Biomedical subjects

Shirley G Fitzgerald

Publications and source records attributed to Shirley G Fitzgerald.

36 records · Page 2Linked to original sources

PubMed2004

The GAME(Cycle) exercise system: comparison with standard ergometry.

BACKGROUND: It is well established that physical activity is beneficial to health. For the individual in a wheelchair, a regular exercise program might not be available or may be too difficult to participate in physically and/or psychologically. Many exercise devices and regimes are boring. The goal, therefore, is to develop a device that makes exercise more exciting and, thus, motivates a person to exercise more or for a longer period of time, yielding increased energy expenditure. Our laboratory developed an interface between an arm ergometer and a computer game that allows the user to control game play on the screen as if using a joystick. The purpose of this study was to determine (a) whether the GAME(Cycle) system would elicit an exercise effect similar to arm ergometry, (b) whether perceived exertion would be different between the 2 devices, and (c) individuals' impressions regarding the GAME(Cycle) system. METHODS: Thirteen individuals who used wheelchairs participated in the study. Participants were asked to exercise for 2 separate, 19-minute sessions. For 1 session, a GAME(Cycle) system was used and for the other session, the same arm ergometer was used, but without the computer game being played. Physiologic data and perceived exertion were collected for each session. RESULTS: There were significant differences between playing the game and not playing the game for VO2 (P = 0.03) and VCO2 (P = 0.02), with higher values being found when the game was played. Perceived exertion was not significantly different between the 2 trials. CONCLUSION: GAME(Cycle) appears to be similar in nature with respect to energy expenditure to arm ergometry. Because this study was conducted on athletes, further research is needed with sedentary individuals to determine exercise effects and perceived exertion.

Adult↗

PubMed2004

Evaluation of selected sidewalk pavement surfaces for vibration experienced by users of manual and powered wheelchairs.

BACKGROUND: Obstacles such as bumps, curb descents, and uneven driving surfaces cause vibrations that affect the wheelchair, and in turn, the wheelchair user. Chronic exposure can cause low-back pain, disk degeneration, and other harmful effects. Little research has been conducted to assess the vibrations experienced by wheelchair users. OBJECTIVE: The purpose of this study was to conduct an evaluation of the vibration exposure during electric-powered wheelchair driving and mechanical energy requirements for manual wheelchair propulsion over selected sidewalk surfaces. The goal was to determine the criteria for a wheelchair-pedestrian access route that does not require excessive propulsive work or expose wheelchair users to potentially harmful vibrations. METHODS: Ten unimpaired individuals participated in this study. Six sidewalk surfaces were tested. Measured variables included power of the acceleration per octave, mechanical work to propel over surfaces, peak acceleration, and frequency at which peak acceleration occurs. RESULTS: For both the manual and electric-powered wheelchair, at 1 m/s, significant differences were found in peak accelerations between the seat and footrest (P < 0.0001) and between the sidewalk surfaces (P = 0.004). The greatest risk for injury caused by shock and vibration exposure occurs at frequencies near the natural frequency of seated humans (4-15 Hz). The values for work required to propel over the surfaces tested were not statistically significantly different. Besides appearance and construction, the only distinguishing characteristic was surface roughness caused by the joints. CONCLUSION: When treating the poured concrete sidewalk as the standard, surfaces 2, 3, 5, and 6 compared most favorably in terms of vibration exposure, whereas surface 4 produced mixed results. Surfaces 2, 3, 5, and 6 yielded results that were similar to the poured concrete sidewalk and could be considered acceptable for wheelchair users. In conclusion, surfaces other than the traditional poured concrete can be used for pedestrian access routes without adding vibration exposure or reducing propulsion efficiency.

Adult↗

PubMed2004

Isokinetic performance after total hip replacement.

