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Biomedical subjects

Stephanie A Studenski

Publications and source records attributed to Stephanie A Studenski.

15 recordsLinked to original sources
PubMed2006

Striatal dopamine denervation and sensory integration for balance in middle-aged and older adults.

UNLABELLED: The dopaminergic system of the basal ganglia has been implicated in the integration of sensory information important for balance based on studies in patients with Parkinson's disease. Striatal dopaminergic activity decreases with normal aging. OBJECTIVE: To investigate the relationship between regional striatal dopaminergic denervation and sensory information integration important for balance in middle-aged and older adults. METHODS: Community-dwelling subjects (N=35; age 41-83) with no clinical diagnoses of conditions affecting balance underwent dynamic posturography testing (Sensory Organization Test/SOT) and C-11-beta-CFT dopamine transporter positron emission tomography. RESULTS: Reduced ventral striatal dopamine was significantly correlated with increased anterior-posterior sway in three SOT conditions. Specifically, during quiet standing (SOT Conditions #1, 2) and when repeatedly to sway-referenced visual environments (SOT Condition #3, Trial #3), pre-synaptic dopaminergic denervation in the anteroventral striatum explained over 20-25% of the variability in sway magnitude above and beyond that explained by age (p<or=0.01). Striatal dopaminergic denervation did not impact balance in sway-referenced floor conditions. CONCLUSIONS: The SOT Condition #3 findings suggest that, in normal aging, the central ability to inhibit balance destabilizing vision-related postural control processes depends at least partially on striatal dopaminergic pathways. In contrast, striatal dopaminergic denervation does not appear to impair the ability to disengage destabilizing proprioceptive inputs and to trigger the vestibular control system during challenging sensory perturbations (SOT Conditions #4-6). Finally, quiet standing results (SOT Conditions #1, 2) justify the need to further investigate the impact of striatal dopaminergic denervation on the ability to tune muscle tone in healthy adults.

Accidental Falls↗
PubMed2006

Association of long-distance corridor walk performance with mortality, cardiovascular disease, mobility limitation, and disability.

CONTEXT: Aerobic fitness, an important predictor of cardiovascular disease and mortality, is difficult to assess by maximal exercise testing in older adults. Extended walking tests have been examined as outcome predictors in medically ill populations but not in community-dwelling older adults. OBJECTIVE: To determine whether an extended walking test predicts poor outcomes in older adults. DESIGN, SETTING, AND PARTICIPANTS: Observational cohort study enrolling 3075 community-dwelling adults aged 70 to 79 years living in Pittsburgh, Pa, or Memphis, Tenn. Of those participating in the Health, Aging, and Body Composition Study, 1584 (52%) were women and 1281 (42%) were black. Participants enrolled from March 1997 to April 1998. Ability to complete the long-distance corridor walk and total performance time was assessed at the baseline examination. MAIN OUTCOME MEASURES: Total mortality, incident cardiovascular disease, incident mobility limitation, and mobility disability were ascertained after a mean (SD) of 4.9 (0.9) years. RESULTS: Among patients eligible to exercise, 351 died, 308 had episodes of incident cardiovascular disease, 1116 had occurrences of mobility limitation, and 509 had occurrences of mobility disability. Inability to complete walking 400 m tended to be associated with a higher risk of mortality and incident cardiovascular disease and, after accounting for potential confounders, was associated with incident mobility limitation (212.6 vs 79.1 events/1000 person-years; adjusted hazard ratio [HR], 1.86; 95% confidence interval [CI], 1.58-2.18; P<.001) and mobility disability (85.2 vs 28.8 events/1000 person-years; adjusted HR, 1.95; 95% CI, 1.56-2.44; P<.001). Of those who completed 400 m, each additional minute of performance time was associated with an adjusted HR of 1.29 (95% CI, 1.12-1.48) for mortality, 1.20 (95% CI, 1.01-1.42) for incident cardiovascular disease, 1.52 (95% CI, 1.41-1.63) for mobility limitation, and 1.52 (95% CI, 1.37-1.70) for disability after adjustment for demographics, health behaviors, clinical and subclinical disease, and cardiovascular disease risk factors. Findings were consistent in both men and women and blacks and whites. Among participants who completed the test and after adjusting for potential confounders, those in the poorest quartile of functional capacity (walk time >362 seconds) had a higher risk of death than those in the best quartile (walk time <290 seconds; adjusted HR, 3.23; 95% CI, 2.11-4.94; P<.001). CONCLUSIONS: Older adults in the community who reported no difficulty walking had a wide range of performance on this extended walking test. Ability to do the test and performance were important prognostic factors for total mortality, cardiovascular disease, mobility limitation, and mobility disability in persons in their eighth decade.

