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Wild K.V.,Oregon Health And Science University | Mattek N.,Oregon Health And Science University | Austin D.,Oregon Health And Science University | Kaye J.A.,Oregon Health And Science University | Kaye J.A.,Portland Veteran Affairs Medical Center
Journal of Applied Gerontology | Year: 2014

Accurate retrospective reporting of activities and symptoms has been shown to be problematic for older adults, yet standard clinical care relies on self-reports to aid in assessment and management. Our aim was to examine the relationship between self-report and sensor-based measures of activity. We administered an online activity survey to participants in our ongoing longitudinal study of in-home ubiquitous monitoring. We found a wide range of accuracies when comparing self-report with time-stamped sensor-based data. Of the 95 participants who completed the 2-hr activity log, nearly one quarter did not complete the task in a way that could potentially be compared with sensor data. Where comparisons were possible, agreement between self-reported and sensor-based activity was achieved by a minority of participants. The findings suggest that capture of real-time events with unobtrusive activity monitoring may be a more reliable approach to describing behavioral patterns and meaningful changes in older adults. © 2016 The Author(s).


Bowman G.L.,Oregon Health And Science University | Kaye J.A.,Oregon Health And Science University | Kaye J.A.,Portland Veteran Affairs Medical Center | Quinn J.F.,Oregon Health And Science University | Quinn J.F.,Portland Veteran Affairs Medical Center
Current Gerontology and Geriatrics Research | Year: 2012

Background. Blood-brain barrier (BBB) dysfunction may have a significant role in the pathogenesis of Alzheimer's disease (AD). Modifiable factors associated with BBB function may have therapeutic implication. This study tested the hypothesis that dyslipidemia is associated with BBB impairment in mild-to-moderate AD. Methods. Thirty-six subjects with AD were followed for 1 year. Fasting CSF and plasma were collected with clinical assessments at baseline and 12 months. BBB impairment was defined as CSF albumin index ≥9. Independent t-tests and linear regression assessed the relationship between plasma lipoproteins and BBB integrity. Results. Dyslipidemia was prevalent in 47 of the population, and in 75 of those with BBB impairment. Subjects with BBB impairment had significantly higher mean plasma triglyceride and lower HDL cholesterol (TG, P = 0.007; HDL, P = 0.043). Plasma triglycerides explained 22 of the variance in BBB integrity and remained significant after controlling for age, gender, ApoE-4 genotype, blood pressure, and statin use. Conclusion. Dyslipidemia is more prevalent in AD subjects with BBB impairment. Plasma triglyceride and HDL cholesterol may have a role in maintaining BBB integrity in mild-to-moderate Alzheimer's disease. Copyright © 2012 Gene L. Bowman et al.


Kaye J.,Oregon Health And Science University | Kaye J.,Portland Veteran Affairs Medical Center | Mattek N.,Oregon Health And Science University | Dodge H.,Oregon Health And Science University | And 6 more authors.
Gait and Posture | Year: 2012

Physical performance measures predict health and function in older populations. Walking speed in particular has consistently predicted morbidity and mortality. However, single brief walking measures may not reflect a person's typical ability. Using a system that unobtrusively and continuously measures walking activity in a person's home we examined walking speed metrics and their relation to function. In 76 persons living independently (mean age, 86) we measured every instance of walking past a line of passive infra-red motion sensors placed strategically in their home during a four-week period surrounding their annual clinical evaluation. Walking speeds and the variance in these measures were calculated and compared to conventional measures of gait, motor function and cognition. Median number of walks per day was 18±15. Overall mean walking speed was 61±17. cm/s. Characteristic fast walking speed was 96. cm/s. Men walked as frequently and fast as women. Those using a walking aid walked significantly slower and with greater variability. Morning speeds were significantly faster than afternoon/evening speeds. In-home walking speeds were significantly associated with several neuropsychological tests as well as tests of motor performance. Unobtrusive home walking assessments are ecologically valid measures of walking function. They provide previously unattainable metrics (periodicity, variability, range of minimum and maximum speeds) of everyday motor function. © 2011.


