Evaluating Cognitive Disorder Screening Programs for Early Detection of Dementia and Alzheimer: A Systematic Review

Abstract

Objective: Cognitive disorders would result in Alzheimer and dementia that have an important effect on individual independence. The Iranian population is evolving from middle age to old age and it is predicted that in the next two to three decades, 25% of the country's population will grow old. 10% of the elderly population will develop Alzheimer's. The purpose of this systematic review is to evaluate cognitive impairment screening programs for early detection of dementia and Alzheimer's. Method : International databases Medline (PubMed), Scopus, Cochrane, Dare, All EBM Reviews, CRD using OVID, ProQuest dissertations were searched from 2012 to 25/11/2019 using the keywords Alzheimer, dementia, screening, mass screening, early detection early diagnosis, predictive value, accuracy, false negative reaction, false positive reaction, diagnostic error, reproductively of result, reference values, reference standard, observer variation predictive value of tests cognitive impairment, cognition disorders, cognitive decline, cognitive loss. And was reviewed by formulating a search strategy for each site. In order to extract the required information, an Excel form designed by the research team was used. Required information included author and year of study, country, population and place of study, sample size, index test and reference test, expected outcome, sensitivity and specificity of diagnostic tests. The QUADAS2 tool was used to assess the risk of study bias. In order to aggregate the findings of studies on the accuracy of diagnosis, the effect sizes related to sensitivity and specificity were aggregated through meta-analysis by random effects method. Results: A total of 18,132 study items were retrieved, leaving 8,285 items for screening after removing duplicates electronically and manually. After reviewing the title and abstract of the studies, 52 original articles were selected for the study. Of these, 33 studies were deleted with reason and 19 articles were included in the qualitative evaluation. After reviewing routine and general disease screening programs conducted in different countries, 7 national screening programs were found in the form of national programs. Although Mini Mental State Examination (MMSE) is the most widely used diagnostic tool, based on the current systematic review of patient assessment tools (MIS) Memory impairment screen, The General Practitioner assessment of cognition (GPCOG) (MOCA) Montreal cognition assessment and the Alzheimer disease 8 item (AD8) and GPCOG General practitioner Cognition (GPCOG), Informant Questionnaire on (IQCODE) Cognitive Decline to assess their caregivers with equal performance or They can be used better than MMSE. The sensitivity and specificity of MMSE was estimated to be 70% with a 95% confidence interval (0.89-0.51) and its specificity was estimated to be 95% equivalent (0.88-0.78). Conclusion : No strong evidence was found for general screening to identify cognitive disorders. However, due to the high incidence of undiagnosed patients and the benefits of early diagnosis in caregiver management, early diagnosis has been integrated into annual or periodic geriatric care programs in most high-income countries. The use of non-medical staff in the initial assessment can be considered as a suitable option, especially in countries that face a shortage of medical staff. GPCOG, IQCODE and CAMCOG tools can provide an accuracy of detection equal to or greater than MMSE in primary care.