Type 2 diabetes may be associated with exacerbated aging-related declines in cognitive neuropsychological performance. The authors examined whether such effects are systematic (i.e., broadly distributed across domains or domain-specific) or moderated by age (i.e., varying across age within older adults). The authors assembled recent cross-sectional data from the Victoria Longitudinal Study (VLS) Sample 3 (Wave 1; initial n = 570; initial age = 53-90 years). Using a comprehensive, multidimensional spectrum of cognitive neuropsychological tests, the authors examined performance differences by diabetes status (diabetes group vs. healthy controls) and age (young-old vs. old-old). Our results showed that healthy controls significantly outperformed the diabetes group only on markers of executive functioning and speed. Notably, the diabetes-related effects were robust across the two late-life age groups. Future research examining longitudinal changes is recommended. Keywordstype 2 diabetes; cognitive aging; executive function; speed Type 2 diabetes is a chronic metabolic condition characterized by abnormally high blood glucose levels as a result of insufficient usage of insulin. Formerly known as Non-Insulin Dependent Diabetes Mellitus or adult-onset diabetes, its prevalence significantly increases across adulthood, typically affecting individuals over the age of 40 years (Votey & Peters, 2005). Recent estimates on the prevalence of diabetes (Type I and Type II) have indicated diagnosis rates for adults over age 60 at about 12% in Canada (Health Canada, 2002) and 20% in the United States (National Institute of Health, 2005). Approximately 90% of these cases are Type II. Associated with Type 2 diabetes are increased risk of hypertension, stroke, and cerebrovascular disease (e.g., Awad, Gagnon, & Messier, 2004;Messier, 2005;Reunanen, Kangas, Martikainen, & Klaukka, 2000). These potential comorbidities have been shown to affect neural integrity and cognition, especially when coexistent with diabetes . Recent literature has reported a relationship between diabetes and an earlier or accelerated decline in cognition (e.g., Awad et al., 2004;Hassing, Grant, et al., 2004;Hassing et al., 2003), including a twofold increase in the risk of dementia (Nilsson, 2006).Few studies have examined whether adverse cognitive effects of diabetes are broad or selective across domains, or whether such effects differ across a broad age band of older adults. We explore these issues with a relatively healthy and generally cognitively intact sample of 53-90 year-old adults tested on multiple domains of cognitive neuropsychological performance. Copyright 2008 by the American Psychological AssociationCorrespondence concerning this article should be addressed to Roger A. Dixon, Department of Psychology, P-217 Biological Sciences Building, University of Alberta, Edmonton, Alberta Canada. E-mail: E-mail: rdixon@ualberta.ca. NIH Public Access Author ManuscriptNeuropsychology. Author manuscript; available in PMC 2009 July 18. Published in final ...

To our knowledge, this study represents the most comprehensive investigation to date of predictors of ToM in aging. Findings highlight the need for continued investigation of ToM within a multidimensional framework.

Type 2 diabetes is associated with cognitive deficits, although inconsistently across neuropsychological domains. We examined 3-year longitudinal data from the Victoria Longitudinal Study, comparing diabetes (n = 28) and control (n = 272) older adults on a comprehensive neuropsychological battery. Assessing potential change and stability, we found that (a) baseline diabetes group deficits in semantic speed and speed-intensive executive function were preserved, (b) new average deficits for reaction time and nonspeeded executive function appeared, and (c) no differential short-term change was observed. It is clinically and theoretically important to examine sequential change in multiple domains over time. KeywordsAging; Cognition; Type 2 diabetes; Longitudinal; Speed Type 2 diabetes is a chronic, aging-related disease with documented deleterious effects on cognitive performance in older adults. Effects of diabetes on the aging brain are of particular interest given its relationship to increased risk of stroke, cerebrovascular disease, and dementia (e.g., Ott et al., 1996;Reunanen, Kangas, Martikainen, & Klaukka, 2000;Stegmayr & Asplund, 1995;Xu, Qiu, Wahlin, Winblad, & Fratiglioni, 2004). Recent estimates on the prevalence of type 2 diabetes in adults over the age of 60 are as high as 18−20% in North America (National Institute of Health, 2005; Public Health Agency of Canada, 2007)-a rate that may increase dramatically in the near future (Wild, Roglic, Green, Sicree, & King, 2004). Although many studies have reported that type 2 diabetes is related to overall cognitive dysfunction, the patterns of results are mixed regarding affected cognitive domains, potentially moderating comorbidities, and suspected underlying neural mechanisms. In fact, studies have reported contrasting effects for some cognitive domains, including the absence of any diabetes-related deficits (e.g., Robertson-Tchabo, Arenberg, Tobin, & Plotz, 1986;Vanhanen et al., 1999). Address correspondence to Roger A. Dixon, Department of Psychology, P-217 Biological Sciences Building, University of Alberta, Edmonton, Alberta, Canada T6G 2E9 (E-mail: rdixon@ualberta.ca).. Publisher's Disclaimer: Full terms and conditions of use: http://www.informaworld.com/terms-and-conditions-of-access.pdf This article may be used for research, teaching and private study purposes. Any substantial or systematic reproduction, re-distribution, reselling, loan or sub-licensing, systematic supply or distribution in any form to anyone is expressly forbidden. The publisher does not give any warranty express or implied or make any representation that the contents will be complete or accurate or up to date. The accuracy of any instructions, formulae and drug doses should be independently verified with primary sources. The publisher shall not be liable for any loss, actions, claims, proceedings, demand or costs or damages whatsoever or howsoever caused arising directly or indirectly in connection with or arising out of the use of this material. NIH Public Access NIH-PA Au...

