Donald A. MacLeod

Wheelchair-related accidents caused by tips and falls among noninstitutionalized users of manually propelled wheelchairs in Nova Scotia.

ABSTRACTThe purpose of this study was to document what proportion of noninstitutionalized users of manually propelled wheelchairs are affected by wheelchair-related accidents caused by tips and falls, determine the nature and severity of the resulting injuries, and, by comparison with an unaffected group, identify factors associated with the risk of such accidents. We administered a postal questionnaire to as many as possible of the estimated 2055 members of the target population in the province of Nova Scotia. Among the 577 appropriate respondents, 57.4% reported they had completely tipped over or fallen from their wheelchairs at least once, and 66.0% reported having partially tipped. Of the falls and tips that were reported, 46.3% were forward in direction, 29.5% backward and 24.2% sideways. Many of the accidents occurred outdoors or on ramps. A total of 292 injuries were reported by 272 (47.1%) respondents. Most of the injuries (84.3%) were minor (e.g., abrasions, contusions, lacerations and sprains). Of the 15.8% of injuries that were serious, the most common were fractures (10.6%) and concussions (2.7%). Factors that appear to be associated with an increased risk of accidents and injuries included younger age, male gender, paraplegia or spina bifida as the reason for wheelchair use, having had a wheelchair prescribed, some wheelchair features (lightweight, camber, adjustable rear-axle positions, a knapsack), daily use of a wheelchair, propelling the chair with both hands, use of the wheelchair for recreation, use of a sideways transfer (without a transfer board) and doing repairs themselves or having them done by the dealer. Factors associated with a decreased risk include multiple sclerosis, stroke or arthritis as the reason for wheelchair use, attendant propulsion and the use of a one-person assist for transfers. The results of this study, that wheelchair-related accidents caused by tips and falls are very common, that serious injuries are not unusual and that there is a pattern of risk factors, should be useful to wheelchair users, clinicians, manufacturers and regulatory bodies.

Ability of people with stroke to learn powered wheelchair skills: a pilot study.

OBJECTIVES Our primary objective was to test the hypothesis that people with stroke can learn to use powered wheelchairs safely and effectively. Our secondary objective was to explore the influence of visuospatial neglect on the ability to learn powered wheelchair skills. DESIGN Prospective, uncontrolled pilot study using within-participant comparisons. SETTING Rehabilitation center. PARTICIPANTS Inpatients (N=10; 6 with visuospatial neglect), all with a primary diagnosis of stroke. INTERVENTIONS Participants received 5 wheelchair skills training sessions of up to 30 minutes each using the Wheelchair Skills Training Program (version 3.2). MAIN OUTCOME MEASURES Powered wheelchair skills were tested before and after training using the Wheelchair Skills Test, Power Mobility version 3.2 (WST-P). RESULTS The groups total mean WST-P scores improved from 25.5% of skills passed at baseline to 71.5% posttraining (P=.002). The participants with neglect improved their WST-P scores to the same extent as the participants without neglect, although their pretraining and posttraining scores were lower. The training and testing sessions were well tolerated by the participants, and there were no serious adverse events. CONCLUSIONS Many people with stroke, with or without visuospatial neglect, can learn to use powered wheelchairs safely and effectively with appropriate training.

The manual wheelchair wheelie: A review of our current understanding of an important motor skill

Purpose. To review the current understanding of the manual wheelchair wheelie. Method. Review of the literature. Results. A rear wheelchair wheelie occurs when the front wheels, ordinarily in contact with the support surface, are intentionally caused, by means of a transient or sustainable rear pitch, to lift from the surface while the rear wheels remain on the surface. Pitch control (partial or full) is the foundation of many wheelchair skills (e.g., negotiating thresholds, potholes, curbs, steep inclines and gravel). Yet, most wheelchair users never learn to perform this valuable skill. Wheelie capability is affected by the characteristics of the clinician, the wheelchair user, the wheelchair and the environment. Although our understanding of wheelie biomechanics and training methods is evolving, much remains to be learned. Three recent wheelchair developments have wheelie-related implications: a new type of rear anti-tip device (Arc-RAD) that permits wheelie-like function, pushrim-activated power-assisted wheelchairs (PAPAWs) that make wheelie-dependent skills more dangerous and difficult, and a powered wheelchair that has robotic wheelie capabilities (the IBOT). Conclusions. Improvements in our understanding of the nature of wheelies, formalization of training protocols and innovations in wheelchair design hold promise for improved activities and participation by wheelchair users.

Comparison between performance with a pushrim-activated power-assisted wheelchair and a manual wheelchair on the Wheelchair Skills Test.

