Patrick J. Potter

Leisure time physical activity in a population-based sample of people with spinal cord injury part I: demographic and injury-related correlates.

OBJECTIVES To estimate the number of minutes a day of leisure time physical activity (LTPA) performed by people with chronic spinal cord injury (SCI) and to identify the demographic and injury-related characteristics associated with LTPA in a population-based sample of people with chronic SCI. DESIGN Cross-sectional telephone survey. SETTING General community. PARTICIPANTS Men and women with SCI (N=695). INTERVENTIONS Not applicable. MAIN OUTCOME MEASURES The number of minutes/day of LTPA performed at a mild intensity or greater. RESULTS Respondents reported mean minutes +/- SD of 27.14+/-49.36 of LTPA/d; however, 50% reported no LTPA whatsoever. In a multiple regression analysis, sex, age, years postinjury, injury severity, and primary mode of mobility each emerged as a unique predictor of LTPA. Multiple correspondence analysis indicated that being a man over the age of 34 years and greater than 11 years postinjury was associated with inactivity, while being a manual wheelchair user and having motor complete paraplegia were associated with the highest level of daily LTPA. CONCLUSIONS Daily LTPA levels are generally low in people with SCI. Women, older adults, people with less recent injuries, people with more severe injuries, and users of power wheelchairs and gait aids are general subgroups that may require special attention and resources to overcome unique barriers to LTPA. Specific subgroups may also require targeted interventions.

Greater daily leisure time physical activity is associated with lower chronic disease risk in adults with spinal cord injury

The objective of this study was to examine the relationship between leisure time physical activity (LTPA) and common risk factors for cardiovascular disease (CVD) and type 2 diabetes in community-dwelling adults with chronic spinal cord injury (SCI). LTPA was measured using the Physical Activity Recall Assessment for People with SCI in 76 men and women with chronic (> or =1 year) paraplegia or tetraplegia, living in or near Hamilton, Ontario. Body mass index (BMI), waist circumference, body composition (fat mass (FM) and fat-free mass (FFM)), blood pressure, and biochemical data were collected. Thirty-seven percent (n = 28 participants) were inactive, reporting no LTPA whatsoever, and were compared with an equal-sized group consisting of the most active study participants (> or =25 min of LTPA per day). After adjusting for significant covariates, BMI (18.7%), %FM (19.4%), and C-reactive protein (143%) were all lower, and %FFM was higher (7.2%), in active participants (all p < or = 0.05). Ten percent of active participants vs. 33% of inactive participants were insulin resistant (p = 0.03). Waist circumference (17.6%) and systolic blood pressure (15.3%) were lower in active vs. inactive participants with paraplegia (both p < or = 0.05), but not tetraplegia. In conclusion, greater daily LTPA is associated with lower levels of selected CVD and type 2 diabetes risk factors in individuals living with SCI. Whether this relationship translates into a lower incidence of these chronic diseases has yet to be determined.

Cranberry juice consumption may reduce biofilms on uroepithelial cells: pilot study in spinal cord injured patients.

Study design: A pilot study of 15 spinal cord injured patients.Objective: To determine whether alteration of fluid intake and use of cranberry juice altered the bacterial biofilm load in the bladder.Setting: London, Ontario, Canada.Methods: Urine samples were collected on day 0 (start of study), on day 7 following each patient taking one glass of water three times daily in addition to normal diet, and on day 15 following each patient taking one glass of cranberry juice thrice daily. One urine sample was sent for culture and a second processed to harvest, examine by light microscopy and Gram stain non-squamous uroepithelial cells to generate bacterial adhesion per 50 cells data.Results: The results showed that cranberry juice intake significantly reduced the biofilm load compared to baseline (P=0.013). This was due to a reduction in adhesion of Gram negative (P=0.054) and Gram positive (P=0.022) bacteria to cells. Water intake did not significantly reduce the bacterial adhesion or biofilm presence.Conclusion: The findings provide evidence in support of further, larger clinical trials into the use of functional foods, particularly cranberry juice, to reduce the risk of UTI in a patient population highly susceptible to morbidity and mortality associated with drug resistant uropathogens.Sponsorship: This study was funded by Ocean Spray Cranberries, Lakeville, MA, USA.Spinal Cord (2001) 39, 26–30.

Pharmacokinetics of an Immediate‐Release Oral Formulation of Fampridine (4‐Aminopyridine) in Normal Subjects and Patients with Spinal Cord Injury

Plasma concentration profiles of the K+ channel‐blocking compound Fampridine were obtained from (1) control subjects (n = 6) following oral administration of doses of 10, 15, 20, and 25 mg and (2) patients with spinal cord injury (SCI) (n = 11) following a single oral dose of 10 mg of an immediate‐release formulation. Plasma concentrations were determined using a reversed‐phase ion‐pair high‐performance liquid chromatography (HPLC) assay with ultraviolet light detection employing liquid extraction. The drug was rapidly absorbed with a tmax ∼1 hour for both groups; tmax was independent of dose. Cmax and AUC0‐∞ were linearly related to dose, and t1/2 was 3 to 4 hours for both groups. There were no obvious differences in the (10‐mg) plasma concentration profiles between control subjects and SCI patients. The drug was well tolerated, with only mild and transient side effects of light‐headedness, dysesthesias, and dizziness.

