Comparison of fatigue life for 3 types of manual wheelchairs.

OBJECTIVES: To examine 3 types of manual wheelchairs-ultralight wheelchairs (UWs), lightweight wheelchairs (LWs), and depot wheelchairs (DWs)-and to compare the fatigue life between the wheelchair types. DESIGN: A database of different manual wheelchairs tested according to the International Organization for Standardization (ISO). Fatigue life was determined by using standards that define methods accepted internationally using double-drum and curb-drop testing equipment. SETTING: A rehabilitation engineering center. SPECIMENS: Sixty-one manual wheelchairs: 25 DWs, 22 UWs, and 14 LWs. MAIN OUTCOME MEASURES: Wheelchairs were examined for differences in fatigue life based on equivalent cycles. Unique survival curves were fit and compared for each wheelchair type. RESULTS: The UWs lasted the longest, with a mean of 309,362 equivalent cycles. The DWs faired the worst, with a mean of 117,210 equivalent cycles. The Kaplan-Meier survival curves were significantly different (p < .001), with the UWs having the longest fatigue life. CONCLUSION: Fatigue life for UWs is significantly greater (p < .05) than LWs and DWs, indicating wheelchairs differ in durability.

Predictive factors for successful early prosthetic ambulation among lower-limb amputees.

OBJECTIVE: To predict successful prosthetic ambulation for patients immediately transferred to an inpatient rehabilitation facility after amputation surgery. METHODS: Seventy-five individuals with lower-limb amputation were studied at a tertiary acute care and rehabilitation facility. Successful prosthetic ambulation, defined as the ability to ambulate with a prosthesis at least 45 m, was measured in addition to other key demographic and medical factors. RESULTS: Sixty-eight percent were successful prosthetic ambulators at rehabilitation discharge. The absence of residual-limb contracture and a longer length of stay during rehabilitation showed a significant relationship to successful prosthetic ambulation with regression analysis. Younger age was modestly correlated to outcome. There were no significant differences when comparing success of the early rehabilitation program with surgical level or etiology of amputation. For successful prosthetic users, mean wear time at rehabilitation discharge was 5.7 hours with a mean distance walked of 67 m. Of those who failed this approach, 70% were related to a failure of wound healing. CONCLUSIONS: In this cohort, 68% of patients who were selected for a trial of early prosthetic rehabilitation ambulated using a prosthesis at rehabilitation discharge. This approach appears to be more effective for younger patients without contractures who are medically stable to participate in the rehabilitation process.

Kinematic comparison of Hybrid II test dummy to wheelchair user.

Hybrid test dummies provide a safe alternative to human subjects when investigating mechanisms of wheelchair tips and falls. The data that researchers acquire from these test dummies are more useful if the test dummy represents the population being studied. The goal of this study was to measure the validity of a 50th percentile Hybrid II test dummy (HTD) as an accurate representation of a wheelchair user. A test pilot with T8 paraplegia due to traumatic spinal cord injury served as a basis for validation. Simple modifications were made to the HTD to approximate the trunk stability characteristics of a person with a spinal cord injury. An HTD, a modified HTD, and a human test pilot were seated in an electric-powered wheelchair and several braking tests performed. The standard HTD underestimated the kinematics when compared to the test pilot. The modified HTD had less trunk stability than the standard HTD during all braking methods. The modified HTD and wheelchair test pilot had similar trunk stability characteristics during kill switch and joystick full-reverse braking conditions. The modified HTD is a satisfactory representation of a wheelchair user with a spinal cord injury; however, the modified test dummy underestimates the trunk dynamics during the less extreme joystick release braking. Work should continue on the development of a low-speed, low-impact test dummy that emulates the wheelchair user population.

Does computer game play aid in motivation of exercise and increase metabolic activity during wheelchair ergometry?

GAME(Wheels) is an interface between a portable roller system and a computer that enables a wheelchair user to play commercially available computer video games. The subject controls the game play with the propulsion of their wheelchair's wheels on the rollers. The purpose of this study was to investigate whether using the GAME(Wheels) System during wheelchair propulsion exercise can help increase the individual's physiological response and aid in the motivation to exercise. Fifteen subjects participated in this study. The subjects propelled their wheelchairs on a portable roller that was equipped with the GAME(Wheels) System. There were two exercise trials consisting of 2 min of warm-up, 16 min of exercise and 2 min of cool-down. Physiological data (ventilation rate, oxygen consumption, heart rate) were collected. A significant difference (P<0.05) was found between exercise with GAME(Wheels) versus without GAME(Wheels) for average ventilation rate and average oxygen consumption. The differences were found during time periods of transition from warm-up to exercise, and before and after the midpoint of exercise. Written questionnaires showed that 87% of the individuals tested reported the system would help them work out on a regular basis. Playing the video game helped these individuals to reach their exercise training zone faster and maintain it for the entire exercise trial.

