Spinal Cord-injured Individuals Research Articles

Increased physical fitness after 4-week training on a new hybrid FES-cycle in persons with spinal cord injury

The purpose of the present study was to determine the effect of a 4-week training program on a newly developed hybrid functional electrical stimulation (FES)-cycle on physical fitness in spinal cord-injured (SCI) individuals. Ten SCI individuals (age 23-53 years, lesion level range T3-T11) participated and trained 8-12 times in 4 weeks on the hybrid FES-cycle (voluntary arm-contractions and stimulation of leg muscles). Leg volume was measured. During a graded hybrid exercise test, peak oxygen consumption (VO2peak), peak power output (POpeak) and power of the legs (dP) were measured pre and post training. Upper leg volume increased significantly (8.5% (p =0 .047) and 8.3% (p =0 .018) for the right and left leg, respectively). POpeak and VO2peak increased 11.7% (p =0 .012) and 9.3% (p =0 .015), respectively. There was no significant difference in dP between pre and post training. After only 4 weeks of training, considerable training effects were observed, which are comparable to longer training studies in literature. The results of this study indicate that hybrid training on the new hybrid FES-cycle is an appropriate training method for individuals with a spinal cord injury to increase physical fitness.

Extremity Fracture Management in Acute Spinal Cord Injury

Extremity fracture management in acute spinal cord-injured individuals can be summarized by the following principles. Fracture management should be based on the belief that the individual, regardless of neurologic dysfunction, will ambulate in his or her lifetime. Nondisplaced, low-energy fractures may be managed nonoperatively. Upper extremity fracture care should follow general orthopedic principles with a tendency toward surgical fixation. Most lower extremity fractures, including the hip, should undergo open reduction and internal fixation (ORIF).

Preserved contribution of nitric oxide to baseline vascular tone in deconditioned human skeletal muscle

Deconditioning is a risk factor for cardiovascular disease. Exercise reduces this risk, possibly by improving the vascular endothelial nitric oxide (NO) pathway. The effect of deconditioning on the NO pathway is largely unknown. This study was designed to assess baseline NO availability in the leg vascular bed after extreme, long-term deconditioning (spinal cord-injured individuals, SCI) as well as after moderate, short-term deconditioning (4 weeks of unilateral lower limb suspension, ULLS). For this purpose, seven SCI were compared with seven matched controls. Additionally, seven healthy subjects were studied pre- and post-ULLS. Leg blood flow was measured by venous occlusion plethysmography at baseline and during infusion of 5 incremental dosages of N(G)-monomethyl-L-arginine (L-NMMA) into the femoral artery. Sodium nitroprusside (SNP) was infused to test vascular responsiveness to NO. Baseline leg vascular resistance tended to be higher in SCI compared with controls (37+/-4 versus 31+/-2 arbitrary units (AU), P=0.06). Deconditioning altered neither the vasoconstrictor response to L-NMMA (increase in resistance in SCI versus controls: 102+/-33% versus 69+/-9%; pre- versus post-ULLS: 95+/-18% versus 119+/-15%), nor the vascular responsiveness to NO. In conclusion, two human in vivo models of deconditioning show a preserved baseline NO availability in the leg skeletal muscle vascular bed.

Decreased Contribution Of Endothelin To Vascular Tone In Spinal Cord-injured Individuals After Training

Increased levels of endothelin (ET), an endogenous peptide with profound vasoconstrictor actions that mediates vascular tone, were reported in conditions characterized by increased vascular tone. Also extreme inactivity, such as spinal cordinjury (SCI), leads to an increased vascular tone and elevated levels of ET. PURPOSE To determine the contribution of ET to the increased vascular tone in SCI individuals and the effect of hybrid FES-training on the contribution. METHODS The contribution of ET to basal vascular tone was assessed in 8 SCI individuals (age 38 ± 9 years) by local intra-arterial (right femoral artery) administration of selective ETA- and ETB-receptor antagonist; BQ-123 and BQ-788, respectively. Bilateral thigh blood flow was measured with plethysmography and vascular resistance was calculated as mean arterial pressure/blood flow. 7 SCI individuals followed the same procedure after 6 weeks of hybrid functional electrical stimulation (FES) cycling (12 sessions). RESULTS The ET-blockade resulted in a significantly higher blood flow and right/left-ratio (response in infused leg divided by non-infused leg) and lower vascular resistance of the infused leg (RM ANOVA; p<0.001). After training, resting blood flow was elevated (T-test; p=0.048) and the effect of ET-blocking on blood flow (RM ANOVA; p=0.08) and right/left-ratio (RM ANOVA; p=0.01) was attenuated after training compared to before. Vascular resistance did not change significantly. DISCUSSION The different responses to ET-receptor blocking before and after training emphasizes the altered contribution of ET to basal vascular tone. The marked differences can be caused by a down-regulation of ET-release, its receptors, or ET-sensitivity. CONCLUSION (1) Endothelin seems to contribute to the increased vascular tone in spinal cord-injured individuals, and (2) hybrid FES-cycling decreases the contribution of ET to baseline vascular tone.