Preclinical trial of 4-aminopyridine in patients with chronic spinal cord injury

4-Aminopyridine (4-AP) is a K+ channel blocking agent that enhances nerve conduction through areas of demyelination by prolonging the duration of the action potential and increasing the safety factor for conduction. We have investigated the effects of 4-AP (24 mg total dose-intravenous) in 6 patients with spinal cord injury (3 complete, 3 incomplete) with the intent of overcoming central conduction block, or slowing, due to demyelination. Vital signs remained stable and only mild side effects were noted. The 3 patients with incomplete injuries all demonstrated enhanced volitional EMG interference patterns and one patient exhibited restored toe movements. The changes were reversed on drug washout. There were no changes in segmental reflex activities. These results are consistent with those obtained from 4-AP trials with animal models of spinal cord injury, showing modest therapeutic benefit attributable to enhanced central conduction.

Electrical Stimulation Therapy Increases Rate of Healing of Pressure Ulcers in Community-Dwelling People With Spinal Cord Injury

OBJECTIVE To investigate whether electric stimulation therapy (EST) administered as part of a community-based, interdisciplinary wound care program accelerates healing of pressure ulcers in people with spinal cord injury (SCI). DESIGN Single-blind, parallel-group, randomized, controlled, clinical trial. SETTING Community-based home care setting, Ontario, Canada. PARTICIPANTS Adults (N=34; mean age +/- SD, 51+/-14y) with SCI and stage II to IV pressure ulcers. INTERVENTIONS Subjects were stratified based on wound severity and duration and randomly assigned to receive either a customized, community-based standard wound care (SWC) program that included pressure management or the wound care program plus high-voltage pulsed current applied to the wound bed (EST+SWC). MAIN OUTCOME MEASURES Wound healing measured by reduction in wound size and improvement in wound appearance at 3 months of treatment with EST+SWC or SWC. RESULTS The percentage decrease in wound surface area (WSA) at the end of the intervention period was significantly greater in the EST+SWC group (mean +/- SD, 70+/-25%) than in the SWC group (36+/-61%; P=.048). The proportion of stage III, IV, or X pressure ulcers improving by at least 50% WSA was significantly greater in the EST+SWC group than in the SWC group (P=.02). Wound appearance assessed using the photographic wound assessment tool was improved in wounds treated with EST+SWC but not SWC alone. CONCLUSIONS These results demonstrate that EST can stimulate healing of pressure ulcers of people with SCI. EST can be incorporated successfully into an interdisciplinary wound care program in the community.

Establishing evidence-based physical activity guidelines: methods for the Study of Health and Activity in People with Spinal Cord Injury (SHAPE SCI)

Study design:Prospective, observational cohort study.Objectives:This paper describes the rationale and methodology for the Study of Health and Activity in People with Spinal Cord Injury (SHAPE SCI). The study aims to (1) describe physical activity levels of people with different injury levels and completeness, (2) examine the relationship between physical activity, risk and/or presence of secondary health complications and risk of chronic disease, and (3) identify determinants of physical activity in the SCI population.Setting:Ontario, Canada.Methods:Seven hundred and twenty men and women who have incurred a traumatic SCI complete self-report measures of physical activity, physical activity determinants, secondary health problems and subjective well-being during a telephone interview. A representative subsample (n=81) participate in chronic disease risk factor testing for obesity, insulin resistance and coronary heart disease. Measures are taken at baseline, 6 and 18 months.Conclusion:SHAPE SCI will provide much-needed epidemiological information on physical activity patterns, determinants and health in people with SCI. This information will provide a foundation for the establishment of evidence-based physical activity guidelines and interventions tailored to the SCI community.

