[093] RELIABILITY AND VALIDITY OF ACCELEROMETRIC GAIT AND BALANCE
Eric E. Sabelman, PhD; Carol H. Winograd, MD; Betty
Troy, MS; Ruth Yap, MS; Deborah Kenney, MS, OTR; Sandra Dunn
Gabrielli; David L. Jaffe, MSEE
Rehabilitation R&D Center, VA Palo Alto Health Care
System, Palo Alto, CA 94304; Department of Functional
Restoration, Stanford University Medical School, Stanford CA
94305; email: sabelman@roses.stanford.edu
Sponsor: Department of Veterans Affairs, VA
Rehabilitation Research and Development Service, Washington,
DC 20420
(Project #E601-3RA)
PURPOSE--The sense of balance declines with age due to combined vestibular, proprioceptive, and visual losses, resulting in impaired mobility and increased risk of injurious falls. Accelerometry is clinically useful as a diagnostic tool to quantify hitherto qualitative measures of balance, as a biofeedback device during therapy, and as a fall-prevention aid--a balance orthosis for fall-prone, elderly individuals. In this phase of the project, we will establish statistical reliability and validity by comparison of accelerometry with conventional laboratory gait and balance measures (force platform, goniometry, and video imaging) using elderly subjects having well-defined gender, age, and mobility status.
METHODOLOGY--The accelerometric motion detection system consists of two small 3-axis sensors attached to the corners of eyeglass frames to measure head motion, a sensor above each hip on a belt at the waist, amd a self-contained data acquisition package. An infrared remote control commands the wearable unit, so the wearer is unencumbered by cables. In a typical test, subjects perform tasks derived from qualitative balance assessment protocols, including: stand eyes open, then closed; rise from and sit in chair; normal walk 10 m; tandem (toe-to-heel) walk 3 m.
Factors that affect consistent interpretation of accelerometric data include: 1) mechanical and electronic stability, 2) installation and calibration (inter-rater reliability), 3) test-retest reliability, 4) accuracy vs. accepted techniques (concurrent validity), and 5) presentation of accelerometric results in a form comparable to currently accepted measures. We are enrolling 240 control subjects to be grouped by gender and age decade (60s, 70s, 80s). Differences between initial and retest values and between accelerometric and conventional measures will be compared using appropriate statistics.
PROGRESS--To date, 43 of the required 240 subjects have received repeat testing, using a protocol to obtain simultaneous accelerometric, video, force platform, and goniometric data. Student assistants at the undergraduate and high school level have assisted in subject testing. A simplified protocol, usable off-site at senior centers and recreation facilities, has been developed that should permit larger numbers of subjects to be tested in a day. Data from subject populations comprised of persons with stroke, Parkinson's disease and hip arthroplasty, as well as control subjects induced to stumble in the laboratory, are being analyzed. Collaborators have used the method to study therapeutic interventions in fall-prone elderly subjects, standing balance, and fatigue in walking, in a variety of subjects. Some investigators are specializing in analysis of specific diagnostic tasks such as sit-to-stand and reaching. Collaborations have been established to develop special-purpose devices for identifying and preventing lateral falls likely to result in hip fracture and for combined head- and eye-tracking for vestibular research. For both these potential application areas, a private company is interested in negotiating a cooperative R&D agreement. Another collaboration to apply the accelerometric method to the diagnosis and treatment of movement disorders in Parkinson's Disease and peripheral neuropathy has been established among researchers in VA Palo Alto Neurology Service, the Parkinson's Institute and University of California-San Francisco.
FUTURE PLANS--In addition to its use as a diagnostic, therapeutic and fall-prevention tool for balance-impaired elderly individuals, real-time accelerometric pattern analysis and feedback can be applied to prevention of reinjury following occupational rehabilitation, and to athletic training.
[094] ADVANCED ACCELEROMETRIC MOTION ANALYSIS SYSTEM (DESIGN/DEVELOPMENT)
Eric E. Sabelman, PhD; Alan Nakahara, MS; David L.
Jaffe, MS
Rehabilitation R&D Center, VA Palo Alto Health Care
System, Palo Alto, CA 94304; email:
sabelman@roses.stanford.edu
Sponsor: Department of Veterans Affairs, VA
Rehabilitation Research and Development Service, Washington,
DC 20420
(Project #E2182-DA)
PURPOSE--Accurately assessing balance and mobility impairment is important for diagnosing and reducing risk of falls, formulating individualized therapies, and monitoring patient progress. Our prior projects have led to the creation of a wearable instrument with wide potential as a diagnostic and therapeutic tool. This project seeks to 1) build and test newly designed post-second (2+) generation equipment and to compare alternative wearable computers; 2) develop software for extracting clinically useful information to make full use of the system's new capabilities, 3) compare results with those obtained using the earlier version, and 4) carry out testing of the advanced system by potential commercial manufacturers and distributors followed by support of further development via a cooperative R&D agreement.
Under an earlier project, we tested subjects as they performed 65 standardized activities, including standing, reaching, bending, walking, and simulated activities of daily living. Algorithms were developed using accelerometric data directly, rather than calculating velocity or position. Currently, we intend to establish reliability and validity of this approach, compared to laboratory-based motion analysis.
PROGRESS--Technical development of accelerometric body motion analysis is continuing by means of three main precommercialization activities:
2+-generation construction and testing: a benchtop system for extracting data from a single digital accelerometer has been tested and its internal data-handling and communicaiton programs are being refined. The new system will be tested using the same methods as the first system (sensor drift, sensitivity to misalignment, and so forth). Attention is being paid to alternative methods of sensor and computer mounting on the body, to accommodate users with special needs. A multilink simulator is being built to reproduce complex body motions like sit-to-stand without artifacts due to human subjects.
Software adaptation: Software for extracting sway angle, time to completion, and the like, from standard tasks using the new system's capabilities, such as real-time alarms and interaction with therapist, is being written. The software allows a therapist to enter protocols for a whole day's balance diagnosis patients, to enter changes as patients are being tested, to include data from timers or footswitches, and to output visual or tactile stimuli intended to improve a patient's performance.