Purpose. To test the hypothesis that people using a pushrim-activated power-assisted wheelchair (PAPAW) can accomplish a wider range of wheelchair skills than when using a manual wheelchair (MWC). Methods. We studied 30 able-bodied participants, using within-participant comparisons. Participants used a manual wheelchair equipped with both PAPAW and regular MWC rear wheels, and rear anti-tip devices (Arc-RADs) that permitted wheelie-like function. We trained participants to perform the wheelchair skills of the Wheelchair Skills Training Program (WSTP, Version 2.4). From the Wheelchair Skills Test (WST, Version 2.4), we calculated pass-fail success rates for the 50 individual skills and a total percentage WST score. Results. The mean (±SD) total WST scores were 89.3 (±7.0)% for the PAPAW and 88.8 (±8.4)% for the MWC, with a mean difference of 0.6 (±5.6)% (p = 0.59). Qualitative observations suggested that skills requiring a higher force on the pushrim (e.g., incline ascent) were performed more easily with the PAPAW, whereas skills requiring greater control of the wheelchair (e.g., wheelie-dependent skills) were performed more easily with the MWC. Conclusion. Overall wheelchair skill performance with the PAPAW is not superior to that when using the MWC. The PAPAW may be helpful for specific skills that require more wheel torque, but the additional torque appears to be disadvantageous when performing skills that require greater control.

Neck discomfort of wheelchair users: effect of neck position

Purpose: To test the hypothesis that wheelchair users experience more discomfort when holding their necks in extended and/or rotated positions than when in their self-selected most comfortable positions (MCPs). Methods: We studied 20 wheelchair users, first determining their MCPs with the eyes closed. Then, subjects assumed and maintained (for 5 min each) four neck positions in random order: level (L) and elevated (E), both straight ahead of the subject (S) and with the neck rotated (R). We measured neck extension angles (from digital photographs) and neck discomfort (using visual analogue scales [VAS], in %). Results: The mean neck-extension angles were MCP − 2.6°, LS 9.5°, LR 8.1°, ES 23.9° and ER 25.4° (ANOVA p < 0.0001). The mean VAS neck discomfort scores were LS 5.7%, LR 17.4%, ES 24.0% and ER 34.1% (ANOVA p < 0.0001). Conclusions: Sustained extension and rotation of the neck, alone or in combination, increase the neck discomfort of wheelchair users. The MCP for most wheelchair users is straight ahead with the neck slightly flexed, about 11° and 27° more flexed, respectively, than when looking at an average-height sitting or standing person. These findings have implications for wheelchair design, the behaviour of clinicians and wheelchair users, and the built environment.

Rates and Predictors of Manual and Powered Wheelchair Use for Persons With Stroke: A Retrospective Study in a Canadian Rehabilitation Center

OBJECTIVES To determine the rates of manual and powered wheelchair use at discharge for people with stroke admitted to a rehabilitation center and to determine whether any predictors of wheelchair use at discharge could be identified. DESIGN Retrospective cohort study. SETTING Rehabilitation center. PARTICIPANTS Consecutive former inpatients (N=100) with a primary diagnosis of stroke, a sample of convenience. INTERVENTIONS None. MAIN OUTCOME MEASURES We reviewed the inpatient health records to determine the rates of wheelchair use at discharge and to record some readily available demographic and clinical data that might serve as predictors of wheelchair use. RESULTS At discharge, 40 people (40%) were using manual wheelchairs, 1 person (1%) was using a powered wheelchair, and 59 (59%) were not using a wheelchair. Of the patients who were walkers on admission (ie, walking FIM scores of 6 or 7), none (0%) used wheelchairs at discharge. Of those with nonwalking FIM scores (1-5) on admission, 56% were using wheelchairs at discharge. Multivariate analyses revealed that the adjusted odds ratios of using a wheelchair (manual or powered) were 3.33 (95% confidence interval [CI], 1.33-8.33) for those with left-hemisphere versus right-hemisphere strokes (P=.010), .94 (CI, .91-.96) for each point rise in the total raw FIM score on admission (P<.0001), and 19.46 (CI, 6.33-59.81) if the total admission FIM score was less than 80 versus greater than or equal to 80 (P<.0001). CONCLUSIONS On discharge from our rehabilitation center, 40% of people with stroke were using manual wheelchairs and 1% powered wheelchairs. People who were not walking on admission, those with left-hemisphere strokes, and those with lower total admission FIM scores were more likely to use a wheelchair. These findings may permit clinicians to predict wheelchair use better early in the rehabilitation process, when it can affect rehabilitation planning.

Cardiac-locomotor coupling while finger tapping.