Aged↗
PubMed2006

Meaningful change and responsiveness in common physical performance measures in older adults.

OBJECTIVES: To estimate the magnitude of small meaningful and substantial individual change in physical performance measures and evaluate their responsiveness. DESIGN: Secondary data analyses using distribution- and anchor-based methods to determine meaningful change. SETTING: Secondary analysis of data from an observational study and clinical trials of community-dwelling older people and subacute stroke survivors. PARTICIPANTS: Older adults with mobility disabilities in a strength training trial (n=100), subacute stroke survivors in an intervention trial (n=100), and a prospective cohort of community-dwelling older people (n=492). MEASUREMENTS: Gait speed, Short Physical Performance Battery (SPPB), 6-minute-walk distance (6MWD), and self-reported mobility. RESULTS: Most small meaningful change estimates ranged from 0.04 to 0.06 m/s for gait speed, 0.27 to 0.55 points for SPPB, and 19 to 22 m for 6MWD. Most substantial change estimates ranged from 0.08 to 0.14 m/s for gait speed, 0.99 to 1.34 points for SPPB, and 47 to 49 m for 6MWD. Based on responsiveness indices, per-group sample sizes for clinical trials ranged from 13 to 42 for substantial change and 71 to 161 for small meaningful change. CONCLUSION: Best initial estimates of small meaningful change are near 0.05 m/s for gait speed, 0.5 points for SPPB, and 20 m for 6MWD and of substantial change are near 0.10 m/s for gait speed, 1.0 point for SPPB, and 50 m for 6MWD. For clinical use, substantial change in these measures and small change in gait speed and 6MWD, but not SPPB, are detectable. For research use, these measures yield feasible sample sizes for detecting meaningful change.

Aged↗
PubMed2006

Research agenda for frailty in older adults: toward a better understanding of physiology and etiology: summary from the American Geriatrics Society/National Institute on Aging Research Conference on Frailty in Older Adults.

Evolving definitions of frailty, and improved understanding of molecular and physiological declines in multiple systems that may increase vulnerability in frail, older adults has encouraged investigators from many disciplines to contribute to this emerging field of research. This article reports on the results of the 2004 American Geriatrics Society/National Institute on Aging conference on a Research Agenda on Frailty in Older Adults, which brought together a diverse group of clinical and basic scientists to encourage further investigation in this area. This conference was primarily focused on physical and physiological aspects of frailty. Although social and psychological aspects of frailty are critically important and merit future research, these topics were largely beyond the scope of this meeting. Included in this article are sections on the evolving conceptualization and definitions of frailty; physiological underpinnings of frailty, including the potential contributions of inflammatory, endocrine, skeletal muscle, and neurologic system changes; potential molecular and genetic contributors; proposed animal models; and integrative, system biology approaches that may help to facilitate future frailty research. In addition, several specific recommendations as to future directions were developed from suggestions put forth by participants, including recommendations on definition and phenotype development, methodological development to perform clinical studies of individual-system and multiple-system vulnerability to stressors, development of animal and cellular models, application of population-based studies to frailty research, and the development of large collaborative networks in which populations and resources can be shared. This meeting and subsequent article were not meant to be a comprehensive review of frailty research; instead, they were and are meant to provide a more-targeted research agenda-setting process.