Technology transfer: Palo Alto Rehabilitation R&D has contacted over 50 companies in the fields of industrial motion/vibration analysis and physical therapy/diagnostic equipment. We also plan to contact companies in the new field of wearable computers, who typically need nonmilitary markets for their products. Discussions are under way with two of these companies.
FUTURE PLANS--Results from control subjects will be compared to the first generation database and to conventional measures (force platform, goniometry, qualitative gait, and balance score). Two additional sets of 2+-generation equipment will be assembled. Training literature and videotapes will be updated to reflect changes from the first generation. The second system will be given to the Technology Transfer Section for demonstration to selected users and manufacturers. The third system will be available to a commercial partner for preproduction trials and modifications. The technology has commercial possibilities in clinical diagnosis of fall risk of patients in nursing homes and hospitals; in addition, it has potential uses in athletic and occupational injury prevention and rehabilitation.
[095] IMPROVING STEPPING-OVER RESPONSES IN THE ELDERLY USING SIMULATED OBJECTS
David A. Brown, PhD, PT; David L. Jaffe, MS
VA Palo Alto Healthcare System, Rehabilitation Research
and Development Center, Palo Alto, CA 94304; Northwestern
University Medical School, Programs in Physical Therapy,
Chicago, IL 60611-2814; email: jaffe@roses.stanford.edu;
d-brown1@nwu.edu
Sponsor: Department of Veterans Affairs, VA
Rehabilitation Research and Development Service, Washington,
DC 20420
(Project #E2167-2RA)
PURPOSE--The long-term goal of this work is to construct and test a system for elderly individuals at high risk for falling, one that employs techniques to monitor and improve their stepping-over response time and trains them in more effective movement strategies. This method is expected to be safer than conventional training and more rapid and precise in the feedback it provides to the patient.
METHODOLOGY--Simulated obstacles of various heights and lengths will be presented to subjects wearing a head-mounted display as they walk on a treadmill. Foot position will be monitored by a computer to detect collisions between the virtual object and the users' feet. During trials, vibrotactile feedback will be presented to the heel or toe of the foot involved in a collision.
PROGRESS--In the past 4 mo a laboratory setup has been developed. Subjects will wear an overhead harness to prevent injury in the case of a fall during treadmill walking. A color video camera will be trained on the subjects' legs from the side. This real-time image will be viewed by the subject wearing a head-mounted display. The computer will add virtual images of rectangular objects of varying heights and lengths at the subjects' feet. The subject will be instructed to step over the obstacles on each step. The computer will capture the images and detect any intersection of the user's feet with the virtual obstacles. A collision by the toe on the front edge of the object would indicate that the subject has not lifted the foot high enough, while a collision with the heel on the top of the object would indicate that the subject has not stepped far enough. Foot switches determine which foot is off the ground. The vibrotactile feedback would then be directed to the heel or toe of the foot that caused the collision.
PRELIMINARY RESULTS--Our pilot project work has led to the four main conclusions regarding stepping over obstacles during overground walking. The most successful technique involves displaying a side-view of stepping on a treadmill while the viewer repeatedly negotiates computer-generated obstacles. Young, healthy persons step over higher objects by increasing knee and hip flexion. This same strategy is employed when stepping over virtual obstacles during treadmill walking. Young, healthy persons step over longer objects by increasing stride length. This same strategy is employed when stepping over computer-generated obstacles displayed during treadmill walking. In a small group of elderly subjects, the proposed training regimen showed a positive result in that subjects were better able to negotiate the course after three training sessions. A randomized, controlled study must be conducted to separate out the nonspecific effects.
FUTURE PLANS--Future studies include studies on frail elderly individuals with a history of falls to determine whether this intervention can result in reduced frequency of falls. In addition, we plan to further develop the system so that it can be used in a wide variety of clinical settings and clinical populations.
Future work in this project area could include employing simulation techniques with walking aids such as canes and crutches. Other potential areas of research include the study of improvements in fitness and gait through simulation of walking situations for ambulatory nursing home patients and teaching environmental factors and modifications to avoid falls. The system could provide an enjoyable and safe environment for general exercise, a safe setting for "wanderers," or a simulated practice session for wayfinding and familiarization of nursing home patients with their facility.
[096] LONG-TERM STRENGTH TRAINING AND FUNCTIONAL STATUS IN OLDER ADULTS
Lisa Boyette, MEd; L. Jerome Brandon, PhD; Beth Sharon,
MS
Atlanta VA Medical Center, Rehabilitation Research and
Development Center (151R), Decatur, Georgia 30033; HEC,
Atlanta, Georgia 30329; email:
Boyette.Lisa_W@Atlanta.VA.gov
Sponsor: Department of Veterans Affairs, VA
Rehabilitation Research and Development Service, Washington,
DC 20420
(Project #E721-4RA)
PURPOSE--This 3-year study is designed to investigate the effects of longitudinal strength training and flexibility exercises on muscle strength, muscle mass, and functional status in typical older adults (controls) and older diabetic adults. Specifically, this project is evaluating the effects of a 2-year muscle fitness program (strength and flexibility training) with four groups of older participants: controls receiving the strength training intervention (TYPICALEX), controls continuing regular lifestyle patterns (TYPICALREG), diabetics receiving the exercise intervention (DIABEX), and diabetics who continuing regular lifestyle patterns (DIABREG).
METHODOLOGY--A repeated measures experimental design is being employed in this study. Outcome measures include muscular strength and endurance, body composition, muscle mass, flexibility, functional status, exercise adherence, and quality of life. We have recruited 30 subjects for each group: 60 controls (65-85 years of age) for TYPICALEX and TYPICALREG, and 60 persons with diabetes (50-70 years of age) for the DIABEX and DIABREG.
Muscle strength and endurance are being measured by a Chattanooga KIN-COM Isokinetic System and for one repetition maximum on a Nautilus multistation system. Balance is being evaluated by a Neurocom Equitest Dynamic Posturography device. Body composition will be assessed using a Harpenden skinfold caliper with a measurement scale precision of 0.2 mm. Muscle mass will be estimated from circumferences and skinfolds. Flexibility will be assessed using a goniometer measuring the actual range of motion for each specific joint. A modification of the Physical Performance Test (PPT) will be used to assess functional ability. Exercise adherence will be assessed using the Physical Exercise Profile (PEP).