Coupling between cardiac and locomotor rhythms has been identified while people walk, run, hop and cycle at cadences natural to them. To test the hypothesis that cardiac-locomotor coupling occurs during finger tapping, we studied 20 normal subjects tapping a telegraph key at a comfortable rate for 10 min. 15 subjects (75%) coupled significantly at one or more single-digit integer ratio (heart/tapping rate), the most common of which was 1:2. Such coupling should be considered a potentially confounding variable when studying finger tapping in subjects with disease or medication affecting heart rate. Also, the identification of coupling during the repetitive activity of small upper-extremity muscles suggests that neither increases in cardiac load nor impact-loading, two suggested explanations for why coupling occurs, are necessary for the phenomenon.

Sitting pressure in the tilted position: manual tilt-in-space wheelchair vs. manual wheelchair with a new rear antitip device.

MacDonald B, Kirby RL, Smith C, MacLeod DA, Webber A: Sitting pressure in the tilted position: Manual tilt-in-space wheelchair vs. manual wheelchair with a new rear antitip device. Am J Phys Med Rehabil 2009;88:61–65. To test the hypothesis that, in comparison with a heavier, larger and more expensive manual tilt-in-space wheelchair, a lightweight manual wheelchair equipped with new rear antitip devices provides comparable mean sitting pressures in the tilted position, each of eight able-bodied participants sat for 8 mins in each wheelchair, upright, and tilted back (38–39 degrees). The mean (±SD) sitting pressures (of all active sensors in a force-sensing array) at the eighth minute in the upright and tilted positions with the new rear antitip device wheelchair were 58.6 (±14.0) and 45.8 (±9.3) mm Hg (a 20.7% reduction) (P = 0.005). For the tilt-in-space wheelchair, the mean values were 55.7 (±13.9) and 47.2 (±10.8) mm Hg (a 26.3% reduction) (P = 0.008). There were no significant differences between the wheelchairs in the upright (P = 0.843) or tilted (P = 0.624) positions. A lightweight manual wheelchair equipped with a new rear antitip device provides equivalent reductions of sitting pressures in the tilted position to a comparably tilted tilt-in-space wheelchair.

Effect of a shock-absorbing pylon on transmission of heel strike forces during the gait of people with unilateral trans-tibial amputations: a pilot study.

The primary objective was to test the hypothesis that walking with a shock-absorbing pylon (SAP) decreases the peak magnitude and frequency content of the heel-strike-initiated shock wave transmitted to the stump. The secondary hypotheses were that walking with a SAP decreases the heel-strike transient force between the ground and the foot and increases function as measured by walking velocity and subjective assessments. Seven people with unilateral trans-tibial amputations walked at self-selected speeds without and with a SAP. As the primary outcome measure, accelerometers were used mounted proximally and distally along the prosthetic pylon to measure the transmitted shock wave. Secondary measures included ground reaction forces from a force plate, a ten-minute walking test to determine walking speed and a questionnaire to evaluate gait function and subjective preference. The SAP provided no significant shock absorption as indicated by either the mean peak proximal accelerations of 3.19 g and 2.82 g (p = 0.28) without and with the SAP respectively or the mean difference between the peak proximal and distal accelerometers, 0.16 g and 0.19 g (p = 0.58). No significant change in the frequency content was found. Variances were high. There were no significant differences noted in the secondary measures. Although this study failed to identify any statistically significant effects due to the SAP, the magnitude and variance of the data will permit an accurate estimation of the appropriate sample size for future studies required to determine the efficacy of SAPs.

Cardiac-Locomotor Coupling While Finger Tapping: Part II. A Cross-Over Control Study

Cardiac-locomotor coupling (CLC) has been reported by us while people finger tap at cadences natural to them. Since then, we have developed a simple crossover control strategy in which the heart rate of one subject is related to the finger-tapping rate of another. Of the 20 normal subjects previously studied while tapping a telegraph key at a comfortable rate for 10 min., reevaluation of their data showed that 9 (45%) and 4 (20%) of them, under test and control conditions, respectively, appeared to couple at a single-digit integer ratio. Neither the incidence nor the intensity of apparent CLC under the two conditions was significantly different. Raster plots of the most tightly related rates gave no evidence of phase locking. These results have two implications. First, previously published reports on CLC (and other entrainment phenomena) should be interpreted with caution, and cross-over controls should be considered in future research. Second, the absence of CLC during finger tapping suggests that CLC may only be functionally significant during exercise of large muscle groups (e.g., by minimization of cardiac afterload) or when impact-loading occurs (e.g., by enhancing cardiac ventricular emptying).