Sustained improvements in neurological function in spinal cord injured patients treated with oral 4-aminopyridine: three cases

Preclinical trials of intravenously administered 4-Aminopyridine (4-AP) have demonstrated transient improvements in neurological function in patients with longstanding spinal cord injury (SCI). The present report describes three patients with SCI who responded favourably in preclinical trials and who were subsequently administered oral (capsule) 4-AP (10 mg b.i.d. or t.i.d.) over a 4 month interval. The three patients (two male: 1 female) all had incomplete tetraplegia (ASIA levels C and D) with the neurological level of the lesion between C5-C7. Following the administration of 4-AP the patients demonstrated marked and sustained reductions in upper (n=1) or lower extremity (n=2) spasticity. Other clinical benefits of 4-AP were reduced pain (n=1), restored muscle strength (n=3), improved sensation (n=2), voluntary control of bowel function (n=1), and sustained penile tumescence (n=2). The patients exhibited improved hand function (n=1), enhanced mobility in transfers and gait (n=2), with improved energy and endurance. Only trivial side effects (transient lightheadedness) were observed. In one case, the enhanced neurological function allowed the patient to stand with support for the first time post injury (16 years). The time course of therapeutic response to the initial dose matched the pharmacokinetic elimination profile derived from serum and urine analysis. There was no evidence of renal or hepatic toxicity with prolonged use. These results indicate a therapeutic benefit of oral 4-Aminopyridine in the management of various neurological deficits in a select group of SCI patients.

Leisure Time Physical Activity in a Population-Based Sample of People With Spinal Cord Injury Part II: Activity Types, Intensities, and Durations

OBJECTIVE To describe the types, intensities, and average duration of leisure time physical activities (LTPAs) performed by people with chronic spinal cord injury (SCI). DESIGN Cross-sectional telephone survey. SETTING General community. PARTICIPANTS Men and women with SCI (N=347) who reported engaging in LTPA over the previous 3 days. INTERVENTIONS Not applicable. MAIN OUTCOME MEASURES Mean minutes a day of LTPA performed at mild, moderate, and heavy intensities; proportion of respondents performing specific types of LTPA. RESULTS Participants reported a mean +/- SD of 55.15+/-59.05min/d of LTPA at a mild intensity or greater. Median LTPA was 33.33min/d. More activity was done at a moderate intensity (mean +/- SD, 25.49+/-42.11min/d) than mild (mean +/- SD, 19.14+/-37.77min/d) or heavy intensities (mean +/- SD, 10.52+/-22.17min/d). Most participants reported mild (54%) or moderate intensity LTPA (68%), while a minority reported heavy intensity LTPA (43%). The 3 most frequently reported types of LTPA were resistance training (33%), aerobic exercise (25%), and wheeling (24%). Craftsmanship (mean +/- SD, 83.79+/-96.00min/d) and sports activities (mean +/- SD, 60.86+/-59.76 min/d) were performed for the longest durations. CONCLUSIONS There is considerable variability in daily LTPA among active people with SCI and variability across different types of LTPA in terms of typical durations and intensities. This information can be used to help people with chronic SCI become more active by highlighting activities that meet individual abilities, needs, and desires.

Pharmacokinetics and Safety of Multiple Oral Doses of Sustained-Release 4-Aminopyridine (Fampridine-SR) in Subjects With Chronic, Incomplete Spinal Cord Injury

OBJECTIVE To examine the pharmacokinetics and safety of sustained-release 4-aminopyridine (Fampridine-SR), a potassium channel blocker, in subjects with chronic, incomplete spinal cord injury (SCI). DESIGN Open-label. SETTING Clinical research unit in Ontario. PARTICIPANTS Sixteen neurologically stable subjects with chronic, incomplete SCI (American Spinal Injury Association Impairment Scale grade B, C, or D). INTERVENTION Oral administration of Fampridine-SR (25, 30, 35, 40, 50, 60 mg twice daily, each for 1 wk). MAIN OUTCOME MEASURES Steady-state pharmacokinetic parameters: maximum observed plasma concentration (Cmax), minimum observed plasma concentration (Cmin), average observed plasma concentration (Cav), area under the plasma concentration-time curve from 0 to 12 hours (AUC(0-12)), time to Cmax (tmax), plasma half-life (t(1/2)), apparent volume of distribution (Vd/F), and apparent total clearance (Cl/F). Safety assessments: physical examinations, vital sign measurements, clinical laboratory tests, electrocardiogram recordings, and adverse events. RESULTS Mean steady-state Cmax, Cmin, Cav, and AUC(0-12) increased over the entire Fampridine-SR dosage range and were dosage dependent up to 50 mg twice daily. Fampridine-SR had a mean tmax of 2.2 to 3.0 hours and a mean t(1/2) of 5.7 to 6.9 hours. Mean Vd/F (415.4-528.0 L) and Cl/F (51.4-57.7 L/h) were independent of dosage, as were mean tmax and t(1/2) across dosages. Adverse events were mild or moderate and were not dosage related. During the entire study period (17 wk), dizziness was the most frequently reported adverse event, followed by urinary tract infection, paresthesia, ataxia, and insomnia. CONCLUSION In subjects with chronic, incomplete SCI, Fampridine-SR was slowly absorbed and eliminated, which will allow Fampridine-SR to be administered in a convenient twice-daily manner. Fampridine-SR was well tolerated at dosages from 25 to 60 mg twice daily.