Dodge H.H.,Oregon Health And Science University | Dodge H.H.,University of Michigan | Mattek N.,Oregon Health And Science University | Gregor M.,Oregon Health And Science University | And 6 more authors.
Current Alzheimer Research | Year: 2015

Background: Detecting early signs of Alzheimer’s disease (AD) and mild cognitive impairment (MCI) during the pre-symptomatic phase is becoming increasingly important for costeffective clinical trials and also for deriving maximum benefit from currently available treatment strategies. However, distinguishing early signs of MCI from normal cognitive aging is difficult. Biomarkers have been extensively examined as early indicators of the pathological process for AD, but assessing these biomarkers is expensive and challenging to apply widely among pre-symptomatic community dwelling older adults. Here we propose assessment of social markers, which could provide an alternative or complementary and ecologically valid strategy for identifying the pre-symptomatic phase leading to MCI and AD. Methods: The data came from a larger randomized controlled clinical trial (RCT), where we examined whether daily conversational interactions using remote video telecommunications software could improve cognitive functions of older adult participants. We assessed the proportion of words generated by participants out of total words produced by both participants and staff interviewers using transcribed conversations during the intervention trial as an indicator of how two people (participants and interviewers) interact with each other in one-on-one conversations. We examined whether the proportion differed between those with intact cognition and MCI, using first, generalized estimating equations with the proportion as outcome, and second, logistic regression models with cognitive status as outcome in order to estimate the area under ROC curve (ROC AUC). Results: Compared to those with normal cognitive function, MCI participants generated a greater proportion of words out of the total number of words during the timed conversation sessions (p=0.01). This difference remained after controlling for participant age, gender, interviewer and time of assessment (p=0.03). The logistic regression models showed the ROC AUC of identifying MCI (vs. normals) was 0.71 (95% Confidence Interval: 0.54 – 0.89) when average proportion of word counts spoken by subjects was included univariately into the model. Conclusion: An ecologically valid social marker such as the proportion of spoken words produced during spontaneous conversations may be sensitive to transitions from normal cognition to MCI. © 2015 Bentham Science Publishers.


Thielke S.M.,University of Washington | Thielke S.M.,Geriatric Research | Mattek N.C.,Oregon Health And Science University | Hayes T.L.,Oregon Health And Science University | And 7 more authors.
Journal of the American Geriatrics Society | Year: 2014

Objectives To ascertain the association between self-report of low mood and unobtrusively measured behaviors (walking speed, time out of residence, frequency of room transitions, and computer use) in community-dwelling older adults using novel monitoring technologies. Design Longitudinal cohort study of older adults whose homes were outfitted with activity sensors. Participants completed Internet-based weekly health questionnaires with questions about mood. Setting Apartments and homes of older adults living in the Portland, Oregon, metropolitan area. Participants Adults, average age 84, followed for an average of 3.7 years (n = 157). Measurements Mood was assessed according to self-report each week. Walking speed, time spent out of residence, and room transitions were estimated using data from sensors; computer use was measured by timing actual use. The association between global or weekly low mood and the four behavior measures was ascertained, adjusting for baseline characteristics. Results Eighteen thousand nine hundred sixty weekly observations of mood were analyzed; 2.6% involved low mood. Individuals who reported low mood more often had no average differences in any behavior parameters from those who reported low mood less often. During weeks when they reported low mood, participants spent significantly less time out of residence and on the computer but showed no change in walking speed or room transitions. Conclusion Low mood in these community-dwelling older adults involved going out of the house less and using the computer less but no consistent changes in movements. Technologies to monitor in-home behavior may have potential for research and clinical care. © Published 2014. This article is a U.S. Government work and is in the public domain in the U.S.A.


Kaye J.,Oregon Health And Science University | Kaye J.,Portland Veteran Affairs Medical Center | Mattek N.,Oregon Health And Science University | Dodge H.H.,Oregon Health And Science University | And 7 more authors.
Alzheimer's and Dementia | Year: 2014

Background: Mild disturbances of higher order activities of daily living are present in people diagnosed with mild cognitive impairment (MCI). These deficits may be difficult to detect among those still living independently. Unobtrusive continuous assessment of a complex activity such as home computer use may detect mild functional changes and identify MCI. We sought to determine whether long-term changes in remotely monitored computer use differ in persons with MCI in comparison with cognitively intact volunteers. Methods: Participants enrolled in a longitudinal cohort study of unobtrusive in-home technologies to detect cognitive and motor decline in independently living seniors were assessed for computer use (number of days with use, mean daily use, and coefficient of variation of use) measured by remotely monitoring computer session start and end times. Results: More than 230,000 computer sessions from 113 computer users (mean age, 85 years; 38 with MCI) were acquired during a mean of 36 months. In mixed-effects models, there was no difference in computer use at baseline between MCI and intact participants controlling for age, sex, education, race, and computer experience. However, over time, between MCI and intact participants, there was a significant decrease in number of days with use (P =.01), mean daily use (∼1% greater decrease/month; P =.009), and an increase in day-to-day use variability (P =.002). Conclusions: Computer use change can be monitored unobtrusively and indicates individuals with MCI. With 79% of those 55 to 64 years old now online, this may be an ecologically valid and efficient approach to track subtle, clinically meaningful change with aging. © 2014 The Alzheimer's Association. All rights reserved.