Aged↗
PubMed2005

Reciprocal influence of concurrent walking and cognitive testing on performance in older adults.

This study investigated how cognitive and walking performance are influenced when performed concurrently in older adults and what factors are associated with poorer dual-task responses. Using a dual-task study design, 217 subjects aged 74-85 years completed three information processing test conditions--(1) no test; (2) push-button simple reaction-time; and (3) visual-spatial decision reaction-time; and three walking test conditions--(1) seated; (2) walking over a 20m straight course; and (3) walking over 20m with a turn. Push-button and visual-spatial reaction-times increased approximately 21% and 6%, respectively, while walking compared to sitting (p<0.008). Reaction-time tests had a relatively weak impact on walking-time. Poorer dual-task walking-time responses correlated with slower walking velocity and weaker muscle strength (p< or =.062). Findings suggest that walking requires significant cognitive resources among older adults and slower-walking adults and weaker adults may require higher cognitive loading while walking.

Age Factors↗
PubMed2005

Too much or too little step width variability is associated with a fall history in older persons who walk at or near normal gait speed.

BACKGROUND: Decreased gait speed and increased stride time, stride length, double support time, and stance time variability have consistently been associated with falling whereas step width variability has not been strongly related to falls. The purpose was to examine the linear and nonlinear associations between gait variability and fall history in older persons and to examine the influence of gait speed. METHODS: Gait characteristics and fall history were obtained in 503 older adults (mean age = 79; 61% female) participating in the Cardiovascular Health Study who could ambulate independently. Gait characteristics were recorded from two trials on a 4 meter computerized walkway at the subject's self-selected walking speed. Gait variability was calculated as the coefficient of variation. The presence of a fall in the past 12 months was determined by interview. The nonlinear association between gait variability and fall history was examined using a simple three level classification derived from the distribution of the data and from literature based cut-points. Multivariate logistic regression was used to examine the association between step width variability (extreme or moderate) and fall history stratifying by gait speed (1.0 m/s) and controlling for age and gender. RESULTS: Step length, stance time, and step time variability did not differ with respect to fall history (p > .33). Individuals with extreme step width variability (either low or high step width variability) were more likely to report a fall in the past year than individuals with moderate step width variability. In individuals who walked > or = 1.0 m/s (n = 281), after controlling for age, gender, and gait speed, compared to individuals with moderate step width variability individuals with either low or high step width variability were more likely to have fallen in the past year (OR and 95% CI 4.38 [1.79-10.72]). The association between step width variability and fall history was not significant in individuals who walked < 1.0 m/s (n = 224). CONCLUSION: Extreme (either too little or too much) step width variability is associated with falls in the past year in older persons who walk at or near normal gait speed and not in older persons who walk slowly (< 1.0 m/s).

Journal Article↗
PubMed2005

Ethnic differences in the frequency and circumstances of falling in older community-dwelling women.

OBJECTIVES: To examine ethnic differences in fall rates and fall circumstances in older community-dwelling Caucasian and African-American women. DESIGN: Prospective analysis of incident falls and a nested retrospective analysis of fall circumstances over 5.7 years. SETTING: Monongahela Valley, Pennsylvania. PARTICIPANTS: A total of 1,821 Caucasian and African-American women (mean age+/-standard deviation 76+/-5) enrolled in the Study of Osteoporotic Fractures and participating in 1993/94. Circumstances of 338 falls were collected on a subsample of 197 women who fell. MEASUREMENTS: Fall rates and fall circumstances. RESULTS: Women reported 4,547 falls in 9,508 person-years, averaging 0.48 falls per woman annually (95% confidence interval (CI)=0.43-0.53). Age-adjusted fall rates were nonsignificantly higher in Caucasians than African Americans (relative risk (RR)=1.30, 95% CI=0.93-1.83%). In women younger than 75, fall rates were similar in Caucasians and African Americans (RR=1.17, P=.46). In women aged 75 and older, fall rates were 50% higher in Caucasians than in African Americans (RR=1.50, 95% CI=0.90-2.49), although this difference was not significant (P=.12). Fall circumstances differed by ethnicity. Caucasian women were significantly more likely than African Americans to fall outdoors versus indoors (odds ratio (OR)=1.6, 95% CI =1.0-2.7) and laterally versus forward (OR=2.0, 95% CI =1.1-3.4) but less likely to fall on the hand/wrist (OR=0.6, 95% CI =0.3-1.0). Ninety-eight percent of individuals falling on their hand/wrist reported that they extended their hand to attempt to break their fall. CONCLUSION: Although the circumstances of falling differed for older Caucasian and African-American women, there were no differences in the frequencies of falling. These findings suggest that ethnic differences in fracture risk in older women may be due in part to the different ways in which older Caucasian and African-American women fall, rather than how often they fall. More information will be needed on fall circumstances to determine whether interventions need to be tailored by ethnic group.