OBJECTIVE: To evaluate differences in isokinetic hip flexion, extension, and abduction muscle performance of operated vs. nonoperated hips in older adults who have undergone elective, unilateral, total hip replacement (THR) surgery and completed rehabilitation. DESIGN: Quasi-experimental study using a nonequivalent posttest-only control group design, comprising 20 unilateral THR patients and a convenience sample of 22 healthy older adults. THR patients participated between 4 and 5 mos after surgery. THR subjects received an average of 13 outpatient or home-based physical therapy sessions. Isokinetic muscle strength and fatigue was assessed through measurement of hip peak torque per body weight, total work, and average power using a robotic dynamometer. RESULTS: Comparisons of THR subjects' operated vs. nonoperated hips showed no significant differences in isokinetic performance for any of the examined variables. THR subjects' operated hips generated significantly less peak torque per body weight, total work, and average power across all exercises as compared with a population of healthy subjects. CONCLUSIONS: THR subjects' operated and nonoperated hips showed similar biomechanical performance. THR patients are not being restored to the same level of strength and muscular endurance as compared with a population of healthy adults. These findings may be useful in providing a preliminary rationale for revising current approaches in THR rehabilitation protocols.

Aged↗

PubMed2004

Preliminary assessment of a prototype advanced mobility device in the work environment of veterans with spinal cord injury.

The INDEPENDENCE 3000 IBOT Transporter (IBOT) is an electronically stabilizing device for people with disabilities. The purpose of this study was to collect qualitative data on the potential for the IBOT to improve employment satisfaction of veterans who use wheelchairs to work. This study was based upon observations by trained clinicians, and responses to a survey completed by four men with traumatic spinal cord injury, who worked in an office environment. The mean age of the subjects was 52 +/- 8.8 years. The subjects used the devices to hold eye-level discussions with colleagues, climb stairs, ascend steep ramps, and negotiate curbs. When subjects were asked to rate the ease of getting around in the IBOT compared to their personal wheelchairs, they responded with a mean of 6.7 +/- 1.8 on a 10-point visual analog scale. The response to rating the overall function of the IBOT within their working environment yielded a rating of 6.0 +/- 2.8. Half of the users felt that the IBOT would help them at work and all thought it should be made available to veterans who use wheelchairs. A larger study should be conducted to determine if the IBOT affects work performance and the ability to return to work.

Employment↗

PubMed2004

The injury risk to wheelchair occupants using motor vehicle transportation.

The transportation safety experience for persons using wheelchairs is largely unknown. Motor vehicle crash involvement and injury frequency was examined in a telephone interview completed by 596 wheelchair users. Overall, 42% were drivers. Most subjects also rode as passengers in private vehicles (87%) and public vehicles (61%). Wheelchair use as a seat in the vehicle was higher among passengers than drivers. Crash involvement was highest among drivers and lower in passengers. Reported injuries from non-crash scenarios, though, were higher in passengers compared to drivers. Persons seated in wheelchairs in vehicles appear to be at a greater safety risk.

Accidents, Traffic↗

PubMed2003

Tips and falls during electric-powered wheelchair driving: effects of seatbelt use, legrests, and driving speed.

OBJECTIVE: To measure the response of a test dummy while traversing common obstacles encountered by users of electric-powered wheelchairs (EPWs) to determine whether optimal wheelchair fit, use of seatbelts, and driving speed affect the frequency and severity of EPW tips and falls. DESIGN: Repeated-measures comparison study. SETTING: Constructed environment both in and around a Veterans Affairs medical center. PARTICIPANT: A 50th percentile Hybrid II anthropometric test dummy (ATD) was used to simulate a person driving an EPW. INTERVENTIONS: The ATD was driven in 4 different EPWs over commonly encountered obstacles at speeds of 1 and 2m/s, with and without the use of a seatbelt, and at varying legrest heights. MAIN OUTCOME MEASURES: The response and motion of the ATD were observed and recorded as no fall, loss of control (the ATD falls forward or sideways but remains in the EPW), the ATD falls out of the EPW, or the EPW tips completely. RESULTS: A total of 97 adverse events out of 1700 trials were recorded: 88 were losses of control (instability) and 9 were ATD falls. No complete tips of any EPW occurred. Univariate statistical analysis indicated a significant relationship between the adverse events and the use of seatbelts, legrest condition, and test obstacles (P<.05). A mixed-model analysis confirmed the significant relationships between the adverse events and the use of seatbelts, legrest condition, and test obstacles (P<.05). However, the mixed model indicated that (1) there was no significant relationship between the adverse events and driving speed and (2) no one obstacle was designated to be the most problematic. CONCLUSION: Persons who use EPWs should use seatbelts and legrests while driving their EPWs, and clinicians should include common driving tasks when assessing the proper set-up of EPWs.