The training sessions will be held for 1 hour every Monday, Wednesday, and Friday for the first 6 mo; thereafter, subjects will attend at least twice weekly. Subjects will complete three sets of 8-12 repetitions at each of 50, 60, and 70 percent of their 1RM; the 1-hr session consists of 50 min of strength training and 10 of flexibility exercises. All subjects will be measured at 6-mo intervals during the training.
PROGRESS--At this writing, 27 TYPICALEX and 23 DIABEX have gone through the first 6 mo and are presently in training; 21 TYPICALREG and 15 DIABREG have completed the 6-mo testing. Twenty-seven TYPICALEX and nine DIABEX have completed the 1-yr evaluation, as have seven TYPICALREG and six DIABREG.
FUTURE PLANS--This research will assist healthcare professionals in establishing guidelines for strength training and flexibility exercises to improve functional ability and independence in aging persons with and without diabetes.
[097] RESTRICTED USEFUL FIELD OF VIEW AS A RISK FACTOR FOR FALLS IN OLDER ADULTS
Lisa Riolo, PhD, PT
Veterans Affairs Rehabilitation Research and Development
Center (151R), 1670 Clairmont Road, Decatur, GA 30033;
email: lriolo@emory.edu
Sponsor: Department of Veterans Affairs, VA
Rehabilitation Research and Development Service, Washington,
DC 20420
(Project #C2140-2RA)
PURPOSE--The purpose of this 3-year study is to investigate the useful field of view (UFOV) as a risk factor for falls in older adults. The proposed research is designed to address the following research questions: 1) Is UFOV an independent predictor of fall occurrence; 2) How does UFOV correlate with measures that have been associated with falls in older individuals (working memory, general cognition, hip flexor and ankle dorsiflexor muscle strength, balance, contrast sensitivity, visual acuity, visual fields, and depth perception); and 3) can UFOV be used to predict frequency of falls?
METHODOLOGY--Risk factors for falls most often studied include impaired sensation, motor control and cognition, environmental hazards, and side effects of medications. One element that blends consideration of sensory impairment with cognition is visual attention. UFOV is a measure of visual attention that requires individuals to select objects from their visual field and simultaneously attend to multiple stimuli. UFOV is a composite score of three different aspects of visual attention: visual processing speed, divided attention, and selective attention. Although the literature supports sensory vision as a predictor of falls, the perceptual requirements of ambulating in a dynamic environment have not been assessed as a potential risk factor for falls in older individuals. UFOV is an ability that can be improved with training to reduce risk of injury and debilitation that results from falls.
This will be a prospective study of 200 individuals who are at relatively high risk for falls (unable to descend steps without using a handrail). Each subject will undergo a comprehensive set of measures that have previously been shown to be associated with falls in the older population. In addition to UFOV, measures of hip flexion and dorsiflexion muscle strength, functional reach, timed up and go, Mini-Mental Status Examination, backward digit recall, spatial working memory, contrast sensitivity, visual acuity, visual fields, and depth perception will be performed during one visit to our Center. Subjects will be followed for 12 mo to collect data on fall occurrence. All data will be evaluated for normality by comparing them to the standards used in protocols for relevant age groups. Data will be summarized descriptively and graphically. Multiple regression analysis will be used to determine the extent to which UFOV predicts falls, a series of correlation analyses will be used to study the relationship among the independent variables, and a linear model with UFOV as the independent variable will be used to determine the ability of UFOV to predict frequency of falls. The interactions among visual perception and measure of fall risk factors are important to the rapidly aging veteran population and may provide insights to wellness and rehabilitation for these individuals. This study area may also have a significant impact on the costs associated with medical treatment required as a consequence of falls.
PROGRESS--The study has been in progress for 4 mo at this writing. The protocol has been finalized, the lab has been set up with necessary equipment, the research assistants have been trained in the protocol, the reliability of measures has been documented, and subject recruitment has begun. Two subjects have completed the protocol and four are scheduled to do so.
FUTURE PLANS--Once UFOV has been shown to predict falls in older adults, a training protocol will be implemented to improve visual attention. The effects of visual attention training on reducing fall occurrence will then be studied in another sample of older adults.
[098] BEHAVIORAL AND FUNCTIONAL PROBLEMS IN DEMENTIA PATIENTS WITH SENSORY LOSS
Bettye Rose Connell, PhD
Rehab R&D Center on Geriatric Rehabilitation (151R),
Atlanta VA Medical Center, Decatur, GA 30033; email:
BRConnell@aol.com
Sponsor: Department of Veterans Affairs, VA
Rehabilitation Research and Development Service, Washington,
DC 20420
(Project #E2044-2RA)
PURPOSE--This 2-yr, multisite study describes the functional and behavioral problems experienced by demented nursing home (NH) patients with sensory impairments and analyzes the relationships among cognition, sensory status, functional status, and behavioral disturbance in this population.
METHODOLOGY--NH staff familiarity with patients' health status and daily functioning are coupled with clinical testing to characterize cognitive and sensory status, along with functional and behavioral problems. Study sites are the Durham, Salisbury, and Atlanta VAMC ECRCs, and the Coble Health Center at the Methodist Retirement Center in Durham, NC.
PROGRESS--Data collection has been completed for 89 (of 150) subjects. Consent and data collection for the remaining subjects are in process.
