Joshua J. Armstrong
Dalhousie University
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Featured researches published by Joshua J. Armstrong.
Age and Ageing | 2010
Joshua J. Armstrong; Paul Stolee; John P. Hirdes; Jeff Poss
439–44. 14. Sharma JC, Ananda K, Ross I, Hill R, Vassallo M. N-terminal proBrain natriuretic peptide levels predict short-term poststroke survival. J Stroke Cerebrovasc Dis 2006; 15: 121–7. 15. Etgen T, Baum H, Sander K, Sander D. Cardiac troponins and N-terminal pro-brain natriuretic peptide in acute ischemic stroke do not relate to clinical prognosis. Stroke 2005; 36: 270–5. 16. Quinn TJ, Dawson J, Walters MR, Lees KR. Reliability of the Modified Rankin Scale. A systematic review. Stroke. Published online ahead of print 13 August 2009. 17. Anand IS, Fisher LD, Chiang YT et al. Changes in brain natriuretic peptide and norepinephrine over time and mortality and morbidity in the Valsartan Heart Failure Trial (Val-HeFT). Circulation 2003; 107: 1278–83. 18. Cowie MR, Mendez GF. BNP and congestive cardiac failure. Prog Cardiovasc Dis 2002; 44: 293–321. 19. Jensen JK, Atar D, Kristensen SR, Mickley H, Januzzi JL Jr. Usefulness of natriuretic peptide testing for long-term risk assessment following acute ischemic stroke. Am J Cardiol 2009; 104: 287–91. 20. Nogami M, Shiga J, Takatsu A, Endo N, Ishiyama I. Immunohistochemistry of atrial natriuretic peptide in brain infarction. Histochem J 2001; 33: 87–90. 21. Sviri GE, Shik V, Raz B, Soustiel JF. Role of brain natriuretic peptide in cerebral vasospasm. Acta Neurochir (Wien) 2003; 145: 851–60. 22. Doust JA, Pietrzak E, Dobson A, Glasziou P. How well does B-type natriuretic peptide predict death and cardiac events in patients with heart failure: systematic review. BMJ 2005; 330: 625.
Journals of Gerontology Series A-biological Sciences and Medical Sciences | 2015
Joshua J. Armstrong; Lenore J. Launer; Lon R. White; Kenneth Rockwood
BACKGROUND A frailty index (FI) based on the accumulation of deficits typically has a submaximal limit at about 0.70. The objectives of this study were to examine how population characteristics of the FI change in the Honolulu-Asia Aging Study cohort, which has been followed to near-complete mortality. In particular, we were interested to see if the limit was exceeded. METHODS Secondary analysis of six waves of the Honolulu-Asia Aging Study. Men (n = 3,801) aged 71-93 years at baseline (1991) were followed until death (N = 3,455; 90.9%) or July 2012. FIs were calculated across six waves and the distribution at each wave was evaluated. Kaplan-Meier analyses and Cox proportional hazard models were performed to examine the relationship of frailty with mortality. RESULTS At each wave, frailty was nonlinearly associated with age, with acceleration in later years. The distributions of the FIs were skewed with long right tails. Despite the increasing mortality in each successive wave, the 99% submaximal limit never exceeded 0.65. The risk of death increased with increasing values of the FI (eg, the hazard rate increased by 1.44 [95% CI = 1.39-1.49] with each increment in the baseline FI grouping). Depending on the wave, the median survival of people with FI more than 0.5 ranged 0.84-2.04 years. CONCLUSIONS Even in a study population followed to almost complete mortality, the limit to deficit accumulation did not exceed 0.65, confirming a quantifiable, maximum number of health deficits that older men can tolerate.
