TY - JOUR T1 - Pattern Recognition to Objectively Differentiate the Etiology of Cognitive Decline: Analysis of the Impact of Stroke and Alzheimer's Disease. JF - Neuroepidemiology Y1 - 2020 A1 - Sean A. P. Clouston A1 - Richmond, Lauren L A1 - Scott, Stacey B A1 - Luhmann, Christian C A1 - Natale, Ginny A1 - Douglas William Hanes A1 - Yun Zhang A1 - Dylan M Smith KW - Adaptive diagnostics KW - Cerebrovascular disease KW - Neuroepidemiology KW - Pattern recognition AB -

BACKGROUND: Undetected Alzheimer's disease (AD) and stroke neuropathology is believed to account for a large proportion of decline in cognitive performance that is attributed to normal aging. This study examined the amount of variance in age-related cognitive change that is accounted for by AD and stroke using a novel pattern recognition protocol.

METHOD: Secondary analyses of data collected for the Health and Retirement Study (N = 17,579) were used to objectively characterize patterns of cognitive decline associated with AD and stroke. The rate of decline in episodic memory and orientation was the outcome of interest, while algorithms indicative of AD and stroke pathology were the predictors of interest.

RESULTS: The average age of the sample was 67.54 ± 10.45 years at baseline, and they completed, on average, 14.20 ± 3.56 years of follow-up. After adjusting for demographics, AD and stroke accounted for approximately half of age-associated decline in cognition (51.07-55.6% for orientation and episodic memory, respectively) and explained variance attributed to random slopes in longitudinal multilevel models.

DISCUSSION: The results of this study suggested that approximately half of the cognitive decline usually attributed to normal aging are more characteristic of AD and stroke.

ER - TY - JOUR T1 - Education and cognitive decline: An integrative analysis of global longitudinal studies of cognitive aging. JF - Journals of Gerontology, Series B: Psychological Sciences & Social Sciences Y1 - 2019 A1 - Sean A. P. Clouston A1 - Dylan M Smith A1 - Mukherjee, Soumyadeep A1 - Yun Zhang A1 - Hou, Wei A1 - Bruce G Link A1 - Richards, Marcus KW - Alzheimer's disease KW - Cognition & Reasoning KW - Cross-National KW - Education AB -

BACKGROUND: The objective of this study was to examine the association between education and incidence of accelerated cognitive decline.

METHODS: Secondary analyses of data from the Health and Retirement Study (HRS), a nationally representative prospective cohort study of U.S. residents were conducted (N=28,417). Cox proportional hazards survival models were layered on longitudinal mixed-effects modeling to jointly examine healthy cognitive aging and incidence of accelerated cognitive decline consistent with patterns seen in preclinical Alzheimer's disease and related dementias (ADRD). Replication analyses were completed on a database including 62,485 additional respondents from HRS sister-studies. Life-expectancy ratios (LER) and 95% confidence intervals were reported.

RESULTS: This study replicated research showing that education was positively associated with cognition at baseline. Model fit improved using the survival method compared to random-slopes models alone. Analyses of HRS data revealed that higher education was associated with delayed onset of accelerated cognitive decline (LER=1.031 95% C.I. = [1.013-1.015], P<1E-06). Replication analyses using data from 14 countries identified similar results.

CONCLUSIONS: These results are consistent with cognitive reserve theory, suggesting that education reduces risk of ADRD-pattern cognitive decline. Follow-up work should seek to differentiate specific dementia types involved and consider potential mechanisms.

