Publications (105) View all
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Article: Psychometric properties of a computerized adaptive test for assessing mobility in older adults using novel video-animation technology.
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ABSTRACT: PURPOSE: This paper reports on the psychometric properties of a computerized adaptive test (CAT) version of the Mobility Assessment Tool (MAT) for older adults (MAT-CAT). METHODS: An item pool of 78 video-animation-based items for mobility was developed, and response data were collected from a sample of 234 participants aged 65-90 years. The video-animation-based instrument was designed to minimize ambiguity in the presentation of task demands. In addition to evaluating traditional psychometric properties including dimensionality, differential item functioning (DIF), and local dependence, we extensively tested the performance of several MAT-CAT measures and compared their performances with a fixed format. RESULTS: Operationally, the MAT-CAT was sufficiently unidimensional and had acceptable levels of local independence. One DIF item was removed. Most importantly, the CAT measures showed that even starting with a single fixed item at the mean ability, the adaptive version delivered better performance than the fixed format in terms of several criteria including the standard error of estimate. CONCLUSION: The MAT-CAT demonstrated satisfactory psychometric properties and superior performance to a fixed format. The video-animation-based adaptive instrument can be used for assessing mobility with specificity and precision.Quality of Life Research 01/2013; · 2.30 Impact Factor -
Article: Effect of varying accelerometry criteria on physical activity: The look ahead study.
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ABSTRACT: The importance of physical activity in weight management is widely documented. Although accelerometers offer an objective measure of activity that provide a valuable tool for intervention research, considerations for processing these data need further development. This study tests the effects of using different criteria for accelerometry data reduction. Data were obtained from 2,240 overweight and obese individuals with type 2 diabetes mellitus (T2DM) from the Look AHEAD study, with 2,177 baseline accelerometer files used for analysis. Number, duration, and intensity of moderate (≥3 metabolic equivalents (METS)) and vigorous (≥6 METS) activity bouts were compared using various data reduction criteria. Daily wear time was identified as 1,440 min/day minus non-wear time. Comparisons of physical activity patterns for non-wear time (using either 20, 30, or 60 min of continuous zeros), minimal daily wear time (8, 10, and 12 h), number of days with available data (4, 5, and 6 days), weekdays vs. weekends, and 1- or 2-min time interruptions in an activity bout were performed. In this mostly obese population with T2DM (BMI = 36.4 kg/m(2) ; mean age = 59.0 years), there were minimal differences in physical activity patterns using the different methods of data reduction. Altering criteria led to differences in the number of available data (sample size) meeting specific criteria. Although our results are likely directly applicable only to obese individuals with T2DM, an understudied population with regards to physical activity, the systematic analysis for data reduction employed can be more generalizable and provide guidance in this area in the absence of standard procedures.Obesity 01/2013; 21(1):32-44. · 4.28 Impact Factor -
Article: The Group Oriented Arterial Leg Study (GOALS) to improve walking performance in patients with peripheral arterial disease.
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ABSTRACT: People with lower extremity peripheral artery disease (PAD) have greater functional impairment and faster functional decline than those without PAD. We describe methods for the Group Oriented Arterial Leg Study (GOALS), an ongoing randomized controlled clinical trial designed to determine whether a Group-Mediated Cognitive Behavioral (GMCB) intervention improves functional performance in PAD participants, compared to a health education control condition. In GOALS, PAD participants were randomized to either an intervention or a health education control condition in a parallel design. Both conditions consist of weekly group sessions with other PAD participants. In the intervention, cognitive behavioral techniques are used to assist participants in setting and adhering to home-based walking exercise goals. Participants are encouraged to walk for exercise at home at least 5days/week. In the control condition, participants receive lectures on health-related topics. After 6months of on-site weekly sessions, participants are transitioned to telephone follow-up for another 6months. Participants in the intervention are asked to continue home walking exercise. The primary outcome is change in six-minute walk performance between baseline and six-month follow-up. Secondary outcomes include change in six-minute walk performance at 12-month follow-up, and change in treadmill walking performance, the Walking Impairment Questionnaire, quality of life, and physical activity at six and 12-month follow-up. In conclusion, if our group-mediated cognitive behavioral intervention is associated with improved walking performance in individuals with PAD, results will have major public health implications for the large and growing number of people with PAD.Contemporary clinical trials 11/2012; 33(6):1311-20. · 1.51 Impact Factor -
Article: Physical Activity Increases Gains in and Prevents Loss of Physical Function: Results From the Lifestyle Interventions and Independence for Elders Pilot Study.
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ABSTRACT: BACKGROUND: Physical activity (PA) appears to have a positive effect on physical function, however, studies have not examined multiple indices of physical function jointly nor have they conceptualized physical functioning as a state rather than a trait. METHODS: About 424 men and women aged 70-89 were randomly assigned to complete a PA or a successful aging (SA) education program. Balance, gait speed, chair stand performance, grip strength, and time to complete the 400-m walk were assessed at baseline and at 6 and 12 months. Using hidden Markov model, empiric states of physical functioning were derived based on these performance measures of balance, strength, and mobility. Rates of gain and loss in physical function were compared between PA and SA. RESULTS: Eight states of disability were identified and condensed into four clinically relevant states. State 1 represented mild disability with physical functioning, states 2 and 3 were considered intermediate states of disability, and state 4 severe disability. About 30.1% of all participants changed states at 6 months, 24.1% at 12 months, and 11.0% at both time points. The PA group was more likely to regain or sustain functioning and less likely to lose functioning when compared with SA. For example, PA participants were 20% more likely than the SA participants to remain in state 1. CONCLUSION: PA appears to have a favorable effect on the dynamics of physical functioning in older adults.The Journals of Gerontology Series A Biological Sciences and Medical Sciences 09/2012; · 4.60 Impact Factor -
Article: Social Cognitive Changes Following Weight Loss and Physical Activity Interventions in Obese, Older Adults in Poor Cardiovascular Health.
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ABSTRACT: BACKGROUND: The study objectives were to determine (a) the effects of group-mediated cognitive-behavioral interventions on change in performance self-efficacy, satisfaction with function, and with appearance among older, overweight/obese adults in poor cardiovascular health and (b) whether self-efficacy mediated change in 400-m walk time. METHODS: This translational, randomized controlled trial of physical activity and weight loss was conducted within community Cooperative Extension Centers. Participants were randomized to three intervention arms: Physical Activity, Weight Loss + Physical Activity, or a Successful Aging education control. RESULTS: Across 18 months, the Weight Loss + Physical Activity intervention demonstrated greater improvements in self-efficacy, satisfaction with function, and appearance versus other trial arms. Physical Activity intervention participants also experienced significant improvements in self-efficacy and satisfaction with function versus those in Successful Aging. Self-efficacy mediated 400-m walk time at 18 months. CONCLUSIONS: Both group-mediated cognitive-behavioral interventions yielded desirable improvements in social cognitions and preserved mobility improvements post-intervention.Annals of Behavioral Medicine 07/2012; · 4.20 Impact Factor