Decreased Contribution Of Endothelin To Vascular Tone In Spinal Cord-injured Individuals After Training

Increased levels of endothelin (ET), an endogenous peptide with profound vasoconstrictor actions that mediates vascular tone, were reported in conditions characterized by increased vascular tone. Also extreme inactivity, such as spinal cordinjury (SCI), leads to an increased vascular tone and elevated levels of ET. PURPOSE To determine the contribution of ET to the increased vascular tone in SCI individuals and the effect of hybrid FES-training on the contribution. METHODS The contribution of ET to basal vascular tone was assessed in 8 SCI individuals (age 38 ± 9 years) by local intra-arterial (right femoral artery) administration of selective ETA- and ETB-receptor antagonist; BQ-123 and BQ-788, respectively. Bilateral thigh blood flow was measured with plethysmography and vascular resistance was calculated as mean arterial pressure/blood flow. 7 SCI individuals followed the same procedure after 6 weeks of hybrid functional electrical stimulation (FES) cycling (12 sessions). RESULTS The ET-blockade resulted in a significantly higher blood flow and right/left-ratio (response in infused leg divided by non-infused leg) and lower vascular resistance of the infused leg (RM ANOVA; p<0.001). After training, resting blood flow was elevated (T-test; p=0.048) and the effect of ET-blocking on blood flow (RM ANOVA; p=0.08) and right/left-ratio (RM ANOVA; p=0.01) was attenuated after training compared to before. Vascular resistance did not change significantly. DISCUSSION The different responses to ET-receptor blocking before and after training emphasizes the altered contribution of ET to basal vascular tone. The marked differences can be caused by a down-regulation of ET-release, its receptors, or ET-sensitivity. CONCLUSION (1) Endothelin seems to contribute to the increased vascular tone in spinal cord-injured individuals, and (2) hybrid FES-cycling decreases the contribution of ET to baseline vascular tone.

Prediction Equations Overestimate Resting Metabolic Rate of Spinal Cord Injured Athletes

Decreased RMR is associated with an increased risk for obesity in the spinal cord injured (SCI) population. Resting metabolic rate (RMR) prediction equations overestimate RMR of people with SCI. Decreased RMR in SCI individuals is thought to be due to decreased physical activity and reductions in fat free mass (FFM). PURPOSE To determine RMR in SCI athletes, and compare measured RMR with the Harris-Benedict (1919), Cunningham et al. (1980) and Buchholz et al. (2003) prediction equations. METHODS RMR and FFM were measured in 11 college-aged (21.1±2.2 y), paraplegic wheelchair athletes (5M, 6F) of which 5 had sustained SCI from trauma (1M, 4F), 4 had spina bifida (3M, 1F), and 2 (1M, 1F) from other causes. Injury levels were between T3-L5. Average time since injury was 17.6 y (range = 10 to 25 y). Athletes were members of a national team and/or currently participated in the university's wheelchair athletics program, which includes 12 hrs/wk of sport specific practice and 3 weight-lifting sessions/wk. RMR was measured in early morning in a fasting state on an out-patient basis, using indirect calorimetry (Deltatrac II Metabolic Monitor, Sensormedics). Body composition was measured using DXA (Hologic QDR-4500A). Cunningham et al. equation [RMR (kcal) = 501.6 + 21.6 (FFM, kg)] has been found to be accurate for highly active people. Buchholz et al. equation [RMR (kJ/d) = 10682–1238(In age) - 521(sex = 0 for men, = 1 for women) - 24(height, cm) +87(FFM, kg)] was developed using paraplegics. RESULTS Mean height and weight were lower than expected for athletes (M±SD: M = 171.8±7.2 cm, 68.3±8.1 kg and F = 152.2±3.4 cm, 50.0±7.5 kg). Expectedly, relative body fat for men and women was higher than typical for athletes (M = 22.6±7.5%, F = 32.7±3.9%) partially due to a reduction in FFM (M = 52.1±6.4 kg, F = 33.3±4.0 kg). Harris-Benedict predicted RMR was significantly higher than actual RMR (1501±236 vs. 1337±291 kcal, p = 0.001) with males having a higher measured RMR than females (1598±187 kcal vs. 1120±129 kcal) as expected due to FFM differences. When prediction equations accounted for FFM using Cunningham et al (1980) and SCI status using Buchholz et al. (2003), RMR was still significantly overestimated (1406±237 kcal, p = 0.039; 1530±223 kcal, p < 0.001, respectively). CONCLUSIONS RMR prediction equations overestimate RMR in people with SCI, an effect that is not ameliorated by high-level participation in physical activity. Further research is needed to determine RMR of physically active SCI and sedentary SCI individuals toward the end of improving obesity prevention initiatives in this population at increased risk for obesity-related diseases. Supported by: UIUC MJ Neer Grant