Archives of Physical Medicine and Rehabilitation | 2012
Joshua J. Armstrong; Mu Zhu; John P. Hirdes; Paul Stolee
OBJECTIVE To examine the heterogeneity of home care clients who use rehabilitation services by using the K-means algorithm to identify previously unknown patterns of clinical characteristics. DESIGN Observational study of secondary data. SETTING Home care system. PARTICIPANTS Assessment information was collected on 150,253 home care clients using the provincially mandated Resident Assessment Instrument-Home Care (RAI-HC) data system. INTERVENTIONS Not applicable. MAIN OUTCOME MEASURES Assessment information from every long-stay (>60 d) home care client that entered the home care system between 2005 and 2008 and used rehabilitation services within 3 months of their initial assessment was analyzed. The K-means clustering algorithm was applied using 37 variables from the RAI-HC assessment. RESULTS The K-means cluster analysis resulted in the identification of 7 relatively homogeneous subgroups that differed on characteristics such as age, sex, cognition, and functional impairment. Client profiles were created to illustrate the diversity of this geriatric population. CONCLUSIONS The K-means algorithm provided a useful way to segment a heterogeneous rehabilitation client population into more homogeneous subgroups. This analysis provides an enhanced understanding of client characteristics and needs, and could enable more appropriate targeting of rehabilitation services for home care clients.
Alzheimer's Research & Therapy | 2015
Joshua J. Armstrong; Melissa K. Andrew; Lenore J. Launer; Lon R. White; Kenneth Rockwood
IntroductionMany factors influence late-life cognitive changes, and evaluating their joint impact is challenging. Typical approaches focus on average decline and a small number of factors. We used multistate transition models and index variables to look at changes in cognition in relation to frailty (accumulation of health deficits), social vulnerability, and protective factors in the Honolulu-Asia Aging Study (HAAS).MethodsThe HAAS is a prospective cohort study of 3,845 men of Japanese descent, aged 71 to 93 years at baseline. Cognitive function was measured using the Cognitive Abilities Screening Instrument (CASI). Baseline index variables were constructed of health deficits (frailty), social vulnerabilities, and protective factors. The chances of improvement/stability/decline in cognitive function and death were simultaneously estimated using multistate transition modeling for 3- and 6-year transitions from baseline.ResultsOn average, CASI scores declined by 5.3 points (standard deviation (SD) = 10.0) over 3 years and 9.5 points (SD = 13.9) over 6 years. After adjusting for education and age, baseline frailty was associated with an increased risk of cognitive decline at 3 years (β = 0.18, 95% confidence interval (CI), 0.08 to 0.29) and 6 years (β = 0.40, 95% CI, 0.27 to 0.54). The social vulnerability index was associated with 3-year changes (β = 0.16, 95% CI, 0.09 to 0.23) and 6-year changes (β = 0.14, 95% CI, 0.05 to 0.24) in CASI scores. The protective index was associated with reductions in cognitive decline over the two intervals (3-year: β = −0.16, 95% CI, −0.24 to −0.09; 6-year: β = −0.21, 95% CI, −0.31 to –0.11,).ConclusionsResearch on cognition in late life needs to consider overall health, the accumulation of protective factors, and the dynamics of cognitive change. Index variables and multistate transition models can enhance understanding of the multifactorial nature of late-life changes in cognition.
Journal of Alzheimer's Disease | 2017
Judith Godin; Joshua J. Armstrong; Kenneth Rockwood; Melissa K. Andrew
BACKGROUND Frailty has been considered an antecedent and, to a lesser extent, an outcome of cognitive impairment. Both frailty and cognitive impairment are multiply determined and each is strongly related to age, making it likely that the two interact, especially as people age. In consequence, understanding their interaction and co-occurrence can offer insight into pathophysiology, prevention, and management. OBJECTIVE To examine the nature of the relationship between frailty and cognitive impairment using longitudinal data from the Survey of Health Aging and Retirement in Europe (SHARE), assessing for bidirectionality. METHODS We conducted secondary analyses using data from the first two waves of SHARE. The sample (N = 11,941) was randomly split into two halves: one half for model development and one half for model confirmation. We used a 65 deficit Frailty Index and combined 5 cognitive deficits into a global cognitive impairment index. Cross-lagged path analysis within a structural equation modelling framework was used to examine the bi-directional relationship between the two measures. RESULTS After controlling for age, sex, social vulnerability, education, and initial cognitive impairment, each 0.10 increase in baseline frailty was associated with a 0.01 increase in cognitive impairment at follow-up (p < 0.001). Likewise, each 0.1 increase in baseline cognitive impairment was associated with a 0.003 increase frailty at follow-up (p < 0.01). CONCLUSION Our findings underscore the importance of considering cognitive impairment in the context of overall health. Many people with dementia are likely to have other health problems, which need to be considered in concert to achieve optimal health outcomes.