Diabetes and postoperative endophthalmitis in the endophthalmitis vitrectomy study.

OBJECTIVES: To determine whether there was a different response to vitrectomy and tap/biopsy with or without systemic antibiotic treatment in the Endophthalmitis Vitrectomy Study and whether the signs and symptoms of endophthalmitis differ between diabetic and nondiabetic patients. DESIGN: A multicenter clinical trial in which patients with acute post-cataract extraction endophthalmitis were randomly assigned in a 2 x 2 factorial design to vitrectomy or tap/biopsy, in each case with or without intravenous antibiotics, and followed up for 9 months. Outcome measures included visual acuity assessed in standardized fashion. RESULTS: Fifty-eight of 420 study patients had diabetes. Diabetic patients had slightly worse vision and ocular media at the baseline assessment. Only 39% of diabetic patients compared with 55% of nondiabetic patients achieved 20/40 final vision. Both diabetic and nondiabetic patients with initial light perception (LP)-only vision had better visual results with immediate vitrectomy. For those with better than LP baseline vision, patients with diabetes achieved visual acuity of 20/40 more often with vitrectomy (57%) than with tap/biopsy (40%), but this difference was not statistically significant. Patients without diabetes did equally well with vitrectomy or tap/biopsy. CONCLUSIONS: For patients with better than LP vision, tap/biopsy is appropriate for those without diabetes. A clinical trial of a sufficient number of diabetic patients with better than LP vision is necessary to determine the best management for this group. At present, initial vitrectomy or tap/biopsy are reasonable approaches for diabetic patients with better than LP vision.

Evaluation of a pushrim-activated, power-assisted wheelchair.

OBJECTIVE: To evaluate a novel pushrim-activated, power-assisted wheelchair (PAPAW) for compliance with wheelchair standards, metabolic energy cost during propulsion, and ergonomics during selected activities of daily living (ADLs). DESIGN: A 3-phase study, the second and third of which were repeated-measures designs. SETTING: A rehabilitation engineering center within a Veterans Affairs medical center. PATIENTS: Eleven full-time, community-dwelling, manual wheelchair users (4 women, 6 men) with spinal cord injuries or multiple sclerosis. INTERVENTIONS: Phase 1: Compliance testing, with a test dummy, in accordance with the wheelchair standards of the American National Standards Institute and the Rehabilitation Engineering and Assistive Technology Society of North America. Phase 2: Metabolic energy consumption testing-at 2 speeds and 3 resistance levels-in subjects' manual wheelchair and the PAPAW. Phase 3: Evaluation of ability to perform ADLs and ergonomics of the PAPAW compared with the subjects personal wheelchair. MAIN OUTCOME MEASURES: Phase 1: The PAPAW's static stability, static strength, impact strength, fatigue strength, environmental response, obstacle climbing ability, range, maximum speed, and braking distance. Phase 2: Subjects' oxygen consumption per minute, minute ventilation, and heart rate during different speeds and workloads with a PAPAW and their own wheelchairs. Phase 3: Subject ratings of perceived comfort and basic ergonomics while performing selected ADLs. Completion time, stroke frequency, and heart rate during each ADL. RESULTS: Phase 1: The PAPAW was found to be in compliance with wheelchair standards. Phase 2: With the PAPAW, the user had a significantly lower oxygen consumption (&Vdot;O(2)mL/min: p <.0001; &Vdot;O(2)mL/kg x min: p <.0001) and heart rate (p <.0001) when compared with a manual wheelchair at different speeds. Phase 3: The PAPAW had a significantly higher mean ergonomic evaluation (p <.01) than the subjects' personal wheelchairs. The results of comparing the ratings of the car transfer between the PAPAW and the subjects' personal wheelchair showed a significant difference in the task of taking the wheels off (p <.001) and putting the wheels back on (p =.001), with the PAPAW receiving lower ratings. CONCLUSION: This study indicated that the PAPAW is compliant with wheelchair standards, reduces the energy demand placed on the user during propulsion, and that subjects rated its ergonomics favorably when compared with their personal wheelchair. PAPAWs may provide manual wheelchairs with a less physiologically stressful means of mobility with few adaptations to the vehicle or home environment.