ER - TY - JOUR T1 - Pattern Recognition to Identify Stroke in the Cognitive Profile: Secondary Analyses of a Prospective Cohort Study JF - Cerebrovascular Diseases Extra Y1 - 2019 A1 - Sean A. P. Clouston A1 - Yun Zhang A1 - Dylan M Smith KW - Cognition KW - Stroke AB - Background: Stroke can produce subtle changes in the brain that may produce symptoms that are too small to lead to a diagnosis. Noting that a lack of diagnosis may bias research estimates, the current study sought to examine the utility of pattern recognition relying on serial assessments of cognition to objectively identify stroke-like patterns of cognitive decline (pattern-detected stroke, p-stroke). Methods: Secondary data analysis was conducted using participants with no reported history of stroke in the Health and Retirement Study, a large (n = 16,113) epidemiological study of cognitive aging among respondents aged 50 years and older that measured episodic memory consistently biennially between 1996 and 2014. Analyses were limited to participants with at least 4 serial measures of episodic memory. Occurrence and date of p-stroke events were identified utilizing pattern recognition to identify stepwise declines in cognition consistent with stroke. Descriptive statistics included the percentage of the population with p-stroke, the mean change in episodic memory resulting in stroke-positive testing, and the mean time between p-stroke and first major diagnosed stroke. Statistical analyses comparing cases of p-stroke with reported major stroke relied on the area under the receiver-operating curve (AUC). Longitudinal modeling was utilized to examine rates of change in those with/without major stroke after adjusting for demographics. Results: The pattern recognition protocol identified 7,499 p-strokes that went unreported. On average, individuals with p-stroke declined in episodic memory by 1.986 (SD = 0.023) words at the inferred time of stroke. The resulting pattern recognition protocol was able to identify self-reported major stroke (AUC = 0.58, 95% CI = 0.57-0.59, p < 0.001). In those with a reported major stroke, p-stroke events were detectable on average 4.963 (4.650-5.275) years (p < 0.001) before diagnosis was first reported. The incidence of p-stroke was 40.23/1,000 (95% CI = 39.40-41.08) person-years. After adjusting for sex, age was associated with the incidence of p-stroke and major stroke at similar rates. Conclusions: This is the first study to propose utilizing pattern recognition to identify the incidence and timing of p-stroke. Further work is warranted examining the clinical utility of pattern recognition in identifying p-stroke in longitudinal cognitive profiles. © 2019 The Author(s) Published by S. Karger AG, Basel. N1 - cited By 0 ER - TY - JOUR T1 - Time Use and Well-being, and Large Survey Studies JF - Forum for Health Economics and Policy Y1 - 2011 A1 - Dylan M Smith KW - Methodology KW - Time Use AB - This paper reviews several methods for measuring how people spend their time, and how they feel during these different activities, and argues that some of these methods could be well suited for large scale longitudinal surveys. Because time use methods allow for the quantitative assessment of the dynamics of human experience, they provide opportunities to explore numerous research questions that cannot be readily answered with more traditional summary measures of well-being. In the last decade or two, techniques have become available that can capture the dynamics of time use and well-being in ways that also reduce methodological problems such as biased recall. The paper describes several such methods, with a discussion of how they are implemented, and a comparison of their relative strengths and weaknesses. In the final section, the paper describes how the addition of time use measures can enhance national surveys such as the Health and Retirement Study by a) opening new avenues of research, and b) clarifying previous findings from more traditional measures of well being. PB - 14 VL - 14 UR - http://www.bepress.com/fhep/14/3/8 IS - 3 U4 - Time Allocation/longitudinal Studies/biased recall/biased recall/mid-term review/mid-term review/Methodology ER - TY - JOUR T1 - Long-term cognitive impairment and functional disability among survivors of severe sepsis. JF - JAMA Y1 - 2010 A1 - Theodore J Iwashyna A1 - E Wesley Ely A1 - Dylan M Smith A1 - Kenneth M. Langa KW - Activities of Daily Living KW - Aged KW - Aged, 80 and over KW - Case-Control Studies KW - Cognition Disorders KW - Disabled Persons KW - Female KW - Health Status KW - Hospitalization KW - Humans KW - Male KW - Prospective Studies KW - Sepsis KW - Severity of Illness Index KW - Survivors KW - United States AB -

CONTEXT: Cognitive impairment and functional disability are major determinants of caregiving needs and societal health care costs. Although the incidence of severe sepsis is high and increasing, the magnitude of patients' long-term cognitive and functional limitations after sepsis is unknown.

OBJECTIVE: To determine the change in cognitive impairment and physical functioning among patients who survive severe sepsis, controlling for their presepsis functioning.