PRELIMINARY RESULTS--Overall, the sample is severely demented (MMSE mean/SD=11.5/7.9, mode=1) with moderate visual acuity impairment (logMAR acuity mean/SD=0.62/0.37). Half have moderate or greater contrast sensitivity impairment. The ability to see in adequate light with glasses if used (everyday vision) of about three-quarters of the subjects was rated by staff as impaired. Thirty-four percent require assistance or are fully dependent in walking/transfer activities, and 58 percent require assistance or are fully dependent in complex ADLs. Several types of behavioral disturbance occurred once a week or more often in one-fourth or more of the subjects: cursing (32 percent), wandering (32 percent), complaining/negativism (33 percent), constant requests for attention or help (29 percent), and repetitive verbalizations (25 percent). Preliminary analyses of bivariate relationships show significant relationships between cognition and aggressive behaviors, physically nonaggressive behaviors, complex ADLs, acuity, contrast sensitivity, and everyday vision. There were also significant relationships between acuity and contrast sensitivity impairment, everyday vision, verbally agitated behaviors, and complex ADLs. Finally, there were significant bivariate relationships between walking/transfer limitations and verbally agitated behaviors, and between complex ADLs and verbally agitated and physically non-aggressive behaviors. There was a strong relationship between walking/transfer limitations and complex ADLs.
Number of medical diagnoses, MMSE score, logMAR acuity, contrast sensitivity impairment, everyday vision, and walking/transfer limitations, along with everyday vision×walking/transfer (model 1) or logMAR acuity×walking/transfer (model 2) were used as predictor variables in hierarchical regression analyses and accounted for 57 percent (model 1) and 59 percent (model 2) of the variance in complex ADL dependence. MMSE score, walking/transfer, and the interaction terms were significant predictors in both models. Everyday vision was significant in Model 1 and logMAR acuity in Model 2. Further regressions were performed using walking/transfer limitation, logMAR acuity, and their interaction as well as walking/transfer limitation, everyday vision, and their interaction in predicting ADL dependence. The models were similar in terms of the variance in ADL dependence explained (48 and 47 percent, respectively). In the model using logMAR acuity, all three predictors were significant. In the model using everyday vision, only the main effects were significant. Walking/transfer limitation has a partial mediation effect on the relationship between everyday vision and ADL dependence. Preliminary multivariate analyses have not yet been completed for the other dependent variable of interest, dementia-related disruptive behavior.
FUTURE PLANS--An intervention study is being planned to examine the effect of improved lighting conditions on ADL dependence, mobility, and dementia-related disruptive behavior in demented NH residents.
[099] NONINVASIVE RECORDINGS OF BLADDER PRESSURE IN ELDERLY MALES
James S. Walter, PhD; John S. Wheeler, MD; Jerome Sacks,
PhD,; Margot S. Damaser, PhD; Paul Zaszczurynski
Rehabilitation Research and Development Center, VA Hines
Hospital, Hines, IL 60141; Loyola University Medical Center,
Department of Urology and Physiology, 2160 South First
Avenue, Maywood, IL 60153
Sponsor: Department of Veterans Affairs, VA
Rehabilitation Research and Development Service, Washington,
DC 20420
(Project #B2025-RA)
PURPOSE--Obstructive voiding often occurs in elderly male individuals. The obstruction is best evaluated with urodynamics, including bladder pressure and urine flow rates. Until recently, recording bladder pressure required passing a catheter through the urethra into the bladder. As an alternative, we are evaluating a noninvasive, back-pressure (BP) recording method. In this project, we assess the reliability and accuracy of the BP recording techniques.
METHODOLOGY--BP recording was conducted with a modified commercial condom catheter (Model Large, Rochester Medical) placed on the penis. An outlet tube was inserted into the side of the condom for pressure recording while clamping the condom exit tube. To evalute pressures during BP procedures, we also passed a small urethral catheter through the condom into the bladder. This allowed us to get simultaneous bladder and BP measurements. Rectal pressures were also recorded.
Eleven subjects with voiding complaints signed informed consent and participated. Studies were conducted in the standing position, and the BPs were obtained at peak urine flow rate. The outlet tube of the external condom was clamped for 1-3 s, and the pressure in the external condom was recorded. The bladder was filled once or twice for repeated voiding studies. The clamping procedure on the outlet tube of the condom induced a back flow of urine that facilitated BP recording. BPs were compared to recorded bladder pressures with the urethral catheter and to detrusor pressures obtained by subtracting the rectal pressure from the bladder pressure.
PROGRESS--BPs recorded during urination and clamping of the external condom were obtained in 10 patients. One additional patient, whose bladder pressure had been recorded during micturition with a urethral catheter prior to this procedure, had BP recorded without catheter.
RESULTS--A typical BP recording showed increases in pressure that reached a plateau in 1 to 5 s. This plateau value was used as an external measure of the internal bladder pressure. The BPs (48±16 cm H2O; N=17 from 11 subjects) were 20 percent higher than detrusor pressures (40±9 cm H2O) but were not significantly different.
Some BP recordings did not reach a stable plateau but had peaks and troughs in the pressure record during clamping. These may have resulted from closure of the urethra during clamping. The pressure and urine flow results from these diagnostic procedures were placed in the patients medical record for use by the urologist.
FUTURE PLANS--Noninvasive recording of bladder pressure could facilitate the diagnosis and treatment of obstructive voiding symptoms. Further studies are proposed that will continue to use simultaneous BP and bladder pressure recording. The possible transmission of abdominal pressures to the BP record will be assessed by having the patient conduct abdominal straining during BP recordings. Procedures will also be conducted in the supine position to test the effects of the abdominal pressure. Additional parameters for BP recording are being tested including clamping procedures, leakage problems, and condom catheter design.
[100] ELEVATED POSTURAL MUSCLE ACTIVITY IN ELDERS AND ITS EFFECT ON QUIET-STANDING DYNAMICS
James J. Collins, PhD; Bryce L. Greenhalgh, BS; Ann E.
Pavlik, BS; A.T. Stamp; Lewis A. Lipsitz, MD
Department of Biomedical Engineering, Boston University,
Boston, MA 02215; Hebrew Rehabilitation Hospital and Harvard
Medical School, Boston, MA 02131; email:
jcollins@enga.bu.edu
Sponsor: Department of Veterans Affairs, VA
Rehabilitation Research and Development Service, Washington,
DC 20420
(Project #E756-4RA)
PURPOSE--Our objectives were to examine cross-sectionally age-related changes in postural control dynamics and to gain insight into the physiological meaning of stabilogram-diffusion analysis (SDA) parameters extracted from quiet-standing posture data. Specifically, we tested the hypotheses that: 1) healthy older adults adopt a postural control strategy whereby they increase the level of muscular activity across the joints of their lower limbs, and 2) lower-limb muscle activity levels are directly correlated with SDA measures of short-term postural sway.