Acceleration↗

PubMed2003

Seat and footrest shocks and vibrations in manual wheelchairs with and without suspension.

OBJECTIVE: To examine differences in the shock and vibration transmitted to an occupant of a manual wheelchair with and without suspension caster forks and with and without rear-suspension systems. DESIGN: Repeated-measures engineering testing. SETTING: Rehabilitation engineering center with a wheelchair standards test laboratory. SPECIMENS: Six manual wheelchairs. INTERVENTIONS: An American National Standards Institute/Rehabilitation Engineering and Assistive Technology Society of North America wheelchair test dummy and a Hybrid III test dummy were used to test shock and vibration transmission in wheelchairs equipped with original equipment manufacturer (OEM) caster forks and suspension caster forks. Ultralight wheelchairs, half of which had factory-equipped rear-suspension systems, were tested. Testing was conducted on a double-drum wheelchair test machine. MAIN OUTCOME MEASURES: Shocks were examined by using peak acceleration and the frequency at which peak acceleration occurs for the seat and footrest. Vibration was characterized by the acceleration power per octave for the seat and footrest. RESULTS: Significant differences were found in the peak accelerations at the seat (P=.0004) and footrest (P=.0007) between the wheelchairs with the OEM caster forks and those with the suspension casters. The wheelchairs with suspension had significantly different frequencies at which the peak accelerations occurred for both the seat (P=.01) and footrest (P=.0001). The wheelchairs with suspension caster forks had a lower total power per octave than the wheelchairs with the OEM caster forks. For the footrest vibrations, significant differences were found between the types of caster forks for all octaves except those associated with frequencies more than 78.75Hz. There were significant differences for wheelchairs with and without rear suspension for total power per octave of seat vibrations in the octaves between 7.81 and 9.84Hz (P=.01) and 12.40 and 15.63Hz (P=.008). CONCLUSIONS: Suspension caster forks reduce the shock and vibration exposure to the user of a manual wheelchair. Rear-suspension systems reduce some of the factors related to shock and vibration exposure, but they are not clearly superior to traditional designs.

Acceleration↗

PubMed2003

A pilot study on community usage of a pushrim-activated, power-assisted wheelchair.

Manual wheelchair propulsion combined with other stresses to the upper extremities may result in secondary injury. Possible solutions would be to devise alternative methods of propulsion, such as a pushrim-activated, power-assist wheelchair (PAPAW). The goals of this study were to examine the usage of the PAPAW in a real world setting and to characterize the driving habits of manual wheelchair users. Feedback was also obtained regarding subjects' opinions with respect to the PAPAW: their likes and dislikes. A PAPAW was provided to subjects for 2 weeks. Usage (average and total distance traveled and velocity) was tracked for both the PAPAW and the subjects' own wheelchairs. Significant differences in usage were not seen between the personal wheelchairs or the PAPAW. As a result, weeks were combined to provide an overall examination of driving characteristics. The average distance traveled over an average day was 1,671.4 +/- 314.8 m with an average velocity of 0.44 +/- 0.09 m/second. This pilot study provides an idea of manual wheelchair usage in a population of individuals with spinal cord injury. The lack of significant findings between the PAPAW and the subjects' own wheelchairs may be a function of study methodology such as sample size and length of follow-up in the new wheelchair. Future studies should expand upon the pilot work completed here, strengthening the design.

Adult↗

PubMed2003

Analysis of whole-body vibration during manual wheelchair propulsion: a comparison of seat cushions and back supports for individuals without a disability.

Whole-body vibration exposure has been found to be detrimental to the health of humans owing to effects such as degraded comfort, disc degeneration, and lower back pain. The purpose of this study was to determine if selected seat cushions and back supports minimize the transmission of vibrations during manual wheelchair propulsion. Ten unimpaired participants traversed an activities of daily living course using four seat cushions and four back supports. Vibrations were measured using triaxial accelerometers. The time domain and frequency domain transmissibility was used to determine if differences exist among seat cushions and back supports. Differences were found among the four seat cushions and four back supports. Seat cushion and back support manufacturers should concentrate on single-event shocks and repeated shocks, as opposed to oscillatory motions and self-generated vibrations, because the vibrations generated by these events tend to reside in the range of frequencies most sensitive to humans. Vibrations in this range of frequencies have the greatest effect on the transmission of whole-body vibration during manual wheelchair propulsion. Differences among the seat cushions and back supports appear to be due to the seat cushion/back support design and postural support. From a clinical perspective, the time domain transmissibility best describes the transmission of whole-body vibration.