DESIGN, SETTING, AND PATIENTS: A prospective cohort involving 1194 patients with 1520 hospitalizations for severe sepsis drawn from the Health and Retirement Study, a nationally representative survey of US residents (1998-2006). A total of 9223 respondents had a baseline cognitive and functional assessment and had linked Medicare claims; 516 survived severe sepsis and 4517 survived a nonsepsis hospitalization to at least 1 follow-up survey and are included in the analysis.

MAIN OUTCOME MEASURES: Personal interviews were conducted with respondents or proxies using validated surveys to assess the presence of cognitive impairment and to determine the number of activities of daily living (ADLs) and instrumental ADLs (IADLs) for which patients needed assistance.

RESULTS: Survivors' mean age at hospitalization was 76.9 years. The prevalence of moderate to severe cognitive impairment increased 10.6 percentage points among patients who survived severe sepsis, an odds ratio (OR) of 3.34 (95% confidence interval [CI], 1.53-7.25) in multivariable regression. Likewise, a high rate of new functional limitations was seen following sepsis: in those with no limits before sepsis, a mean 1.57 new limitations (95% CI, 0.99-2.15); and for those with mild to moderate limitations before sepsis, a mean of 1.50 new limitations (95% CI, 0.87-2.12). In contrast, nonsepsis general hospitalizations were associated with no change in moderate to severe cognitive impairment (OR, 1.15; 95% CI, 0.80-1.67; P for difference vs sepsis = .01) and with the development of fewer new limitations (mean among those with no limits before hospitalization, 0.48; 95% CI, 0.39-0.57; P for difference vs sepsis <.001 and mean among those with mild to moderate limits, 0.43; 95% CI, 0.23-0.63; P for difference = .001). The declines in cognitive and physical function persisted for at least 8 years.

CONCLUSIONS: Severe sepsis in this older population was independently associated with substantial and persistent new cognitive impairment and functional disability among survivors. The magnitude of these new deficits was large, likely resulting in a pivotal downturn in patients' ability to live independently.

PB - 304 VL - 304 UR - http://jama.ama-assn.org/content/304/16/1787.abstract IS - 16 U1 - http://www.ncbi.nlm.nih.gov/pubmed/20978258?dopt=Abstract U2 - PMC3345288 U4 - Sepsis/Cognitive psychology/Disability/Disability/Survivor/Inpatient care ER - TY - JOUR T1 - Caregiving behavior is associated with decreased mortality risk. JF - Psychol Sci Y1 - 2009 A1 - Stephanie Brown A1 - Dylan M Smith A1 - Schulz, Richard A1 - Mohammed U Kabeto A1 - Peter A. Ubel A1 - Poulin, Michael A1 - Yi, Jaehee A1 - Kim, Catherine A1 - Kenneth M. Langa KW - Altruism KW - Caregivers KW - Humans KW - Mortality AB -

Traditional investigations of caregiving link it to increased caregiver morbidity and mortality, but do not disentangle the effects of providing care from those of being continuously exposed to an ailing loved one with serious health problems. We explored this possible confound in a national, longitudinal survey of elderly married individuals (N= 3,376). Results showed that spending at least 14 hr per week providing care to a spouse predicted decreased mortality for the caregiver, independently of behavioral and cognitive limitations of the care recipient (spouse), and of other demographic and health variables. These findings suggest that it may be premature to conclude that health risks for caregivers are due to providing active help. Indeed, under some circumstances, caregivers may actually benefit from providing care.

