM, Goldstein B, Hammond MC. Provider perspectives on soldiers with new spinal cord injuries returning from Iraq and Afghanistan.

Objective

The military conflicts in Iraq and Afghanistan have resulted in many soldiers returning with serious combat injuries, including spinal cord injuries (SCIs). The purpose of this study was to query providers regarding any unique problems or needs in a cohort of these soldiers treated in Veterans Health Administration (VHA) SCI Centers.

Design

Semistructured questionnaire.

Setting

Seventeen VHA SCI Centers.

Participants

Thirty-eight providers, including physicians, nurses, therapists, social workers, and psychologists who volunteered to return completed questionnaires.

Interventions

Not applicable.

Main Outcome Measures

Identification of medical and psychosocial issues, rehabilitation delays, therapy and vocational needs, social support, and discharge planning.

Results

Providers identified several injuries and conditions beyond SCI that were experienced by these soldiers including fractures, pressure ulcers, traumatic brain injuries, posttraumatic stress disorder, and resistant infections. Rehabilitation was often delayed because these problems needed to be addressed first. Soldiers' family and friends provide considerable support. Vocational needs include use of technology, especially computers; education; and participation in sports. Although most return to the community after discharge, many soldiers are still active duty, and some return to military base housing.

Conclusions

Combat soldiers returning with SCI often have additional medical and psychosocial problems that require appropriate and timely intervention. They have strong support from family and friends and are motivated to integrate back into the community after discharge.     

Asymptomatic median mononeuropathy among men with chronic paraplegia

Liang H-W, Wang Y-H, Pan S-L, Wang TG, Huang T-S. Asymptomatic median mononeuropathy among men with chronic paraplegia.

Objectives

To compare electrophysiologic abnormalities of the median nerve in asymptomatic paraplegic subjects and able-bodied controls and to examine the influence of personal factors on these parameters.

Design

Cross-sectional survey.

Setting

University hospital.

Participants

Forty-seven men with paraplegia and 36 able-bodied controls underwent nerve conduction studies on both upper limbs. All were free of hand numbness in the past month, diabetic mellitus, or neuromusculoskeletal injuries to the upper limbs.

Interventions

Not applicable.

Main Outcome Measure

Nerve conduction studies of the bilateral median and ulnar nerves.

Results

Although the 2 groups were of comparable age and had a similar body mass index (BMI), the subjects with paraplegia had a significantly higher proportion of asymptomatic median mononeuropathy than the controls (25.5% vs 5.6%, P=.02). The spinal cord injury (SCI) group had a prolonged median distal latency and a slowed digit-wrist sensory nerve conduction velocity. Multivariate general linear model analysis showed that prolonged motor and sensory latencies of the median nerve were associated with the SCI group and with greater BMI.

Conclusions

The asymptomatic subjects with paraplegia had a significantly higher frequency of median mononeuropathy than the able-bodied controls. There was also an association between BMI and distal latency of the median nerve.     

Determinants of utilization of physical rehabilitation services for persons with chronic and disabling conditions: an exploratory study

Elrod CS, DeJong G. Determinants of utilization of physical rehabilitation services for persons with chronic and disabling conditions: an exploratory study.

Objective

To determine which variables influence the receipt of physical rehabilitation services (ie, physical, occupational, speech therapy) for a population of people with chronic and disabling conditions.

Design

A convenience sample of 502 adults with cerebral palsy (CP), multiple sclerosis (MS), and spinal cord injury (SCI), drawn from diverse parts of the United States.

Setting

Respondents were surveyed in the general community.

Participants

Persons (91% under the age of 65y) with CP, MS, or SCI who responded to the 1999 component of a national longitudinal survey.

Interventions

Not applicable.

Main Outcome Measures

Self-reported need for physical rehabilitation services. Bivariate and multivariate analyses were used to examine variables that influenced utilization of services.

Results

Some 53% of respondents did not receive self-reported needed physical rehabilitation services. Respondents who had Medicaid were more likely than those with Medicare or private insurance to receive physical rehabilitation services. Respondents having a lower household income and poorer health were less likely to receive services.

Conclusions

Our findings indicate that health care funding sources provide widely disparate coverage for physical rehabilitation services to persons with 3 specific chronic and disabling conditions. Policy-makers and health plan administrators should re-evaluate their coverage of physical rehabilitation services designed to enhance quality of life and reduce the burden of lost independence.     

Validity and Reliability of Assessment Tools for Measuring Unsupported Sitting in People With a Spinal Cord Injury

Boswell-Ruys CL, Sturnieks DL, Harvey LA, Sherrington C, Middleton JW, Lord SR. Validity and reliability of assessment tools for measuring unsupported sitting in people with a spinal cord injury.

Objectives

To develop simple tests to assess the abilities of people with spinal cord injury (SCI) to sit unsupported and to assess the construct validity and test-retest reliability of these tests.

Design

Cross-sectional comparisons, convenience sample.

Setting

Biomechanical laboratory.

Participants

People (N=30) with SCI between the C6 and the L2 level of 2 months to 37 years duration before assessment. The sample was stratified by impairment level (at T8) and time since injury (1y postinjury).

Interventions

Not applicable.

Main Outcome Measures

On 2 separate occasions, participants performed tests that measured the distance of upper-body sway and maximal torso leaning, errors made during a coordinated stability task, timed dressing/undressing of the upper body and alternating arm reaching, and percentage change in seated upper body/arm reaching.