METHODOLOGY--Twenty nonimpaired young subjects (21-28 years) and 20 nonimpaired older adults (72-83 years) were studied under quiet-standing conditions for multiple 60-s trials. A force platform was used to measure the time-varying displacements of the center of pressure (COP) under the feet of each. Surface electromyographic (EMG) signals were recorded bilaterally from five lower-limb muscles: tibialis anterior, soleus, gastrocnemius, vastus lateralis of quadriceps, and biceps femoris of hamstrings. The COP trajectories were analyzed as one-dimensional random walks, according to SDA. We considered two SDA measures of short-term postural sway: short-term scaling exponents and short-term effective diffusion coefficients.
PROGRESS--The following parameters were computed from the EMG signals: 1) the mean root-mean-square (RMS) amplitude of each muscle, 2) ON%: the percentage of trial time for which a given muscle was activated, and 3) AON%: the percentage of trial time for which both muscles in an antagonistic muscle pair were simultaneously activated.
RESULTS--We found the RMS amplitude and ON% of each muscle and the AON% of each antagonistic muscle pair, respectively, to be significantly greater in the elderly subjects. We also found the RMS amplitude of hamstrings to be significantly correlated with the short-term anteroposterior (AP) scaling exponent and the short-term AP effective diffusion coefficient, respectively. We also found the ON% of hamstrings to be significantly correlated with the short-term AP effective diffusion coefficient.
IMPLICATIONS--This study demonstrated cross-sectionally that healthy aging is associated with elevated postural muscle activity during quiet standing. This work also showed that SDA parameters can be directly related to the neuromuscular mechanisms underlying balance control.
[101] TRUNK FUNCTION AND RISING FROM A BED IN NURSING HOME OLDER ADULTS
Neil B. Alexander, MD; J.C. Grunawalt, RNC; J.
Augustine, BA; S. Carlos, BA; A.B. Schultz, PhD; J.A.
Ashton-Miller, PhD; V. Skiba
Geriatrics Center, University of Michigan, Ann Arbor MI
48109-0926; GRECC Department of Veterans Affairs Medical
Center, Ann Arbor MI, 48105; email:
nalexand@umich.edu
Sponsor: Department of Veterans Affairs, VA
Rehabilitation Research and Development Service, Washington,
DC 20420
(Project #E2023-RC)
PURPOSE--We previously found that trunk and extremity movements help characterize bed rise difficulty in community older adults. What is the importance of the trunk and extremities in nursing home older adults who require bed transfer assistance?
METHODOLOGY--We compared the bed rise performance of independent, retirement center-dwelling older adults (RC, n=29, mean age=84), with nursing home older adults requiring assist in transfers from bed (NH, n=20, mean age=77). As a marker of difficulty, we timed subjects as they rose from supine to sitting at the edge of a bed (SS). Subjects performed 21 bed mobility tasks (BMT), focusing on the contribution of the trunk and extremity movements to rising from bed, including a 10-s lateral trunk lean (LTL), and a 10-s single leg elevation off the bed surface (ELG). To facilitate trunk elevation in the very disabled, subjects also sat up in bed with the addition of an overhead trapeze (TRA) and with 30° elevation of the head of the bed (HBE).
RESULTS--Using a hand-held stopwatch, the NH were slower in SS (mean seconds±SD, RC 5.3±5.2, NH 14.7±17.0, p<0.005). There were few differences in ability to perform BMT between RC and NH; challenging tasks such as LTL were equally difficult for both groups (42 percent NH vs. 41 percent RC unable), while few subjects had trouble with easier tasks such as ELG (range of 0-16 percent unable in both groups). Twenty percent of NH were unable to complete TRA (vs. none of RC, p<0.01). In addition 20 percent of NH (vs. 3 percent of RC) were unable to complete HBE (p<0.03). Stepwise regression was then used to determine which BMT might best predict SS. Only TRA was significant, predicting 29 percent of the variance in rise time (p<0.005).
IMPLICATIONS--In summary, these data suggest that the ability to perform two sitting-up in bed tasks, using a trapeze and with head of the bed elevation, may be useful in identifying older adults with difficulty in rising from a bed. Frail older adults unable to perform these two tasks may have such severe trunk elevation difficulty that rehabilitation might focus on trunk strengthening to improve bed rise performance.
[102] PREVENTING SLIPS AND FALLS IN THE ELDERLY: EFFECTS OF SIMPLE BIOMECHANICAL INTERVENTIONS
Lars I.E. Oddsson, Dr Med Sc; Carlo J. De Luca, PhD;
Jonathan Bean, MD
NeuroMuscular Research Center, Boston University,
Boston, MA 02215; Physical Medicine and Rehabilitation
Service, Boston VA Medical Center, Boston, MA 02130; email:
loddsson@bu.edu
Sponsor: Department of Veterans Affairs, VA
Rehabilitation Research and Development Service, Washington,
DC 20420
(Project #E2184-RA)
PURPOSE--Acute injuries occurring as a result of slips and falls are a common source of morbidity, impairment and even death, thus constituting a serious public health problem in association with high health care costs. A better knowledge about mechanisms causing slip and fall injury events will help prevent such injuries from occurring.
The overall long-term objective of the proposed project is to provide new knowledge to decrease the number of slip and fall injury events that occur in our community, especially in the elderly.
Balance loss is by definition the beginning of a fall. Thus, a balance disturbance, such as a slip, constitutes a risk situation for acute injuries, especially if the person is lifting, carrying or reaching for a load. All voluntary movements are accompanied by so called associated postural adjustments. These involuntary "automatic" movements are smoothly incorporated into our movement repertoire to ensure accurate and harmonious motion. Any external perturbation of balance triggers activation of specific muscle synergies which act to restore balance. These well-known mechanisms have been studied mainly during upright quiet stance, whereas effects of balance perturbations occurring during an ongoing voluntary movement, are virtually unknown. This project will explore such situations in a younger and an elderly population of healthy subjects.
