Background: Frailty is considered highly prevalent in old age and to confer high risk for falls, disability, hospitalization, and mortality. Frailty has been considered synonymous with disability, comorbidity, and other characteristics, but it is recognized that it may have a biologic basis and be a distinct clinical syndrome. A standardized definition has not yet been established. 

Methods: To develop and operationalize a phenotype of frailty in older adults and assess concurrent and predictive validity, the study used data from the Cardiovascular Health Study. Participants were 5,317 men and women 65 years and older (4,735 from an original cohort recruited in 1989-90 and 582 from an African American cohort recruited in 1992-93). Both cohorts received almost identical baseline evaluations and 7 and 4 years of follow-up, respectively, with annual examinations and surveillance for outcomes including incident disease, hospitalization, falls, disability, and mortality. 

Results: Frailty was defined as a clinical syndrome in which three or more of the following criteria were present: unintentional weight loss (10 lbs in past year), self-reported exhaustion, weakness (grip strength), slow walking speed, and low physical activity. The overall prevalence of frailty in this community-dwelling population was 6.9%; it increased with age and was greater in women than men. Four-year incidence was 7.2%. Frailty was associated with being African American, having lower education and income, poorer health, and having higher rates of comorbid chronic diseases and disability. There was overlap, but not concordance, in the cooccurrence of frailty, comorbidity, and disability. This frailty phenotype was independently predictive (over 3 years) of incident falls, worsening mobility or ADL disability, hospitalization, and death, with hazard ratios ranging from 1.82 to 4.46, unadjusted, and 1.29-2.24, adjusted for a number of health, disease, and social characteristics predictive of 5-year mortality. Intermediate frailty status, as indicated by the presence of one or two criteria, showed intermediate risk of these outcomes as well as increased risk of becoming frail over 3-4 years of follow-up (odds ratios for incident frailty = 4.51 unadjusted and 2.63 adjusted for covariates, compared to those with no frailty criteria at baseline). 

Conclusions: This study provides a potential standardized definition for frailty in community-dwelling older adults and offers concurrent and predictive validity for the definition. It also finds that there is an intermediate stage identifying those at high risk of frailty. Finally, it provides evidence that frailty is not synonymous with either comorbidity or disability, but comorbidity is an etiologic risk factor for, and disability is an outcome of, frailty. This provides a potential basis for clinical assessment for those who are frail or at risk, and for future research to develop interventions for frailty based on a standardized ascertainment of frailty.

https://www.sharp.com/services/hospice/upload/phenotype5-13.pdf

Frailty in Older Adults Evidence for a Phenotype

Despite the concern that has been expressed about potential method biases, and the pervasiveness of research settings with the potential to produce them, there is disagreement about whether they really are a problem for researchers in the behavioral sciences. Therefore, the purpose of this review is to explore the current state of knowledge about method biases. First, we explore the meaning of the terms “method” and “method bias” and then we examine whether method biases influence all measures equally. Next, we review the evidence of the effects that method biases have on individual measures and on the covariation between different constructs. Following this, we evaluate the procedural and statistical remedies that have been used to control method biases and provide recommendations for minimizing method bias.

Sources of Method Bias in Social Science Research and Recommendations on How to Control It

because observed behavior is the result of interactions between environmental factors and genes during the extended period of development. Therefore, to better understand expert and exceptional performance, we must require that the account specify the different environmental factors that could selectively promote and facilitate the achievement of such performance. In addition, recent research on expert performance and expertise (Chi, Glaser, & Farr, 1988; Ericsson & Smith, 1991a) has shown that important characteristics of experts' superior performance are acquired through experience and that the effect of practice on performance is larger than earlier believed possible. For this reason, an account of exceptional performance must specify the environmental circumstances, such as the duration and structure of activities, and necessary minimal biological attributes that lead to the acquisition of such characteristics and a corresponding level of performance. An account that explains how a majority of individuals can attain a given level of expert performance might seem inherently unable to explain the exceptional performance of only a small number of individuals. However, if such an empirical account could be empirically supported, then the extreme characteristics of experts could be viewed as having been acquired through learning and adaptation, and studies of expert performance could provide unique insights into the possibilities and limits of change in cognitive capacities and bodily functions. In this article we propose a theoretical framework that explains expert performance in terms of acquired characteristics resulting from extended deliberate practice and that limits the role of innate (inherited) characteristics to general levels of activity and emotionality. We provide empirical support from two new studies and from already published evidence on expert performance in many different domains.