Effect Of Arm Powered Passive Leg Cycling On Heart Rate Variability In Spinal Cord Injured

Heart rate variability (HRV) has emerged as a reproducible, non-invasive technique to assess autonomic influences on the heart. Studies have shown that exercise in ablebodied individuals decreases high frequency (HF) and low frequency (LF) components of HRV. The effect of arm powered passive leg exercise on HRV in spinal cord injured (SCI) individuals is not known. PURPOSE The purpose of this investigation was to determine the effects of an acute bout of exercise on cardiac autonomic function in SCI as indicated by time and frequency-domain measures of HRV. METHODS HRV values were obtained (Welch Allyn CardioPerfectTM, Skareateles Falls, NY) during 300 sec recordings from three paraplegic and two tetraplegic SCI subjects (mean age: 33.4 ± 20.1 yrs, range 21–69 yrs) at rest (W0) and immediately following an acute bout of passive exercise on the PsycleTM (Intellifit, Inc., Wichita Falls, TX) at a target heart rate of 65% of age-adjusted maximum (W1). Frequency domain measures were calculated by Fast Fourier Transform including high frequency (HF, 0.15–0.4 Hz), low frequency (LF, .04−.15 Hz), and the ratio of LF to HF (LF/HF). A 2X2 ANOVA was used to identify changes in LF, HF, LF/HF and the raw time domain data obtained from R-R intervals from W0 to W1. RESULTS No significant difference (P >.05) was determined between paraplegic and tetraplegic individuals on criterion measures from W0 to W1. Arm powered passive leg cycling was accomplished for 35 min at 35±17.5 rpm, for 1227±663 total revolutions, at 9.7±6.8 W, and at heart rates of 122±22 bpm. Mean HF values (ms2) were reduced from 423±427 to 30±30 [F 1,6) = 12.1, p< 0.05] for W0 and W1, respectively. Mean LF values (ms2) were 692±841 and 104±142 [F(1,6) = 2.3, P>.05), respectively for W0 and W1. Mean LF/HF values were 1.8±1.3 and 2.7±1.3 [F (1,6) = 2.4, P>.05) for W0 and W1, respectively. Mean R-R intervals were reduced from 810±60 to 655±109 ms [F (1,6) = 7.8, p<.05] for W0 and W1, respectively. Although LF did not reach statistical significance, the tendencies of reduced HF and LF values with exercise is consistent with reported responses from able-bodied subjects. CONCLUSION These data suggest that arm powered passive leg cycling produces a shift in autonomic influences on the heart of spinal cord injured.