Mechanical efficiency and user power requirement with a pushrim activated power assisted wheelchair.

The objective of this study was to quantify the difference in mechanical efficiency and user power generation between traditional manual wheelchairs and a pushrim activated power assisted wheelchair (PAPAW). Ten manual wheelchair users were evaluated in a repeated measures design trial with and without the PAPAW for propulsion efficiency. Subjects propelled a Quickie GP equipped with the PAPAW and their own chair on a computer controlled wheelchair dynamometer at five different resistance levels. Power output, user power with the PAPAW hubs, subjects' oxygen consumption per minute and mechanical efficiency were analyzed. Metabolic energy and user power were significantly lower (p<0.05), and mechanical efficiency significantly higher with the PAPAW than with subjects' own chairs. Subjects needed to generate on average 3.65 times more power when propelling their own wheelchairs as compared to PAPAW. Mean mechanical efficiency over all trials was 80.33% higher with the power assisted hubs. PAPAW provides on average 73% of the total power when subjects propel with power assistance. Significantly increased efficiency and reduced requirement of user power is achieved using the PAPAW. With use, the PAPAW may contribute to delaying secondary injuries of manual wheelchair users. In addition, it may be suitable for people who have (or at risk for) upper extremity joint degeneration, reduced exercise capacity, low strength or endurance who currently use electric powered wheelchairs.

Global improvement in intellectual and neuropsychological functioning after removal of a suprasellar cystic craniopharyngioma.

This is a case report of a patient who presented with cognitive and behavioral decline and underwent surgery for removal of a suprasellar craniopharyngioma. Previous studies have reported memory impairments in the presence of craniopharyngioma, but information is lacking regarding the impact of craniopharyngioma on other brain functions as well as on intellectual abilities. In this study, comprehensive neuropsychological testing, including intellectual testing, was conducted 9 to 14 days before surgery and 16 to 22 days after surgery. Results before surgery demonstrated average intellectual abilities, which were decreased from premorbid estimates, and diffuse neuropsychological impairments. Postoperatively, significant improvement in both intellectual abilities and neuropsychological test scores was observed. These results suggest that craniopharyngiomas can be associated with impairments in intellectual abilities and in brain functions aside from memory. The results are contrasted with those of previous reports, and implications for future research are discussed.

Evaluation of a manual wheelchair interface to computer games.

The sedentary lifestyle of many people with spinal cord injury (SCI) has lead to cardiovascular diseases being a major health concern. A suitable exercise program may help improve the SCI individual's cardiovascular fitness level. GAMEWheels is an interface between a custom wheelchair roller system and a computer that enables an individual to control computer video games by driving his or her wheelchair. The purpose of Phase 1 was to evaluate the design of the GAMEWheels system and to determine the type of computer video game that is likely to motivate wheelchair users to exercise. Phase 2 included physiologic testing of wheelchair users and the GAMEWheels system to investigate whether the system elicits an exercise training response. Thirty-five subjects were recruited to evaluate the GAMEWheels by playing three commercial computer games (Phase 1) and to identify the computer game that they would prefer to use when exercising. The feedback from Phase 1 was used with test subjects to verify that the GAMEWheels system elicits an exercise training effect (Phase 2). Phase 2 included 10 subjects using the GAMEWheels system to play Need for Speed II. During game play, physiologic data were collected and the subjects' oxygen consumption and heart rate were analyzed. Analysis showed that the GAMEWheels system induced nine subjects to reach their training zone, defined as 50% and 60% of their maximum oxygen consumption and heart rate, respectively. This study demonstrates that the GAMEWheels system elicits an exercise training response.

The Lupus Foundation as an additional source for case ascertainment: developing a community-based lupus registry.

OBJECTIVE: To determine whether the local Lupus Foundation of America (LFA) chapter would provide a unique source of additional lupus incident cases for a population-based incidence registry of SLE. METHODS: We reviewed membership and telephone records from the LFA to identify potential lupus cases. These potential cases were compared with the names on our previously developed incidence registry. Non-matches were interviewed concerning demographic characteristics and the signs and symptoms of lupus. RESULTS: Of the 449 potential lupus cases identified through the LFA Western Pennsylvania Chapter (WPC), 108 (24%) were already in the incident lupus registry. Of the remaining unmatched cases, 26 reported a diagnosis of lupus in Allegheny County between 1985 and 1990. Of these, 5 patients met the criteria for definite or probable lupus. CONCLUSION: The LFA-WPC provided a negligible advantage in identifying additional incident lupus cases to those already identified through an established registry.