/pdf/the-role-of-deliberate-practice-in-the-acquisition-of-expert-3j9768t5su.pdf

The role of deliberate practice in the acquisition of expert performance.

Recent studies of eye movements in reading and other information processing tasks, such as music reading, typing, visual search, and scene perception, are reviewed. The major emphasis of the review is on reading as a specific example of cognitive processing. Basic topics discussed with respect to reading are (a) the characteristics of eye movements, (b) the perceptual span, (c) integration of information across saccades, (d) eye movement control, and (e) individual differences (including dyslexia). Similar topics are discussed with respect to the other tasks examined. The basic theme of the review is that eye movement data reflect moment-to-moment cognitive processes in the various tasks examined. Theoretical and practical considerations concerning the use of eye movement data are also discussed.

/pdf/eye-movements-in-reading-and-information-processing-20-years-3z5ay8hdwc.pdf

Eye movements in reading and information processing: 20 years of research.

A theory is proposed to account for some of the age-related differences reported in measures of Type A or fluid cognition. The central hypothesis in the theory is that increased age in adulthood is associated with a decrease in the speed with which many processing operations can be executed and that this reduction in speed leads to impairments in cognitive functioning because of what are termed the limited time mechanism and the simultaneity mechanism. That is, cognitive performance is degraded when processing is slow because relevant operations cannot be successfully executed (limited time) and because the products of early processing may no longer be available when later processing is complete (simultaneity). Several types of evidence, such as the discovery of considerable shared age-related variance across various measures of speed and large attenuation of the age-related influences on cognitive measures after statistical control of measures of speed, are consistent with this theory.

http://www.anitacrawley.net/Resources/Articles/salthouse%20The%20Processing%20Speed%20Theory%20of%20Adult%20Age%20Differences%20in%20Cognition.pdf

The processing-speed theory of adult age differences in cognition.

Increased age is often associated with lower levels of performance in tests of memory for spatial information. The primary question in the current study was whether this relationship could be moderated as a function of one's relevant experience and/or knowledge. Stimulus materials consisted of short (7-11 note), visually presented musical melodies and structurally equivalent nonmusical stimuli. Participants (N = 128) were recruited from a wide range of age and experience levels. Although there were strong main effects of age and experience on memory for music, there was no evidence that the age-related differences in memory for these stimuli were smaller for individuals with moderate to large amounts of experience with music.