Effect Of Arm Powered Passive Leg Cycling On Heart Rate Variability In Spinal Cord Injured

Heart rate variability (HRV) has emerged as a reproducible, non-invasive technique to assess autonomic influences on the heart. Studies have shown that exercise in ablebodied individuals decreases high frequency (HF) and low frequency (LF) components of HRV. The effect of arm powered passive leg exercise on HRV in spinal cord injured (SCI) individuals is not known. PURPOSE The purpose of this investigation was to determine the effects of an acute bout of exercise on cardiac autonomic function in SCI as indicated by time and frequency-domain measures of HRV. METHODS HRV values were obtained (Welch Allyn CardioPerfectTM, Skareateles Falls, NY) during 300 sec recordings from three paraplegic and two tetraplegic SCI subjects (mean age: 33.4 ± 20.1 yrs, range 21–69 yrs) at rest (W0) and immediately following an acute bout of passive exercise on the PsycleTM (Intellifit, Inc., Wichita Falls, TX) at a target heart rate of 65% of age-adjusted maximum (W1). Frequency domain measures were calculated by Fast Fourier Transform including high frequency (HF, 0.15–0.4 Hz), low frequency (LF, .04−.15 Hz), and the ratio of LF to HF (LF/HF). A 2X2 ANOVA was used to identify changes in LF, HF, LF/HF and the raw time domain data obtained from R-R intervals from W0 to W1. RESULTS No significant difference (P >.05) was determined between paraplegic and tetraplegic individuals on criterion measures from W0 to W1. Arm powered passive leg cycling was accomplished for 35 min at 35±17.5 rpm, for 1227±663 total revolutions, at 9.7±6.8 W, and at heart rates of 122±22 bpm. Mean HF values (ms2) were reduced from 423±427 to 30±30 [F 1,6) = 12.1, p< 0.05] for W0 and W1, respectively. Mean LF values (ms2) were 692±841 and 104±142 [F(1,6) = 2.3, P>.05), respectively for W0 and W1. Mean LF/HF values were 1.8±1.3 and 2.7±1.3 [F (1,6) = 2.4, P>.05) for W0 and W1, respectively. Mean R-R intervals were reduced from 810±60 to 655±109 ms [F (1,6) = 7.8, p<.05] for W0 and W1, respectively. Although LF did not reach statistical significance, the tendencies of reduced HF and LF values with exercise is consistent with reported responses from able-bodied subjects. CONCLUSION These data suggest that arm powered passive leg cycling produces a shift in autonomic influences on the heart of spinal cord injured.

Leg vascular resistance increases during head-up tilt in paraplegics

Despite loss of centrally mediated sympathetic vasoconstriction to the legs, spinal cord-injured individuals cope surprisingly well with an orthostatic challenge. This study assessed changes in leg vascular resistance following head-up tilt in healthy (C) and in paraplegic (P) individuals. After 10 min of supine rest, subjects were tilted 30 degrees head-up. Mean arterial pressure (MAP) and total peripheral resistance (TPR) increased in C (MAP from 76.7 +/ -6.6 mmHg to 80.6 +/- 8.2 mmHg; TPR from 1.12 +/- 0.26 AU to 1.19 +/ -0.31 AU) while both remained unchanged in P. Echo Doppler ultrasound determined red blood cell velocity in the femoral artery, which decreased (P from 18.9+/-6.2 cm/s to 12.5 +/- 4.5 cm/s, P = 0.001; C from 16.3 +/- 6.2 cm/s to 10.8 +/- 5.0 cm/s, P = 0.001) and leg vascular resistance, which increased (P from 402 +/- 137 AU to 643 +/- 274 AU, P = 0.001; C from 238 +/- 68 AU to 400 +/- 122 AU, P = 0.003) from supine to upright. The present study shows that independent of supraspinal sympathetic control, humans are able to increase leg vascular resistance and maintain blood pressure during head-up tilt.

Kinematic analyses of semireclined leg cycling in able-bodied and spinal cord injured individuals

Retrospective descriptive study. To evaluate the leg kinematics and motion characteristics within able-bodied (AB) and spinal cord injured (SCI) individuals during stationary semireclined cycling. Functional Performance Laboratory, Connecticut, USA. Three SCI and three AB subjects participated in steady-state leg pedaling (50 revolutions per minute). The SCI group participated in electrical stimulation (FES)-induced cycling at resistances of 0, 6.25, and 12.5 Watts (W). The AB group cycled on the same ergometer without FES at resistances of 0, 60, and 120 W. Motion capture analysis recorded joint angular position, velocity, and acceleration at hip, knee, and ankle. Joint kinematics of hip, knee, and ankle were measured during steady-state leg cycling and comparisons were made between AB and SCI subjects as resistance proportionally and relatively increased. Intrasubject hip and knee movement patterns showed minimal variability across resistance levels. Comparisons between AB and SCI subjects showed that the hip and knee kinematics were very similar at all resistance levels. However, ankle movement patterns appeared to increase in variability (increased dorsiflexion) with increased resistance level in AB subjects and less so with SCI subjects. Overall, the ankle kinematics for AB and SCI subjects were dissimilar at resistance levels greater than zero. The joint kinematics of the hip, knee, and ankle were found to be periodic, but the differences in ankle kinematics in AB and SCI subjects suggest more emphasise should be placed on the current design of the bike-pedal and subject-specific seat configurations.

