Kristin Flegal

Oregon Health and Science University, Portland, OR, United States

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Publications (5)7.79 Total impact

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    ABSTRACT: Expectancy or placebo effects on cognitive function have not been well studied. To determine the effect of taking pills on cognitive function, 40 participants were randomly assigned to a pill or no-pill condition. Healthy seniors who took a 2-week supply of methylcellulose pills, which they were told was an experimental cognitive enhancer, were compared to seniors not taking any pills. There were 2 primary outcome measures defined prior to the study-Consortium to Establish a Registry for Alzheimer's Disease (CERAD) Word List delayed recall and Stroop color word task time-as well as 7 other cognitive outcome measures. There was a significant effect of pill taking on the 2 primary outcome measures. There was also an effect of pill taking on choice reaction time and Word List immediate recall but not on the other 5 secondary cognitive outcome measures. In an exploratory analysis of potential predictors of the expectancy effect, perceived stress and self-efficacy but not personality traits interacted with the pill-taking effect on cognitive function. Further characterizing and understanding this observed expectancy effect is important to maximize cognitive health and improve clinical trial design.
    Journal of Clinical and Experimental Neuropsychology 02/2008; 30(1):7-17. · 2.16 Impact Factor
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    ABSTRACT: To determine factors that predict adherence to a mind-body intervention in a randomized trial. We analyzed adherence data from a 3-arm trial involving 135 generally healthy seniors 65-85 years of age randomized to a 6-month intervention consisting of: an Iyengar yoga class with home practice, an exercise class with home practice, or a wait-list control group. Outcome measures included cognitive function, mood, fatigue, anxiety, health-related quality of life, and physical measures. Adherence to the intervention was obtained by class attendance and biweekly home practice logs. The drop-out rate was 13%. Among the completers of the two active interventions, average yoga class attendance was 77% and home practice occurred 64% of all days. Average exercise class attendance was 69% and home exercise occurred 54% of all days. There were no clear effects of adherence on the significant study outcomes (quality of life and physical measures). Class attendance was significantly correlated with baseline measures of depression, fatigue, and physical components of health-related quality of life. Significant differences in baseline measures were also found between study completers and drop-outs in the active interventions. Adherence was not related to age, gender, or education level. Healthy seniors have good attendance at classes with a physically active intervention. Home practice takes place over half of the time. Decreased adherence to a potentially beneficial intervention has the potential to decrease the effect of the intervention in a clinical trial because subjects who might sustain the greatest benefit will receive a lower dose of the intervention and subjects with higher adherence rates may be functioning closer to maximum ability before the intervention. Strategies to maximize adherence among subjects at greater risk for low adherence will be important for future trials, especially complementary treatments requiring greater effort than simple pill-taking.
    BMC Complementary and Alternative Medicine 02/2007; 7:37. · 2.08 Impact Factor
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    ABSTRACT: The design and development of a 24-hour ambulatory physiological data collection system is reported. The system was designed specifically to support the needs of investigators studying mind-body interventions but could be used for a variety of research needs. The system is novel in that it supports a wide variety of physiologic sensors with a relatively high sample rate, full data storage, and standalone run-time of greater than 24 hours. Experience with data acquisition and methods for post-acquisition data analysis are also discussed.
    Conference proceedings: ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Conference 02/2006; 1:5928-31.
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    ABSTRACT: To evaluate the potential effects of medications with central nervous system (CNS) activity on cognitive function and fatigue in multiple sclerosis (MS), we performed a retrospective analysis of medication use among 70 subjects with MS who were participating in a clinical trial for evaluation of the effects of yoga and exercise programs on cognition and fatigue. Among these MS subjects, 74% were taking at least one potentially CNS-active medication. These 70 subjects were divided into two groups: those taking at least one CNS-active medication (n = 52) and those not on any medications with potential CNS activity (n = 18). We compared assessments of cognitive function and fatigue using an analysis of covariance. MS subjects on CNS-active medication had greater impairment on measures of processing speed, sustained attention, and fatigue than those not on these medications. While these findings do not establish a causal relationship between medication use and cognitive impairment and fatigue, the data indicate that researchers need to control for use of CNS-active medications when conducting studies of cognitive impairment and fatigue in MS subjects.
    The Journal of Rehabilitation Research and Development 01/2006; 43(1):83-90. · 1.78 Impact Factor
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    ABSTRACT: There are potential benefits of mind-body techniques on cognitive function because the techniques involve an active attentional or mindfulness component, but this has not been fully explored. To determine the effect of yoga on cognitive function, fatigue, mood, and quality of life in seniors. Randomized, controlled trial comparing yoga, exercise, and wait-list control groups. One hundred thirty-five generally healthy men and women aged 65-85 years. Participants were randomized to 6 months of Hatha yoga class, walking exercise class, or wait-list control. Subjects assigned to classes also were asked to practice at home. Outcome assessments performed at baseline and after the 6-month period included a battery of cognitive measures focused on attention and alertness, the primary outcome measures being performance on the Stroop Test and a quantitative electroencephalogram (EEG) measure of alertness; SF-36 health-related quality of life; Profile of Mood States; Multi-Dimensional Fatigue Inventory; and physical measures related to the interventions. One hundred thirty-five subjects were recruited and randomized. Seventeen subjects did not finish the 6-month intervention. There were no effects from either of the active interventions on any of the cognitive and alertness outcome measures. The yoga intervention produced improvements in physical measures (eg, timed 1-legged standing, forward flexibility) as well as a number of quality-of-life measures related to sense of well-being and energy and fatigue compared to controls. There were no relative improvements of cognitive function among healthy seniors in the yoga or exercise group compared to the wait-list control group. Those in the yoga group showed significant improvement in quality-of-life and physical measures compared to exercise and wait-list control groups.
    Alternative therapies in health and medicine 12(1):40-7. · 1.77 Impact Factor