Our basic hypothesis is that certain combinations of balance perturbation and voluntary movement cause a "conflict" between motor commands, simultaneously requiring different functions of a certain muscle/muscle group, one related to the voluntary movement and one related to the postural perturbation. This conflict may increase the risk of a fall injury event. Elderly subjects react differently from younger ones in this situation, which makes them more susceptible to slip and fall injuries.
The short-term objectives of this study are to establish:
METHODOLOGY--Kinematics and muscle activity information will be acquired during combinations of voluntary reaching and balance perturbation. A total of 32 young control subjects (ages 18-45) and 32 elderly controls (above the age of 65) will be tested in the current project. It is believed that new knowledge acquired from this project will provide an important basis for the understanding and design of efficient intervention programs for prevention of slip and fall related injuries. The project will be conducted in collaboration between the NeuroMuscular Research Center and the Boston VA Medical Center. We will use an advanced computerized balance platform termed BALDER (BALance DisturbER) to realistically simulate slip and fall situations in the laboratory.
PROGRESS--The development of the experimental setup and protocol is almost finished. Subjects will be standing behind a table and a set of shelves during the experiments thus excluding the use of traditional camera-based systems to record kinematic information due to obstructed views of the subject. To resolve this problem we have acquired an electromagnetic system that provides kinematic information in real-time with 6 degrees of freedom, through a series of small receivers attached to the subject at locations of interest. This system will be synchronized with the acquisition systems for EMG and ground reaction data. A system of aluminum tubing has been attached to the ceiling above the BALDER platform to support the table top and shelves to be used during the load handling experiments. Software for acquisition of data has been developed and implemented on the computer controlling the BALDER platform.
PRELIMINARY RESULTS--Randomized sequences of perturbations have been applied to subjects to assess the level of perturbation that is required to force an individual to lose balance. Subjects are more sensitive to backward perturbations than lateral and forward ones. The test protocol will be adjusted to incorporate these results.
FUTURE PLANS--The experimental setup will be tested with complete data collection during November 1998. Data collection on the young subject population will begin immediately afterwards. Testing of the elderly will begin during the spring of 1999.
[103] LONG-TERM EVALUATION OF MAXILLARY SINUS BONE GRAFTS WITH DENTAL IMPLANTS
Jon Tom McAnear, DDS; Pirkka V. Nummikoski, DDS, Marden
E. Alder, DDS
South Texas Veterans Healthcare System, Audie L. Murphy
Memorial Veterans Hospital Division (160A), 7400 Merton
Minter Boulevard, San Antonio, Texas 78284-0001
Sponsor: Department of Veterans Affairs, VA
Rehabilitation Research and Development Service, Washington,
DC 20420
(Project #A649-3RA)
PURPOSE--Dental implants can greatly improve oral function. However, many candidates for the procedure have resorbed too much bone to support maxillary implants. Our first studies were designed to determine whether autologous cortico/cancellous bone grafts from the ilium to the maxillary sinuses will mature (consolidate) and support titanium cylindrical implants that will, in turn, support a fixed prosthesis capable of withstanding the masticatory forces of a similar prosthesis in the mandible. It is expected that this protocol will determine whether the bite force of subjects will be less than, remain the same, or improve over that documented last year and whether the bone density at implant/graft bone interface will be less than, equal to, or greater than that at implant/native bone interface. Bone loss (height) at implant/bone interface will be measured.
METHODOLOGY--An attempt to recruit the 20 subjects who completed the treatment protocol in our earlier studies has been made: 18 have agreed to take part. These persons have had the following evaluations:
PROGRESS--Of the eighteen subjects who have agreed to take part in this 3-year protocol, all have been studied during the first year and sixteen have been studied, to date, during the second. Two are scheduled for study at this writing.
RESULTS--No data have as yet been analyzed.
[104] ASSESSMENT OF INTERVENTION EFFICACY FOR STRESS URINARY INCONTINENCE USING VESICO-URETHRAL PRESSUREGRAM METHOD
Kyu-Jung Kim, PhD; Catalin D. Jurnalov, MD; Maurice J.
Webb, MD; Deborah J. Lightner, MD; Raymond A. Lee, MD;
Kai-Nan An, PhD
Mayo Clinic/Mayo Foundation, Rochester, MN 55905; email:
kimk2@mayo.edu
Sponsor: Mayo Foundation, Rochester, MN 55905; National Institutes of Health, Bethesda, MD 20832
PURPOSE--Stress urinary incontinence (SUI) is the involuntary leakage of urine during activities, such as a cough or sneeze, that increase intra-abdominal pressure. The functional mechanisms of female continence function are not fully understood in clinical or research aspects. A new investigative method, urethro-vesical pressuregram analysis, has been developed for the analysis of female continence function by quantifying urethral functions into two parameters: Pura-intercept and slope of the regression line fitted to the cough pressure measurement data. The leak point pressure (PE) is predicted regardless of visible leakage using the two pressuregram parameters, enabling objective assessment. The purpose of this study is twofold: 1) Baseline study: to determine the leak point pressure through the pressuregram analysis along the urethral length for two different groups, premenopausal versus postmenopausal normal continent volunteers. 2) Clinical study: to build a clinical database for each patient which can enable pre- and postsurgical assessment of the urodynamic parameters including pressuregram parameters for each group of three anti-incontinence surgeries.
METHODOLOGY--We shall recruit 40 nonimpaired, multiparous, continent females, pre- and postmenopausal (20 in each group) for the baseline data and assessment of functional changes due to menopause. A dual micro-tip urethral catheter is used for the simultaneous measurement of intravesical (Pves) and intraurethral (Pura) pressures at selected urethral locations during coughing. Pura measurements are made during a series of three increasing cough efforts (light, medium, and strong) at proximal and midurethral locations. Valsalva leak point pressure will be measured at the midurethral location. Two resting urethral pressure profiles (UPPs) will be measured using the catheter puller. Statistical analyses are performed for the full sequence of coughs.
PROGRESS--At this writing, 11 nonimpaired volunteers and 7 stress incontinent patients before surgery have participated in the study.