Journal of Alzheimer's Disease | 2016
Joshua J. Armstrong; Judith Godin; Lenore J. Launer; Lon R. White; Kenneth Rockwood; Melissa K. Andrew
BACKGROUND As cognitive decline mostly occurs in late life, where typically it co-exists with many other ailments, it is important to consider frailty in understanding cognitive change. OBJECTIVE Here, we examined the association of change in frailty status with cognitive trajectories in a well-studied cohort of older Japanese-American men. METHODS Using the prospective Honolulu-Asia Aging Study (HAAS), 2,817 men of Japanese descent were followed (aged 71-93 at baseline). Starting in 1991 with follow-up health assessments every two to three years, cognition was measured using the Cognitive Abilities Screening Instrument (CASI). For this study, health data was used to construct an accumulation of deficits frailty index (FI). Using six waves of data, multilevel growth curve analyses were constructed to examine simultaneous changes in cognition in relation to changes in FI, controlling for baseline frailty, age, education, and APOE-ɛ4 status. RESULTS On average, CASI scores declined by 2.0 points per year (95% confidence interval 1.9-2.1). Across six waves, each 10% within-person increase in frailty from baseline was associated with a 5.0 point reduction in CASI scores (95% confidence interval 4.7-5.2). Baseline frailty and age were associated both with lower initial CASI scores and with greater decline across the five follow-up assessments (p < 0.01). DISCUSSION Cognition is adversely affected by impaired health status in old age. Using a multidimensional measure of frailty, both baseline status and within-person changes in frailty were predictive of cognitive trajectories.
Disability and Rehabilitation | 2015
Joshua J. Armstrong; Mu Zhu; John P. Hirdes; Paul Stolee
Abstract Purpose: To examine regional variation in service provision and identify the client characteristics associated with occupational therapy (OT) and physiotherapy (PT) services for older adults in the Ontario Home Care System. Methods: Secondary analyses of a provincial database containing comprehensive assessments (RAI-HC) linked with service utilization data from every older long-stay home care client in the system between 2005 and 2010 (n = 299 262). Hierarchical logistic regression models were used to model the dependent variables of OT and PT service use within 90 d of the initial assessment. Results: Regional differences accounted for 9% of the variation in PT service provision and 20% of OT service provision. After controlling for the differences across regions, the most powerful predictors of service provision were identified for both OT and PT. The most highly associated client characteristics related to PT service provision were hip fracture, impairments in activities of daily living/instrumental activities of daily living, cerebrovascular accidents, and cognitive impairment. For OT, hazards in the home environment was the most powerful predictor of future service provision. Conclusions: Where a client lived was an important determinant of service provision in Ontario, raising the possibility of inequities in access to rehabilitation services. Health care planners and policy makers should review current practices and make adjustments to meet the increasing and changing needs for rehabilitation therapies of the aging population. Implications for Rehabilitation For older adults in home care, the goal of rehabilitation therapy services is to allow individuals to maintain or improve physical functioning, quality of life and overall independence while living within their community. Previous research has demonstrated that a large proportion of home care clients specifically identified as having rehabilitation potential do not receive it. This article used clinical assessment data to identify the predictors of and barriers to rehabilitation services for older adults in the Ontario Home Care System. Barriers of PT included dementia diagnosis and French as a first language. Barriers to OT included dementia diagnosis. Policies and practices related to service provision for older adults should be reconsidered if we are going to meet the demands of aging populations and increasing rates of functional and cognitive impairments.
