AUTHOR=Tao Chunhua , Yuan Yuan , Xu Yijun , Zhang Song , Wang Zheng , Wang Sican , Liang Jingyan , Wang Yingge 

TITLE=Role of cognitive reserve in ischemic stroke prognosis: A systematic review

JOURNAL=Frontiers in Neurology

VOLUME=Volume 14 - 2023

YEAR=2023

URL=https://www.frontiersin.org/journals/neurology/articles/10.3389/fneur.2023.1100469

DOI=10.3389/fneur.2023.1100469

ISSN=1664-2295

ABSTRACT=Objective: This systematic review was performed to identify the role of cognitive reserve (CR) proxies in functional outcome and mortality prognostication of patients after acute ischemic stroke. 
Methods: Pubmed, Embase, Web of Science and Cochrane databases were comprehensively searched by 2 independent reviewers from inception to August 31, 2022, with no restrictions of language. The reference lists of reviews or included articles were also searched. Cohort studies with follow-up period ≥3 months identifying the association between CR indicators and post-stroke functional outcome and mortality were included. Excluded were outcome records of patients with hemorrhagic and ischemic stroke not reported separately. The Quality In Prognosis Studies Tool (QUIPS) was used to assess the quality of included studies. 
Results: Our search yielded 28 studies (n=114,212) between 2004 and 2022, of which 14 were prospective cohort studies and 14 retrospective cohort studies. The follow-up period ranged from 3 months to 36 years, and a mean or median age varied from 39.6 to 77.2 years. Fifteen of the 28 studies included functional outcome as their primary outcome interest and 11 of the 28 studies included the end-point interest of mortality after ischemic stroke. Besides, two of the 28 studies focused on the interest of functional outcome and mortality. Among the included studies, CR proxies were measured by education, income, occupation, premorbid intelligence quotient, bilingualism and socioeconomic status respectively. The quality of reviewed studies was at low to high risk of bias. 
Conclusion: Based on the current literature, ischemic stroke patients with higher CR proxies may have lower risks of unfavourable outcome. Further prospective studies involving a combination of CR proxies and residuals of fMRI measurements are warranted to determine the contribution of CR to adverse outcome of ischemic stroke.