RESULTS--Most continent women demonstrated a pressuregram slope greater than unity at midurethra while close to unity at proximal urethra. Pura-intercept ranged between 40 and 120 cm H2O. Preoperative urodynamic measurements for surgical patients demonstrated significantly smaller pressuregram slopes and intercepts.
FUTURE PLANS--Both continent women and surgical patients will be recruited for urodynamic measurement; 60 surgical patients will be divided into 3 groups of 20 patients each for Marshall, Marchetti, Krantz, modified anterior Kelly, Kennedy colporrhaphy, and paravaginal defect repair.
[105] TENSILE STRENGTH OF ENDOPELVIC FASCIA AND ITS ASSOCIATION WITH PELVIC ORGAN PROLAPSE
Catalin D. Jurnalov, MD; Kyu-Jung Kim, PhD; Maurice J.
Webb, MD; Kai-Nan An, PhD
Mayo Clinic/Mayo Foundation, Rochester, MN 55905;
email: Jurnalov.catalin@mayo.edu
Sponsor: Mayo Foundation, Rochester, MN 55905; National Institutes of Health, Bethesda, MD 20892
PURPOSE--The endopelvic fascia is that network of fibromuscular connective tissue attaching the bladder, uterus, vagina, and rectum to the lateral pelvic walls. This condensation of connective tissue supports the pelvic organs in concert with the levator ani muscles. Genitourinary prolapse is a common problem but the underlying physiology is unknown at present. The current research on the material properties of the endopelvic fascia will give us a better understanding of the role that mechanical forces contribute to the etiology of genitourinary prolapse. Knowledge of differences in fascial tensile strength between women with and without prolapse will allow us to better understand the role the endopelvic fascia has in the support of the pelvic organs vis-à-vis the role of the levator ani muscles and the innervation of the pelvic floor. This may lead to development of new surgical approaches for the reconstitution of the pelvic floor at the time of reconstructive surgery, or new means of increasing the strength of the supporting tissue of the pelvis. Alternatively, there may not be a difference in the groups studied, and the strength of the fascia may be less important. This may lead to more research into the mechanical properties of other pelvic structures responsible for prolapse.
METHODOLOGY--The International Continence Society approved Pelvic Organ Prolapse Quantification (POPQ) system was used to grade the stages of prolapse in the subjects used in this study. Pre- and postmenopausal women presenting for hysterectomy for pelvic organ prolapse and for other benign gynecologic causes not involving prolapse comprised the study population. Full thickness vaginal mucosa and underlying connective tissue, uterosaccral ligaments, and endopelvic fascia from the inferior aspect of the bladder were harvested. Tissue strips with standardized uniform cross-sectional areas were secured with special grips designed for the mechanical testing device. Using an INSTRON machine, the tissue was loaded in tension until failure. Ultimate tensile stress and stain at which tissue failure started were obtained.
PROGRESS--Seven (four with prolapse) pre- and seven postmenopausal women have participated in the study. Of the latter, three have prolapse and are on hormone replacement, three have prolapse and are not on HRT; the remaining woman does not have prolapse, and is on hormones.
RESULTS--Preliminary results demonstrated that the nonprolapse group of women had a significantly smaller ultimate tensile strain of 0.21 for posterior vaginal wall tissue with endopelvic fasica than the prolapse group, 0.51 (p<0.01). On the other hand, for the same tissue the prolapse group had a lower ultimate tensile strength (1.04 vs. 3.07 MPa, p<0.1). The Young's modulii of the nonprolapse group had higher values (14.0 vs. 2.1 MPa, p<0.03).
FUTURE PLANS--Approximately 150 women will participate in this study, 25 for each group depending on prolapse, parity, age, hormone replacement therapy and menopause.
[106] REHABILITATION RESEARCH AND TRAINING CENTER ON AGING WITH A DISABILITY: OVERVIEW AND RESEARCH PROJECTS
Bryan Kemp, PhD
Rehabilitation Research and Training Center on Aging with
Disability Rancho Los Amigos Medical Center, Downey, CA
90242; email: info@ranchorep.org
Sponsor: National Institute of Disability and Rehabilitation Research (NIDRR), U.S. Department of Education, Washington, DC 22202
PURPOSE--The Rehabilitation Research and Training Center on Aging with a Disability (RRTC), located at Rancho Los Amigos Medical Center, operates in collaboration with the University of Southern California (USC) and the University of California, Irvine (UCI). In view of the emerging public health issue of persons with physical disabilities experiencing a multitude of premature medical, functional, and psycho-social problems as they age, this Center was established to develop a coordinated program of research and training, and to advance basic knowledge of aging with a disability. The Center has a database of preliminary information on over 1,000 persons with polio, stroke, rheumatoid arthritis, cerebral palsy, and spinal cord injury which will be used for a longitudinal, cross-sequential study of aging and disability and for intervention studies.
RESEARCH PROJECTS--The Natural Course of Aging study will examine changes over a 10-yr period of a subsample of the database subjects in areas of health conditions, physical symptoms, functional changes, psychological impact, and social and vocational changes. The second set of studies will implement and test the effectiveness of different interventions designed to improve health care for the participants to meet their changing psycho-social and vocational needs. The intervention studies are: 1) assisting family caregivers of persons aging with a disability: a cross-ethnic comparison; 2) improving community integration and adjustment among persons aging with disability; 3) prevention of secondary complications in people aging with a disability; 4) improving bone density in people who are aging with a disability; and 5) effectiveness of assistive technology and environmental interventions in maintaining functional performance for persons aging with a physical disability.
TRAINING--This Center has established a variety of training activities designed to acquire and transfer both knowledge and skills learned from the Center to a wide audience of health professionals, consumers, family members, and community service providers. Some training components will include in-hospital training of medical students and residents, training in the geriatric medicine fellowship program at UCI, community and conference presentations, continuing education courses for professionals, and the development of a special conference on the Natural Course of Aging with Disability during the third year of the Center.