Does peripheral nerve degeneration affect circulatory responses to head-up tilt in spinal cord-injured individuals?

Despite the loss of centrally mediated sympathetic vasoconstriction, spinal cord-injured (SCI) individuals cope surprisingly well with orthostatic challenges. In the pathophysiology of this intriguing observation spinal sympathetic-, veno-arteriolar-(VAR), and myogenic reflexes seem to play a role. The purpose of this study was to assess whether central (stroke volume, heart rate, blood pressure and total peripheral resistance) and peripheral (leg blood flow, leg vascular resistance and femoral arterial diameter) hemodynamic responses to head-up tilt are different in two groups of SCI patients, i. e., SCI individuals with upper motor neuron lesions (who have spinal reflexes, VAR and myogenic reflexes) (U; n=6) and those with lower motor neuron lesion (who have no spinal reflexes, perhaps no VAR due to nerve degeneration, but intact myogenic reflexes) (L; n=5). Ten healthy male individuals served as controls (C) (normal supraspinal sympathetic control and presence of all reflexes). After 10 min supine rest all individuals were tilted to 30 degrees head-up tilt. Red blood cell velocity (measured by echo Doppler ultrasound) in the femoral artery decreased and vascular resistance increased significantly in all three groups in the upright position compared with supine. Mean arterial pressure (MAP) remained unchanged in U and L and increased significantly in C in the upright versus supine position. The present study shows that all SCI individuals were able to maintain MAP by increasing leg vascular resistance during head-up tilt, despite nerve degeneration in L and lack of centrally mediated sympathetic control in all SCI individuals. Results of the present study suggest that not spinal reflexes but local (myogenic) reflex activity plays a pivotal role in peripheral vascular responses upon head-up tilt when central control mechanisms fail.

The intralimb coordination of the flexor reflex response is altered in chronic human spinal cord injury

The current study compared the intralimb coordination of flexor reflex responses in spinal intact and complete chronic spinal cord injured (SCI) individuals. Noxious electrocutaneous stimulation was applied at the apex of the medial arch of the foot (50 mA, 500 Hz, 1 ms pulse width, 20 ms) in 21 complete chronic SCI and 19 spinal intact volunteers and the flexor reflex response was quantified by measuring the isometric joint torques at the ankle, knee and hip. The results showed that SCI individuals had significantly smaller peak knee and hip joint flexion torques, often exhibited a net knee extension torque, and produced a much smaller hip joint flexion torque during the flexor reflex response in contrast to the spinal intact individuals. The latency of the reflex response, measured from the tibialis anterior electromyogram, was comparable in both test populations. These findings indicate that the intralimb coordination of the flexor reflex response of chronic complete SCI individuals is altered, possibly reflecting a functional reorganization of the flexion pathways of the spinal cord.

Ultrasound: a reproducible method to measure conduit vein compliance

Classical venous occlusion plethysmography (VOP) of the leg, often used to assess venous compliance, measures properties of the whole calf, including volume changes at the arterial side and the interstitial fluid accumulation that occurs as a result of the enhanced capillary pressure during venous occlusion. We present an ultrasound technique to measure the compliance of one major conduit vein in the leg. Ultrasound measurements of the popliteal vein were compared with classical VOP measurements, which were performed simultaneously in one subject. Six healthy individuals were measured on three occasions to assess short- and long-term reproducibility of the measurements. Six motor complete spinal cord-injured (SCI) individuals were included to compare venous compliance in subjects with known pathological changes of the venous system with controls. The ultrasound and VOP measurements of venous compliance correlated significantly (r(2) = 0.39, P = 0.001). Ultrasound provides reproducible measurements with short- and long-term coefficients of variation ranging from 10 to 15% for popliteal vein compliance and from 2 to 9% for absolute diameters at the different venous pressure steps. In addition, by using ultrasound, we were able to detect an 80% reduction in the compliance of the popliteal vein in SCI individuals compared with controls (P < 0.01). In conclusion, ultrasound is a suitable and reproducible method to measure conduit vein compliance and provides the possibility to specifically assess compliance of one vein instead of the whole calf.