Accidental Falls↗
PubMed2005

Coordination of hemiparetic locomotion after stroke rehabilitation.

OBJECTIVES: Determine whether a rehabilitation program targeting functional motor recovery of persons with poststroke hemiparesis improved motor coordination. METHODS: A subgroup of 20 persons with poststroke hemiparesis (n = 11 in intervention and n =9 in control group) was investigated from within a larger randomized controlled single-blind clinical trial of 100 patients. Motor coordination was measured using a pedaling task, and subjects in the intervention group pedaled during an intensive broad-based home exercise program that targeted flexibility, strength, balance, and endurance. Coordination variables based on paretic leg pedal forces and EMG of 4 thigh muscles were measured while pedaling pre- and postintervention. RESULTS: Despite extensive pedaling practice, up to 30 half-hour sessions that were progressively more intense, there was no effect (P > 0.05) of the intervention on percent of total work done by the paretic leg, quantitative measures of EMG, or pedaling speed. However, walking speed was improved and pedaling and walking faster were associated after the intervention. CONCLUSIONS: There is no evidence of improved locomotor coordination postintervention. The increased walking and pedaling speed was likely achieved by a more proficient use of the same impaired pattern without EMG timing changes, likely because of increased strength and endurance postintervention. A more task-specific intervention may be required to improve coordination, consistent with principles of use-dependent plasticity.

Aged↗
PubMed2004

Medication error reporting in long term care.

BACKGROUND: Medication errors are common causes of medical error in the long-term care (LTC) setting. Despite their frequency and potential clinical impact, most medication errors in LTC facilities remain unreported. Before better reporting systems can be developed to reduce clinically significant medication errors, it is necessary to understand how current medication error reporting systems function. OBJECTIVE: This study describes the medication use and medication error reporting processes, and characterizes the knowledge, attitudes, and beliefs about medication errors of the nursing staff at a single LTC facility. METHODS: Three methods were used to characterize the medication use and medication error reporting processes and the nursing staff's perceptions about such errors. First, key elements and basic processes were defined through observation and semi-structured interviews. Second, medication error reports were reviewed and summarized over a 21-month period. Third, nursing facility staff were surveyed about their knowledge, attitudes, and beliefs concerning medication errors. RESULTS: The medication use process in the LTC setting is similar to that employed in the acute care setting, consisting of 5 steps: prescribing, documenting, dispensing, administering, and monitoring. In the facility studied, an average of 4.7 medication error reports were submitted per month. Staff felt that half of all medication errors were identified and communicated informally through change-of-shift reports rather than through medication error reports. Most staff (85%) believed that disciplinary action was taken against the person who committed an error. CONCLUSIONS: The medication error policies and processes of the LTC facility studied were associated with a low frequency of formal reporting, a narrow perspective on the sources of error, and concerns about disciplinary action. Research is needed to better identify errors, develop interventions that broaden the monitoring perspective to include all health care professionals, reduce the work of reporting, standardize the information collected, and create an institutional atmosphere of participation rather than punishment.

Data Collection↗
PubMed2002

Spirituality Index of Well-Being Scale: development and testing of a new measure.