[107] EXERCISE PROGRAM DESIGNS FOR OLDER ADULTS
Lisa Boyette, MEd; James E. Boyette, MS
Atlanta VA Medical Center, Rehabilitation Research and
Development Center (151R), Decatur, Georgia 30033; HEC,
Atlanta, Georgia 30329; email:
Boyette.Lisa_W@Atlanta.VA.gov
Sponsor: Department of Veterans Affairs, VA
Rehabilitation Research and Development Service, Washington,
DC 20420
(Project #E825-3RA)
PURPOSE--This 2-year study will develop an exercise expert system that creates individualized exercise plans for older adults using factors, or determinants, that affect their starting and/or maintaining an exercise routine. The plans produced can be used by practitioners during routine medical visits to help older adults initiate and adhere to exercise programs.
METHODOLOGY--A knowledge base containing factors and recommended strategies affecting exercise in older adults, based on an extensive literature review and research findings conducted at the Atlanta VA Rehab R&D Center, will be critiqued by local and national experts in the fields of medicine, exercise physiology, health promotion, exercise psychology, psychometry, and gerontology. Using case-study analyses, the experts will develop a rule base defining the relationships between the determinants and the recommended strategies. Then, the knowledge base will be translated into a diagnostic questionnaire and implemented in a computerized expert system.
A meeting of all the experts will be held to validate the recommendations created by the system by group consensus. The expert system will be used as a consensus-building tool at the meeting: case studies of older adults will be analyzed using it, with the analyses focusing on examination of the exercise plans and strategies created in response to each subject's profile on exercise initiation and adherence determinants. The experts will independently rate the 29 determinants according to importance for initiation and adherence to exercise in older adults using a Likert scale. Discrepancies between recommended strategies in the plan and expert opinion will be cross examined until group consensus is reached concerning the appropriateness of the exercise plan developed for each older adult.
PROGRESS--The team has developed the Physical Exercise Profile (PEP) diagnostic questionnaire needed to gather appropriate exercise determinant information, validated the knowledge base and rule base underlying the expert system, and created output report formats. The PEP has also been revised based on pre-testing by 53 older adults. The PEP and the decision rules are now implemented into the computerized expert system. During the workshop, the experts critiqued all of these decision rules. Both inter-rater reliability and criterion validity were found to be at acceptable levels (>0.80) by all expert groups. There was an 88 percent agreement that the user interface was excellent in terms of user-friendliness. The remaining raters rated it as good.
FUTURE PLANS--The goal of the next project is to measure the effectiveness of the system on exercise habits by examining the differences between the exercise patterns of two groups of ambulatory elderly individuals, one of which receives the exercise assessment and counseling protocol (EACP). The key behavioral outcome of exercise--adherence to a regimen--will be investigated by self-report data using the EACP and by fitness testing, consisting of strength, aerobic, and flexibility measures. The second objective is to measure the impact of the EACP on a person's quality of life, health maintenance, and functional status.
[108] A STUDY OF POLICY BARRIERS IMPEDING USE OF ASSISTIVE TECHNOLOGY BY PERSONS AGING WITH DISABILITIES
Phoebe S. Liebig, PhD; Debra J. Sheets, ABD, RN; Mary
Froehlig, BA
Andrus Gerontology Center, University of So. California,
University Park, Los Angeles, CA 90089-0191; email:
dsheets@frazmtn.com
Sponsor: Rehabilitation Research and Training Center on Aging with Disabilities, Rancho Los Amigos Medical Center, Downey, CA; National Institute on Disability and Rehabilitation Research (NIDRR), U.S. Department of Education, Washington, DC 22202
PURPOSE--The purpose of this research is to describe current patterns of assistive technology and home modification (AT/HM) use and recent changes in patterns of use; examine the impact of AT/HM on health status and on quality of life issues; identify the barriers, both attitudinal and financial, which may limit access to AT/HM; investigate the adequacy of current policies on AT/HM; and identify the need, if any, for policy changes.
METHODOLOGY--Three separate studies were conducted. The first involved a mail-back survey of state-level vocational rehabilitation and blind and visually impaired agencies; its objectives were to examine agency policies and programs for providing AT/HM to middle-aged and older persons; to identify possible explanations for barriers that impede access to AT/HM; and to explore changes that would promote AT/HM availability. The second study involved a telephone survey of AT/HM efforts among state units on aging (SUA) in 10 states selected as exemplars in providing access to AT/HM. This survey focused on a range of issues, including agency priorities and capacity to meet the AT/HM needs of older adults; barriers that limit access to AT/HM; innovative strategies; and state-level policy efforts. The third study conducted in-home interviews with consumers aging with long-standing physical disabilities (i.e., polio, rheumatoid arthritis (RA), and stroke). Our primary objective was to describe access to, use of, and unmet need for AT/HM.
PROGRESS--We have completed state-level and SUA data collection; analysis of the first is underway. On the second, analysis is complete and a technical report in process. We are continuing the ongoing analyses of the consumer data.
RESULTS--Preliminary results from the rehabilitation study indicate that lack of funding remains the primary barrier limiting the provision of AT/HM. Others include problems of interagency coordination and the need to increase training and awareness about AT/HM.
The SUA study indicates that only about one-half of these agencies have given any attention to considering the AT needs of older adults with disability. Only one state reports collecting data on the needs of older adults with disability and only 20 percent felt that AT/HM was an important issue for their agency. The SUAs noted that they lack adequate funding and/or training to improve access to AT/HM. Despite these issues, several innovative strategies for improving access to AT/HM were identified. Examples include using an interagency shared application form to streamline eligibility, targeting seniors using AT/HM outreach programs, sharing AT/HM funds across agencies, fostering public/private partnerships, and involving consumers in political advocacy efforts.
Analyses of the polio and RA data indicate that AT/HM needs change considerably over time as persons with long-term disability experience changes in health and function. Higher use of AT/HM was associated with increasing age, comorbidity, and activity limitations (e.g., difficulty with bathing, walking). Unmet need for AT was reported by 37 percent of polio survivors and 23 percent of persons with RA. The most common type of AT needed was mobility devices (e.g., cane, crutches, walker, wheelchair). The most common reason given for not having a needed AT/HM accommodation was lack of financial resources.
FUTURE PLANS--This is the final year of this project. The technical reports for the State Rehabilitation study and the SUA study were available in December 1998.
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