PB - 20 VL - 20 UR - http://pss.sagepub.com/content/20/4/4 IS - 4 U1 - http://www.ncbi.nlm.nih.gov/pubmed/19320860?dopt=Abstract U2 - PMC2865652 U4 - Caregivers/Mortality/Risk assessment/Psychology/Older people ER - TY - JOUR T1 - Health, wealth, and happiness: financial resources buffer subjective well-being after the onset of a disability. JF - Psychol Sci Y1 - 2005 A1 - Dylan M Smith A1 - Kenneth M. Langa A1 - Mohammed U Kabeto A1 - Peter A. Ubel KW - Activities of Daily Living KW - Cross-Sectional Studies KW - Disability Evaluation KW - Female KW - Follow-Up Studies KW - Happiness KW - Health Status KW - Humans KW - Male KW - Middle Aged KW - Quality of Life KW - Socioeconomic factors AB -

We examined the hypothesis that the relationship between financial status and subjective well-being, typically found to be very small in cross-sectional studies, is moderated by health status. Specifically, we predicted that wealth would buffer well-being after the onset of a disability. Using data from the Health and Retirement Study, a longitudinal study of people at and approaching retirement age, we employed within-subjects analyses to test whether wealth measured prior to the onset of a disability protected participants' well-being from some of the negative effects of a new disability. We found support for this hypothesis: Participants who were above the median in total net worth reported a much smaller decline in well-being after a new disability than did participants who were below the median. We also found some evidence that the buffering effect of wealth faded with time, as below-median participants recovered some of their well-being.

PB - 16 VL - 16 IS - 9 U1 - http://www.ncbi.nlm.nih.gov/pubmed/16137249?dopt=Abstract U4 - Health Status/Subjective/Wealth/Disability/Disability ER - TY - JOUR T1 - What is perfect health to an 85-year-old?: evidence for scale recalibration in subjective health ratings. JF - Med Care Y1 - 2005 A1 - Peter A. Ubel A1 - Jankovic, Aleksandra A1 - Dylan M Smith A1 - Kenneth M. Langa A1 - Angela Fagerlin KW - Activities of Daily Living KW - Age Factors KW - Aged KW - Aged, 80 and over KW - Analysis of Variance KW - Attitude to Health KW - Calibration KW - Female KW - Geriatric Assessment KW - Health Status KW - Humans KW - Interviews as Topic KW - Male KW - Prospective Studies KW - Psychometrics KW - Self Concept AB -

BACKGROUND: If an 85-year-old man rates his health as 90 on a scale in which 100 represents "perfect health," would his rating mean the same thing as a 90 rating from a 25-year-old? We conducted a randomized trial of 3 different ways of eliciting subjective health ratings from participants in the Health and Retirement Study to test whether the meaning of perfect health changes as people age, causing people to recalibrate their self-reported health ratings to account for their age.

METHODS: The Health and Retirement Study (HRS) is a nationally representative, prospective study of 22,000 persons born in 1947 or earlier. The data analyzed in this study come from the self-assessed health utilities module administered in 2002 to 1031 randomly selected HRS respondents. Respondents were randomized to receive one of 3 versions of a subjective health rating task. In the perfect health version, they were asked how they would rate their "current health on a scale from 0 to 100, in which 0 represents death and 100 represents perfect health." In the your-age version, the phrase "for someone your age" was added to the end of the question to encourage people to recalibrate their responses based on age, and in the 20-year-old version, the phrase "for a 20-year-old" was added to minimize recalibration.

RESULTS: A total of 1015 subjects responded to the rating task (98% response rate). Health ratings varied significantly across versions, with subjects responding to the 20-year-old version reporting lower health (mean rating 66 of 100) than those responding to the your-age version (mean rating of 73, P<0.001) or the perfect health version (mean rating of 73, P<0.001). This result suggests that subjects interpret perfect health to mean "perfect health for someone your age." However, additional analysis showed that the interpretation of the phrase perfect health lies somewhere between the other 2 versions. For example, responses to the perfect health and 20-year-old versions varied significantly by respondent age (both P's<0.075), whereas responses to the your-age scale did not (P=0.8).

CONCLUSION: The phrase "perfect health" is ambiguous, causing some people to recalibrate their responses based on their age. Such ambiguity threatens the validity of common subjective health ratings, thereby reducing the comparability of responses across people of different ages or different circumstances.

PB - 43 VL - 43 IS - 10 U1 - http://www.ncbi.nlm.nih.gov/pubmed/16166876?dopt=Abstract U4 - Subjective phenomena/Methodology ER -