Canadian Geriatrics Journal | 2015
Theodore D. Cosco; Joshua J. Armstrong; Blossom C. M. Stephan; Carol Brayne
The conceptualization of positive and negative states of aging is contentious at the inter- and intraparadigm level; lack of consensus exists within and between states. Working within their respective paradigms, successful aging and frailty researchers may have lost sight of the larger picture. Are successful aging researchers describing nonfrail individuals? Are frailty researchers describing unsuccessful aging? It is imperative that researchers are cognizant of the ways in which their perspectives are contextualized within the literature and within related paradigms, so as to be able to clearly communicate their research and to ensure they are working within the appropriate paradigm to facilitate desired outcomes. Here we discuss the similarities and differences between successful aging and frailty in terms of the scope and emphasis of their constituent components and functioning: both SA and frailty include biomedical components; SA examines the high end, whilst frailty predominately examines the low end of the functioning spectrum. Frailty models emphasize the biomedical realm, whilst SA models emphasize both the biomedical and the psychosocial.
Age and Ageing | 2010
Joshua J. Armstrong; Christine Glenny; Paul Stolee; Katherine Berg
frontotemporal dementia and Alzheimers disease: a meta-analytic review. J Neurol Neurosurg Psychiatry 2007; 78: 917–28. 3. Larner AJ. Addenbrookes Cognitive Examination (ACE) for the diagnosis and differential diagnosis of dementia. Clin Neurol Neurosurg 2007; 109: 491–4. 4. Larner AJ, Hancock P. Re: Activities of daily living in frontotemporal dementia and Alzheimer disease. Neurology 2008; 70: 658. 5. Larner AJ, Hancock P. The Utility of the Cambridge Behavioural Inventory in Neurodegenerative Disease. http://jnnp. bmj.com/cgi/eletters/79/5/500 (accessed 29 May 2008). 6. Jorm AF. The Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE): a review. Int Psychogeriatr 2004; 16: 275–93. 7. Hancock P, Larner AJ. Diagnostic utility of the Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE) and its combination with the Addenbrookes Cognitive Examination-Revised (ACE-R) in a memory clinic-based population. Int Psychogeriatr 2009; 21: 526–30. 8. McKhann G, Drachman D, Folstein M et al. Clinical diagnosis of Alzheimers disease: report of the NINCDS-ADRDAWork Group under the auspices of Department of Health and Human Services Task Force on Alzheimers disease. Neurology 1984; 34: 939–44. 9. Neary D, Snowden JS, Gustafson L et al. Frontotemporal lobar degeneration: a consensus on clinical diagnostic criteria. Neurology 1998; 51: 1546–54. 10. Jorm AF, Jacomb PA. The Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE): socio-demographic correlates, reliability, validity and some norms. Psychol Med 1989; 19: 1015–22. 11. Ehrensperger MM, Berres M, Taylor KI et al. Screening properties of the German IQCODE with a two-year time frame in MCI and early Alzheimers disease. Int Psychogeriatr 2010; 22: 91–100. 12. Rosness TA, Haugen PK, Passant U et al. Frontotemporal dementia: a clinically complex diagnosis. Int J Geriatr Psychiatry 2008; 23: 837–42.
Alzheimer's Research & Therapy | 2016
Penny A. Dacks; Joshua J. Armstrong; Stephen Brannan; Aaron J. Carman; Allan M. Green; M. Sue Kirkman; Lawrence R. Krakoff; Lewis H. Kuller; Lenore J. Launer; Simon Lovestone; Elizabeth Merikle; Peter J. Neumann; Kenneth Rockwood; Diana W. Shineman; Richard G. Stefanacci; Priscilla Velentgas; Anand Viswanathan; Rachel A. Whitmer; Jeff D. Williamson; Howard Fillit
Common diseases like diabetes, hypertension, and atrial fibrillation are probable risk factors for dementia, suggesting that their treatments may influence the risk and rate of cognitive and functional decline. Moreover, specific therapies and medications may affect long-term brain health through mechanisms that are independent of their primary indication. While surgery, benzodiazepines, and anti-cholinergic drugs may accelerate decline or even raise the risk of dementia, other medications act directly on the brain to potentially slow the pathology that underlies Alzheimer’s and other dementia. In other words, the functional and cognitive decline in vulnerable patients may be influenced by the choice of treatments for other medical conditions. Despite the importance of these questions, very little research is available. The Alzheimer’s Drug Discovery Foundation convened an advisory panel to discuss the existing evidence and to recommend strategies to accelerate the development of comparative effectiveness research on how choices in the clinical care of common chronic diseases may protect from cognitive decline and dementia.