Acceleration↗

PubMed2003

Use of the Independence 3000 IBOT Transporter at home and in the community.

BACKGROUND: The INDEPENDENCE 3000 IBOT Transporter (IBOT) is an electronically stabilizing mobility device for people with disabilities. It operates in 4 functions: Standard, Balance (raised on 2 rear wheels), 4 Wheel (for inclines, curbs, and uneven terrain), and Remote (for loading into a vehicle). OBJECTIVE: The purpose of this study was to observe the IBOT at use in the home and in the community. METHODS: Data were obtained via observations by trained clinicians, data recorded from a computerized data logger, and reports from each expert. PARTICIPANTS: Participants included 10 unimpaired nonwheelchair users (6 men, 4 women) and 4 expert wheelchair users (men with spinal cord injuries, T7-L1). The participants used the IBOT to perform a variety of activities, including holding eye-level discussions with colleagues and shopping by balancing on 2 wheels, going up and down steep ramps, traversing outdoor surfaces (eg, grass, dirt trails), and climbing curbs. OBSERVATIONS: The Balance and 4-Wheel functions were helpful and worked well. The IBOT required attention to control in the Standard function. The seat height was too high for most tables and desks, and the IBOT was challenging to use in the bathroom. CONCLUSION: The IBOT is a functional mobility device that expands the options of wheelchair users. It is most useful outdoors and where there is sufficient space to use its unique Balance function.

Activities of Daily Living↗

PubMed2003

Range of motion and stroke frequency differences between manual wheelchair propulsion and pushrim-activated power-assisted wheelchair propulsion.

BACKGROUND/OBJECTIVE: The objective of this study was to examine the use and efficacy of a pushrim-activated power-assist wheelchair (PAPAW) in the reduction of upper extremity range of motion (ROM) and stroke frequency in manual wheelchair users. METHODS: Ten manual wheelchair users were evaluated using a repeated-measures design with and without the use of a PAPAW for maximum ROM of shoulder flexion/extension, abduction/adduction, internal/external rotation, and horizontal flexion/extension; elbow flexion/extension; wrist flexion/extension, supination/pronation, and ulnar/radial deviation; and stroke frequency. Participants propelled a Quickie 2 manual wheelchair configured as a PAPAW and their own wheelchair on a computer-controlled dynamometer at 3 different resistance levels and 2 different speeds. RESULTS: The use of the PAPAW significantly (P < 0.05) decreased shoulder flexion/extension and horizontal flexion/extension, elbow flexion/extension, and wrist flexion/extension and ulnar/radial deviation for many speed and resistance combinations. Univariate analysis revealed that stroke frequency was unaltered in all cases. CONCLUSION: These findings provide the foundation for studying the utility of the PAPAW in reducing the risk of upper limb injury and neuropathy in the manual wheelchair user population.

Adult↗

PubMed2003

Investigating neck pain in wheelchair users.

OBJECTIVE: Despite the fact that wheelchair users are exposed to risk factors for neck and upper back pain (NP), little is known about the impact and possible diagnoses associated with NP. The purpose of this study was to examine the significance of NP in wheelchair users and to determine if a portion of the NP may be myofascial in origin. DESIGN: Cross-sectional cohort study using questionnaires and physical exams to evaluate NP in a convenience sample of wheelchair users from the National Veteran's Wheelchair Games. Main outcome measures included reported NP, visual analog scale of neck complaints, Neck Disability Index, and physical examination findings of trigger points. RESULTS: Sixty-six percent of subjects reported NP since becoming a wheelchair user and, 60% reported pain during the past month. Neither age nor length of time in a wheelchair was significantly different between those subjects who did and those subjects who did not report pain. Of those respondents who reported NP, 60% visited the doctor about the pain and 40% limited their daily activities due to the pain. Trigger-point palpation reproduced pain in 54% of those respondents who experienced pain in the past month (n = 34). CONCLUSION: This study provides a first step in defining the prevalence and significance of NP among wheelchair users. Clinicians who work with this population need to ask subjects about symptoms and consider a myofascial origin for that pain when considering treatment.