OBJECTIVE: To evaluate the reliability and validity of the Spirituality Index of Well-Being (SIWB) Scale in a patient population. STUDY DESIGN: Cross-sectional survey. POPULATION: Community-dwelling elderly individuals (n = 277) recruited from primary care clinic sites in the Kansas City metropolitan area. OUTCOMES MEASURED: Internal consistency, concurrent construct validity, discriminant validity, and factor analysis with Varivax rotation. RESULTS: The initial version of the SIWB contained 40 items: 20 from a self-efficacy domain and 20 from a life scheme domain. Factor analysis yielded 6 items loaded most strongly on factor 1 (intrapersonal self-efficacy) and 6 other items loaded strongly on factor 2 (life scheme). The Self-efficacy subscale had an alpha of.83 and the Life Scheme subscale had an alpha of.80; the total 12-item SIWB Scale had an alpha of.87. The SIWB had significant and expected correlations with other quality-of-life measures related to subjective well-being: EuroQol (r =.18), Geriatric Depression Scale (r = -35), the Physical Functioning Index from the Short Form 36 (r =.28), and the Years of Healthy Life Scale (r = -.35). Religiosity did not correlated significantly with the SIWB (r =.12, P =.056). CONCLUSIONS: The 12-item SIWB Scale is a valid and reliable measure of subjective well-being in an older patient population.

Age Factors↗
PubMedDate not supplied

Religion, spirituality, and health status in geriatric outpatients.

BACKGROUND: Religion and spirituality remain important social and psychological factors in the lives of older adults, and there is continued interest in examining the effects of religion and spirituality on health status. The purpose of this study was to examine the interaction of religion and spirituality with self-reported health status in a community-dwelling geriatric population. METHODS: We performed a cross-sectional analysis of 277 geriatric outpatients participating in a cohort study in the Kansas City area. Patients underwent a home assessment of multiple health status and functional indicators by trained research assistants. A previously validated 5-item measure of religiosity and 12-item spirituality instrument were embedded during the final data collection. Univariate and multivariate analyses were performed to determine the relationship between each factor and self-reported health status. RESULTS: In univariate analyses, physical functioning (P < .01), quality of life (P < .01), race (P < .01), depression (P < .01), age (P = .01), and spirituality (P < .01) were all associated with self-reported health status, but religiosity was not (P = .12). In a model adjusted for all covariates, however, spirituality remained independently associated with self-appraised good health (P = .01). CONCLUSIONS: Geriatric outpatients who report greater spirituality, but not greater religiosity, are more likely to appraise their health as good. Spirituality may be an important explanatory factor of subjective health status in older adults.

Activities of Daily Living↗
PubMedDate not supplied

Development and evaluation of a charge capture program for long-term care providers.

OBJECTIVE: Clinicians often have difficulty determining the appropriate Current Procedural Terminology Evaluation and Management code to assign to the type and intensity of patient care they provide. The purpose of this study was to develop, implement, and evaluate a handheld charge capture program for use by providers in the long-term care setting. DESIGN: Using a pre-post study design, we compared the coding accuracy and user satisfaction of an established paper process with a handheld charge capture program created for this study by means of: (1) preimplementation and postimplementation assessment of coding accuracy, and (2) preimplementation and postimplementation clinician survey. SETTING: We studied an academic division of geriatric medicine. PARTICIPANTS: Participants consisted of six clinicians who currently spend at least 50% of their clinical time practicing in the long-term care setting. INTERVENTION: A handheld charge capture program to replace the current paper-based charge capture process was reviewed. RESULTS: Overall coding accuracy improved by approximately 20% when the handheld program was used instead of a paper coding process. The majority of clinicians found that the handheld program was more widely available, efficient, easier to use, and encouraged the participants to document more completely and accurately in the patient's medical record. CONCLUSION: A handheld billing and coding program used by clinicians who provide care for long-term care residents is not only feasible, but leads to an improvement in coding accuracy when compared with a paper process. In addition, clinician satisfaction toward the billing and coding processes improved with the use of the handheld program.

Attitude of Health Personnel↗