False-belief reasoning, defined as the ability to reason about another person’s beliefs and appreciate that beliefs can differ from reality, is an important aspect of perspective taking. We tested 266 individuals, at various ages ranging from 3 to 92 years, on a continuous measure of false-belief reasoning (the Sandbox task). All age groups had difficulty suppressing their own knowledge when estimating what a naïve person knew. After controlling for task-specific memory, our results showed similar false-belief reasoning abilities across the preschool years and from older childhood to younger adulthood, followed by a small reduction in this ability from younger to older adulthood. These results highlight the relative similarity in false-belief reasoning abilities at different developmental periods across the lifespan.

Objective-The general goal of this study was to advance our understanding of Type 2 diabetes (T2D)-cognition relationships in older adults by linking and testing comprehensive sets of potential moderators, potential mediators, and multiple cognitive outcomes.Method-We identified in the literature 13 health-related (but T2D-distal) potential covariates, representing four informal domains (i.e., biological vitality, personal affect, subjective health, lifestyle activities). Cross-sectional data from the Victoria Longitudinal Study (age range = 53-90 years; n = 41 T2D and n = 458 control participants) were used. We first examined whether any of the 13 potential covariates influenced T2D-cognition associations, as measured by a comprehensive neuropsychological battery (15 measures). Next, using standard regression-based moderator and mediator analyses, we systematically tested whether the identified covariates would significantly alter observed T2D-cognition relationships.Results-Six potential covariates were found to be sensitive to T2D associations with performance on seven cognitive measures. Three factors (systolic blood pressure, gait-balance composite, subjective health) were significant mediators. Each mediated multiple cognitive outcomes, especially measures of neurocognitive speed, executive functioning, and episodic memory.Conclusions-Our findings offer a relatively comprehensive perspective of T2D-related cognitive deficits, comorbidities, and modulating influences. The implications for future research reach across several fields of study and application. These include (a) neuropsychological research on neural and biological bases of T2D-related cognitive decline, (b) clinical research on intervention and treatment strategies, and (c) larger-scale longitudinal studies examining the potential multilateral and dynamic relationships among T2D status, related comorbidities, and cognitive outcomes. KeywordsAging; Cognition; Type 2 Diabetes; Mediator; Moderator Contact: Roger A. Dixon, Department of Psychology, P-217 Biological Sciences, University of Alberta, Edmonton, Alberta T6G 2E9, Canada, rdixon@ualberta.ca. Publisher's Disclaimer: The following manuscript is the final accepted manuscript. It has not been subjected to the final copyediting, fact-checking, and proofreading required for formal publication. It is not the definitive, publisher-authenticated version. The American Psychological Association and its Council of Editors disclaim any responsibility or liabilities for errors or omissions of this manuscript version, any version derived from this manuscript by NIH, or other third parties. The published version is available at www.apa.org/pubs/journals/neu NIH Public Access Author ManuscriptNeuropsychology. Author manuscript; available in PMC 2011 September 1. Published in final edited form as:Neuropsychology. 2010 September ; 24(5): 547-562. doi:10.1037/a0019246. NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author ManuscriptThe prevalence of Type 2 diabetes (T2D) is increasing among ...