Adult↗

PubMed2003

Whole-body vibration during manual wheelchair propulsion with selected seat cushions and back supports.

Although the exposure to whole-body vibrations (WBV) has been shown to be detrimental to seated humans, the effects of wheelchairs and seating systems on the transmission of vibration to an individual have not been thoroughly examined. The purpose of this study was to determine if the selected wheelchair seat cushions and back supports minimize the transmission of vibrations. Thirty-two wheelchair users traversed an activities of daily living course three times using 16 randomly selected seating systems as well as their own. Vibrations were measured using triaxial accelerometers at the seat and participant's head. The weighted fore-to-aft (Tx), vertical (Tz), and resultant (Tr) transmissibility based on the vibrational-dose-value (VDV) were used to determine if differences existed among the four seat cushions and back supports. The obstacles that seem to have the largest effect on the transmission of WBV are the single event shocks and the repeated event shocks. Comparisons between the individuals own seating system and the tested seating systems suggest that the individuals are not using the most appropriate seating system in terms of the reduction of vibration transmission.

Acceleration↗

PubMed2002

Comparison of virtual and real electric powered wheelchair driving using a position sensing joystick and an isometric joystick.

There are limited interface options for electric powered wheelchairs, which results in the inability of some individuals to drive independently. In addition, the development of new interface technologies will necessitate the development of alternative training methods. This study compares a conventional position sensing joystick to a novel isometric joystick during a driving task in a virtual environment and a real environment. The results revealed that there were few differences in task completion time and root-mean-square error (RMSE) between the two types of joysticks. There were significant correlations between the RMSE in the virtual environment and the real environment for both types of joysticks. The data indicate that performance in the virtual environment was representative of driving ability in the real environment, and the isometric joystick performed comparably to the position sensing joystick.

Algorithms↗

PubMed2002

Driving characteristics of electric-powered wheelchair users: how far, fast, and often do people drive?

OBJECTIVES: To determine the driving characteristics of electric-powered wheelchair users during unrestricted community activities and to compare the activity levels among an active group and a group of regular users. DESIGN: Multisite engineering evaluation of electric-powered wheelchair driving activity during unrestricted community mobility. SETTING: Data were collected in the communities of Pittsburgh, PA, and the National Veterans Wheelchair Games (NVWG) in San Antonio, TX. PARTICIPANTS: Seventeen people participated, all of whom used electric-powered wheelchairs as their primary means of mobility. INTERVENTION: Each subject was asked standarized questions about self and wheelchair use. Data logger and sensor installed on wheelchair. Data downloaded from logger. MAIN OUTCOME MEASURES: Speed, distance traveled, and the time that each subject's personal wheelchair was being driven were recorded for 24hr/d over approximately 5 days for each subject by using a custom-built data logger. RESULTS: The NVWG group traveled faster than the Pittsburgh group, but this difference was only statistically significant on the first day. The NVWG group was more likely to travel longer than the Pittsburgh group with significant differences seen in day 4 (P = .03) and day 5 (P = .05). Total distance traveled during the 5-day period and average distance traveled per day were also significantly different between the groups (P = .02 for both 5-day distance and daily distance), with the NVWG group traveling longer (17,164 +/- 8708m) when compared with the Pittsburgh group (8335 +/- 7074m) over the 5-day period. Both distance traveled and speed increased during afternoon and evening hours. The maximum distance traveled by any subject for each hour across the 2 groups was used to create the theoretic maximum distance day, which resulted in 7970m of driving. CONCLUSION: Drivers of electric-powered wheelchairs are most active during the afternoon and evening hours. Over the 5-day period of this study, there was little variation in the speed or distance driven per day. The subjects participating in the NVWG were more active than their counterparts during a typical week at home. The maximum theoretic distance that a wheelchair user in our group would travel is less than 8km. The range of current electric-powered wheelchairs appears adequate, if not generous, for the subjects in our study.