Prevalence and risk factors of carotid plaque in women with systemic lupus erythematosus.

OBJECTIVE: To determine the prevalence of carotid atherosclerosis and associated risk factors in women with systemic lupus erythematosus (SLE). METHODS: Carotid plaque and intima-media wall thickness (IMT) were measured by B-mode ultrasound in women with SLE. Risk factors associated with carotid plaque and IMT were determined at the time of the ultrasound scan and included traditional cardiovascular risk factors, SLE-specific variables, and inflammation markers. RESULTS: The 175 women with SLE were predominantly white (87%), with a mean age of 44.9 years (SD 11.5). Twenty-six women (15%) had a previous arterial event (10 coronary [myocardial infarction or angina], 11 cerebrovascular [stroke or transient ischemic attack], and 5 both). The mean +/- SD IMT was 0.71 +/- 0.14 mm, and 70 women (40%) had focal plaque. Variables significantly associated with focal plaque (P < 0.05) included age, duration of lupus, systolic, diastolic, and pulse pressure, body mass index, menopausal status, levels of total and low-density lipoprotein (LDL) cholesterol, fibrinogen and C-reactive protein levels, SLE-related disease damage according to the Systemic Lupus International Collaborating Clinics (SLICC) damage index (modified to exclude cardiovascular parameters), and disease activity as determined by the Systemic Lupus Activity Measure. Women with longer duration of prednisone use and a higher cumulative dose of prednisone as well as those with prior coronary events were more likely to have plaque. In logistic regression models, independent determinants of plaque (P < 0.05) were older age, higher systolic blood pressure, higher levels of LDL cholesterol, prolonged treatment with prednisone, and a previous coronary event. Older age, a previous coronary event, and elevated systolic blood pressure were independently associated with increased severity of plaque (P < 0.01). Older age, elevated pulse pressure, a previous coronary event, and a higher SLICC disease damage score were independently related to increased IMT (P < 0.05). CONCLUSION: B-mode ultrasound provides a useful noninvasive technique to assess atherosclerosis in women with SLE who are at high risk for cardiovascular disease. Potentially modifiable risk factors were found to be associated with the vascular disease detected using this method.

Dissociative states induced by relaxation training in a PTSD combat veteran: failure to identify trigger mechanisms.

PTSD is often treated with anxiety management techniques, including relaxation training. A case report is presented which describes a PTSD combat veteran who experienced dissociative states induced by relaxation training. Hypnotherapy subsequently identified traumatic memories which were recalled during relaxation training but triggering mechanisms for the recall of these traumatic memories were not identified.

The relationship between internal attentional control and sleep-onset latency in elderly adults.

Cognitive hyperactivity has been hypothesized to be one cause of sleep-onset insomnia in elderly adults. This study examined the relationship between one factor that may mediate cognitive hyperactivity--internal attentional control, the ability to direct and control one's attention while processing stimuli from memory--and sleep-onset latency. Twenty-six elderly individuals with self-reported sleep-onset latencies ranging from 5 to 75 min were brought into a sleep laboratory for a multimethod assessment of internal attentional control. Factor analysis was used to develop a composite measure of this construct. Each person then completed three 2-hr afternoon naps while multiple electrophysiological responses were monitored. The results of canonical correlations with the derived composite scores suggested that a significant proportion of the variance in sleep-onset latency in elderly adults was related to internal attentional control.

The utility and validity of daytime naps in the assessment of sleep-onset insomnia.

This study examined the discriminant validity, consistency, and reactivity of afternoon naps for assessing sleep-onset insomnia. Eleven insomniac and 17 noninsomniac subjects came to a sleep laboratory for three afternoon naps while multiple electrophysiological and subjective measures were taken. The results indicated that sleep-onset latencies during the afternoon naps significantly discriminated between insomniac and noninsomniac subjects. Further, significant correlations were found among most measures of sleep-onset latency measured both electrophysiologically and subjectively. The proportion of variance in sleep-onset latency accounted for by groups (insomniac vs. noninsomniac) increased over the three naps. Finally, a comparison of the results from this study with those from three all-night studies using identical facilities and procedures revealed that the sleep-onset latencies from this nap study were within the ranges expected on the basis of the all-night studies.