Vascular Adaptations after 4 Weeks Training with a Hybrid FES-Cycle Ergometer in Spinal Cord-Injured Individuals

Vascular Adaptations after 4 Weeks Training with a Hybrid FES-Cycle Ergometer in Spinal Cord-Injured Individuals

Vascular Adaptations after 4 Weeks Training with a Hybrid FES-Cycle Ergometer in Spinal Cord-Injured Individuals

Vascular Adaptations after 4 Weeks Training with a Hybrid FES-Cycle Ergometer in Spinal Cord-Injured Individuals

Relationship between the duration of paralysis and bone structure: a pQCT study of spinal cord injured individuals

The aim of the present study was to describe bone loss of the separate compartments of trabecular and cortical bone, as well as changes in bone geometry of a large number of spinal cord injured (SCI) individuals. Eighty-nine motor complete spinal cord injured men (24 tetraplegics and 65 paraplegics) with a duration of paralysis of between 2 months and 50 years were included in the study. Distal epiphyses and midshafts of the femur, tibia, and radius were measured by peripheral quantitative computed tomography. The same measurements were performed in a reference group of 21 healthy able-bodied men of the same age range. In the femur and tibia, bone mass, total and trabecular bone mineral density (BMDtot and BMDtrab, respectively) of the epiphyses, as well as bone mass and cortical cross-sectional area of the diaphyses, showed an exponential decrease with time after injury in the spinal cord injured subjects. The decreasing bone parameters reached new steady states after 3–8 years, depending on the parameter. Bone mass loss in the epiphyses was approximately 50% in the femur and 60% in the tibia, while the shafts lost only approximately 35% in the femur and 25% in the tibia. In the epiphyses, bone mass was lost by reducing BMD, while in the shaft bone mass was lost by reducing cortical wall thickness, a process achieved by endosteal resorption advancing at a rate of about 0.25 mm/year within the first 5–7 years after injury. Except for a slight transient decrease in cortical BMD of the femoral and tibial shaft during the first 5 years after the spinal cord lesion, cortical BMD of the spinal cord injured subjects was found to be at reference values. Bone parameters of the radial epiphysis in paraplegic subjects showed no deficits compared to the reference group. Furthermore, a trend for an increased radial shaft diameter suggests periosteal apposition as a consequence of increased loading of the arms.

Preserved flow-mediated dilation in the inactive legs of spinal cord-injured individuals.

The aim of the study was to assess endothelial function, measured by flow-mediated dilation (FMD), in an inactive extremity (leg) and chronically active extremity (arm) within one subject. Eleven male spinal cord-injured (SCI) individuals and eleven male controls (C) were included. Echo Doppler measurements were performed to measure FMD responses after 10 and 5 min of arterial occlusion of the leg (superficial femoral artery, SFA) and the arm (brachial artery, BA), respectively. A nitroglycerine spray was administered to determine the endothelium independent vasodilatation in the SFA. In the SFA, relative changes in FMD were significantly enhanced in SCI compared with C (SCI: 14.1 +/- 1.3%; C: 9.2 +/- 2.3%), whereas no differences were found in the BA (SCI: 12.5 +/- 2.9%; C: 14.2 +/- 3.3%). Because the FMD response is directly proportional to the magnitude of the stimulus, the FMD response was also expressed relative to the shear rate. No differences between the groups were found for the FMD-to-shear rate ratio in the SFA (SCI:0.061 +/- 0.023%/s(-1); C: 0.049 +/- 0.024%/s(-1)), whereas the FMD-to-shear rate ratio was significantly decreased in the BA of SCI individuals (SCI: 0.037 +/- 0.01%/s(-1); C: 0.061 +/- 0.027%/s(-1)). The relative dilatory response to nitroglycerine did not differ between the groups. (SCI: 15.6 +/- 2.0%; C: 13.4 +/- 2.3%). In conclusion, our results indicate that SCI individuals have a preserved endothelial function in the inactive legs and possibly an attenuated endothelial function in the active arms compared with controls.

Quality of life in spinal cord injured individuals and their caregivers during the initial 6 months following rehabilitation.

