Association between perceived psychological stress and cognitive decline in aging: a systematic review protocol Juliana Nery de Souza-Talarico 1,3  Sonia Betzabeth Ticona Benavente 1,3  Andrea Regiani Alves 1  Fla ´via Oliveira de Motta Maia 2,3  Ana Lu ´ cia Siqueira Costa 1 1 School of Nursing, University of Sa ˜o Paulo, Sa ˜o Paulo (SP), Brazil, 2 University Hospital, University of Sa ˜o Paulo, Sa ˜o Paulo (SP), Brazil, and 3 The Brazilian Center for Evidence-based Healthcare: a Joanna Briggs Institute Center of Excellence Review question/objective: The objective of this review is to identify, appraise and synthesize the best available evidence on the association between perceived psychological stress and cognitive decline in aging. Keywords Aging; cognitive decline; perceived psychological stress JBI Database System Rev Implement Rep 2017; 15(2):220–229. Background C ognitive disorders such as Alzheimer’s disease and other types of dementia are considered the most devastating illnesses worldwide, affecting over 36 million individuals. 1 Dementia is estimated to double by 2030 and more than triple by 2050, with the highest rates occuring in middle- and low-income countries. 1 The World Health Organization has recently established dementia as a public health priority in the global health agenda, highlighting primary prevention measures as the main target of strategies to delay disease onset, even to a modest degree, and to modify dementia prevalence world- wide. 2 Identification of preclinical stages and mod- ifiable risk factors for dementia constitutes the central focus of prevention measures. 2 Subjective cognitive impairment (SCI) and mild cognitive impairment (MCI) have attracted special attention from the scientific community, given their associ- ation with the high risk of dementia. 3,4 Subjective cognitive impairment is described as a persistent complaint of poor performance in memory or other cognitive domains such as attention or executive function; in SCI, however, no abnormalities are detected on neuropsychological assessment. 3 This differs from MCI, which requires evidence of cog- nitive deterioration based on objectively measured decline, with preserved independence in functional abilities and complex instrumental activities of daily living. 4 Given that neurodegeneration may precede the onset of dementia by several years, individuals with SCI and MCI represent target populations so as to better identify preclinical signs and modifiable risk factors and to support primary preventive strat- egies. 3,4 Indeed, interventions to minimize exposure to these risk factors, such as improvement in health services and health promotion, have demonstrated their effectiveness in reducing dementia prevalence. 2 Poor cardiovascular health, low education and physical inactivity are known risk factors linked to dementia. 2 However, other modifiable risk factors should be identified to better detect vulnerable popu- lations and define target interventions. 2 Exposure to psychological stress over one’s lifespan has been proposed as a potential risk factor for dementia largely owing to the clear relationship between the biological mechanism of stress response and brain structures involved in cognitive function. 5,6 The concept of stress and its relationship with cognitive performance Stress is the body’s response to events that represent a real threat (i.e. natural disasters) or a relative or psychological threat induced by the interpretation of a situation as being novel, unpredictable, uncon- trollable or social-evaluative. 7 The individual’s interpretation of the situation moderates the intensity of the stress reaction, which may be mild or intense. 7 Consequently, psychological threats elicit a stress response only in certain individuals, according to their cognitive evaluation of the situation. 7 In summary, Correspondence: Juliana Nery de Souza-Talarico, junery@usp.br There is no conflict of interest in this project. DOI: 10.11124/JBISRIR-2016003281 JBI Database of Systematic Reviews and Implementation Reports ß 2017 THE JOANNA BRIGGS INSTITUTE 220 SYSTEMATIC REVIEW PROTOCOL ©2017 Joanna Briggs Institute. Unauthorized reproduction of this article is prohibited.