Activities of Daily Living↗

PubMed2002

Propulsion patterns and pushrim biomechanics in manual wheelchair propulsion.

OBJECTIVES: To classify stroke patterns of manual wheelchair users and to determine if different patterns of propulsion lead to different biomechanics. DESIGN: Case series. SETTING: Biomechanics laboratory. PARTICIPANTS: Thirty-eight individuals with paraplegia who use manual wheelchairs for mobility. INTERVENTION: Subjects propelled their own wheelchair on a dynamometer at 2 different steady state speeds. Bilateral biomechanical data were obtained by using a force and moment sensing pushrim and a motion analysis system. MAIN OUTCOME MEASURES: The propulsive stroke of each participant for each speed and side was classified as following 1 of 4 patterns. These 4 patterns were then compared by using a mixed-model analysis of variance. The biomechanical variables that were compared were cadence, peak and rate of rise of the resultant force, mechanical effective force, push angle, and ratio of time spent pushing to time in recovery. RESULTS: The most common propulsive stroke involved the user lifting the hand over the pushrim during the recovery phase. The stroke pattern was independent of axle position and varied from side to side and between speeds. After controlling for subject characteristics, significant differences were observed between stroke patterns in cadence and ratio of time spent pushing to time in recovery. A stroke pattern that involves using a semicircular motion with the hand below the pushrim during the recovery phase of the propulsion stroke was associated with a lower cadence and more time spent in the push phase relative to the recovery phase. CONCLUSION: The semicircular motion of propulsion displayed characteristics consistent with reduced repetition and more efficient propulsion. Use of this propulsion style may reduce trauma to the upper extremities. Clinicians should consider training individuals in this propulsion style.

Adult↗

PubMedDate not supplied

Issues in maintenance and repairs of wheelchairs: A pilot study.

In this pilot study, we assessed wheelchair durability and its effect on user satisfaction. Specifically, we examined the characteristics of the participants' wheelchairs, the types of maintenance and repairs completed, and whether the participants' satisfaction was affected by problems with their wheelchairs. A convenience sample of 130 participants who used wheelchairs as their primary means of mobility was recruited. Participants completed a questionnaire about their wheelchairs, the maintenance and repair history, and their satisfaction levels. Results showed that 26% of the participants had completed a wheelchair repair in the past 6 months, 16% had completed general maintenance, and 27% had completed tire repairs. Neither hours of wheelchair use nor wheelchair age affected repair or maintenance frequency. Participants were generally satisfied with their wheelchairs. Better understanding of wheelchair maintenance and repair issues will guide improvements in wheelchair design and enhance the community participation of individuals who use wheelchairs.

Adult↗

PubMedDate not supplied

Isometric performance following total hip arthroplasty and rehabilitation.

We compared differences in isometric strength between older adults who have undergone elective unilateral total hip arthroplasty (THA) and completed rehabilitation with a population of community-dwelling older adults who have not had THA. The study was a cross-sectional design, and 22 unilateral THA subjects and 38 community-dwelling older adults participated. THA subjects received on average 13 outpatient or home-based physical therapy sessions before evaluation. THA subjects were evaluated 4 to 5 months postsurgery. We assessed isometric muscle strength by measuring peak hip torque per body weight with a robotic dynamometer during abduction, flexion, and extension. No significant performance differences were observed between operated and nonoperated hips of THA subjects. THA subject operated and nonoperated hips generated significantly less peak torque per body weight during flexion (p = 0.03) compared with community-dwelling older adult hips (THA subject operated hips = 6.96 ft-lb/lb, THA subject nonoperated hips = 8.26 ft-lb/lb, community-dwelling older adult hips = 11.56 ft-lb/lb). No significant differences were observed between THA subjects and community-dwelling older adults during hip extension (p = 0.55) or abduction (p = 0.17). At 4 to 5 months postsurgery, THA subjects were not at the same level of biomechanical performance as community-dwelling older adults. Significant strength deficits were found in THA subject operated versus nonoperated hips during isometric flexion. Additional or modified physical therapy that targets the hip flexors is recommended after THA.

Aged↗