Results

All tests showed good construct validity in that they distinguished between participants with higher (C6-T7) and lower (T8-L2) level impairments (P<.05) and between participants with acute (≤1y) and chronic (>1y) lesions (P<.05). The tests also showed good to excellent test-retest reliability (intraclass correlation coeffiecient_3,1 range, .51-.91).

Conclusions

These simple and quick-to-administer tests have both construct validity and test-retest reliability. They would be appropriate for research and clinical purposes to quantify the abilities of people with SCI to sit unsupported.     

The effectiveness of progressively increasing stimulation frequency and intensity to maintain paralyzed muscle force during repetitive activation in persons with spinal cord injury

Chou L-W, Lee SC, Johnston TE, Binder-Macleod SA. The effectiveness of progressively increasing stimulation frequency and intensity to maintain paralyzed muscle force during repetitive activation in persons with spinal cord injury.

Objective

To compare the effectiveness of progressively increasing stimulation intensity, progressively increasing frequency, or progressively increasing both frequency and intensity on paralyzed quadriceps femoris muscle force maintenance during repetitive activation.

Design

Factorial design with different stimulation protocols as independent variables.

Setting

A muscle performance laboratory.

Participants

People (N=8) with spinal cord injury (SCI) (age, 14.63±1.77y).

Interventions

Not applicable.

Main Outcome Measure

Number of contractions when the peak force was 90% or more of a subject's maximal twitch force.

Results

The protocol involving progressively increasing stimulation intensity and then frequency generated more successful contractions (189.88±53.33) than progressively increasing the frequency followed by intensity (122.75±26.56 contractions). Regardless of the order, progressively increasing both intensity and frequency generated more successful contractions than progressively increasing intensity (97 contractions) or frequency (62 contractions) alone.

Conclusions

Our findings suggest that during repetitive electric activation, progressively increasing both stimulation frequency and intensity can produce more successful contractions than progressively increasing only frequency or intensity. These findings can help researchers and clinicians design more effective stimulation protocols for persons with SCI during functional electric stimulation applications.     

Cardiovascular and metabolic responses during functional electric stimulation cycling at different cadences

Fornusek C, Davis GM. Cardiovascular and metabolic responses during functional electric stimulation cycling at different cadences.

Objective

To determine the influence of pedaling cadence on cardiorespiratory responses and muscle oxygenation during functional electric stimulation (FES) leg cycling.

Design

Repeated measures.

Setting

Laboratory.

Participants

Nine subjects with T4 through T10 spinal cord injury (SCI) (American Spinal Injury Association grade A).

Interventions

FES cycling was performed at pedaling cadences of 15, 30, and 50 revolutions per minute (rpm).

Main Outcome Measures

At each cadence, heart rate, oxygen uptake, and cardiac output were recorded during 35 minutes of cycling. Near infrared spectroscopy was used to quantify quadriceps muscle oxygenation.

Results

All pedaling cadences induced similar elevations in cardiorespiratory metabolism, compared with resting values. Higher average power output was produced at 30rpm (8.2±0.7W, P<.05) and 50rpm (7.9±0.5W, P<.05) compared with 15rpm (6.3±0.6W). Gross mechanical efficiency was significantly higher (P<.05) at 30 and 50rpm than at 15rpm. Quadriceps muscle oxygenation did not differ with pedaling cadences.

Conclusions

Cardiorespiratory responses and muscle metabolism adjustments during FES leg cycling were independent of pedal cadence. FES cycling at a cadence of 50rpm may not confer any advantages over 30 or 15rpm for cardiovascular fitness promotion in persons with SCI.     

Comparison of Single Bout Effects of Bicycle Training Versus Locomotor Training on Paired Reflex Depression of the Soleus H-Reflex After Motor Incomplete Spinal Cord Injury

Phadke CP, Flynn SM, Thompson FJ, Behrman AL, Trimble MH, Kukulka CG. Comparison of single bout effects of bicycle training versus locomotor training on paired reflex depression of the soleus H-reflex after motor incomplete spinal cord injury.

Objective

To examine paired reflex depression changes post 20-minute bout each of 2 training environments: stationary bicycle ergometer training (bicycle training) and treadmill with body weight support and manual assistance (locomotor training).

Design

Pretest-posttest repeated-measures.

Setting

Locomotor laboratory.

Participants

Motor incomplete SCI (n=12; mean, 44±16y); noninjured subjects (n=11; mean, 30.8±8.3y).

Intervention

All subjects received each type of training on 2 separate days.

Main Outcome Measure

Paired reflex depression at different interstimulus intervals (10s, 1s, 500ms, 200ms, and 100ms) was measured before and after both types of training.

Results

(1) Depression was significantly less post-SCI compared with noninjured subjects at all interstimulus intervals and (2) post-SCI at 100-millisecond interstimulus interval: reflex depression significantly increased postbicycle training in all SCI subjects and in the chronic and spastic subgroups (P<.05).

Conclusions

Phase-dependent regulation of reflex excitability, essential to normal locomotion, coordinated by pre- and postsynaptic inhibitory processes (convergent action of descending and segmental inputs onto spinal circuits) is impaired post-SCI. Paired reflex depression provides a quantitative assay of inhibitory processes contributing to phase-dependent changes in reflex excitability. Because bicycle training normalized reflex depression, we propose that bicycling may have a potential role in walking rehabilitation, and future studies should examine the long-term effects on subclinical measures of reflex activity and its relationship to functional outcomes.