Hoang P.D.,University of New South Wales | Cameron M.H.,Oregon Health And Science University | Cameron M.H.,Portland Veteran Affairs Medical Center | Gandevia S.C.,University of New South Wales | Lord S.R.,University of New South Wales
Archives of Physical Medicine and Rehabilitation | Year: 2014

Objectives To determine whether impaired performance in a range of vision, proprioception, neuropsychological, balance, and mobility tests and pain and fatigue are associated with falls in people with multiple sclerosis (PwMS). Design Prospective cohort study with 6-month follow-up. Setting A multiple sclerosis (MS) physiotherapy clinic. Participants Community-dwelling people (N=210; age range, 21-74y) with MS (Disease Steps 0-5). Interventions Not applicable. Main Outcome Measures Incidence of falls during 6 months' follow-up. Results In the 6-month follow-up period, 83 participants (39.7%) experienced no falls, 57 (27.3%) fell once or twice, and 69 (33.0%) fell 3 or more times. Frequent falling (≥3) was associated with increased postural sway (eyes open and closed), poor leaning balance (as assessed with the coordinated stability task), slow choice stepping reaction time, reduced walking speed, reduced executive functioning (as assessed with the difference between Trail Making Test Part B and Trail Making Test Part A), reduced fine motor control (performance on the 9-Hole Peg Test [9-HPT]), and reported leg pain. Increased sway with the eyes closed, poor coordinated stability, and reduced performance in the 9-HPT were identified as variables that significantly and independently discriminated between frequent fallers and nonfrequent fallers (model χ2 3=30.1, P<.001). The area under the receiver operating characteristic curve for this model was.712 (95% confidence interval,.638-.785). Conclusions The study reveals important balance, coordination, and cognitive determinants of falls in PwMS. These should assist the development of effective strategies for prevention of falls in this high-risk group. © 2014 by the American Congress of Rehabilitation Medicine.


Dodge H.H.,Oregon Center for Aging and Technology | Dodge H.H.,Portland Veteran Affairs Medical Center | Mattek N.C.,Oregon Center for Aging and Technology | Mattek N.C.,Portland Veteran Affairs Medical Center | And 5 more authors.
Neurology | Year: 2012

Objective: To determine whether unobtrusive long-term in-home assessment of walking speed and its variability can distinguish those with mild cognitive impairment (MCI) from those with intact cognition. Methods: Walking speed was assessed using passive infrared sensors fixed in series on the ceiling of the homes of elderly individuals participating in the Intelligent Systems for Assessing Aging Change (ISAAC) cohort study. Latent trajectory models were used to analyze weekly mean speed and walking speed variability (coefficient of variation [COV]). Results: ISAAC participants living alone included 54 participants with intact cognition, 31 participants with nonamnestic MCI (naMCI), and 8 participants with amnestic MCI at baseline, with a mean follow-up of 2.6 ± 1.0 years. Trajectory models identified 3 distinct trajectories (fast, moderate, and slow) of mean weekly walking speed. Participants with naMCI were more likely to be in the slow speed group than in the fast (p = 0.01) or moderate (p = 0.04) speed groups. For COV, 4 distinct trajectories were identified: group 1, the highest baseline and increasing COV followed by a sharply declining COV; groups 2 and 3, relatively stable COV; and group 4, the lowest baseline and decreasing COV. Participants with naMCI were more likely to be members of either highest or lowest baseline COV groups (groups 1 or 4), possibly representing the trajectory of walking speed variability for early- and late-stage MCI, respectively. Conclusion: Walking speed and its daily variability may be an early marker of the development of MCI. These and other real-time measures of function may offer novel ways of detecting transition phases leading to dementia. Copyright © 2012 by AAN Enterprises, Inc.