/pdf/the-effects-of-age-and-experience-on-memory-for-visually-4io1ca4gni.pdf

The Effects of Age and Experience on Memory for Visually Presented Music

Two studies were conducted to investigate the aspect(s) of processing involved in the hypothesized speed mediation of adult age differences in memory. Both studies involved a serial memory task in which information was to be recalled either in the original order of presentation, or in a reordered sequence. Results from both studies indicated that taskspecific processing durations were slower among older adults thon among loung adults, but that the attenuation of the age-related variance in memory was nearly as great after statistical control of a task-independent speed measure as after conlrol of nsk-specffic speed measures. These findings are consistent with the hypothesis that a substantial proportion of the adult age-related differences in memory is associated with a decrease with increased age in the speed of executing many cognitive processes, and not simply the speed of one or two specific processes. 'JHE goal of the studies described in this report was to r investigate how processing speed contributes to the relations between age and memory. The relations of interest have been documented. and some initial evidence relevant to this issue has been provided, with data from earlier research (Salthouse, 1983, in press). The memory tasks in the previous studies were free recall of two lists of, l2 unrelated nouns presented auditorily at a rate of -2 seconds/word, and paired associatc recall <lf six pairs of unrelated nouns also presented at -2 secondsiword. The speed measures were derived from three paper-and-pencil tests of perceptual speed; digit symbol substitution, letter comparison, and pattern comparison. The average of the z-scores in the three tests served as a composite index of the speed with which the individual could execute elementary operations. The results of these earlier studies are summarized in Table I . Notice that in the first study there was a large attenuation of the age-related variance in the memory measures when the variance associated with the processing speed measure was statistically controlled (i.e., 87o/o attenuation with free recall, from an R' for age of . 162-.O2l , and 857o attenuation with paired associates, from an R2 for age of .162-.024). An extreme-groups design was used in the second study, which resulted in larger age-related effects than those in the first study because of the omission of the variance associated with the intermediate ages. [The memory data were not reported in the Salthouse (1993) article, but most of the subjects from the second study in that project performed these tasks after completing the tasks reported in the article.l The speed and memory tasks were identical to those of the first study, but also included were measures of associational fluency that might be expected to be important in the performance of many memory tasks if effectiveness of elaborative encoding is related to the number of relevant associations that can be produced in a limited time. The measures were from tasks requiring the generation of as many words as possible, beginning with one of two stems (pro- and sub-) or ending with one of two terminations (-ay and -ow), and the average of the z-scores in the two tasks served as the measure of associational fl uency. It is apparent in the bottom panel of Table l that the major findings of the first study were replicated, as there was 9l7o attenuation of the age-related variance in free recall performance and 88o/o attenuation of the age-related variance in paired associates performance after control of the same composite speed measure. However, it was surprising that the attenuation of the age-related variance in memory was smaller after control of the presumably more specific fluency measure than after control of the more general speed measure; that is, only 44.5o/o attenuation with fiee recall performance and 37 .l%o attenuation with paired associates performance. Taken together, the results of these earlier studies suggest that processing speed, as indexed by various perceptual comparison tasks, is involved in the mediation of age differences in memory, and that the speed influence appears to be fairly general, in that it does not seem to be restricted to measures postulated to reflect memory-relevant processes. The existence of significant residual age-related variance even when the variation in speed is controlled indicates that other factors also contribute to the age differences evident in these tasks. Nevertheless, the discovery that influences independent of speed are associated with <157o of the total agerelated variance for free recall and paired associate measures of memory suggests that some aspect of speed plays a major role in the relations between age and memory. The purpose of the current project was to conduct a more detailed examination of the relation between speed and memory with a simpler task in which it might be possible to identify the mechanisms responsible for the apparent speed mediation of age-related differences in memory. The research strategy consisted of three distinct steps or phases. The first step was to determine the amount of age-related variance in the criterion measure of memory before and after controlling the variance in an index of processing speed derived from independent tasks. The goal of these analyses

Influence of Task-Specific Processing Speed on Age Differences in Memory

A battery of cognitive tests designed to measure the constructs of episodic memory, perceptual speed, fluid ability, executive functioning, and vocabulary was administered to 330 adults between the ages of 18 and 89. Each participant also performed 4 different tasks designed to assess source memory. Structural equation modeling was used to evaluate the validity of a source-memory construct and to explore the relation of the source-memory construct to age and to the other cognitive variables. The variance common to the source-memory variables was strongly related to other cognitive abilities, suggesting that source memory may not have discriminant validity, and there were only small unique age-related effects on the source-memory construct after the influence of other abilities was considered.

Is there anything special about the aging of source memory

Steps toward the explanation of adult age differences in cognition.

Process analysis of adult age effects on a computer-administered Trail Making Test.

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Timothy A. Salthouse

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