Addressing quality of life (QOL) issues in the spinal cord injured (SCI) population is imperative as the majority survive their initial injury and longevity now approaches that of the general population. The purpose of this mixed method, descriptive, longitudinal feasibility study was to describe and compare QOL in 10 adult SCI individuals and their family caregivers (FCs) during the initial 6 months following rehabilitation. Instruments used were the SF-36 and two horizontal visual analog scales, one for pain and one for QOL. Participants completed the instruments and a face-to-face in-depth interview at 1-, 3-, and 6-months following inpatient rehabilitation. SCI individuals reported low physical function, role physical (RP), and role emotional (RE) scores on the SF-36, while reporting high general health (GH), mental health and social functioning on the SF-36. FCs reported lower RP, GH and vitality scores, while reporting higher physical functioning and RE scores. On the visual analog scales, persons with SCI reported lower QOL while FCs reported more pain at 3 and 6 months. This study suggests that more work is needed to identify interventions which could enhance QOL during the transition from rehabilitation to home for SCI individuals and their FCs.

The effects of arm cranking exercise and training on platelet aggregation in male spinal cord individuals

Platelet aggregation at rest and in responses to exercise and training were compared between spinal cord injured (SCI) individuals ( N=5) and able-bodied subjects ( N=7). All participants performed arm cranking exercise at 60–65% VO 2peak for 30 min. Venous blood samples were obtained before and after sub-maximal exercise and measured for platelet aggregation using ADP and collagen. To assess the effects of arm cranking training, platelet aggregation was re-measured in all subjects at rest and in response to the sub-maximal arm cranking exercise after 12 weeks of individually supervised training programme. Before training, the resting mean values of platelet aggregation induced by ADP and collagen were not different ( P>0.05) between SCI and able-bodied. However the SCI individuals, but not the able-bodied subjects, exhibited a significantly ( P<0.05) higher maximal platelet aggregation induced by ADP and collagen following sub-maximal arm cranking exercise. Although VO 2peak after training was significantly increased ( P<0.05) in both groups, the resting mean values of platelet aggregation induced with ADP and collagen were not significantly different ( P>0.05) from those observed before training and were not different ( P>0.05) between SCI and able-bodied. Post-training, the SCI individuals, but not able-bodied individuals, exhibited a significant decrease ( P<0.05) in platelet aggregation following sub-maximal arm cranking exercise and this occurred with both ADP and collagen. These results suggest that SCI individuals, but not normal subjects increase their platelet aggregation following sub-maximal arm cranking exercise. Furthermore, arm cranking training in SCI individuals, appears to diminish the percentage of platelet aggregation ex vivo.

Time course of arterial vascular adaptations to inactivity and paralyses in humans.

The aim of the present study was to assess the time course of vascular adaptations to inactivity and paralyses in humans. The spinal cord-injured (SCI) population offers a unique "human model of nature" to assess peripheral vascular adaptations and its time course to extreme inactivity and paralyses. Arterial diameters and red blood cell velocity of the carotid artery (CA), common femoral artery (FA), and brachial artery (BA) were measured using echo Doppler ultrasound. Fifteen SCI persons with lesions varying from 6 wk to 13 months postinjury participated in a cross-sectional study (SCI-CS), 6 SCI individuals were included for longitudinal measurements (SCI-L) at weeks 6, 8, 12, 16, 20, and 24 after the trauma, and 16 able-bodied individuals served as a control group (C). Within 6 wk after the SCI, diameter (SCI-CS: 0.68 +/- 0.09 cm, SCI-L: 0.67 +/- 0.04 cm, C: 0.95 +/- 0.07 cm) and blood flow (SCI-CS: 299 +/- 112 mL x min(-1), SCI-L 279: +/- 52 mL x min(-1), C: 405 +/- 97 mL x min(-1)) of the femoral artery were significantly reduced (P < 0.001), and local femoral wall shear rate was almost doubled in SCI-CS and SC-L compared with C (P < 0.001). No further changes in femoral arterial properties were observed between week 6 and 13 months postinjury in SCI-L as well as SCI-CS. Carotid and brachial artery diameter and flow were similar in SCI and C and did not change between 6 wk and 13 months after the injury. We conclude that the process of vascular adaptations to inactivity and paralyses in humans seems to be largely completed within weeks.