Wild K.V.,Oregon Health And Science University | Mattek N.C.,Oregon Health And Science University | Maxwell S.A.,Oregon Health And Science University | Dodge H.H.,Oregon Health And Science University | And 3 more authors.
Alzheimer's and Dementia | Year: 2012

Background: This study examines differences in computer-related self-efficacy and anxiety in subgroups of older adults, and changes in those measures after exposure to a systematic training program and subsequent computer use. Methods: Participants were volunteers in the Intelligent Systems for Assessment of Aging Changes study (ISAAC) carried out by the Oregon Center for Aging and Technology. Participants were administered two questionnaires before training and again 1 year later, which were related to computer self-efficacy and anxiety. Continuous recording of computer use was also assessed for a subset of participants. Results: Baseline comparisons by sex, age, education, living arrangement, and computer proficiency, but not cognitive status, yielded significant differences in confidence and anxiety related to specific aspects of computer use. At 1-year follow-up, participants reported less anxiety and greater confidence. However, the benefits of training and exposure varied by group and task. Comparisons based on cognitive status showed that the cognitively intact participants benefited more from training and/or experience with computers than did participants with mild cognitive impairment (MCI), who after 1 year continued to report less confidence and more anxiety regarding certain aspects of computer use. Conclusion: After 1 year of consistent computer use, cognitively intact participants in this study reported reduced levels of anxiety and increased self-confidence in their ability to perform specific computer tasks. Participants with MCI at baseline were less likely to demonstrate increased efficacy or confidence than their cognitively intact counterparts. © 2012 The Alzheimer's Association. All rights reserved.


Kimball T.A.,University of Colorado at Denver | Barz K.,Colorado Prevention Center | Dimond K.R.,University of Colorado at Denver | Edwards J.M.,Portland Veteran Affairs Medical Center | Nehler M.R.,University of Colorado at Denver
Journal of Vascular Surgery | Year: 2011

Background: The National Kidney Foundation-Kidney Diseases Outcomes Quality Initiative (KDOQI) for vascular access guidelines state that patients with late-stage chronic kidney disease (CKD) should undergo native arteriovenous fistula (AVF) creation at least 6 months before anticipated start of hemodialysis (HD) treatments to obviate the need for other vascular access types, such as grafts or central catheters. Objective: The objective of this study was to determine the incidence of HD, the functional patency, and associated morbidity of AVFs in patients with late-stage CKD placed according to KDOQI. Methods: Consecutive patients with late-stage CKD who underwent AVF creation using KDOQI guidelines for anatomy between January 2003 and December 2007 at two tertiary academic centers were retrospectively evaluated. Baseline demographics, AVF type, and clinical comorbidities were recorded. Patients were stratified into one of four groups (groups A-D) over the follow-up course based on two end points: patency of their AVF and whether or not they began HD. The ideal primary outcome was AVF maturation and use for HD (group A; cumulative functional patency). Other outcomes included AVF patency but no HD (group B), HD with AVF failure (group C), or no HD and AVF abandonment (ie, death, refused hemodialysis, kidney transplant, or fistula failure; group D). Secondary outcomes were time to first cannulation, complications, and secondary interventions. Results: AVFs were created (46% forearm and 54% upper arm) in 150 patients with CKD (85% men, median age 63 years old). At a median follow-up of 10 months, 74 patients (49%) were receiving HD and of these, 48 patients (65%) were using their AVF (group A), whereas 26 patients (35%) were not due to fistula failure (group C). Thirty-four patients (23%) never initiated HD treatments, but had a viable AVF (group B), and 42 patients (28%) never initiated HD and abandoned their AVF (group D). Overall, AVF abandonment was 51%. Mean maturation time of all AVFs successfully cannulated was 285 days (range, 30-1265 days). Complications encountered were maturation failure for cannulation (15%), focal stenosis requiring intervention (13%), inadequate flows on HD (9%), steal syndrome (9%), and thrombosis (8%). Cumulative functional patency for all AVFs was 19% and 27% at 6 and 12 months, respectively, with a mean number of two interventions per AVF (range, 1-10). Mortality during the study was 23%. Conclusion: Despite successful creation and maturation of a preemptive AVF in nearly two-thirds of patients who started HD during the follow-up and given the following observations: the high overall mortality of the population, the morbidity and costs in secondary procedures of AVF creation, and the high incidence of abandonment, it is unclear if this strategy would demonstrate a benefit in a randomized trial when compared to other access strategies. © 2011 Society for Vascular Surgery.

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